Ry Adams and Matt Anti. lived. The exercise and sport science world is extremely fascinating, and it is also still very young.

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1 CWHP Health & Fitness Journal (Spring 2015 Issue) 1 Ry Adams and Matt Anti Abstract Constant technological advancements and medical strategies are changing the way active lives are lived. The exercise and sport science world is extremely fascinating, and it is also still very young. Athletes receive advice from anyone who can get a chance to speak with them, which results in many opinionated tactics and styles. As future kinesiologists and coaches, our goal is to formulate multiple findings and opinions into a systemized journal article. Stretching is very important for the high physical demands of weight lifting, not only for safety but also to achieve peak performance. So what is the best tactic? There may not be a right answer yet, but we plan on formulating a system that follows some of the best insight into this conundrum. Research First and foremost, this article is based on the principles, strategies, and successes of optimal stretching techniques. Although many fields of study are possible, the concentration here is on which pre-exercise stretching technique reserves the most power. Both dynamic stretching and static stretching are analyzed. Dynamic stretching consists of active mobility of a desired muscle through a full range of motion (ROM) in a repetitive pattern. Marching with high knees to the end of the court and back, for example, would warm up ligaments of the lower limbs, but will it exert proficient power? Static stretching consists of a more passive type of stretching, where motion is

2 CWHP Health & Fitness Journal (Spring 2015 Issue) 2 limited and elasticity is tested, truly stretching the muscle to full ROM and holding. Our research is based on studies using these techniques as a pre-workout warm-up. To begin, we would like eliminate the use of any no-stretch techniques. The assumption made by those who promote this idea is that when thrown directly into exercise, with no elongating of the muscle fibers, athletes are more explosive and quick reacting. It is a common misconception that stretching those muscles you are about to work greatly weakens them: The results suggested that (a) static stretching has not been shown to reduce injury risk or muscle soreness; (b) some stretching protocols have demonstrated reduced strength and performance; (c) low-back pain is not correlated to trunk flexibility; (d) cardiorespiratory fitness, muscular fitness, and body composition have been identified to correlate with future health-related benefits, and flexibility has not (Parrott and Xihe, 2013). Think of a rubber band, which is stronger and more elastic before it is stretched and becomes brittle. However, in terms of avoiding injury, it is an ill-educated idea and form of exercise preparation. Therefore, we will be focusing on stretching as a means of a warm-up and a powerincreasing component, and the benefits of each type. We will not be touching on the exact injury prevention, but the fact that warming up puts individuals at less risk of injury. One study analyzed 40-yard-dash sprinting as it is associated with a stretching warm-up, and the subjects run times were not greatly affected by stretching methods (Wallman, Christensen, Perry, & Hoover, 2012). Although they did not waver too much in the aspect of which stretching had the most proficient results, they were slightly different in terms of individual benefits. It is possible that stretching in certain ways fires specific types of muscle tissues, but does not affect the overall performance

3 CWHP Health & Fitness Journal (Spring 2015 Issue) 3 ability of individuals. Therefore, it can be assumed that exercisers will respond differently to varying types of exercises. It is repeated and acknowledged throughout the research that stretching a muscle or ligament will cause a decrease in its full power-exerting ability. This led to a question of which stretching technique reserves the most power, when following a proper stretching routine. It is possible that through static stretching, muscles would become lackadaisical and reach a state of declined reaction: The decrease in the EMG [electromyographic] amplitude of the three muscles studied found in the SG [static group] suggests that the reduction in muscle activation can be a part of the explanation for the reduction in strength performance (Leone et al., 2014). Leone and colleagues (2014) also recorded evidence that static stretching has negative effects on muscle output. Furthermore, unlike other studies, it found no decline in power, and sometimes even an increase in power output, after dynamic stretching. However, this study did find that dynamic stretching can limit power exertion, just not as much as static stretching would. This can be concluded to be a result of the elasticity that is retained throughout dynamic movements. If both styles have some limiting factors, then muscle cells in general must not respond to stretching in terms of power threshold (Leone et al., 2014). Evidence shows that dynamic and static stretching directly impact muscle hypertrophy and atrophy. Being able to understand how these stretches affect muscle cells is vital for us to infer what type of stretching would be most appropriate to limit power loss. Performing stretching exercises dynamic or static has been shown to promote protein synthesis, which is an important

4 CWHP Health & Fitness Journal (Spring 2015 Issue) 4 component of muscle hypertrophy. It has also been observed that stretching exercises can prevent the increase in sarcomeres in muscle fibers that cause muscle atrophy. Muscle fibers adapt to stretching by adding new sarcomeres to their ends, influencing flexibility and total muscle strength (Salvini, Durigan, Peviani, & Russo, 2012). Static stretching that lasts for one minute per repetition with 30 seconds of rest between repetitions was shown to affect genes that are a part of the hypertrophy of the muscle and beneficially control muscle mass systems (Figure 1). On the other hand, stretching for more than 30 minutes per session will negatively affect these genes as well as affect the genes for atrophy (Salvini, Durigan, Peviani, & Russo, 2012). From our research, we now know that doing any stretching for longer than 30 minutes at a time will not only decrease power production, but also lead to a loss in muscle mass and flexibility. Figure 1: Mechanism of cell mechanotransduction. The mechanical stimulus promoted, for example, by stretching is transmitted to the components of extracellular matrix (ECM), which in turn activated membrane integrins. This activation promotes a cascade of intracellular signaling by altering the transcription of muscle-specific genes that regulate the translation of proteins and myofibrillogenesis (adapted from Salvini, 2012).

5 CWHP Health & Fitness Journal (Spring 2015 Issue) 5 In a study based on the maximal isometric peak force (MIPF), time to maximal isometric force (TMIF), and rate of force production (RFP) values before and immediately after the stretching protocols, some very interesting information was found (Leone et al., 2014). First, strength was shown to decrease when exercises were performed immediately following a stretching routine. However, those individuals still reached a maximum around the same time. For this reason, evidence suggests that static stretching is great when an individual has 30 minutes or more before a workout, in order to maintain power yet elongate the muscle fibers. For this reason, although force is obviously decreased during these controlled studies, one thing remains the same: they are training immediately after stretching. Further investigation on the issue requires a look at the time frame in which stretching is facilitated. In other words, optimal force retention could require a time-based study. Figure 2 shows that the maximal isometric force decreased for all of the groups immediately after static stretching, dynamic stretching, and the control group (no stretching). The time to reach their maximal isometric force decreased for the static stretching group and control group, but increased for the dynamic group after they performed their stretches. Rate of force production followed the same trend, as the static group and control group saw their rates increase, while the dynamic group s rate decreased. By looking at these results, it can be seen that in terms of overall explosiveness and force production, static stretching would be the most appropriate form of warmup. Although the control group showed better results, we do not advocate the idea of exercising without any kind of warm-up for health concerns. For this reason, conclusions and opinions must be formed from the given research regarding the optimal stretching for pre-exertion exercise.

6 CWHP Health & Fitness Journal (Spring 2015 Issue) CG SG DG Maximal Isometric Peak Force Figure 2: Maximal isometric peak force (MIPF) before and immediately after the stretching protocols (SG, static group; DG, dynamic group; CG, control group; Orange is post-stretching) Adapted from Leone et al., Conclusion Conflicting views are expected, and in a sense cherished, in all fields of exercise physiology. In terms of limiting power loss from stretching techniques, the opinions are widespread. One study, found to be reliable and accurate, reached the conclusion that stretching should be administered throughout the day or post-exercise, in order to elongate the muscle tissues and assist reconstruction (Costa, Herda, Herda, & Cramer, 2014). Although it is true that no stretching retains power by eliminating atrophy, the focus is on individuals who stretch. A static-stretching technique may limit musculotendinous stiffness and cause increases in electromechanical delay, meaning that the muscle would respond faster to stimulus and is less likely to be strained during activation (Costa, Herda, Herda, & Cramer, 2014). Conversely, dynamic stretching is usually found to be the

7 CWHP Health & Fitness Journal (Spring 2015 Issue) 7 preferred of the two. However, it has acute negative effects on the muscular system and leads toward decreases in strength (Costa, Herda, Herda, & Cramer, 2014). By analyzing the evidence, we have concluded that depending on the purpose of the exercises, both dynamic and static stretching can be appropriate. For exercises that need more sustained power, static stretching would be the most useful, while dynamic stretches are best for exercises that require quick, explosive power. References Costa, P. B.., Herda, T. J., Herda, A. A., & Cramer, J. T. (2014). Effects of dynamic stretching on strength, muscle imbalance, and muscle activation. Medicine & Science in Sports & Exercise, 46(3), Leone, D. G., Pezarat, P., Valamatos, M. J., Fernandes, O., Freitas, S., & Moraes, A. C. (2014). Upper body force production after a low-volume static and dynamic stretching. European Journal of Sport Science, 14(1), Parrott, J. & Xihe, Z. (2013). A critical view of static stretching and its relevance in physical education. Physical Educator, 70(4), Salvini, T. F., Durigan, J. Q., Peviani, S. M., & Russo, T. L. (2012). Effects of electrical stimulation and stretching on the adaptation of denervated skeletal muscle: Implications for physical therapy. Brazilian Journal of Physical Therapy, 16(3), Wallmann, H. W., Christensen, S. D., Perry, C. & Hoover, D. L. (2012). The acute effects for various types of stretching: Static, ballistic, and no stretch of the iliopsoas on 40-yard sprint times in recreational runners. International Journal of Sports Physical Therapy Recommended Readings Amiri-Khorasani, M. & Kellis, E. (2013). Static vs. dynamic acute stretching effect on quadriceps muscle activity during soccer instep kicking. Journal of Human Kinetics, Arazi, H., Asadi, A., & Hoseini, K. (2012). Comparison of two different warm-ups (static stretching and massage): Effects on flexibility and explosive power. Acta Kinesiologica, 6(1),

8 CWHP Health & Fitness Journal (Spring 2015 Issue) 8 Ayala, F., De Ste Croix, M., Sainz de Baranda, P., & Santonja, F. (2014). Acute effects of static and dynamic stretching on hamstrings response times. Journal of Sports Sciences, 32(9), Sampaio-Jorge, F., Rangel, L. C., Mota, H. R., Morales, A. P., Costa, L., Coelho, G. O., & Ribeiro, B. G. (2014). Acute effects of passive stretching on muscle power performance. Journal of Exercise Physiology Online, 17(6), Yamaguchi, T. & Ishii, K. (2005). Effects of static stretching for 30 seconds and dynamic stretching on leg extension power. Journal of Strength and Conditioning Research, (3), 677. Yapicioglu, B., Colakoglu, M., Colakoglu, Z., Gulluoglu, H., Bademkiran, F., & Ozkaya, O. (2013). Effects of a dynamic warm-up, static stretching or static stretching with tendon vibration on vertical jump performance and EMG responses. Journal of Human Kinetics, Yıldız, S., Çilli, M., Gelen, E., & Güzel, E. (2013). Acute effects of differing duration of static stretching on speed performance (English). International Journal of Human Sciences, 10(1), (5), SPORTDiscus with Full Text, EBSCOhost (accessed March 13, 2015).