A Dissertation. Entitled. Kinematic Gait Analysis of Children with Neurological Impairments Pre and Post. Hippotherapy Intervention. Jenna L.

Transcription

1 A Dissertation Entitled Kinematic Gait Analysis of Children with Neurological Impairments Pre and Post Hippotherapy Intervention By Jenna L. Encheff Submitted as partial fulfillment of the requirements for The Doctor of Philosophy degree in Exercise Science Adviser: Dr. Charles W. Armstrong Dr. Phillip Gribble Dr. Michelle Masterson Dr. Christine Fox College of Health Science and Human Service Graduate School The University of Toledo December 2008

2 Copyright 2008 This document is copyrighted material. Under copyright law, no parts of this document may be reproduced without the expressed permission of the author.

3 An Abstract of Kinematic Gait Analysis of Children with Neurological Impairments Pre and Post Hippotherapy Intervention Jenna L. Encheff Submitted as partial fulfillment of the requirements for The Doctor of Philosophy degree in Exercise Science The University of Toledo December 2008 Background and Purpose. The purpose of this study was to investigate the effects of a ten-week hippotherapy (HPOT) program on several temporal-spatial variables of gait as well as range of motion (ROM) at the trunk, pelvis, and hip joints in all three planes of motion over the stance phase of the gait cycle. Hippotherapy has been used as a tool by therapists for several decades to address functional limitations in patients with neuromusculoskeletal diagnoses, however, more objective measurements and data supporting HPOT as a therapeutic tool to help improve ambulation are needed. Subjects. Eleven children (6 males, 5 females; 7.9 ± 2.7 years) with neurological disorders resulting in impairments in ambulation and gross motor control in standing participated in this study. Methods. All subjects were receiving weekly traditional land- iii

4 based physical or occupational therapy and elected to participate in HPOT for ten weekly sessions instead. Three-dimensional (3-D) gait analyses were performed with each child prior to the first session of HPOT. Data on cadence, velocity, stride length and step width were collected along with data regarding trunk, pelvis, and hip joint ROM. Subjects then participated in ten weekly sessions of HPOT and a second gait analysis was completed for each subject after completion of the sessions. A series of paired t-tests was performed on the temporal-spatial and kinematic data for each segment. Families of pairwise comparisons were used with the family-wise error rate set at Results. Although no statistically significant differences were found from pre to post test for temporal-spatial data, trends in improved cadence, velocity, and stride length were seen. Significant improvements in sagittal plane pelvic and hip joint positions at initial contact (IC) and toe off (TO) phases of the gait cycle were found, and each demonstrated large effect sizes as determined via Cohen s d. No differences in trunk ROM were determined, although trends towards more normal values were observed in all three planes at IC and TO. Discussion and Conclusion. The group s improvement in sagittal plane pelvic and hip joint positioning and trends for improvement in trunk position, cadence, velocity, and stride length during ambulation may indicate increased postural control during the stance phase of gait after ten sessions of HPOT. iv

5 Dedication This dissertation is dedicated to my parents who have encouraged and supported me throughout my academic endeavors from kindergarten through PhD. v

6 Acknowledgements I very much appreciate the support and assistance provided to me along the path to this degree by Dr. Charles Armstrong. He offered a mix of guidance and independence which allowed me to design and complete a study that not only met the requirements for my degree, but that was also a study very relevant to my background in physical therapy as well as extremely interesting to me as an equestrian. I would like to thank my other committee members for their guidance and assistance. Dr. Christine Fox provided excellent suggestions and immeasurable help with the statistical analysis of the data and interpretation and presentation of the results. Dr. Michelle Masterson was always supportive in my efforts and provided equipment and suggestions, as well as a calm demeanor, which definitely helped my state of mind throughout the course of the study. Dr. Phillip Gribble provided excellent insight at the proposal to help shape the final study, and was always available for questions as they arose. I would like to thank the children and their parents or guardians who participated in this study as well as the therapists, Betsy Hyde, PT, Tracey Lewis, PT, and Michelle Bieszki, OT who provided hippotherapy services through St. Vincent Mercy Medical Center in Toledo, OH. I would like to extend my appreciation to all the volunteers who helped me in data collection and processing. In particular, I would like to thank Josh Baker, PT, for his expertise and assistance with data collection and processing in the University of Toledo Applied Biomechanics Laboratory. Josh s help was monumental and this study could not vi

7 have been completed without him. I would also like to thank Peggy Arnos, PhD for her help with subject preparation and data collection. Peggy was always willing to assist and was very patient with the children! Thank you to Anu Mukherjee who also assisted in data collection. I would like to thank my colleagues at The University of Findlay Physical Therapy Program for their support and understanding when I missed meetings or was a little preoccupied over the last four years and for their help in talking me in off the ledge on occasion. Finally, a huge thank you to my family and friends who consistently encouraged and supported me along the path to this degree. Thank you for helping me study for comps and for listening to all my talk about hippotherapy and gait. Thank you especially for not getting irritated when it took me three weeks to return phone calls and for your understanding when I was in quarantine. vii

8 Table of Contents Abstract Dedication Acknowledgements. Table of Contents List of Tables... List of Figures.. iii v vi viii x xiii I. Introduction. 1 II. Review of Literature 8 III. Methodology IV. Results. 58 V. Discussion VI. References VII. Appendix A- Copies of IRB Approval Forms 114 The University of Toledo 115 The University of Findlay St. Vincent Mercy Medical Center. 117 VIII. Appendix B- IRB Consent Forms The University of Toledo The University of Findlay St. Vincent Mercy Medical Center. 134 IX. Appendix C- Testing Intake Form X. Appendix D- Marker Placements for 3-D Gait Analysis 144 XI. Appendix E- Activities Performed During Hippotherapy Sessions XII. Appendix F- Pre and Post Test Range of Motion Values for Initial Contact, Toe Off, and Across the Stance Phase in All Planes of Motion for Trunk, Pelvis, and Hips. 148 viii

9 XIII. Appendix G- Formula and t Statistics Used for Calculation of Effect Sizes. 159 ix

10 List of Tables Page Table 1. Table 2. Table 3. Table 4. Normal Range of Motion Measurements at Initial Contact, Toe-off, and Throughout Stance. 36 Trunk Movement at Initial Contact, Toe-off, and Throughout Stance 37 Mean Temporal-Spatial Values for Children Aged Three and One Half to Seven.. 38 Mean Temporal-Spatial Values for Children Aged Eight to Twelve Table 5. Subject Demographics 43 Table 6. Subject Kinematic Values Over the Gait Cycle. 53 Table 7. Subject Normalized Kinematic Variables.. 56 Table 8. Normalized Group Means and Standard Deviations for Temporal-Spatial Variables 58 Table 9. Results of Temporal-Spatial Variables from Pre to Post Test 59 Table 10. Group Means in Degrees for Trunk Position at Initial Contact and Toe Off. 60 Table 11. Statistical Summary of Trunk Variables.. 61 Table 12. Group Means in Degrees for Pelvic Position at Initial Contact and Toe Off., 63 Table 13. Statistical Summary of Pelvic Variables.. 64 Table 14. Group Means in Degrees for Hip Position at Initial Contact and Toe Off. 66 Table 15. Statistical Summary of Hip Variables.. 67 Table 16. Group Means in Degrees for Trunk, Pelvic, and Hip Range of Motion Over the Stance Phase. 68 x

11 Table 17. Table 18. Table 19. Table 20. Table 21. Table 22. Table 23. Table 24. Table 25. Table 26. Table 27. Table 28. Statistical Summary of Total Trunk Range of Motion Over the Stance Phase. 69 Statistical Summary of Total Pelvic Range of Motion Over the Stance Phase 69 Statistical Summary of Total Hip Range of Motion Over the Stance Phase 69 Subject Trunk Positioning in Sagittal Plane at Bilateral Lower Extremity Initial Contact and Toe Off and Total Trunk Range of Motion in Sagittal Plane Over Gait Cycle Subject Trunk Positioning in Frontal Plane at Bilateral Lower Extremity Initial Contact and Toe Off and Total Trunk Range of Motion in Frontal Plane Over Gait Cycle Subject Trunk Positioning in Transverse Plane at Bilateral Lower Extremity Initial Contact and Toe Off and Total Trunk Range of Motion in Transverse Plane Over Gait Cycle. 151 Subject Pelvic Positioning in Sagittal Plane at Bilateral Lower Extremity Initial Contact and Toe Off and Total Pelvic Range of Motion in Sagittal Plane Over Gait Cycle Subject Pelvic Positioning in Frontal Plane at Bilateral Lower Extremity Initial Contact and Toe Off and Total Pelvic Range of Motion in Frontal Plane Over Gait Cycle Subject Pelvic Positioning in Transverse Plane at Bilateral Lower Extremity Initial Contact and Toe Off and Total Pelvic Range of Motion in Transverse Plane Over Gait Cycle Subject Hip Positioning in Sagittal Plane at Bilateral Lower Extremity Initial Contact and Toe Off and Total Hip Range of Motion in Sagittal Plane Over Gait Cycle Subject Hip Positioning in Frontal Plane at Bilateral Lower Extremity Initial Contact and Toe Off and Total Hip Range of Motion in Frontal Plane Over Gait Cycle Subject Hip Positioning in Transverse Plane at Bilateral Lower Extremity Initial Contact and Toe Off and Total Hip Range of Motion in Transverse Plane Over Gait Cycle. 157 xi

12 Table 29. Table 30. Table 31. Table 32. t Statistics from Independent t Tests for Temporal Spatial Variables t Statistics from Independent t Tests for Joint Positions at Initial Contact t Statistics from Independent t Tests for Joint Positions at Toe Off t Statistics from Independent t Tests for Total ROM Over Stance Phase 162 xii

13 List of Figures Page Figure 1. Figure 2. Figure 3. Figure 4. Subject with markers and electrodes in place for ambulation trials Set up of UTABL during pre and post testing gait analysis.. 48 A subject participating in hippotherapy intervention with volunteers.. 49 A surcingle and bareback pad used during hippotherapy sessions Figure 5. Changes in cadence for subjects from pre to post test.. 73 Figure 6. Changes in velocity for subjects from pre to post test.. 74 Figure 7. Changes in stride length for subjects from pre to post test 77 Figure 8. Changes in step width for subjects from pre to post test.. 78 Figure 9. Subject during hippotherapy showing abducted and slightly externally rotated hip joint. 86 xiii

14 Chapter One Introduction Participation in horseback riding to aid in health and wellness may have been first documented in approximately 400 B.C when Hippocrates mentioned horseback riding in a chapter he wrote on Natural Exercise (American Hippotherapy Association (AHA), 2003). Since those ancient days, the suggestion of utilizing horseback riding for rehabilitation has appeared in papers or texts throughout the centuries. Horseback riding as a potential rehabilitative tool became internationally recognized in the early 1950 s when Liz Hartel, a Danish woman with a history of a debilitating case of poliomyelitis, won a silver medal in dressage in the 1952 Helsinki Olympic Games. Ms. Hartel began horseback riding for her own perceived therapeutic benefits and strongly believed that riding helped with her recovery and subsequent success in dressage. The announcement of this belief to the world after placing at the Olympics brought the potential of horseback riding as a rehabilitative tool into the international light. Approximately fifteen years later, the first center specifically for horseback riding for rehabilitation was started, and in the 1960 s therapeutic riding centers were developed throughout Europe, the United States (US), and Canada (Bertoti, 1988; AHA, 2003). The North American Riding for the Handicapped Association (NARHA) was formed in the US in According to the NARHA website, NARHA is a 1

15 membership organization that fosters safe, professional, ethical and therapeutic equine activities through education, communication, standards and research for people with and without disabilities (NARHA, 2005). With membership throughout North America of approximately 4,000 individuals, and 670 NARHA certified equestrian facilities, the organization strives to promote safe and accessible equine assisted activities (EAA) for those who may benefit (NARHA, 2005). According to NARHA (2005), EAA include all of the following: therapeutic riding (TR) for those with disabilities, hippotherapy (HPOT), equine assisted psychotherapy, carriage driving, competition on horseback, and other therapeutic activities involving horses such as leading, vaulting, longeing, or grooming. Over 30,000 individuals are involved in EAA each year according to NARHA (2005), with a large proportion of individuals being involved in TR or HPOT. The delineation between TR and HPOT is often misunderstood not only by participants or parents of participants, but also by professionals involved in providing or promoting EAA. The American Hippotherapy Association (AHA) was formed in 1992 and has defined hippotherapy as the use of the movement of the horse as a tool by Physical Therapists, Occupational Therapists, and Speech-Language Pathologists to address impairments, functional limitations, and disabilities in patients with neuromusculoskeletal dysfunction. This tool is used as part of an integrated treatment program to achieve functional outcomes. (American Hippotherapy Association Practice Committee (AHAPC), 2000). This distinguishes the term, hippotherapy from therapeutic riding, as TR is more of an umbrella term. Therapeutic riding can be provided by non-therapists unlike hippotherapy, and although some form of rehabilitation is a likely occurrence, the primary goal in therapeutic riding is the learning of 2

16 horsemanship and riding skills. Therapeutic riding also integrates some aspects of horse care and stable management, which hippotherapy does not (AHA, 2003; All, Crane, & Loving, 1999; MacKinnon, 1995a). Thus, in HPOT, it is the movement of the horse that influences and imparts movements to the rider who is encouraged to actively respond, while TR is more inclined to teach the rider to control the horse and have the horse respond to the rider, which is a more traditional relationship during horseback riding (AHAPC, 2000; Garone, 2007; Rolandelli & Dunst, 2003). Hippotherapy has been used in the treatment of adults and children with a variety of diagnoses. According to NARHA (2005), clients with disabilities related to a multitude of diagnoses have participated in and can benefit from HPOT. These diagnoses include, but are not limited to: muscular dystrophy, cerebral palsy, visual or hearing impairments, mental retardation, down syndrome, brain injuries, multiple sclerosis, and spinal cord injuries (AHA, 2003). Although HPOT has been used in the United States as a therapeutic tool since the 1960 s, very little objective research has been done on this therapy as compared to other therapeutic interventions that have been in use for over 40 years. Much of the information regarding the benefits of horseback riding as a therapeutic tool is subjective feedback from the participants and clinicians. Over the past 20 years, a number of more objective studies have been conducted on the proposed benefits of HPOT in attempt to quantify the changes in clients mobility and function that are often observed by therapists. These studies have demonstrated gains in areas such as ambulation efficiency (Sterba, 2002), static and dynamic posture and trunk stability (Bertoti, 1988; Wingate, 1981), and motor performance as measured by the Gross Motor Function Measure 3

17 (GMFM) and Pediatric Evaluation of Disability Inventory (PEDI) (Casady, 2004; Haehl, Giuliani, & Lewis, 1999; MacKinnon, Noh, Laliberte, Lariviere, & Allen, 1995). Although the data presented by these and other authors are beneficial and important to the research on HPOT, much of the work has involved subjective observational scales, small sample sizes, limited information on treatment strategies utilized during riding sessions, limited intervention durations, and caregiver reports that occur after the intervention has concluded. Evans (1996) stated in his review of the literature relating to hippotherapy that the relative lack of objective, scientific research that confirms the benefits of therapeutic riding is a critical void in efforts to expand therapeutic riding and educate the public about its effectiveness. More objective measurements and data supporting horseback riding as a therapeutic tool to help improve function and ambulation are needed. Improving ambulation skills is an area of intervention that physical therapists often focus on when treating pediatric clients, and hippotherapy has been purported to positively affect gait in children who have participated in this type of therapy. In children who present with neurological diagnoses, arguably the population most often involved in HPOT, it is necessary to not only study the possible kinematic changes that may occur in a child s gait due to HPOT, but also kinetic changes. Possible adaptations and changes in muscular activity of the trunk and lower extremities (LE) that may promote a more stable and/or efficient gait, should be examined, as well as possible increases in standing motor control and postural stability that may positively affect ambulation and function. 4

18 Statement of the Problem The aim of this study, therefore, was to examine the effects of a ten-week HPOT program on the ambulation of eleven children with neurological pathologies. Analysis focused on several temporal-spatial variables of gait such as cadence, velocity, stride length, and step width, as well as the range of motion at the hip joints, pelvis and trunk over the gait cycle. Specific focus was on hip, pelvic, and trunk positioning at initial contact and toe-off of the lower extremities, as well as the full ranges of motion the segments traveled through over the stance phase of the gait cycle. The temporal-spatial variables and positions and ranges of motion pre and post HPOT intervention were compared with previously determined normal values for the variables over the gait cycle to determine if participation in HPOT aided in normalizing the gait of participants. Research questions included: Does incorporation of a ten-week HPOT intervention program into the therapeutic plan of care (POC) of pediatric subjects with neurological impairments promote improvements in gait as determined via: a. analysis of the kinematic variables of cadence, velocity, step width, and stride length? b. three-dimensional videography (3-D video) data on ROM of the hips, pelvis, and trunk? 5

19 Hypotheses included: H 1-4 ) Children involved in 10 weeks of HPOT intervention will display improvements in gait as measured pre- to post test via 3-D video gait analysis, as demonstrated by more normalized: a. cadence b. velocity c. stride length d. step width H 5-10 ) Children involved in 10 weeks of HPOT intervention will display improvements in gait as measured pre to post test via 3-D video gait analysis, as demonstrated by more normalized: a. trunk positions at initial contact, bilaterally b. pelvis positions at initial contact, bilaterally c. hip positions at initial contact, bilaterally d. trunk positions at toe-off, bilaterally e. pelvis positions at toe-off, bilaterally f. hip positions at toe-off, bilaterally H ) Children involved in 10 weeks of HPOT intervention will display improvements in gait as measured pre to post test via 3-D video gait analysis, as demonstrated by more normalized: g. total range of motion of the trunk over the stance phase of the gait cycle h. total range of motion of the pelvis over the stance phase of the gait cycle i. total range of motion of the hips over the stance phase of the gait cycle 6

20 In summary, hippotherapy has been utilized as a treatment intervention for children with neurological diagnoses in various therapies including physical and occupational therapy sessions. However, the effects of this treatment strategy are still unclear due to the relative lack of experimental and scientific evidence and the use of subjective assessment tools in the majority of studies, versus more objective data collection measures. The use of more objective data collection strategies such as 3-D video gait analysis may demonstrate both statistically significant and clinically significant improvements in gait in children involved in HPOT and provide further, more concrete evidence of the positive effects of this treatment strategy. 7

21 Chapter Two Review of the Literature A large proportion of children who participate in hippotherapy (HPOT) as a therapeutic intervention present with various neurological diagnoses that result in impairments which lead to difficulties with functional mobility and ambulation. These impairments may include decreased strength, poor postural control, impaired coordination, decreased balance, diminished motor control and abnormal muscle tone. Hippotherapy has been suggested to lead to improvements in these areas as well as improvements in righting and equilibrium reactions (Biery & Kaufmann, 1989), decreases in hypertonicity (Brock, 1988; Benda, McGibbon, & Grant, 2003), increased joint range of motion (Biery, 1985), and improved upper extremity function (Bertoti, 1991). The three-dimensional movement of a horse s back as it walks imparts to the rider s pelvis a three-dimensional movement that is likened to the movement of the human pelvis that occurs during walking (Bertoti, 1988; Strauss, 1991; Fleck, 1992; Spink, 1993). Thus, because of this similarity in pelvic movement during riding to that which occurs when ambulating, some authors have attempted to quantify improvements in gait post hippotherapy. Various methods have been used to research the effects of HPOT and draw the above conclusions. Research methods have included both subjective 8

22 and objective rating scales and functional assessments, surface electromyography, static photographs of posture, digital heart rate monitoring, videography, and the use of force platforms. This literature review will provide information from past research on the effects of horseback riding for those with disabilities, briefly discuss impairments that have shown favorable responses to HPOT or TR or may have been affected by such, and examine instrumentation and assessments used in past studies as well as those that were utilized in this study. Hippotherapy and Therapeutic Riding As presented previously, there is a clear distinction between the terms and focus of HPOT and TR; however, studies performed on the effects of horseback riding for those with disabilities have examined both TR and HPOT with a general implication that the benefits determined from a TR study can be generalized to HPOT and vice versa. This especially seems the case in those studies written prior to the early nineties and before the development of the AHA which clarified the delineation between the two horseback interventions. Because very few studies on TR or HPOT present specific treatment strategies utilized during riding sessions, it would stand to reason that perhaps many similar strategies were used in the sessions whether they were TR or HPOT sessions. Postural awareness, adjustment to the horse s movement, stretching, utilization of the reins or grasping of the handles on a sursingle, and basic upper extremity (UE) tasks such as reaching are utilized in both TR and HPOT (All, Crane, & Loving, 1999; AHA, 2000; NARHA, 2005). In addition, several psychosocial and cognitive skills may be addressed during TR or HPOT including right/left discrimination, reasoning and 9

23 judgment, sequencing, motivation, socialization, communication, self-image, and concentration (Wingate, 1982; Brock, 1989; MacKinnon et al., 1995a; All et al., 1999; Rolandelli & Dunst, 2003). Because of the potential overlap in activities performed in TR and HPOT sessions, for the purposes of this literature review, studies examining both interventions and the effects presented therein are discussed here although the current study examines only the effects of HPOT and not TR. According to results of a survey of HPOT practitioners from 24 countries conducted by Copeland-Fitzpatrick (as cited in Rolandelli & Dunst, 2003) the six most common disabilities treated in HPOT sessions were: cerebral palsy (CP), traumatic brain injury (TBI), multiple sclerosis (MS), hemiplegia, developmental delay/down syndrome and sensory integration deficit. Hippotherapy treatments have been utilized not only for many diagnoses and impairments, but also for clients of all ages. Hornacek (2005) suggests that HPOT can and should begin with a child of only a few months to promote a more extended posture. However, a study conducted at six therapeutic riding centers in Germany by Heipertz-Hengtz (as cited in Rolandelli & Dunst, 2003) reported that children in the age range between 7 and 11 years of age appear to benefit the most from HPOT, followed by those children aged A majority of published studies on the benefits of HPOT and TR have focused on how children with neurological diagnoses are affected by the interventions. Many publications, such as those by Bertoti (1991), and Haehl, Giuliani, and Lewis (1999) involved a case study design. Bertoti (1991) examined the effects of TR on weightbearing through all four extremities in a child with right hemiplegic CP. The child was involved in two one-hour riding sessions per week for six weeks that included 10

24 various stretching, strengthening, and balance activities for the extremities and trunk. The author determined via use of a digital scale, that weight bearing increased in all four extremities, and also concluded, via observation, that the child s motor abilities had improved after six weeks of intervention, especially the use of the right UE and LE during activities. Haehl, et al. (1999) investigated the effects of HPOT on the function of two children with CP, one diagnosed with spastic diplegia, and the other child with spastic/athetoid quadriplegia. The children were involved in HPOT sessions for twelve weeks with session durations ranging between 20 to 40 minutes on horseback. Similar activities as performed in Bertoti s (1991) study were performed by the children including activities designed to enhance postural control. Data collected via the use of observational qualitative postural control assessments and the Pediatric Evaluation of Disability Inventory (PEDI) after the twelve weeks demonstrated that one child displayed no improvements in posture and function via these assessments, while the other child did. The child who demonstrated improvements did so in areas of general mobility and social domains as tested via the PEDI. Although these case study reports by Bertoti (1991) and Haehl et al. (1999) along with various other reports contribute to the knowledge base and information available on HPOT or TR, case reports are merely extremely detailed descriptions of treatment; they cannot establish cause and effect (McEwen, 2001). Case studies serve as stimuli for additional research, and these studies demonstrated that experimental research into the effects of horseback riding for therapeutic gains was warranted, especially in the areas of posture and functional mobility. 11

25 Bertoti (1988) had, in fact, performed a quasi-experimental study three years earlier than her case report that examined the effects of TR on the posture of children with CP. Eleven children, aged two to nine years, with various types and severity of spastic CP were involved in 10 weeks of TR. The children rode twice weekly for an hour each session with focus on reducing spasticity and facillitating normal movement while maintaining good posture on the horse. Bertoti (1988) reported that the sessions goals were similar to those goals set by therapists who utilize neurodevelopmental techniques (NDT) in the treatment of children with CP or other diagnoses during traditional landbased therapy. Posture was scored for each participant by three therapists not involved in the HPOT sessions who were all pediatric therapists. The scale used to evaluate posture was developed by Bertoti, herself, for this study and it was determined to be a valid measure of postural assessment in CP by five other pediatric physical therapists. The postural scale consisted of assigning a score from zero to three in determining symmetry or alignment of five segments or areas of the body while in quiet stance. The three therapists who assessed the posture of the children involved in this study completed their individual postural assessments, and then an aggregate score was utilized for data analysis to determine potential changes in standing posture from the initiation of the TR program to the end of the program, ten weeks later. Bertoti (1988) reported significantly improved postural control (p < 0.05) for the group as determined by performing a Friedman test on the composite scores from the assessments. Eight of the eleven subjects were determined to have moderately improved posture while two of the other participants displayed only minimal improvements. One participant actually displayed slight decreases in postural control after the intervention as 12

26 determined by a lower composite score at post testing. All eight subjects who displayed improved postural control demonstrated positive changes in head and neck alignment. Those participants diagnosed with spastic diplegia demonstrated better gains in trunk and pelvic alignment and posture than those diagnosed with spastic quadriplegia, although all showed some degree of improvement in these segments, as well. Bertoti (1988) explained the minimal gains or no gains in the three other subjects were due to the fact that two had some degree of anxiety or apprehension regarding horseback riding that affected their participation levels, and one child presented with an extensive history of surgical interventions and chronic poor posture. This study was the first objective analysis of the therapeutic effects of horseback riding for the child with CP (Bertoti, 1988). Bertoti s results may have been biased, however, due to the fact that the author was the therapist who provided the actual TR interventions to the subjects and the author s own developed postural scale was used in the study. Effects of HPOT and TR on Postural Control The results of Bertoti s 1988 and 1991 studies provided impetus for further study into the effects of HPOT and TR on postural control, especially studies that provided more objective, experimental results. MacKinnon et al. (1995b) also examined the therapeutic effects of TR in children with CP. Their study utilized an experimental group of ten children who participated in six months of once weekly TR sessions. A group of nine age and diagnosis matched children served as a control group and no effort was made to change or stop therapies that either group of children was already involved in during the six month study. Measurements regarding posture were obtained utilizing Bertoti s scale (Bertoti, 1988). MacKinnon et al. (1995b) found no significant 13

27 differences in posture after the six months of the study between the TR group and the control group, however, within the TR group, the authors found differences between subgroups of mildly impaired children (n=5) and moderately impaired children (n=5), with the moderately impaired showing improvements in posture and the mildly impaired actually demonstrating minimal decreases in posture as demonstrated by slightly lower scores on Bertoti s scale. Small sample sizes and the use of Bertoti s ordinal level scale, may have contributed to the insignificant findings between the TR and control groups. Improvement of posture in children participating in TR or HPOT is a factor many others authors have attempted to quantify over the past twenty years or so. Quint and Toomey (1998) utilized a mechanical apparatus that was shaped similarly to and moved in a pattern comparable to the movement of a horse s back during walking. Fifteen children with CP were assigned to an experimental group that sat astride and rode the mechanical horse ten times a day in 10 minute increments for four weeks. A control group of fifteen diagnosis and sitting-ability matched children sat on a static saddle for the same amount of time and frequency. The authors quantified postural changes in each group by analyzing the passive range of motion (PROM) of the subjects pelvises in the sagittal plane (anterior and posterior pelvic tilt) after four weeks using standard photography to visualize and measure end range positions. Statistical analysis revealed that the group who had sat astride the mechanical horse demonstrated significantly greater increases in total pelvic PROM than the control group, although the control group did display gains in PROM, as well. The authors partially attributed the differences between the groups to the rhythmical movement of the mechanical horse which may 14

28 have served to inhibit co-contraction of the muscles around the hip joints and pelvis of the children in the experimental group. This co-contraction of muscles around a joint leading to reduced range of motion (ROM) is common in children with CP (Campbell, 1995). In fact, a study by Brogren, Hadders-Algra, and Forrsberg (1996) determined that children with spastic diplegia showed co-contraction at the hip and decreased reciprocal inhibition while sitting on a moveable platform and exposed to random perturbations in the sagittal plane and had muscle activation patterns that were in a reversed recruitment order (superior to inferior versus inferior to superior) as compared to healthy children. These anomalies in muscle activation patterns and levels appear to contribute to dysfunction in postural control in children with spastic diplegia (Brogren et al., 1996). Thus, with the increase in pelvic ROM observed in the study by Quint and Toomey (1998), this could theoretically lead to improved postural control, as they theorized that the simulated riding may have stretched tight pelvic and hip muscles, but also may have facilitated more normalized movement of the pelvis while on the mechanical apparatus and enhanced the subjects feedforward and feedback mechanisms of control over the pelvis. It is well known that pelvic position and control affects the position and curvature of the lumbar spine and subsequently also the thoracic and cervical spine, i.e. posture (Norkin & Levangie, 1992; Neumann, 2002). The influence of mechanical horseback riding or artificial saddle riding was also investigated by Kuczynski and Slonka (1999) and involved 25 children diagnosed with CP, however, these authors quantified improvements in posture with the use of a force platform versus pelvic ROM as Quint and Toomey (1998) had. As in Quint and Toomey s study, the artificial saddle utilized in this study was shaped like a typical 15

29 English saddle and the mechanism of the artificial saddle attempted to re-create the threedimensional movement of a horse s back while walking. Static standing force platform assessments were performed prior to riding sessions and immediately after riding sessions during the first session and last session in a three-month program of artificial saddle riding. The three months of the program involved artificial saddle riding at a frequency of twice a week for twenty minutes each session. Force platform assessments were also performed with a control group of 33 healthy children of similar ages, immediately before and after one session of artificial saddle riding. Results demonstrated that the 25 children who participated in the artificial saddle riding program displayed improved postural control in standing in both the frontal and sagittal planes as determined by force platform data on the center of pressure (COP) and center of gravity (COG) movement of the subjects. The shape and angle of a typical English saddle, which was used in Quint and Toomey s (1998) and Kuczynski and Slonka s (1999) investigation, or even a bareback pad on the back of a horse promotes more normalized sitting posture, in itself. When sitting on a flat surface, the natural lumbar lordosis is flattened and posture is compromised. An English saddle, however, promotes a neutral to slightly anteriorly tilted pelvis due to the angle of the seat, which in turn enhances proper lumbar lordosis in the sitting position. A bareback pad also appears to promote enhanced sitting posture due to the slope of the horse s back which is higher caudally and lower cranially, thus promoting a slight anterior tilt in the rider s pelvis, as well. Similarly, clinicians often utilize saddle-shaped seats during traditional land-based therapy for children with postural control problems to enhance posture and improve UE function in sitting. In a 16

30 1996 study, Reid investigated the effects of a saddle shaped seat on posture and UE movement in children with CP as compared to the same children s posture and UE movement when sitting on a flat surface. Postural effects from each seating surface were measured by use of the Sitting Assessment for Children with Neuromotor Dysfunction (SACND) scale which was developed by Reid to measure proximal stability, postural tone, postural alignment, and balance in sitting. Significantly better postural control was determined via use of this scale in the children when seated on the saddle-shaped seat as compared to a flat bench surface. The improved postural control in children with neuromotor impairments observed while seated on a saddle or saddle-shaped surface that promotes a slight anterior pelvic tilt may correlate to findings that when a child s head, trunk and arms are anterior to the ischial tuberosities, postural control increases as compared to when the segments are aligned with or posterior to the ischial tuberosities (Myhr & von Wendt, 1991; Hadders-Algra et al., 2007). The abduction allowed at the hips as well as the greater than 90 degrees hip-to-thigh angle that is promoted by a saddle-shaped seat on and/or off a horse also has been shown to contribute to more stable, symmetrical, functional, and erect posture in children with neuromotor diagnoses such as CP as well as in healthy children (Myhr & von Wendt, 1990; Myhr & von Wendt, 1993, Sarrni, Clas-Hakan, Arja, Tapio, & Anneli, 2007). Postural control assessment via the use of a force platform system was also utilized to assess one individual after participation in a HPOT program as described in a case report by Hakim, Collins, Jamieson, Knueven, and Sensbach (2005). An 11 year old who was three years status post diagnosis of cerebellar ganglioglioma with resection participated in HPOT 30 minutes a week for 12 weeks. Along with several functional 17

31 test measurements, force platform measurements were taken before, at the midpoint of, after, and at eleven weeks post HPOT intervention. During the HPOT sessions, focus was on proper posture, weight bearing through the affected UE, reaching tasks across midline, and other UE reaching tasks and movements performed while attempting to maintain a stable trunk while riding. The force platform system utilized for assessments was the Biodex Balance System, a clinical balance system often used to assess fall risk in the elderly or for balance training applications (Biodex, 2003). Hakim, et al. (2005) utilized the Dynamic Limits of Stability test of the system to collect the data on their subject s limits of stability. The authors report that the subject s directional control scores on the Dynamic Limits of Stability test improved from pre-test to post test (33/100 to 34/100) and also from post-test to follow-up (34/100 to 38/100) indicating improved balance, but statistical significance was not reported, nor were the specific values to which numbers were correlated. Effects of HPOT and TR on Functional Movements and Tasks Several of the aforementioned studies not only examined the effects of HPOT or TR on postural control, but also included measurements or assessments designed to potentially determine change in functional status of the individuals who participated in the riding sessions. With increased postural control and stability, oftentimes a corresponding improvement in mobility occurs, as it is imperative that a child be able to stabilize the trunk and pelvis during ambulation as the body passes over the support leg and the opposite extremity advances. Bertoti (1988, 1991) and Haehl, et al. (1999) both involved qualitative assessment of functional changes via observation of participants motor abilities. Bertoti (1988) reported improvement in trunk control, and strength gains 18

32 in trunk, hip, and shoulder musculature which transpired to obvious functional gains. The author, however, was the person who provided the instruction during the TR sessions which may have induced some bias, and no information was provided on how the author determined strength gains in the children or what functional gains were allegedly achieved. Haehl et al. (1999) also reported mobility gains in one of the two participants in their study as determined by the mobility domains of the PEDI. Conversely, the other subject in this study demonstrated no appreciable gains, therefore inconclusive evidence on functional improvement is presented in both Bertoti s (1988) and Haehl et al. s (1999) studies. Several studies on HPOT and TR effects have utilized the Gross Motor Functional Measure (GMFM) (Russell et al., 1989) as a measurement tool in attempts to quantify changes in functional abilities post riding sessions. The GMFM analyzes five dimensions of functional movements and postures in children with a variety of neurological or cognitive pathologies that cause motor delay or impairment. The dimensions include: A) lying and rolling, B) sitting, C) crawling and kneeling, D) standing, and E) walking, running and jumping. In MacKinnon et al. s (1995b) study previously described, the authors utilized the GMFM in the analysis of the 10 children who participated in six months of once weekly TR sessions as well as the nine children in their control group. Although total GMFM scores improved for both groups, there were no significant differences between the two groups on either total score or in any sub-scores in each of the three dimensions of the GMFM the authors chose to analyze (Dimensions B, D, and E). In contrast to these findings, Sterba et al. (2002) noted significant increases (p < 0.04) in GMFM total score (Dimensions A-E) in 17 children with CP after 18 weeks of 19

33 horseback riding. The most noticeable gains were in Dimension E, walking, running, and jumping. Similarly, McGibbon and colleagues (1998) and Cherng, Liau, Henry, and Hwang (2004) demonstrated significant improvements in GMFM Dimension E scores in children with CP after eight weeks and sixteen weeks, respectively, of HPOT. McGibbon et al. (1998), however, did not find significant changes in GMFM total score, while Cherng and colleagues (2004) did. Winchester, Kendall, Peter, Sears, and Winkley (2002) also utilized the GMFM to quantify changes in gross motor function in seven developmentally delayed children pre and post participation in seven weeks of TR as well as seven weeks after the riding had ceased. A repeated measures within-subjects analysis of variance (ANOVA) demonstrated significant improvements in GMFM scores between pre-test and immediately post, as well as between pre-test and at the seven week follow-up (p < 0.01). No significant differences were found between the total scores between the two post tests, however, suggesting gains in function, as measured by total GMFM score improvements, are maintained several weeks beyond the cessation of the riding program. A limitation to this study, however, is that not all the same dimensions of the GMFM were measured for each child due to differing levels of impairments. Some children only had Dimension E tested, while others had various other dimensions tested, and not Dimension E due to non-ambulatory status. The authors identified five ambulatory subjects in their study, yet only four subjects were scored on Dimension E. Although scores were converted to a percentage of total points for comparison of participants (Winchester et al., 2002), obtaining data from the same dimensions for each child may have served to increase the 20

34 strength of the claims that gross motor function, in general, is improved and maintained after participation in horseback riding. Casady and Nichols-Larsen (2004) used a repeated measures design to examine the effects of HPOT on gross motor function of ten children with CP. The authors performed two pre-test GMFM assessments, and then two post test GMFM assessments after ten weeks of HPOT one time a week for approximately 30 minutes each session. The authors reported a significant treatment effect due to HPOT intervention, with statistically significant increases in GMFM total scores and also Dimension C scores from pre-hpot intervention to post HPOT intervention, although, again, not every subject was able to perform all dimensions of the GMFM, specifically Dimension E. The results of this study and others that have included the GMFM as a measurement tool to determine the effects of TR or HPOT suggest that horseback riding may lead to increased function off the horse due to the rhythmic gait of the horse promoting not only postural reactions and control, but also the opportunity to organize, practice and improve feedforward and feedback postural control (Casady & Nichols-Larsen, 2004; Sterba et al., 2007). A limitation to this study, however was that the primary investigator was also the therapist who provided the HPOT to the subjects which may have induced bias when assessing the subjects. Theoretically, improved postural control, and enhanced motor function should correlate to improved gait, and will be further discussed later in the literature review. A few studies on HPOT or TR have attempted to determine improvements in gait post participation in a horseback riding intervention by means other than Dimension E of the GMFM. For example, McGibbon and colleagues (1998) not only analyzed changes in 21

35 scores in Dimension E (walking, running and jumping) of the GMFM, they also examined changes in gait speed of children after participation in the HPOT sessions. As mentioned previously, the authors determined statistically significant changes in GMFM Dimension E scores from pre-test to post test in the subjects. The authors also analyzed the time it took the children to walk across a ten meter segment of a walkway. They also examined changes in cadence and stride length of the children, which were normalized to each child s height, gender, and velocity. The authors also examined energy expenditure via the Energy Expenditure Index (EEI) which measures energy cost as a function of heart rate during walking (Rose, Medeiros, & Parker, 1985). Data analysis including a two-way ANOVA for within subject differences on the four factors (GMFM, EEI, stride length, and cadence) revealed statistically significant changes in energy expenditure (p < 0.05) along with Dimension E of the GMFM, but no significant changes in stride length or cadence. The authors suggested the improved efficiency of walking may have been a result of increased stability at the hip and knee which may have been enhanced by HPOT. They also surmised that possible improvements in equilibrium reactions due to HPOT could have positively affected postural control during gait, thus reducing energy expenditure (McGibbon et al., 1998). Low et al. (2005) also found statistically significant changes in scores in Dimension E of the GMFM in their study on gait and gross motor function in 14 children with CP. Bi-weekly, 30 minute sessions of TR for eight weeks revealed statistically significant changes in Dimension E of the GMFM, but did not reveal significant improvements in spatial and temporal characteristics of the subjects ambulation utilizing the GAITRite as a measurement tool. The GAITRite is a portable walkway mat 22

36 imbedded with thousands of pressure sensors that allows collection of data regarding cadence, step and stride lengths, single and double limb support times, speed of gait, and step width as a subject ambulates across the mat. The authors did report trends towards increased cadence, stride length, single-leg stance time and percent swing duration, however, as demonstrated by data obtained via the GAITRite system (Low et al., 2005). Winchester et al. (2002) looked at changes in gait speed in seven subjects with developmental delay. The authors found no significant differences in gait speed as measured in meters per minute for a 10 meter walkway segment from pre-test to post test although they reported significant improvements in Dimension E of the GMFM. The authors suggested that gait speed may have been affected by each child s motivation, cooperation, and distractibility on the testing days (Winchester et al., 2002). The authors also reported that gait speeds of the children were also near normal at pre test, therefore substantial improvements in speed were not likely, although they did report a trend towards increased speed at post testing. Small sample size, therefore, could have been a factor in the inability to determine statistical significance. A case study by Whitmore and Aldridge (2007) attempted to quantify changes in gait in a six year-old female post addition of HPOT treatments once a week in adjunct to her normal once a week land-based therapy sessions. The HPOT sessions were added to her plan of care for ten weeks (condition A). After the ten weeks, the HPOT sessions ceased, and traditional therapy, alone, continued for an additional ten weeks (condition B). Gait analysis was performed using the GAITRite System after every HPOT session and every land-based session for the entire 20 weeks. Statistical analysis using an exact binomial test with level of significance set at p 0.05 revealed differences from 23

37 condition A to condition B in the realms of single support length of the right LE, double support time of both extremities, swing duration of the left LE, stance time of the left LE, and cadence (Whitmore & Aldridge, 2007). The authors identified a number of potential limitations to their findings, however, the use of the GAITRite system in this case report and the significant findings justify the exploration of the use of this gait analysis tool in future studies on HPOT or TR. Postural Development and Control in Hippotherapy and Effects on Gait Although human gait is individualistic with each person displaying his or her own characteristics of gait, the phases of the gait cycle in normal locomotion remain consistent across the board (Norkin & Levangie, 1992). It has been determined that human locomotion is a series of repeatable, cyclical patterns of the lower extremities, and is produced by coordinated rhythmic movements of body segments. (Norkin & Levangie, 1992; Cromwell, Aadland-Monahan, Nelson, Stern-Sylvestre, & Seder, 2001). Additionally, Cromwell et al. (2001) propose that as the lower extremities provide the propulsive and retropulsive motions necessary for locomotion, the role of the trunk and upper body is to remain balanced and to act as a stable system in dynamic equilibrium (pg. 255). Subtle movements and reactions of the trunk musculature, therefore, are necessary in response to movement of the lower extremities. These subtle movements are necessary to prevent excess body motion and to provide stability and counter balance to pelvic rotation. (Norkin & Levangie, 1992; Cromwell et al., 2001). Children with neurological diagnoses such as CP often present with decreased postural control, thus this is one of many factors that contributes to abnormal gait patterns often seen in these children. As mentioned, children with CP often present with a 24

38 reversed pattern of muscular activation for stabilization and postural control when exposed to external perturbations (Nasher, Shumway-Cooke, & Marin, 1983; Brogren, Hadders-Algra, & Forrsberg, 1996). Unlike healthy children and adults, children with CP recruit muscles for stabilization superiorly to inferiorly. The body s ability to recognize and prepare for voluntary movements is due to the close interaction of the sensorimotor, visual, and auditory systems which are utilized when the body encounters an unexpected disturbance or perturbation. Upon preparing for an anticipated movement or in response to unexpected movement, postural adjustments are needed prior to initiating voluntary movement (Umphred, 2001). Disturbances in the sensorimotor systems of children with neurological impairments disrupt the ability to properly prepare for or respond to movement. The reversed recruitment order of the stabilizing muscles further adds to the lack of proper postural control in response to perturbations (Brogren et al., 1996). Development of posture and postural control is often delayed or impaired in children with neurological diagnoses such as CP. In Cech and Martin s (1995) textbook on functional movement development, VanSant identifies two facets of posture: 1) preservation of balance and alignment and 2) the ability to move from one posture to another to attain controlled standing (VanSant, 1995). A contemporary belief on postural development is the Dynamical Systems Theory (DST) (Thelen & Cooke, 1987). The DST suggests that postural control is the result of many systems working together in a goal directed situation (Cech & Martin, 1995). These systems and sub-systems may include nervous, muscular, vestibular, visual, proprioceptive, and reflexive systems, as well as the effects of gravity, arousal, body mass, motivation, and force (Kamm, Thelen, & Jensen, 1990; VanSant, 1995; Bradley, 1995). In the DST, it is assumed that all 25

39 systems contribute to the development of motor control, with no one system having the ultimate effect (Kamm et al., 1990). A main tenet of DST is that self-organization which contributes to mature motor control, including postural control, results from these many systems working efficiently and in cooperation (Kamm et al., 1990). Additionally, the development of mature motor control and transition from a lower stage of control to a higher stage occurs due to re-organization among the systems and sub-systems, as well as flexibility of and changes within the systems during contribution to specific tasks (VanSant, 1995; Kamm et al., 1990). Because, in total, dynamical systems are nonlinear systems, Kamm et al. (1990) suggest that small changes within a system or sub-systems, can have large effects on the development course, especially at critical points of reorganization. Development of postural control in sitting, the transition to postural control in stance, and the eventual transition to postural control during locomotion, then, according to DST, is a series of phase shifts in which the child must find and self-organize motor solutions utilizing the appropriate systems and/or sub-systems to promote the most efficient progress towards stability and control (Kamm et al., 1990). Phase shifts result from challenges to the whole system that necessitate re-organization, i.e., the child must test his or her limits of stability in order to self-organize and re-organize postural control and select appropriate patterns (Hadders-Algra, Brogen & Forrsberg, 1996; VanSant, 1995; Kamm et al., 1990; Reed, 1989). Proponents of HPOT suggest that the constantly moving, rhythmical sway of the horse s back during riding challenges the rider s postural control via movement in all three planes, and variations in movements and perturbations encountered as the horse 26

40 decreases or increases speed or changes direction while being led. In agreement with the DST of postural control development, these rhythms and variations in movement by the horse allow the rider to practice postural strategies and self-organize and re-organize balance strategies as his or her center of mass (COM) is constantly being displaced (Biery & Kauffman, 1989; MacKinnon et al., 1995b; MacPhail et al., 1998; Snider, Korner- Bitensky, Kammann, Warner, & Saleh, 2007). With each step of the horse in walk, trot, or canter, the COM of the rider is displaced as the trunk changes position in response to the horse s movements. Lovett, Hodson-Tole, and Nankervis (2005) examined the trunk displacement of five healthy female riders riding the same horse to determine if significant differences existed in the position of the rider when assessed at different points in the horse s gait cycles during walk, trot and canter. Video analysis was used to find the absolute angles of four markers placed on bony landmarks of the riders including, lateral malleolus, middle of the femoral condyles, greater trochanter and the glenohumeral joint. This allowed determination of range of trunk movement of the rider. Significant differences in riders trunk angles between forelimb and hind limb placements of the horse during walking and trotting were found (p < 0.05). Therefore, as each forelimb and hindlimb of the horse hits the ground, there is shifting of the rider s trunk in between impacts (Lovett et al., 2005). This constant motion of the trunk would seemingly affect a HPOT rider s vestibular, proprioceptive, and neuromuscular systems, stimulating righting and equilibrium responses, and allowing enhancement of preparatory and anticipatory trunk muscle activity for proximal stability (Spink, 1993; Shumway-Cooke & Woolacott, 1995). 27

41 Contribution of the Core Musculature to Postural Control and Stability Appropriate muscle recruitment for postural stability is a cooperative effort among many systems and sub-systems identified in DST. Visual, vestibular, and proprioceptive input, gravitational and other external forces, and reflexes may contribute to appropriate muscular recruitment within the trunk and lumbo-pelvic complex to maintain stable, proper posture. Muscle strength and appropriate neuromuscular responses are two sub-systems that are extremely important, as well, in postural control. Proper postural alignment, as related to muscular strength and response, begins at the core. The core, comprised of multiple muscles within and around the lower trunk, pelvis, and hips, is often integrated as one functional unit working to not only produce forces, but also to stabilize against forces such as perturbations in sitting or stance. The core muscles consist of rectus abdominis, external oblique, internal oblique, multifidus, longissimus, iliocostalis, intertransversarii, transverse abdominus, quadratus lumborum, and gluteus maximus. Some authors also include the gluteus medius, latissimus dorsi, and iliopsoas as part of the core musculature (Clark, 2001). As a system, if the muscles of the core work together producing well-coordinated contractions, the body is able to respond effectively when exposed to external postural disturbances. Stability is compromised when asymmetries occur in the timing of muscle contractions or when there are imbalances in the strength of core muscles (Granata & Wilson, 2001; Cook, Cook, & Fleming, 2004). It has also been established that anticipatory contractions of the core musculature occur prior to goal-directed movement in order to stabilize the trunk to allow effective 28

42 distal mobility (Brooks, 1986; Reed, 1989; Hodges & Richardson, 1997; and Hodges, Cresswell, & Thorstensson, 1998). Hodges and Richardson (1997) recorded electromyographical (EMG) activity from the left transversus abdominus and external oblique in subjects asked to perform hip flexion, abduction and extension movements with a stabilized and contralaterally weight-shifted pelvis. Analysis of EMG recordings of the transversus abdominus and external oblique compared with EMG recordings of the primary muscles involved in the hip motions supported the authors hypothesis that the abdominal muscles are active immediately preceding and during lower extremity movement. Through this EMG data, Hodges and Richardson concluded that contraction of abdominal muscles occurs through feedforward mechanisms dictated by the central nervous system in order to contribute to the maintenance of the position of center of mass over the base of support and the stability of the lumbar spine. A 1998 study by Hodges, Cresswell, and Thorstensson also determined that contraction of the abdominal muscles occurs prior to the initiation of shoulder muscle contractions when subjects were asked to perform rapid shoulder movements, again, as an anticipatory mechanism to promote postural stability and equilibrium. Sahrmann (as cited in Clark, 2002) suggested that if a person has a weak core or if feedforward contraction of the abdominal musculature is disrupted due to a neurological condition, unavoidable patterns of dysfunction, known as serial distortion patterns, will be seen throughout the entire body. These dysfunctional patterns result as the lengthtension relationship of agonists and antagonists of the core and the pelvis is disrupted due to the weakness or decreased neuromuscular control and/or timing of the muscles due to malalignment. If these functional relationships and force couples of the muscles of the 29

43 core and lumbo-pelvic region are not maintained, Sarhmann (as cited in Clark, 2002) further suggested that arthrokinematics in the pelvic girdle and hip region during closed chain lower extremity (LE) motions will then be altered due to the lack of stability at the core. Distal mobility, such as LE motion during ambulation, is then affected due to the lack of proximal stability. Optimal LE stabilization such as during stance phases and acceleration/deceleration requirements such as during swing will be compromised. Therefore, if any of the proximal muscles are weak, the distal extremities will be unable to perform at their optimal level, and ambulation skills will suffer. Strengthening of the trunk and core muscles, promotion of postural and equilibrium reactions, and focus on postural alignment in sitting and stance have long been components of physical therapy treatment plans for pediatric therapists who work with children with neurological conditions affecting postural control. Conventional methods of postural training for pediatric clients have included use of Swiss balls, bolsters, bolster swings, foam rollers, wobble boards, and barrels to encourage postural reactions, sensory-motor stimulation, and core control. Among these, hippotherapy may best be likened to the use of the Swiss ball or bolster swing to promote postural control (Sterba et al., 2002). The Swiss ball was developed in Switzerland in the 1960 s as first a toy, and then soon after was recognized for its value in promoting postural reactions, postural control, balance in sitting, and vestibular and proprioceptive input as a child sat upon it and the ball was either stationary, allowed to move slightly, or was moved by the therapist (Flett, 2003). The potential for three dimensional (3-D) challenges to the child sitting on the ball, including vertical challenges if the child is slightly bounced, provides a wide array 30

44 of input to the child to allow the child to experience motion in three planes and practice and re-organize strategies to adapt to these challenges. The bolster swing can also provide 3-D input as well as a sense of rhythm as the child swings. Both of these pieces of traditional therapy equipment challenge stability in sitting in three planes and are widely accepted to promote and enhance postural control, but neither can impart 3-D movement to the child s pelvis that is so like the normal 3-D movement of the pelvis during gait that HPOT can. The bond between the child and the horse, the warmth of the horse, and the socialization that often occurs during group HPOT sessions only further add to the benefits and the sensory-motor stimulation that horseback riding can provide to the participant that sitting on a Swiss ball or a bolster swing cannot (Sterba et al., 2002; MacKinnon et al., 1995a; Bertoti, 1988; All et al. 1999; Rodanelli & Dunst, 2003). The variability in the horse s gait as he is led at faster or slower paces or made to change direction, as well, contributes to the development of feed-forward and feedback responses necessary to control for unexpected perturbations in sitting. According to Bradley (1995) learning to predict (feed-forward reactions) and control for (feedback reactions) unexpected perturbations lead to determinations of postural requirements for a selected task. These reactions are said to be refined in children of ages four to ten, and in those children with decreased postural control, these factors of decreased feedforward and feedback strategies and responses may be limiting factors in their control (Bradley, 1995). In fact, it has been determined that when children with Down Syndrome are exposed to perturbations in static stance, proper postural responses do occur, but they occur after a latency period as compared to healthy children (Shumway-Cook & 31

45 Woolacott, 1985). Thus, even if the proper feedback and feedforward responses are elicited in children with neurological diagnoses, the timing that is so critical may be disrupted and may be the limiting factor in postural control as related to neuromuscular responses (Shumway-Cook & Woolacott, 1985; Bradley, 1995). A main component in the development of normal gait is the ability to maintain and control stability in stance (Gage, 1991). A prerequisite, or rate controller, to stability in stance and the development of ambulation skills is the ability to maintain postural control in sitting which is developed within the first nine months (Stout, 1995). Thelen, Ulrich, and Jensen (1989) proposed that in order to achieve the milestone of independent walking, children must display sufficient strength in the trunk to maintain erect posture on a base of support that is inherently smaller than a base of support present during sitting, creeping, or cruising. Additionally, control of the trunk and stability at the pelvis and hip is a necessity as a child changes the single-leg base of support from one side to the other with each step (Clark & Phillips, 1993). Children with diagnoses of neurological conditions such as mental retardation/developmental delay (MRDD), CP, and traumatic brain injury (TBI) often have associated impairments affecting motor development and control (McEwen, 1995; Olney & Wright, 1995; Phillips, 1995; Rosenbaum, 2007). Delays in sitting postural control may be seen in younger children, which then may lead to delays and impairments in stance and gait as the child grows. These delays may be due to factors such as decreased strength, sensory disturbances, decreased neuromuscular control, impaired equilibrium reactions, and/or impaired coordination of voluntary muscle contractions (McEwen, 1995; Olney & Wright, 1995; Phillips, 1995; Wiley & Damiano, 1998). 32

46 Children with diagnoses of CP have been identified as having decreased anticipatory or feedforward activation of postural muscles when attempting postural correction (Nasher, Shumway-Cook, & Marin, 1983). Additionally, children with diagnoses of MRDD, CP, and/or TBI or other neurological diagnoses may present with secondary impairments such as hyper- or hypotonia, exaggerated or dampened reflexes, joint contractures, dyskinesia, ataxia, decreased endurance, learning disabilities, cognitive delays, and behavioral issues, all of which may contribute to disturbances in postural control and therefore gait (Kramer & MacPhail, 1994; McEwen, 1995; Olney & Wright, 1995; Phillips, 1995; Johnson, Damiano, & Abel, 1997; Wiley & Damiano, 1998; Berger, 1998). In some children, especially those diagnosed with CP or TBI, abnormal reflexes may be present. Persistence of abnormal reflexes inhibits normal functional development (Gotts, 1972). Previous research in HPOT and TR has attempted to document effects on several of these impairments in children, the majority of which presented with spastic CP. Positive effects on postural control (Bertoti, 1988), tone (Benda, et al., 2003; Cherng et al., 2004), energy expenditure (McGibbon et al., 1998), social-emotional behaviors (Rolandelli and Dunst, 2003), balance (Biery et al., 1989), speech and language abilities (Macauley & Gutierrez, 2004), range of motion (Quint & Toomey, 1998), gait (Low, et al, 2005), and gross motor function (Haehl, et al. 1999) via HPOT or TR have all been reported; all of which are impairments that have been identified as potential limiting factors in functional tasks in children with neurological diagnoses. 33

47 Normal Pediatric Gait In order to understand and potentially improve impairments that lead to abnormal gait in children with neurological diagnoses, one needs to not only understand the impact of decreased postural control, but one also must understand normal pediatric gait. As in normal adult gait, ambulation in children consists of a repeatable cycle of stance and swing phases on each lower extremity. Stance phase consists of the subdivisions of initial contact, loading response, midstance, terminal stance, and pre-swing which occurs immediately before the toe comes off the ground, or toe-off. The swing phase consists of initial swing, midswing, and terminal swing (Perry, 1992). By examining ROM and joint positioning occurring in each of these subdivisions, one can often visually determine abnormalities in gait that may be due to decreased ROM or strength. Norms for ROM at each of the major joints of the lower extremities, pelvis, and trunk for each subdivision of the gait cycle have been determined for both normal adults (Murray, Drought, & Kory, 1964; Murray, Kory, & Sepic, 1970), and normal children aged one to seven (Sutherland et al., 1988). Ambulation without support usually begins at approximately age one, however the child typically ambulates with high-guard, or flexed and abducted upper extremities, a wide base of support (step width), shortened steps and stride, fast cadence (steps per minute), increased hip external rotation, slightly decreased hip flexion and extension, and absence of heel strike at initial contact (Sutherland, Olshen, Cooper & Woo, 1980). As the child ages, lower extremity and trunk motions and many temporal-spatial variables mature and stabilize. Many experts acknowledge that most gait kinematic variables stabilize and reach adult-like values by the age of three and a half to age four 34

48 (Sutherland et al., 1980; Biafore et al., 1991). Ounpuu, Gage, and Davis support this view in their 1991 study acknowledging that children reach maturity in kinematic joint patterns at the pelvis, hip, knee, and ankle by at least as early as five years. By age three and a half, children begin to demonstrate a heel to toe gait that is quite similar to that of an adult (Sutherland et al., 1980). Also, around this age, the percent of time spent in single limb stance approaches the normal adult percentage of 38%. This indicates the ability of the child to sufficiently stabilize and balance the body as it passes over the stance limb while ensuring adequate time for the opposite limb to complete its swing phase (Sutherland et al., 1980). Step width is another kinematic variable that reaches stabilization and an adultlike value by age three and a half to age four. Children younger than three years old walk with a wide base of support in order to promote maximal stability. As a child approaches age four, the step width decreases to the adult-like average of eight cm (Murray, 1964; Sutherland et al., 1980). This indicates increased motor control and coordination during ambulation as the child is able to maintain balance over a smaller base of support (Sutherland et al., 1980). Lower extremity, pelvic, and trunk ranges of motion during ambulation also appear to stabilize and reach normal adult values by the age of four (Sutherland et al., 1980; Ganley & Powers, 2005). By examining joint positioning at initial contact and at the end of pre-swing, also known as toe-off, (which corresponds to loading response of the contralateral limb), one can identify possible deviations from normal during these subdivisions (Sartor, Alderink, Greenwald, & Elder 1999). Typical adult ranges of motion for the hips and pelvis during initial contact and toe-off, as well as typical total 35

49 ROM for each joint throughout the stance phase as determined by Murray et al. (1964 & 1970) and Perry (1992) and compiled and reported by Perry (1992) are presented in Table 1. Table 1: Normal Range of Motion Measurements at Initial Contact, Toe-off, and Throughout Stance Joint and Plane of Position at Initial Position at Toe-off a Total Joint ROM during Motion Contact a Stance a Pelvis (sagittal) 0 º 0 º 4 º Pelvis (frontal) 0 º 5 º (inferior) 5 º Pelvis (transverse) 5 º (anterior) ~ 0 º 10 º Hip (sagittal) 30 º (flexion) 0 º 40 º Hip (frontal) 10 º (adduction) 0 º 15 º Hip (transverse) 0 º 4 º (external rotation) 8 º a. Joint ROM representative of and in reference to a unilateral lower limb Trunk deviations in all three planes also occur during ambulation, as the center of mass (COM) moves in a smooth sinusoidal curve superiorly/inferiorly and from side to side (Norkin & Levangie, 1992). Movement of the COM, which is theoretically located just anterior to the second sacral vertebra, deviates laterally as the body shifts rhythmically over each supporting limb during stance, and deviates superiorly as the body vaults over the stance limb, and then inferiorly during double limb support phases of initial contact and terminal stance (Norkin & Levangie, 1992; Perry, 1992). Energy expenditure is directly related to the amount of movement of the COM during ambulation (Perry, 1992). Saunders, Inman, and Eberhart s 1953 study (as cited in Perry, 1995) concluded that normal excursion of the movement of the COM during ambulation is approximately 2 cm to the left and right and 2 cm vertically. 36

50 Sartor, Alderink, Greenwald, and Elder (1999) attempted to quantify movement of the trunk in relationship to the pelvis during gait in terms of degrees rather than cm in their study, and also to relate the movements of the trunk to subdivisions of the gait cycle. Their findings regarding trunk movements and the positions at initial contact and toe-off, as well as total trunk motion over the stance phase are found in Table 2. Table 2: Trunk Movement at Initial Contact, Toe-off, and Throughout Stance Trunk Plane of Position at Initial Position at Toe-off a Total Joint ROM during Motion Contact a Stance a Sagittal 5º (extension) ~5 º (extension) ~2 º Frontal 1 º (ipsalateral flexion) ~ 0 º ~ 6 º Transverse 8 º (posterior) ~ 6º (anterior) ~ 14º a. Joint ROM representative of and in reference to a unilateral lower limb Excursion of the trunk and pelvis greater than these normal values may indicate pathologies that affect the normal ranges of motion of the limbs and/or motor control that contribute to the smooth and rather limited movement of the COM. Saunders, Inman, & Eberhart suggested (as cited in Perry, 1995) that larger than normal COM excursion also directly relates to energy expenditure during ambulation. Movements of the trunk and/or pelvis that are less than normal may lead to reduced step length and may also contribute to increased energy expenditure as the body compensates (Sartor, Alderink, Greenwald, & Elder 1999). Unlike the variables described previously, the temporal-spatial variables of step length, stride length, cadence, and velocity continue to mature past the age of four, and do not reach adult-like values until skeletal growth is complete. Because step length is 37

51 related to lower limb length, step length, and in association, stride length, will continue to increase until the limbs have fully matured and full body height is attained. Sutherland, et al. (1980) reported that stride length increases rapidly from initiation of walking until about age four, and then continues to increase until maturity is reached, although at a slower rate. Others have reported that limb length and body height also affect cadence and velocity during ambulation (Murray, Drought, & Kory, 1964; Sutherland, Olshen, Biden, & Wyatt, 1988; Beck, Andriacchi, Kuo, Fermier, & Galante, 1981; Wheelwright, Minns, Law, & Elton, 1993). Cadence in children tends to decrease with age, with an average cadence of 176 steps per minute (spm) in one year old children which then drops sharply to an average of 152 as the child approaches age four (Sutherland et al., 1988). Despite decreasing cadence in children as they approach age four, velocity increases because it is the product of cadence and step length, and step length is increasing in these children as their lower extremities grow (Sutherland et al., 1980; Sutherland, 1997). Children at the age of one ambulate with an average velocity of 60 cm/s and a step length of 20 cm, while children aged four display an average velocity of 99 cm/s and a step length of 39 cm (Sutherland et al., 1988). Therefore, step length, cadence, and velocity are dependent on body height and limb length, and do not stabilize until full skeletal growth is achieved (Sutherland, 1997). Mean temporal-spatial values for main kinematic variables of gait in children aged three and one half to seven as determined by Sutherland et al. (1988) are presented in Table 3. 38

52 Table 3: Mean Temporal-Spatial Values for Children Aged Three and One Half to Seven Age Cadence(spm) Velocity(cm/s) Step length(cm) Stride Length(cm) Stansfield and colleagues (2001) performed a longitudinal study to examine the relationship of age and ambulation speed on ground reaction forces in children. Over the course of the study, 26 healthy five year old children were tested for seven consecutive years in a gait analysis laboratory using 3-D gait analysis. Along with information regarding ground reaction forces at self selected speeds, data on cadence and velocity were also collected each year. Because the norms that Sutherland et al. (1988) determined for kinematic variables end at age seven, norms for cadence and velocity in children aged eight to twelve from Stansfield s (2001) study were used for comparison in the current study. These data were garnered from an average of gait trials per age group and these norms are presented in Table 4. Table 4: Mean Temporal-spatial Values for Children Aged Eight to Twelve Age Cadence(spm) Velocity(cm/s)

53 Temporal-spatial variable values continue to approach normal adult values as children age and grow. The average adult male ambulates with a cadence of 110 spm and a velocity of 137 cm/s. (Finley & Cody, 1970). Adult women display a slightly faster cadence of 116 spm. (Inman, Ralston, & Todd, 1981). Step length average in men is 72 cm, with a stride length mean of 144cm. (Neumann, 2002). Assessment of HPOT and TR Effects on Gait and Function A majority of studies examining the effects on function have included assessments of function often utilized in therapy clinics. Two of these, the Pediatric Evaluation of Disability Inventory (PEDI) (Haley, Coster, & Ludlow, et al., 1992). and the Gross Motor Functional Measure (GMFM) (Palisano, Rosenbaum, & Walter, et al., 1997) have categories within them that also serve as assessors of gait. Studies utilizing the GMFM have included those studies by Winchester et al. (2002) and Casady & Nichols-Larsen (2004) among several others already discussed. As mentioned, however, the GMFM is a tool used to assess children with CP only, and the PEDI has limitations on age. Both tools are also somewhat subjective as they are rated by therapists or via feedback from parents or guardians. More objective gait assessments include the use of the GAITRite system which was utilized in HPOT and/or TR studies by Whitmore & Aldridge (2007) and Low et al. (2005). However, this system cannot provide important information on the ROM of the extremities and trunk or on kinetic variables such as joint moments or muscle firing patterns that occur over the gait cycle. This information, however, along with many other kinematic variables such as cadence and step length can be performed via the use of a 3-D computerized gait analysis system. 40

54 During 3-D gait analysis, digital cameras track movement of retroflective markers placed over bony landmarks of subjects. These markers are tracked in all three planes during movement and this information is then utilized to generate 3-D figures of the subject via special software. Numerical values for the kinematic variables can be produced and a series of graphs and spread sheets showing range of motion of the major joints of the LE and UE as well as the trunk and pelvis in three planes can be produced. Used in conjunction with surface electromyography (semg) and force platforms, this system can also provide information on muscle activity, joint moments, and ground reaction forces of the subject during ambulation. No studies were found by this author that utilized a 3-D gait analysis system in conjunction with force platform and semg instrumentation to analyze gait post HPOT or TR intervention. Summary In summary, HPOT has been a treatment intervention used for rehabilitation of children with neurological deficits for over forty years. Several studies have demonstrated the possible positive effects of this strategy on areas such as posture and balance. Theoretically, the impact that HPOT may have on promoting improved proximal postural control may also translate to improvement distally during functional movement such as ambulation. A few studies have attempted to quantify improvements in ambulation post HPOT intervention; however, more objective data are needed to associate HPOT with improved postural control and ultimately improvements in ambulation in children with deficits in ambulation due to neurological diagnoses and impairments. 41

55 Chapter Three Methodology This chapter outlines the procedures and methods used in this pre test/post test quasi-experimental study. Institutional Review Board (IRB) approval was obtained through The University of Toledo, The University of Findlay, and St. Vincent Mercy Medical Center of Toledo. Copies of these documents can be found in Appendix A. Subjects Eleven pediatric subjects (mean age 7.9 ± 2.7 years; ht ± 22.5 cm; wt ± 7.9 kg) with neurological disorders that have resulted in impairments in ambulation and gross motor control in standing were recruited to participate in this study. The sample consisted of five females and six males and diagnoses included, spastic diplegic or hemiplegic cerebral palsy, traumatic brain injury (TBI), cerebrovascular accident (CVA), and Guillain Barre. Demographics of the subjects can be found in Table 5. 42

56 Table 5: Subject Demographics Subject Age Gender Height(cm) Weight(kg) Diagnosis 1 8 Male Brain Injury 2 5 Female Guillain Barre 3 11 Female Spastic Diplegia 4 8 Male Spastic Hemiplegia 5 5 Male Spastic Diplegia 6 9 Male Spastic Diplegia 7 9 Male Spastic Diplegia 8 9 Male Guillain Barre 9 12 Female Spastic Hemiplegia 10 5 Female Spastic Diplegia 11 3 Female CVA Recruitment of these children occurred via snowball and convenience sampling through contact with physical and occupational therapists who provide hippotherapy via the St. Vincent Mercy Medical Center hippotherapy program. The rationale and objectives of the research were explained to these healthcare professionals and they were asked to identify potential patients who would fit the inclusion criteria. Inclusion criteria included: physician approval to ride a horse, age in between 3-12 years, neurological pathology affecting ambulation and gross motor control in standing as determined by physical therapy (PT) or occupational therapy (OT) evaluation, ability to ambulate a minimum of 30 feet with or without assistive device, and passive bilateral hip abduction to at least 20 degrees in the sitting position. Exclusion criteria included: cognitive or attentional disabilities which would limit involvement in HPOT and/or gait analysis sessions, medical complications such as seizures which could increase risk of injury 43

57 during HPOT including those serious health conditions on the NARHA list of contraindications (NARHA, 2005), and orthopedic surgery within the past six months. Once the healthcare professionals identified potential subjects, the subjects parents or guardians were given basic verbal and/or written information on the study and contact information of the primary researcher, and were asked to contact the researcher if they and their children were interested in participating in the study. Once contact was initiated by the parents or guardians, the researcher then verbally explained the study in more detail, and confirmed inclusion/exclusion criteria. Gait Analysis Protocol and Instrumentation Within two weeks of the initiation of the ten week HPOT session, the subjects reported to the Applied Biomechanics Laboratory (UTABL) in the Health and Human Services building on the campus of the University of Toledo (UT). Subjects and parents or legal guardians were informed of the basis and expectations of the study verbally in layman s and age-appropriate terminology, and parents or legal guardians were asked to sign a written informed consent form after verbal and written explanations of the study were presented to them. Children who could sign their names were also asked to sign an assent form. Copies of consent/assent forms can be found in Appendix B. After collection of informed consent, demographic and descriptive information about each subject, such as age, height, weight, and diagnosis for each subject was collected on a basic intake form. The intake form can be found in Appendix C. After subjects measurements were completed, self-sticking, disposable, pregelled, Ag-Ag-Cl dual surface electrodes (Noraxon U.S.A., Inc., Scottsdale, AZ) were placed over the distal 1/3 of eight LE and trunk muscles on one side of the subjects 44

58 bodies to allow acquisition of surface electromyographic (semg) (Noraxon U.S.A., Inc., Scottsdale, AZ) information during ambulation. For all subjects, the more affected side according to subject and/or parent, was chosen as the side of the body on which to apply the electrodes, and the same researcher placed all pre- and post test electrodes on the subjects after thoroughly cleansing the skin with alcohol. The muscles monitored included: lumbar erector spinae, rectus abdominus, external oblique, gluteus maximus, gluteus medius, hamstring group, adductor group, and quadriceps femoris. This semg information was gathered for use in future studies, and was not analyzed for the current study. Concurrently with semg, 22 retroflective markers (Motion Analysis Corp., Santa Rosa, CA) were placed on anatomical landmarks according to the full body Helen Hayes Marker Set pattern (Kadaba et al, 1989). A list of marker locations can be found in Appendix D. Figure 1 shows a subject with markers and electrodes in place. Figure 1. Subject with markers and electrodes in place for ambulation trials 45

59 During trials, a three-dimensional (3-D) motion capture system (Motion Analysis Corporation, Santa Rosa, CA) was used to track the movements of the subjects limbs and trunks as they ambulated at self-selected speeds. Eight synchronized Falcon High Resolution digital cameras (Motion Analysis Corporation, Santa Rosa, CA), were used for capturing the movements of each of the retroflective markers on the subjects. To allow for accurate conversion of the marker movements into 3-D coordinate values, calibration of the motion analysis system was performed prior to the data collection session of the first subject. A metal cube with eight retroflective markers attached in specific locations was placed in the center of the testing area and the cameras captured data regarding the location of these markers at 60 Hz for one second. After this, an investigator holding and waving a metal wand with three precisely spaced retroflective markers attached walked throughout the testing area to expand the calibration volume. The investigator walked the wand around the testing area for 90 seconds while data was sampled at 60 Hz. Additional calibration sessions were periodically performed during the course of the study to ensure accuracy of marker movement conversion into 3-D coordinates. After calibration, data were sampled at 60 Hz during subject static and ambulation trials. Data collection periods for each ambulation trial were between 5 and 10 seconds depending on the ambulation velocity of each child and to allow the subjects to ambulate the length of the testing area or approximately 20 feet. For each trial, a minimum of at least one full gait cycle was captured. Subjects performed an average of 14 barefoot trials per testing session. EVaRT 7.0 software (Motion Analysis Corporation, Santa Rosa, CA) was used for video and analog data acquisition and 46

60 processing. Data were saved on a Dell computer hard drive (Dell, Round Rock, TX) as binary files and were eventually exported to Orthotrak software (Motion Analysis Corporation, Santa Rosa, CA) for quantification. Data on trunk, pelvis, and hip positions at initial contact (IC) and toe off (TO) of each LE as well as total ROM over the stance phase were gathered and processed along with information on cadence, velocity, step width, and stride length during ambulation. In addition to the acquisition of information regarding joint and segment movement via 3-D videography and muscular activity via semg during ambulation trials, two force platforms (AMTI, Watertown, MA) imbedded and camouflaged in the walkway allowed simultaneous acquisition of information regarding joint moments during a gait cycle. Each forceplate measured 50.8 x 46.4 cm and data were collected at a frequency of 960 Hz. If a foot strike of either lower extremity occurred on either of the force plates during an ambulation trial, it was noted by a research assistant. This information was also collected for analysis in the future. Figure 2 shows the UTABL set up that was used during data collection including camera and force plate locations. 47

61 Figure 2. Set up of UTABL during pre and post testing gait analysis. Post testing gait analysis for all subjects was performed within two weeks after the children had completed their ten sessions of HPOT and was performed in the same manner as pre testing. An average of 16 gait trials was performed by subjects at post testing. Therapeutic Interventions Although each child is an individual with individual needs and varying levels of involvement, many aspects of HPOT treatment interventions are similar among children with neurological diagnoses. Interventions often include the focus on postural stability in sitting in various positions, general range of motion exercises for the upper and lower extremities, balance training in static and dynamic sitting, and functional task training such as reaching in various directions for items while riding. All children had personalized plans of care (POC) based on the PT and/or OT evaluations, but focus on 48