[This post is written by Justin Hardy who is currently working as a Sport Performance Intern at Athletic Lab]

Stretching has various benefits, but many of us do not fully understand when it is appropriate. Should we stretch before or after exercise, and what kind of stretches are best for each scenario? This post will help answer the various questions surrounding the topic of stretching.

There are various types of stretching one can perform: dynamic, static, ballistic, passive, etc. However, there is no clear research that determines one to be superior to the other; rather they can all be beneficial. Arguably, the two most common types are static and dynamic. Static stretching is when a muscle is gradually lengthened to a point of limitation and held. It is recommended to hold a stretch for at least two sets of 15 seconds to 30 seconds, for minimum of two to three times a week. Dynamic stretching is when a muscle or group of muscles is actively taken through a range of motion that generally mimics or relates to movements that will be attempted during the upcoming workout or sporting event.(1)

How does stretching affect performance and training? Contrary to popular belief, stretching has not been proven to help reduce muscle soreness. Moreover, static stretching for long periods of time of the same musculature (120-36000 seconds) has been shown to marginally reduce max strength in participants.(1) While it is unlikely that you would stretch one muscle for this lengthy of a period, it is important to keep this in mind before any workouts or sporting events that will require a maximal strength effort. Small doses of static stretching 15 seconds or less, has not shown the same decreases in performance.(3)

In contrast, dynamic stretching has not shown these results, and can be an essential part of a warm up. Dynamic stretching increases blood flow to activated musculature, enhances the removal of waste products and can help the body increase force production. Furthermore, research shows that there may be positive long term effects of chronic stretching when related to performance, such as sprinting. A specific example is a study conducted by Young and Behm that found submaximal running and practice jumps prior to two max jump performance tests was beneficial to jump height, whereas static stretching prior to the jumps negatively affected jump height.(2)

Ultimately, some strength exercises, such as squats performed to full range of motion, can help maintain an athlete’s mobility overtime. If an athlete can reach full range of motion, static stretching may only be needed in small doses prior to a workout. If an athlete cannot reach full range of motion, short periods of static stretching prior to a workout can allow an increase in mobility for a short time to help maintain proper form during movements.

References:

1. Bruno, B. (2013). Long Live Static Stretching. T-Nation. Retrieved from https://www.t-nation.com/free_online_article/most_recent/long_live_static_stretching

2. Kravitz, L. (2009). Stretching–a research retrospective. IDEA Fitness Journal, 6(10), 34-43. Retrieved from

3. Young, W. B., & Behm, D. G. (2003). Effects of running, static stretching and practice jumps on explosive force production and jumping performance. Journal of Sports Medicine and Physical Fitness, 43(1), 21-27.