By: Juliana Gullotta and Laura Sturgill
If you’ve participated in any athletic event, you know that one of the first things you do is to start stretching before any activity takes place. Coaches and trainers emphasize that stretching should occur on a regular basic, and become part of an individual’s workout routine. These stretches are usually static stretches (holding a stretch for 20-30 seconds). The intent of prescribing stretching before exercise, is based on the assumption that by stretching you enhance performance, prevent injuries, and increase flexibility. However, several studies, including one from the Journal of Applied Physiology, Nutrition, and Metabolism, have shown that stretching before exercise can actually do more harm than good, and increase your risk of injury.
While stretching before exercise does activate the muscles and increase blood flow to the areas as a “warm up”, it can be potentially very detrimental to an athlete’s workout. This conclusion is especially pertinent when the sport in question requires maximal force production. In a study conducted at the University of Nevada, researchers determined that leg muscles generate less force after static stretching than if they did not stretch at all. When muscles are subject to the strain of static stretching, they remain in a weakened state, thereby temporarily reducing the force that it can produce. The researchers evaluated two types of stretching, ballistic (bouncing) and static (control is no stretching). After stretching for 3 sets of 30 seconds, subjects performed a vertical jump on a force plate. Power values were compared for each of the conditions (Figure 1). From this graph it is clear to see a significant difference in the power values observed in the control group and static group. The decrease in power after stretching could inhibit a good muscle building workout. For sports that require maximum power (ex. football), static stretching should be limited before activity.
Static stretching intervals should last for no more than 60 seconds, or moderate reduction in maximal muscle performance may be observed. In a study conducted by Behm et. al. the effects of static stretching on power-speed and strength tasks were compared. One of the main components of this study involved investigating the relationship between time spent holding a stretch and subsequent performance in a physical activity. In order to perform these tests, two groups of healthy and active adults were randomly assigned, with one group holding their static stretch for less than 60 seconds and the other for a period of time greater than 60 seconds. On average there was a mean reduction of muscle performance for both test groups, but the group that held the stretch for a longer period of time experienced significantly higher reduction rates in performance. For the individuals that held the stretch for less than 60 seconds, a mean reduction of 1.1% was observed and categorized by the researchers as a small reduction in performance. However, a moderate reduction of 4.6% was noted in the population that held the stretch for longer than 60 seconds, indicating that there is a dose-response relationship between stretching and maximal muscle performance.
To investigate this relationship further, two types of physical activity were studied. Power-speed tasks were given to both groups and the results supported the notion that on average static stretching, especially when held at higher intervals, impaired muscle performance in the test subjects. While only a small mean reduction rate of 1.3% was observed for this type of exercise, this change could be extremely detrimental to an athlete’s performance where maximal speed is critical (i.e. sprinters). Power tasks were also completed, and the negative effects of static stretching on performance became more apparent. On average there was a 4.6% reduction in an individual’s maximum muscle performance, with a higher instance of 5.1% reduction when the activities were completed after a period of stretching lasting longer than 60 seconds. In another study also conducted by Behm et. al, these findings were not only supported by additional trials, but also expanded upon to look at the long term effects of stretching on overall performance. In his initial study that looked at power and speed tasks, maximal muscle performance was calculated minutes after the the stretching was complete. The second study, however, observed the prolonged effects that static stretching would have on an athlete, and concluded that even 2 hours after the last set of static stretching, instances of decreased performance existed.
The results from these studies suggest that time spent holding a stretch and subsequent muscle performance have an inverse relationship. For this reason more and more coaches and athletes are looking to implement a different approach to their warm up routine.
Dynamic stretching (Figure 2) is simply the act of stretching your muscles while moving, and it is an effective method to get your blood flowing and increase your power, flexibility, and range of motion prior to working out. This type of stretching is unique in that the activities performed have the ability to target specific muscles necessary for the task at hand. In other words, different forms of dynamic stretching would be used for a sprinter and a volleyball player because each sport requires a different amount and variety of muscle activity. Dynamic stretching allows athletes to engage their bodies’ muscles in a way that static stretching cannot, thereby quickly earning its place as a replacement to static stretching in many pre-workout routines.
While the value of traditional static stretching before exercise may be an outdated concept, the benefit of increased flexibility in athletes should not be ignored. For this reason post workout stretching is recommended as a “cool down”. If necessary, short duration, lasting less than 30 seconds, low intensity static stretches could be implemented before activity to get blood flowing to muscles and reduce stiffness, but this does not offer the best possible results. The ideal warm-up routine for athletes to minimize risk of injury and maximize performance should include aerobic activity, dynamic stretching, and sport specific dynamic exercises.
Questions to consider:
How would the stretching routine you made for football players differ from that of a sprinter?
There is a lot of information about how bad form or technique during exercise can cause injury, should there be attention called to the potential adverse effects of stretching improperly?
Samuel, M. N., Holcomb, W. R., Guadagnoli, M. A., Rubley, M. D., & Wallmann, H. (January 01, 2008). Acute effects of static and ballistic stretching on measures of strength and power. Journal of Strength and Conditioning Research, 22, 5, 1422-8.
Behm, D. G., Blazevich, A. J., Kay, A. D., & McHugh, M. (January 01, 2016). Acute effects of muscle stretching on physical performance, range of motion, and injury incidence in healthy active individuals: a systematic review. Applied Physiology, Nutrition, and Metabolism =, 41, 1, 1-11.
Shrier, I. (October 01, 1999). Stretching Before Exercise Does Not Reduce the Risk of Local Muscle Injury. Clinical Journal of Sport Medicine, 9, 4, 221-227.
Behm, D. G., & Chaouachi, A. (November 01, 2011). A review of the acute effects of static and dynamic stretching on performance. European Journal of Applied Physiology, 111, 11, 2633-2651.
Shrier, I. (January 01, 2000). Stretching before exercise: an evidence based approach. British Journal of Sports Medicine, 34, 5, 324-325.
Herbert, R. D., & Gabriel, M. (January 01, 2002). Effects of stretching before and after exercising on muscle soreness and risk of injury: systematic review. Bmj (clinical Research Ed.), 325, 7362.)
Reynolds, Gretchen. (2008) Stretching: The Truth. The New York Times. Retrieved from: http://www.nytimes.com/2008/11/02/sports/playmagazine/112pewarm.html
Reynolds, Gretchen. (2016) The Right Way to Stretch. The New York Times. Retrieved from: https://well.blogs.nytimes.com/2016/01/21/stretching-back-to-the-past/
You mentioned that post workout stretching is still recommended, but to what degree? Do you think that athletes should limit themselves to 30 second stretches, or stretch for up to a minute to increase flexibility? I think this would depend on the athlete and what they’re trying to achieve physically. That being said, do you think it’s also important for non-athletes to consider changing their stretching methods? I’d argue that a person going to the gym doesn’t need to generate as much muscle force as a professional athlete. I’ve always been told how important it is to stretch both pre- and post workout, so as not to injure myself. To answer your question, yes I think attention should be called to the potential adverse effects of stretching.
Stretching should be sports-specific, and it’s beneficial to stretch post-exercise. The New York Times article (from where Figure 2 came from) covers this in more detail and has more examples. Even if you aren’t using as much force as a professional athlete, exercises wouldn’t be as efficient on weaker muscles. (However, I’m not a personal trainer so if it’s working for you then stick with it!) As for how long to stretch, I think it would also be specific to the sport. I know when I used to be a diver, we did lots of static stretching before practice even though reading these articles make it seem like not a good idea. It’s most likely a combination of which combination would be more beneficial to a particular athlete. (For diving, it’s probably better to be more flexible than force producing since most of the work is done by the board).
Attention should most definitely be called to the potential detriments of stretching. I was always taught to stretch before and after every practice, scrimmage, and game in every sport I played from elementary to high school. The science behind athletics is changing so quickly that coaches for non-collegiate sports can’t stay on top of all the research that is going on, at least in my experience where coaching was a part time job as opposed to them being a full time D1 coach. This research should be spread by means such as word of mouth or training seminars, so that athletes of all ages have the best chance possible to succeed. I think it should also be emphasized that there should still be stretching post-activity though.
After playing soccer from elementary school through high school, stretching pre- and post-workout are practically ingrained in my mind, but my coaches were pretty up-to-date with the latest sports research and often included a combination of both static and dynamic stretching. When you were going through the research, did you find any sport-specific conclusions on the recommended type of stretching? Also, you mentioned the muscle power losses with static stretching, but how is injury rate affected?
The New York Times article (from where Figure 2 came from) covers this in more detail and has more examples. Since those are pretty general, I’m sure there are more sport-specific dynamic stretching options. The Journal of Applied Physiology, Nutrition, and Metabolism study yielded no conclusive data in regards to overuse injuries. I think that muscles being unable to operate at power could indirectly cause injury if someone was trying to lift more than the power they could produce, but that could be more correlation that causal. “Stretching before exercise” (http://bjsm.bmj.com/content/34/5/324) Which we cited but didn’t link, shows mostly inconclusive evidence on stretching before and a higher/lower risk for injury.
I am curious to know if potentially this reduced muscle performance is beneficial in intense and violent sports such as football? The study noted reduced performance output after holding static stretches, however it was for a low intensity exercise such as the vertical jump. Is it possible that the small reduction in output performance reduces the likelihood of injury in athletes participating in violent sports such as football?
At the end of paragraph two, we considered football to be a sport that requires maximum power, but I think it would actually depend more on the position an athlete would play. This study: https://www-ncbi-nlm-nih-gov.udel.idm.oclc.org/pubmed/16596099?dopt=Abstract concludes that static stretching helped the cyclists reach maximum power more quickly. I’m not very familiar with different football positions, so I’m not sure how the results would change with different positions.
If both static and dynamic stretching, stretch and warm up your muscles and could contribute to a loss of power and force output. Do you know if there are power decreases with both types of stretching but they are just less for dynamic compared to static? For example if someone is about to engage in a powerlifting competition should they avoid all types of warm up stretching to maximize power output and performance in the competition?
These are very interesting results. I am surprised that static stretching can lead to a decrease in muscle performance. I did some research on stretching in high school, and found that people that stretch everyday, or not at all, are at much lower risk of injury than athletes that stretch off and on every so often. I wonder why this could be? Possibly a consistent warm up, leading into static stretching would be a better take. Dynamic stretching in a sense “warms up” the muscle, and this could be what static stretching is missing. A warm up, quick run, and static stretching could yield much better results compared to “cold” static stretching.
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