Stretching is a an important topic that is often overlooked. We all get told from a young age that we should stretch before and after bouts of exercise, but nobody really tells us how to stretch and, even when they do, they don’t properly tell us why we should. So this blog is probably well overdue, but with the help of a couple of systematic reviews we are going to cover the two most common forms of stretching (static and dynamic), what they are, and how they help and/or hinder us. I’ll then run through my top recommendations so that stretching can aid your performance and your recovery the best way possible.
What is stretching?
Stretching is an action whereby a person’s muscle and accompanying tendons are lengthened to a point of resistance to help improve the muscles elasticity in order to produce increased flexibility, joint range of motion and force output.
Above I mentioned two specific types of stretching which we will now cover with more detail so you can understand the differences between them
A brief introduction
Static stretching: This occurs when a muscle is held in a stretched position for a prolonged period of time (10s-60s usually) and not left to relax or contract at any point within this time. This can be beneficial for increasing a joints full range of motion in the long term as well as reducing the level of muscle soreness post exercise. It has also been said that static stretching has the ability to increase levels of athletic performance due to its ability to decrease muscle stiffness however, this has been challenged in recent years and I’ll go into depth on this later.
Dynamic stretching: This occurs when a muscle or joint is taken through a controlled movement within its active range of movement. The key here is the active range of movement, meaning the joint is only moved within a range that is achieved by our own muscles working rather than us forcing extra movement with our hands or other external tools. This type of stretching tends to be favoured for a number of reasons. Firstly the movements used during dynamic stretching often replicate exercise movement patterns which are used in sport. Secondly they increase total body temperature which can increase nerve conduction velocity, muscle compliance and accelerated energy production (Behm et al. 2015).
Static stretching and performance effects
Now you have been introduced to the main two types of stretching that you will come across, let’s see how these have been shown to affect performance.
A large magnitude of studies show that strength and power outputs decrease when static stretching is used prior to activity. These studies also suggest that these decreases in performance can last up to 2 hours after (Power et al. (2004)), so it is important to be careful when and how we choose to stretch statically prior to exercise. However, the vast majority of these studies use stretching protocols (90-480s) that were much longer than the average stretch held in real gym or sporting environments in the preparation for exercise (Behm and Chaouachi. 2011).
This may sound like I’m instantly shutting out the idea of static stretching completely, but bare with me. Static stretching protocols using less than 30s of total stretch time prior to exercise have highlighted no significant change to performance measures, whilst still helping to increase joint range of movement (Behm and Chaouachi. 2011). This means that static stretching can still be very useful to us if used in the right way and with the right intention
The two ways in which I therefore recommend using static stretching are:
1. Prior to exercise, to increase joint movement capability. This must be done after a 2-5 minute aerobic warm up (such as rowing) to increase body temperature and must contain no more than 30s of total stretch time per muscle group. This can be a single stretch of course however, I prefer to use up to 6 stretches of about 5 seconds per muscle group (totalling 30s stretch time).
2. Post exercise or as a stand alone stretch session done hours away from a training session. This would be used for reducing levels of muscle soreness and increasing overall flexibility. If you need to improve the mobility of a certain area of the body, this is a great way of doing it without impacting your training too. In this situation I would recommend using stretch durations of 60-90s per muscle group in one single stretch.
Dynamic stretching and performance effects
Research into dynamic stretching prior exercise has shown to elevate core body temperate and increase short term flexibility as well as increase strength and power output potential (Behm et al. 2015). Interestingly, it has also been reported that dynamic stretching frequency (the number of movements conducted per minute) has an effect on how effective the stretching is for performance. For example, dynamic leg swings at a speed of 100 per minute resulted in better force output scores than when athletes did dynamic leg swings at 50 per minute. However, even the slower one here brought out better force production from athletes than when they had not stretched at all.
The majority of the research conducted on this topic uses explosive tasks – such as jumps or throws – to test the effectiveness of these types of stretching. However, some have also used isometric or slower dynamic movements, such as squats (Behm et al. 2015). What is interesting is that dynamic stretching seems to have a much lower effect on these slower, strength based movements (in comparison to more explosive exercises) which are likely going to make up the workouts done by the majority of people reading this article.
What we can take from this is that the type, duration and frequency of stretching can be completely influenced by the type of activity you are about to do. If you are preparing yourself for a sport or a workout which contains power based movements then dynamic stretching with a high frequency of movement is clearly your best option to increase performance. You can then opt for static stretching recommendation 2 from above to help with your long term mobility and joint health.
A quick note on injury. It is suggested that the majority of research that has been conducted shows short duration stretching of any kind before exercise can help reduce injury risks in running, sprinting or other power based movements (Behm et al. (2015)). They also showed that endurance based sports or traditional weight training had no reduced injury risk however, this is likely to be due to the types of injuries associated and most commonly seen within these types of activities.
My final recommendations
If you are performing regular weight training then short static stretching following an aerobic warm up will be sufficient to increase temporary range of movement and assist strength output (option 1 above). You can also follow your short duration static stretching protocol with some low frequency dynamic stretching work which directly replicates the movements you’ll be performing in your training to further increase force output (my clients will know these as warm up sets or other bodyweight exercise done during our warm ups). That being said, dynamic stretching has never been shown to impair performance so, if you were keen on doing that type of warm up for whatever session you were going into, it is very unlikely to hinder your results.
So, we have benefits of both major forms of stretching. Which you choose to use and for how long will be governed by your reason for using it and what you want to achieve by it. Think before you stretch, you now have the information you need to make the informed decision. Thanks as always for reading!
Behm, D., Blazevich, A., Kay, A., and McHugh. M. 2015. Acute effects of muscle stretching on physical performance, range of motion and injury incidence in healthy active individuals: A systematic review. Journal Of Applied Physiology, Nutrition and Metabolism.
Behm, D., and Chaouachi, A. 2010. A review of the acute effects of static and dynamic stretching on performance. European Journal Of Applied Physiology.
Power, K., Behm, D., Cahill, F., Carroll, F., and Young, W. 2004. An acute bout of static stretching: effects of force and jumping performance. Journal Of Medicine In Sport And Exercise