Flexibility Explained: How to Measure & How to Train

Flexibility is most commonly defined as the ability of a joint or group of joints to move through a range of motion.

For example, if you can reach down and touch your toes with straight legs, we would say that you have flexible hamstrings (the muscles in the back of your leg).

Many definitions also add ‘pain free’ as a component of flexibility, i.e. if you can move your joint through a full range of motion but it really hurts, you don’t class as flexible.

How do we measure flexibility?

Essentially, we simply pick a few stretches and see how far we can reach.  A classic example is the sit and reach test.

We can also take videos or pictures of ourselves in certain stretches, and compare the positions over time.

Benefits of flexibility: fact or fiction

This section may very well surprise you.

Commonly held “knowledge” passed down through years of fitness magazines suggests that stretching can have benefits such as…

  • Increased neuromuscular coordination
  • Return of muscle to natural resting state
  • Modifying blood pooling and recirculation
  • Reducing injury risk
  • Lessened risk of falls
  • Improving athletic performance

However, there is actually very little to no literature to support these suggested benefits.

  • Neuromuscular coordination is developed through exploration of complex dynamic movement patterns, not by sitting in a gentle stretch.  This is why athletes run, side step, skip, jump, throw, lift and lunge rather than just sitting around stretching.
  • Static stretching doesn’t change muscle architecture so it doesn’t return a muscle to a natural state.
  • Blood pooling is massively over exaggerated, and a gentle walk would be a far better way of encouraging recirculation than stretching.
  • Fall risk is best reduced through strength and proprioception training, not flexibility training.
  • And athletic performance is not enhanced through flexibility unless the sport specifically requires it.  In fact, too much flexibility work can negatively impact muscle stiffness qualities.

Effects of being inflexible

For the most part, there are no negative effects of being inflexible, unless your lack of flexibility impacts your ability to conduct day to day tasks.

As an example, if you’re recovering from a shoulder injury and your flexibility is very poor, preventing you from reaching overhead or properly out to the side, then it would be a good idea to follow a flexibility programme to restore full joint range of motion.

There’s also some mixed evidence suggesting inflexibility at certain joints can contribute to less desirable postures; for example tight pecs contributing to rounded shoulders, or tight hips contributing to an anterior pelvic tilt.  So if you believe your posture to be a problem, introducing some simple flexibility exercises might have some benefits.

Types of Flexibility Training

Static Stretching

For the most part, when people talk about flexibility training, this is what they’re referring to.  It involves moving into a position that lengthens a muscle, and then holding that position for anything from 20 seconds to 5 minutes.  This is frequently used as part of yoga and pilates routines.

If you’re going to use this type of stretching, the best time to do so is when you’re already warm, with good blood flow, so right after a workout is ideal.

Myofascial Release

Myofascial release is often seen around the gym in the form of foam rolling.  People argue that foam rolling can break up adhesions in muscle and connective tissue, increasing flexibility.

These people are wrong.

The amount of pressure you would have to exert on human muscles to actually physically change their structure would be at least 50-100 times that of anything a foam roller could apply.  It would also be excruciating, we’re talking medieval torture levels of painful.

So what does foam rolling do?  Well, put simply, it feels nice, sort of like a massage, which helps you to relax, and relaxed people tend to be more flexible.  But this effect only lasts for around 10-15 minutes.

Dynamic Stretching

Dynamic stretching involves moving in and out of various positions that lengthen certain muscles.  For example, performing leg swings, shoulder and arm rotations, or exercises like squats and lunges.

There is good evidence to suggest that dynamic stretches can be used as part of exercise warm ups to increase blood flow, improve joint range of motion and enhance performance.

Personally, this is something that I’ve used as part of my coaching practices with numerous high-performance sports teams and athletes.

Flexibility versus mobility: health and performance considerations

So why is dynamic stretching so much more effective than static stretching?  Well, that’s because it falls into the category of ‘mobility’ training rather than simply flexibility training.

Mobility is best defined as a combination of strength and flexibility, i.e. not only do your joints have large ranges of motion, but you also have plenty of active strength throughout those ranges.

A good example of this is the 7 year old kid in the playground versus the professional gymnast.  Both of them can touch their toes, and put their legs behind their head, and do back bridges and something akin to a front and side split.  But only one of them can move in and out of those positions with control, grace and precision.

With good mobility based training, you can become more like the gymnast, and less like the 7 year old.

Sport performance benefits of flexibility?

If you’ve been paying attention all the way through, then you’ll probably be able to guess that there are not very many sport performance benefits associated with flexibility.

For all sports, so long as you have the necessary range of motion to achieve the positions required to play the sport, you have enough range of motion for optimal performance. There’s no evidence to suggest that spending hours increasing your flexibility beyond that point is anything other than a massive waste of time.

Within most sports, an athlete’s ability to contract muscles and express force rapidly through a range of motion is paramount.  Adding additional range of motion without also building the strength and force generation capacities through this new range of motion is a poor idea.

Now, before you go completely losing hope, there are SOME benefits of static stretching for sports performance.  Research has shown that static stretching after hard workouts can reduce the amount of range of motion temporarily lost due to muscle damage from 10% down to about 6%.  For athletes who participate in multiple day competitions, this may be useful to know.

Frequently Asked Flexibility Questions

What is the impact of age on flexibility?

Over time, if you’re inactive, your flexibility will reduce as you age.  Regularly engaging in any form of exercise has been shown to help maintain your flexibility.  Dynamic mobility work which combines strength and flexibility is the single best way to maintain your flexibility for as long as possible.

When is the best time to do flexibility exercises?

Static flexibility exercises are best performed when already warm, so right after a workout or walk is a great time.

Dynamic mobility exercises can be performed as part of your warm up, as well as being part of your main training session.  For example, light bodyweight lunges are a great warm up exercise, and can also be loaded with dumbbells or barbells as part of the main session.

Next steps: recommendations on how to improve flexibility 

  1. If your goal is to increase flexibility simply because you wish to be more flexible, then feel free to do as much static stretching as you want.  A good starting point is 10-15 minutes per day.
  1. However, if your goal is to improve sport performance, reduce injury risk or improve coordination, then we recommend using dynamic mobility based exercises that build strength through range of motion.  Here’s a great video example of what that might look like for hip and ankle mobility.  
  1. For further reading on key sport science concepts, check out our articles on muscular strength, muscular endurance and power.

Or for more on the 5 components of fitness, check out this article.

Further Reading


If you quote information from this page in your work, then the reference for this page is:

Parry, A (2021). Muscular strength: defined, explained & how to train. Available from: https://sportscienceinsider.com/flexibility-workouts-explained-how-to-measure-how-to-train/ [Accessed dd/mm/yyyy].

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Alex Parry header image
Alex Parry
British Weightlifting Tutor & Educator at Character Strength & Conditioning | Website | + posts

Alex is the Owner and Head Coach of Character Strength & Conditioning, and specialises in strength & power development for athletes.

He currently works as a Tutor & Educator for British Weightlifting, and has previously delivered S&C support to gymnastics and swimming talent pathways.