Low back pain in athletes requires unique rehab approach

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1 UBM logo BioMechanics November 2004 spacer Printable Version spacer Low back pain in athletes requires unique rehab approach By: Michael Higgins, PhD, ATC, PT Many athletes sustain low back injuries that cause them to lose hours of practice and competition. Additionally, many athletes unknowingly put their backs at risk during daily training. Healthcare professionals can provide sound research-based exercise programs that help reduce the occurrence of injuries in this population. Exercise programs for the low back should enhance strength, range of motion, and, most important, endurance of the spinal stabilizers or "core muscles." Sound programs must also incorporate appropriate motor control patterns for specific activities and ways to educate an athlete about proper motor patterns. It is important to address all of the above principles-not just one or two of them-in a routine to reduce strain on and compression of the low back during activity. Practitioners need to be aware of urban legends that have been perpetuated over the years, such as: - increasing lumbar range of motion reduces back pain; - performing bent-knee sit-ups will reduce the muscle activation of the psoas and strengthen the abdominal muscles; - leg raises concentrate on the lower portion of the abdominal muscles; - strength of low back muscles is the most important factor in reducing the risk of low back injury; and - training the back with a traditional strength training program is optimal. Research is demonstrating that many of these recommendations either add more stress to the spine or simply do not accomplish the intended goal. In fact, research has shown that people who have greater range of motion of the spine have a greater risk of future back problems.1 This is because the lumbar stabilizers are frequently not strong enough to control the excessive motion. The spine is at greater risk of injury at the end ranges of motion, when the stabilizing muscles have the least amount of control. Sit-ups should not be performed by any athlete, because they replicate potential injury mechanisms by increasing compression of the lumbar spine and disks.2 Bent-knee sit-ups should not be performed either, because in this position, the psoas actually have higher activation levels due to the fact that hip flexion torque has to come from them.2,3 Crunches will allow the athlete to strengthen trunk flexors without increasing spinal compressive forces. 1 of 6 8/6/08 4:40 PM

2 Many practitioners believe that leg raises isolate and/or emphasize the lower abdominal region. This has been proven to be untrue, since all sections of the rectus abdominis are activated similarly when torque is generated by the trunk flexors.3 Leg raises also increase psoas activation, which in turn increases spine compression. Finally, it has been noted that there is a poor association between strength of the lumbar stabilizers and spinal health.4-6 Endurance of the lumbar stabilizers is potentially the most important aspect of maintaining and preventing lumbar pain. Motor control is important for spine stability, and motor control errors resulting in improper muscle forces increase with fatigue or reduced endurance.1,6,7 It has been postulated that improper muscle forces resulting from fatigue put the athlete at risk for low back injury.1,6,7 Traditional weight training protocols that focus on strength only are most likely not applicable to the lumbar stabilizers because strength is less important than endurance for lumbar health. Stabilizing system The spine's stabilizing system has three components. The passive component comprises the vertebrae, disks, and ligaments. The active component incorporates the muscles and tendons that apply force to the spine. Finally, the neural component communicates with both the active and passive subsystems. To be considered a trunk stabilizer, a structure must attach directly to the vertebrae. The importance of each spinal stabilizer varies with activity depending on the direction of spinal motion.6 Active spinal stabilizing muscles can be categorized as unisegmental or multisegmental. Unisegmental muscles serve primarily as force transducers, which provide feedback on spinal position to the major force-producing muscles. These unisegmental muscles also work in close conjunction with the nervous system to provide stability to the spine. Unisegmental muscles include the intertransversi, interspinalis, and the multifidus muscles. The rotators and intertransversi have very small cross-sectional areas and contribute very little to spinal rotation. According to McGill, the small rotators have very little to do with spinal rotary movement. Rotation is produced mainly by the obliques.6,7 Multisegmental muscles produce and control spinal motion. Transversus abdominis, rectus abdominis, lumbar erector spinae, quadratus lumborum, and obliquus externus and internus are examples of multisegmental muscles. All trunk muscles play important roles in providing stability for the spine during activity. The rectus abdominis is the major trunk flexor. All sections of the rectus are activated together and no functional separation appears to exist between upper and lower abdominals.3 The transversus abdominis provides stability and should be activated by an abdominal brace (a contraction of the abdominal muscles when the abdomen is not sucked in or pushed out), rather than abdominal hollowing (sucking in the gut), because when activated in isolation-when the abdomen is hollowed-its base of support for spine stabilization is narrowed. In contrast, an abdominal brace activates the obliques in conjunction with the transversus, and the cross-bracing strut can provide stability in all planes of movement.8 The obliques and transversus abdominis create "hoop stresses" and stiffness that assist in spinal stability. 9 A continuation of the transversus abdominis, internal and external obliques, and rectus abdominis forms a muscular "hoop" around the body. Activating that hoop increases spinal stability. The obliques are also regionally activated and show increased activity when the spine is axially compressed. This is important because different sections of the obliques will have different activation levels with different exercises.6,7 The quadratus lumborum acts as a buttress against lateral instability and as such is also an important muscle in spinal stability. The major trunk extensors are the muscles in the erector spinae group. The healthcare professional must use caution when prescribing exercises to increase erector spinae strength, however, because of the risk of increased spinal compression.2,8 Preventing low back injuries in atheletes When designing a program for athletes, there are several questions a practitioner should ask. Will free weights or machine exercise better replicate a specific sport task? Is strength the main requirement for a particular task? Is spine ROM a requirement, or does the spine need to stiffen to transmit forces from the upper body through the legs to the ground?6 With the answers to these questions in mind, the following program guidelines should be utilized: 2 of 6 8/6/08 4:40 PM

3 - Stabilization exercises are most beneficial when performed daily.5 Training daily helps stimulate sound patterns of activation and also increases endurance in the muscles that are utilized in spinal stabilization. - Traditional strength training routines for other body parts are not applicable to the spinal stabilizers. If an exercise is painful for an athlete to perform, then it should be stopped because it may put undesirable compressive or shear loads on the spine. Large one-time power outputs are not how spinal stabilizers are used. Rather, they must provide feedback and stability throughout the course of an activity. - Cardiovascular health is important for low back health and endurance. Aerobic conditioning seems to enhance the effects of low back exercise programs.10,11 - Strength training should not be emphasized at the expense of endurance training, because endurance of the spinal stabilizers has been shown to play a role in prevention of low back pain Increasing endurance of the spinal stabilizers as well as the total body is important. It is also important to train the back muscles utilized in sport-specific tasks for endurance. - Functional ROM spinal exercise should be avoided early in the day due to the increase in disk pressures.13 Athletes should warm up sufficiently before exercising in the morning. - Normal breathing during stabilization exercises helps to maintain abdominal activation for spinal stability.6,7,12 - Motion and muscular activation patterns should be repeated (grooved) to prepare the spine for athletic performance, according to our clinical experience. Groove these specific motion patterns to reduce loads on the spine while preparing for and participating in competition. Sport-specific training should be incorporated to help groove the desired patterns for each athlete. Cocontracting core muscles will help increase spinal stability. - To be effective, grooving of spinal stabilization patterns should be independent of lung function during exercise.6,7,14,15 This ensures that the athlete can stabilize the spine during inhalation or exhalation. It is up to the healthcare professional to determine whether a player has deficits that need to be addressed during the exercise program. - Repetitive activities in positions associated with high disk pressures should be avoided. Prolonged bench sitting in a flexed position, for example, increases pressure on the disks and could potentially lead to injury. It has been documented that the benefits of a warm-up routine for the spine are negated by 20 minutes of bench sitting.16 Athletes should rewarm up their backs before returning to play and could benefit from sitting in chairs with angulated seats. - Flexible hips and knees reduce stress on spinal structures. The athlete must be able to reduce the forces on the spine by absorbing force through the hips. It is important to ensure that the hip muscles are functioning properly when lifting is required. Squatting increases the force on the erector spinae and hamstrings, thereby increasing compressive forces on the spine when the hip muscles are not utilized. Proper lifting with spine-sparing techniques will utilize a powerful hip muscle group, such as the gluteals, to extend the hip from a squat and thereby reduce the force on the spine. Clinical application Three easy endurance tests can be used to determine flexor, extensor, and oblique muscle deficits. The side bridge test assesses lateral musculature, the flexion test assesses the trunk flexors, and the extensor text assesses the trunk extensors. Description of the endurance tests, the norms for endurance tests, and ratios that may show weakness in the spinal stabilizers can be found in previous research articles.14,17 A preventive exercise program promoting good spinal health should incorporate one warm-up, "cat/camel," and the three exercises referred to as McGill's Big Three (Figure 1): curl up, side bridge (plank), and "bird dog" exercises.6,7,18-23 All of these exercises stimulate activation in the target muscles without compressing or putting unnecessary stress or compression on the lumbar spine. When performing these exercises it is important for the athlete to breathe normally, hold the contraction for approximately eight seconds, maintain a neutral spine position, and use an abdominal brace.6,7,18-23 When designing an exercise program for the back, the practitioner should emphasize not only joint stability but 3 of 6 8/6/08 4:40 PM

4 whole-body stability as well. This helps with grooving proper motor patterns, which will allow athletes to better protect their backs in awkward positions. Central trunk stability gives the extremities a solid "core" to work from. An advanced exercise program for the more competitive athlete should incorporate exercises that focus on increasing the endurance, strength, and power of the core muscles. During all of the following exercises it is critical that the athlete breathe normally, keep a neutral spine, and use impeccable form. Sample exercises include the lat pull-down, (standing lat pull-down for basketball players) (Figure 2), the overhead squat, the reverse curl up, medicine ball lifts, cable exercises such as pull-throughs (Figure 3), weighted lunges (all directions), rotation exercises (dumbbell rows), chops and lifts with tubing, one-legged leg presses, star pattern exercises, squats with chains or bands, physioball exercises, plyometrics, and Romanian dead lifts. Athletes should progress to using resistance with sport-specific exercises requiring activation of spinal stabilizers to groove motion and motor patterns. More detail on specific exercises can be found in references 19 through 23. It is important that the athlete realize the benefit of the abdominal brace during activity. It requires only about 10% of maximum voluntary contraction for the core muscles to provide stability to the spine.21 A sample exercise program that can be utilized during a practice session is described in Table 2. The athletic trainer may substitute any variation of these exercises as he or she sees fit. To increase the difficulty of these exercises, increase the hold time and add an abdominal brace before and during the exercise. Performing stabilization exercises during periods of elevated cardiovascular function requires the athlete to use the same muscles to stabilize the spine and assist with breathing. This trains the athlete to cocontract the abdominal wall musculature (stabilizing the spine) during periods of vigorous exercise. With an understanding of the functional anatomy of the lumbar spine and its surrounding musculature and sound knowledge of the lumbar spine and the muscles that stabilize it, the healthcare professional can provide individualized exercise programs for athletes in a wide variety of sports. But in designing such programs, it is important to remember that exercises that work well with one athlete may not benefit another. Athletic trainers must consider strength, endurance, and neuromuscular factors when designing low back routines. Michael Higgins, PhD, ATC, PT, is athletic training education program director at Towson University in Towson, MD. References 1. Biering-Sorensen F. Physical measurements as risk indicators for low-back trouble over a one-year period. Spine 1984;9(2): Juker D, McGill S, Kropf P, Steffen T. Quantitative intramuscular myoelectric activity of lumbar portions of psoas and the abdominal wall during a wide variety of tasks. Med Sci Sports Exerc 1998;30(2): Lehman G, McGill SM. Quantification of the differences in electromyographic activity magnitude between the upper and lower portions of the rectus abdominis muscle during selected trunk exercises. Phys Ther 2001;81(5): Alaranta H, Louto S, Heliovaara M, Hurri H, et al. Static back endurance and the risk of low back pain. Clin Biomech 1995;10(6): Mayer TG, Gatchel RJ, Kishino N, et al. Objective assessment of spine function following industrial injury: a prospective study with comparison group and one-year follow-up. Spine 1985;10(6): McGill SM. Low back disorders: evidence-based prevention and rehabilitation. Champaign, IL: Human Kinetics Publishers, McGill SM. Low back stability: From formal description to issues for performance and Rehabilitation. Exerc Sport Sci Rev 2001;29(1): Juker D, McGill SM, Kropf P. Quantitative intramuscular myoelectric activity of lumbar portions of psoas and the abdominal wall during cycling. J Appl Biomech 1998;14(4): Porterfield JA, DeRosa C. Mechanical low back pain: perspectives in functional anatomy. Philadelphia: W.B. 4 of 6 8/6/08 4:40 PM

5 Saunders, Nutter P. Aerobic exercise in the treatment and prevention of low back pain. Occ Med 1988;3(1): Callaghan JP, Patla AF, McGill SM. Low back three-dimensional joint forces, kinematics and kinetics during walking. Clin Biomech 1999;14(3): Leino P, Aro S, Hasan J. Trunk muscle function and low back disorders. J Chron Disease 1987;40(4): Snook SH, Webster BS, McGarry RW, et al. The reduction of chronic nonspecific low back pain through the control of early morning lumbar flexion: a randomized controlled trial. Spine 1998;23(23): McGill SM, Grenier S, Bluhm M, et al. Previous history of LBP with work loss is related to lingering effects in biomechanical, physiological, personal, and psychosocial characteristics. Ergonomics 2003;46(7): Axler CT, McGill, SM. Low back loads over a variety of abdominal exercises: searching for the safest abdominal challenge. Med Sci Sports Exerc 1997;26(6): Green J, Grenier S, McGill SM. Low back stiffness is altered with warm-up and bench rest: implications for athletes. Med Sci Sports Exerc 2002;34(7): McGill SM, Childs A, Liebenson C. Endurance times for stabilization exercises: clinical targets for testing and training from a normal database. Arch Phys Med Rehab 1999;80(8): McGill SM. Low back exercises: evidence for improving exercise regimens. Phys Ther 1998;78(7): Vera-Garcia FJ, Grenier SG, McGill SM. Abdominal response during curl-ups on both stable and labile surfaces. Phys Ther 2000;80(6): Callaghan JP, Gunning JL, McGill SM. Relationship between lumbar spine load and muscle activity during extensor exercises. Phys Ther 1998;78(1): Cholewicki J, Panjabi MM, Khachatryan A. Stabilizing function of trunk flexor-extensor muscles around a neutral spine posture. Spine 1997;22(19): Danneels LA, Vanderstraeten GG, Cambier DC, et al. Effects of three different training modalities on the cross sectional area of the lumbar multifidus muscle in patients with chronic low back pain. Br J Sports Med 2001;35(3): McGill SM. Ultimate back fitness and performance. Waterloo, ON: Wabuno Publishers, Table 1. Endurance tests Flexion test (tests abdominal muscles [rectus]) - Hips and knees at 90¼ angle; feet held in place by an examiner or strap - Trunk rests against a board angled at 60¼ off the horizontal - Board is pulled back 4 inches - Failure occurs when any part of the back touches the board Extension test (tests back muscles [erector]) - Position patient prone with trunk off the end of a plinth, with the end of the plinth at approximately the ASIS level 5 of 6 8/6/08 4:40 PM

6 - Hold trunk in horizontal position with feet strapped to the table - Failure occurs when upper body drops from horizontal Side bridge test (tests lateral muscles [obliques]) - Start in side-lying position - Top foot placed in front of bottom foot - Support upper body on bent arm - Lift hips until body is in a straight line position - Failure occurs when straight line position is lost and hip touches table CMP Media LLC, a United Business Media company Privacy Statement - Terms of Service 6 of 6 8/6/08 4:40 PM