How to get flexible | The complete Science Proven Guide (32 studies)

So what does real science have to say about getting flexible fast and easily? In this article, I will present you the most effective strategy proven by 32 recent studies, and my 10-year personal experience as a coach!


What will you need for a successful flexibility training session?

The first thing that I want you to understand is that getting flexible is not about the type of exercise you’re doing. The exercises that stretch the muscles that you want, are all over the internet and are very easy to find. Just type the words full-body stretch or flexibility workout and you’ll have millions of results. The thing is, how are you going to apply them to your session. This is the only thing that makes a difference. It’s like searching for a good leg exercise and finding squats, what are you going to do with them? Even though you know the right exercise you still have to find the right weight, sets, reps, rests, and sessions per week to get the results that you want. It’s the same with flexibility, it’s easy to find the exercises, but they are only one component of your flexibility session.

The other components are:

  • The type of stretching that is most effective for getting flexible
  • the method that you’re going to use,
  • the time of stretch per set,
  • the number of sets per session,
  • the duration of rest between sets
  • and the number of sessions per week.

Only if you set all these components right, you will get flexible fast and easily.  So without further ado let’s see what science has to say about all these.

What science says on ‘’how to get flexible’’?


The right type of stretching for getting flexible fast (according to science)

So the consensus view of the scientists as you already know, is that regular stretching increases ROM. This is supported by numerous studies that have tested the effects of various types of stretching on flexibility.

But which of them is more effective in increasing flexibility. The 4 big categories of stretching techniques are:

  • Dynamic Stretching, where the person moves dynamically through his range of motion with controlled mobility drills.
  • Ballistic stretching, which involves a less controlled muscular effort and uses a bouncing-type movement in which the end position is not held.
  • Static Stretching, where you stretch and hold your position for a specific amount of time.
  • And Proprioceptive Neuromuscular Facilitation or else PNF techniques. These techniques are performed mostly with a partner and are combined in 3 different phases. A passive pre-stretch, a type of muscle activation, and a passive stretch again.

Some of these methods are combined with different techniques, but we use these 4 big categories to distinguish the main characteristics of the type of stretching that we are using.

Now the current literature suggests that static stretching and PNF are superior in increasing flexibility compared to dynamic stretching and ballistic stretching. Specifically, in studies that compared static stretching to dynamic and ballistic stretching, static streching was superior in increasing flexibility.

In addition, in a recent review from 2018, where scientists compared the efficiency of all methods in terms of improving flexibility, ballistic stretching was found to have the smallest effect in comparison to all the other types of stretching.

This doesn’t mean that you can’t increase your flexibility with dynamic and ballistic stretching but only that you’ll have a smaller improvement compared to the benefits of static stretching and PNF.

Also, ballistic stretching is considered to be the riskiest in terms of injuries and some scientists suggest that it is no longer recommended. I personally believe that every type of stretch is suitable for specific occasions and that ballistic stretching could be beneficial for specific movements.

So from the literature, it’s clear that both static stretching and PNF are the most successful methods in terms of increasing range of motion. But which of the 2 is the most effective and suitable for you?

Right now there are studies that support that PNF is better than static stretching, but also others that found no differences between them and some that found SS to be better than PNF.

A review on this topic from Sharman and coworkers in 2006 conclude that PNF is the most effective means to increase ROM by way of stretching, particularly with respect to short-term gains in ROM.

On the other hand, in a review from Lepke and colleagues in 2018, the authors came to the result that PNF stretching was not demonstrated to be more effective at increasing hamstring extensibility compared to static stretching.

Finally, in another review in the same year that compared 23 studies with all stretching typologies, authors conclude that the static stretching protocols showed significant gains when compared to the ballistic and PNF protocols.

What I’m trying to say here is that the results are mixed but the main point is that both methods are very close in terms of increasing flexibility. Slight differences that may have been found between them will not make the difference in the average person in practice.

For me,  the major difference is that static stretching can be more easily applied by the person itself and in every muscle group. In contrast, and as NSCA states in the fourth edition of the essentials, PNF stretching is often impractical because most of the stretches require a partner and some expertise. But even if you do it yourself it is much harder and almost impossible to correctly apply it on some very important muscle groups like the glutes and muscles of the lower back.

So for these reasons and with the data that we currently have, I think that SS is probably the most suitable method for the average person out there in terms of increasing flexibility. But that doesn’t mean that you can’t get equally flexible PNF. I just think that both methods are very effective and close in terms of results, but static stretching is easier to apply on yourself and in every muscle.


How to structure a successful flexibility training session (reps, sets, rests & number of sessions per week)

Knowing the right type of stretching is just the beginning of a successful flexibility program.  The next step is to look for the optimal parameters of your stretching session. These parameters are:

  • the duration of stretching per set
  • The number of sets per session
  • The duration off rests between sets
  • And the number of sessions per week

Early studies of Bandy and coworkers in 1994 and 1997 showed that the optimal duration of a stretch is 30 seconds. In their studies, they used 15, 30 and 60 second-sets and found that stretching for 30 seconds significantly improved flexibility while no increase in flexibility occurred when the duration was increased from 30 to 60 seconds.

On the other hand, a review that I mentioned before from Thomas and colleagues in 2018 puts the weight on a different aspect of training. In this review the authors found that:

‘’Time spent stretching per week seems fundamental to elicit range of movement improvements when stretches are applied for at least or more than 5 min, whereas the time spent stretching within a single session does not seem to have significant effects for ROM gains.’’

So the actual goal is to reach somewhere close to 10’ per week total stretching duration while stretching more than 10’ per week will not elicit more gains in your flexibility. If we combine these results with the two papers of Bandy and colleagues, it would be fair to say that the optimal strategy is to have:

3 sets of 30 seconds for 6 days per week

With this training regimen, you reach 9’ total stretching duration per week and you are in agreement with both the findings of Bandy and the big recent review of Thomas. If you can’t have so many sessions per week and given the fact that the total duration per week seems to be the most important factor, you should try to make the total duration in less sessions. For example:

3 sets of 60 seconds for 3 days per week

So the number of sessions per week, the sets per session, and the duration per set are mostly determined by the total duration per week which is around 10’.

To my knowledge, the duration of the rests between sets hasn’t been studied yet, so I would say that anywhere between 1 to 2 minutes should be ok and it’s pretty much what was used in most of the studies I presented.


The best stretching method for getting flexible

And now, an essential clue for successful stretching that I bet you didn’t know. This one came from Wyon and coworkers in 2009. In their study, they had 24 adolescent dancers in a 6-week intervention program that compared low-intensity stretching (Microstretching) with moderate-intensity static stretching on active and passive ranges of motion. According to them, ‘’Microstretching is a new modality that reduces the possibility of the parasympathetic system being activated’’. The main finding of this study was that very-low-intensity stretching had a greater positive effect on flexibility than moderate-intensity static stretching. If you are familiar with high intensity and painful stretching, just forget about it. A gentle and controlled stretch with low intensity will produce greater flexibility results as was found by Wyon and coworkers.

And this is why the most effective stretching method for getting flexible is the Anderson method. In this method, you simply do an easy pre-stretch of 10-30seconds, and then you go on a developed stretch for 30-60 seconds which is your main training. The easy pre-stretch must be done in every single set!


3 additional components on how to get flexible easier!

  • Warm-up
  • Breathing
  • And periodization

Should you warm up before a flexibility training session?

It is common sense that you shouldn’t go completely cold into a full stretch and you’ll get flexible a lot easier if you make sure to be warm during stretching. For most people The simplest way to warm up before stretching is to put your flexibility training at the end of your normal workout. That way, your muscles are already warm and ready to go.

But if you prefer to do your stretching separately from your other workouts, you should take the time to warm up before your stretch.

I personally use a 5’ to 10’ low intensity physical activity to increase my temperature and after that I do my whole flexibility session with the Anderson method. This way I’m already warm in terms of temperature and also easing into a full stretch.

What about breathing?

Always make sure that you gently breathe out during your stretches. Calm and slow breathing can help your muscles relax and decrease the activity of neural reflexes, like the ‘’stretch reflex’’, that oppose your stretch. In my opinion, the ideal breath rate is around six breaths per minute, with an exhalation that is twice as long as the inhalation

What does getting flexible have to do with periodization?

I think that it’s a simple but essential concept that people just forget when it comes to flexibility training. When you try to get flexible you’re not just doing a warm-up routine or making a quick pass from recovery exercises. You are training your flexibility, so this can be an independent training session throughout your day. As a training procedure, every 6 to 8 weeks there should be a rest period of 3 to 5 days or a deload week where you will do 20 to 30% less than your typical training. (photo)


The most successful formula to get flexible – (Practical Advice)

So what you can personally do when you want to get flexible in a certain joint, movement, or muscle is to follow these steps:

  1. Select the exercises that stretch the muscles that are involved in this movement (the exercise)
  2. After a 5’ minute low-intensity warm-up I get right into the first set with static stretching and the Anderson method. (the method & type of stretching)
  3. Pre-stretch for 20 seconds and then develop stretch for 30 or 60 seconds according to the regimen that fits best your schedule

3 sets of 30 seconds for 6 days per week


3 sets of 60 seconds for 3 days per week

4. Test your results after 6 to 8 weeks, take a small rest, and continue.


What science taught as (Summary of the theory)

  • Static stretching and PNF are both very effective methods in terms of increasing flexibility
  • Static stretching might have a slight advantage over PNF because it’s easier to apply it yourself and in every muscle.
  • Time spent stretching per week is more important for getting flexible than time spent stretching within a single session so if you can, stretch regularly up to 6 times per week, for 3 sets and 30 seconds every set. If you can’t, 3 sets of 60 seconds 3 times per week will be equally effective.
  • Very-low-intensity (Microstretching) stretching seems to have a greater positive effect on getting flexible than moderate-intensity static stretching, so don’t try to tear your muscles apart
  • Make sure to warm up before going to a full stretch, if you don’t train your flexibility after your normal workout.
  • Keep your breath calm during stretching and maintain a rest period every 6 to 8 weeks of consistent flexibility training.


Want to get flexible in every joint?

Get the full Flexibility & Mobility guide today! All the exercises that you need + follow along videos with all the routines! (get it here)


For more content and the links to all the studies I presented you can see my video on YouTube: