The Effects Of Inter-Set Stretching On Muscle Growth
When we think about building muscle, developing strength, and generally increasing performance, strength training often sits right at the top of the lift.
Which is fair enough, because it works, and works incredibly well.
But what if I was to tell you that there are certain techniques you can implement to improve the results of your strength training? More importantly, what if I told you that you could gain these improvements without much more time or effort?
Enter inter-set stretching.
What is inter-set stretching?
So, inter-set stretching – what is it, and how does it work?
Fortunately, inter-set stretching is pretty much exactly what it sounds like – stretching in between sets.
To implement it correctly, you simply perform a set of a given exercise. Then during your rest period, you stretch the same muscle you just worked. It is typically recommended that you hold the stretch for around 30 seconds.
In practice, this might look something like this:
- Squat 12 repetitions
- Stretch your quads for 30 seconds each side
- Use the remaining 60 seconds of your rest period to rest completely
- Repeat the process for another 2-3 sets
You get the picture.
Related Article: The Truth Behind Static & Dynamic Stretching
Why inter-set stretching?
You might be wondering why in the world you would want to start stretching between sets. There is some pretty good rationale behind it.
First and foremost, there is some evidence to suggest that coupling stretching with weight training within a set has the potential to improve muscle flexibility. This has obvious implications for injury prevention.
Secondly, the application of inter-set stretching has been shown to increase the number of repetitions performed in the subsequent set. This may have the potential to increase the volume of your training session, which therefore has the potential to enhance muscle growth.
Finally, stretching itself actually places the muscle tissue under tension. Given that time under tension is considered to be a key driver for muscle growth, inter-set stretching may increase growth even further by causing an immediate increase in time under tension.
But won’t Inter-set stretching affect the nervous system?
One of the biggest criticisms surrounding inter-set stretching is the suggestion that it may decrease power output (Kendall, 2017).
You see, there is some research showing that bouts of prolonged static stretching immediately before the explosive movement has been shown to decrease performance in those movements. Although, the thing to note here is that in these studies the participants held a hard stretch for around 1-2 minutes – which is much longer than recommended when using inter-set stretching.
In fact, stretches that last 30 seconds or less don’t appear to have any negative influence on power output – so you have no need to worry here.
Does inter-set stretching effect strength, flexibility, and hormone levels?
We know what inter-set stretching is supposed to do.
But does it work?
Well, to answer that question we are going to take a bit of a look at the first study to investigate the influence of inter-set stretching on the development of muscle strength, flexibility, and hormone levels – all of which are of particular interest to athletes and gym junkies alike (Souza, 2013).
In this study, sixteen men were divided into two groups, an inter-set stretching group, and a group that simply rested between sets. All participants performed three training sessions per week for eight weeks in duration.
This is where things get a little bit interesting.
Both groups saw the same improvements in strength, and neither group saw any significant change in their resting growth hormone levels or resting cortisol levels. However, the stretching group did see some small improvements in flexibility that were not seen in the normal group.
With this in mind, we can safely say that inter-set stretching does not harm strength development and may even improve flexibility.
But what about muscle growth?
Does inter-set stretching improve muscle growth?
Now for the big one.
Does inter-set stretching boost muscle growth?
Well, fortunately for us, a recent study looked to answer this question specifically (Evangelista, 2019).
This study essentially compared the effects of traditional strength training with and without inter-set stretching over an 8-week period on measures of muscle growth and muscle strength. Both groups completed the same full body strength training program two days per week, with the only difference being that the inter-set stretching group stretched between each set of exercises (obviously…).
And the results were very interesting to say the least.
First and foremost, both groups saw significant improvements in their muscle strength. This again shows that stretching in between sets (or during your workout at all) will not negatively impact your performance or your ability to develop muscle strength.
Secondly, both groups increased their muscle size significantly from baseline.
However (and this is where things get interesting), the inter-set stretching group actually saw greater improvements in muscle size. It indicates that it may offer a more valuable tool for promoting muscle growth than traditional strength training alone.
Inter-set vs static vs dynamic stretching
With all this in mind, I thought it might be worth touching on the main differences between static stretching, inter-set stretching, and dynamic stretching – because they all have their place in an exercise regime, dependant on your goal.
Static stretching is hands down the most common form of stretching used today. It very simply involves holding a stretch for anywhere between 10 seconds and 2 minutes.
It offers an extremely effective method of improving muscle flexibility. However, as I touched on above, if held for more than 60 seconds, it can impact power output – so maybe keep it for your cooldowns or your rest days.
Dynamic stretching is a more active mode of stretching. It has you dynamically moving through a muscles full range of motion for a set number of repetitions (around 10-15 is about normal). This type of stretching is best used immediately before exercise. It improves range of motion and prepares you for your upcoming workout.
Finally, inter-set stretching (which we have spoken about a lot today) has you performing brief bouts of static stretching between sets of strength training – and it is best used to promote improved muscle growth.
Related Article: Fascia Warm Up, Strength, & Stretch Plan
Future research on inter-set stretching
Taking all this information into consideration, it is important to note that to date there have only been a couple of good quality studies performed on inter-set stretching, and even they have their downfalls.
To put it simply, more research is needed.
Future research should look at a longer duration of training. Anywhere between 12-16 weeks would be ideal, as it would provide more information around the long-term implications of using inter-set stretching in your training.
More importantly, studies that use well-trained participants (such as athletes) are essential. This would provide insight into how inter-set stretching affects those individuals who already have a high training status, and therefore a large amount of muscle bulk.
Take Home Message
While there are only a couple of good quality studies looking into the effects on inter-set stretching, the early results are promising.
Inter-set stretching appears to enhance muscle growth and flexibility, without mitigating any potential strength adaptations. This suggests that if your goal is to build as much muscle as possible, it is a perfect option.
If you have used inter-set stretching in the past then we would love to hear about it, so drop us a comment and we will get back to you ASAP!
Souza, Antônio Claudio, et al. “Influence of inter-set stretching on strength, flexibility and hormonal adaptations.” Journal of human kinetics 36.1 (2013): 127-135.
Evangelista, Alexandre L., et al. “Interset Stretching vs. Traditional Strength Training: Effects on Muscle Strength and Size in Untrained Individuals.” Journal of strength and conditioning research (2019).
Kendall, Bradley J. “The acute effects of static stretching compared to dynamic stretching with and without an active warm-up on anaerobic performance.”. International journal of exercise science 10.1 (2017): 53.