The Difference Between Mobility and Flexibility

There are some things in life that get interchanged and used as one and the same. One example that comes to mind is dietitian and nutritionist.

A dietitian is the professional designation reserved for those that are accountable to a regulatory college. The same is not required to be a nutritionist. So the term nutritionist can be used by anyone and can be hard to know what is meant when it is used.

Another example of terms that get mixed up can flexibility and mobility. While they are related they are not the same.

An article by Eric Cressey and Toby Brooks does a great job of distinguishing between the two. The table below highlights some of the key differences between mobility and flexibility.

Flexibility is typically something we consider in a clinical setting. For example, you might be on a table at the physiotherapist and they check the flexibility of your hamstrings. Compare this to our mobility which we would tend to look at when loaded, such as when we are standing. A coach might look at whether an athlete can touch their toes or what their hinge looks like.

With flexibility adding strength or power to the mix has a detrimental effect. Imagine performing a stretch but doing so with added external force or speed and this may lead to a poor outcome. Mobility however can be improved when we add some resistance to the drill. The swimmers we work with will be familiar with performing some banded shoulder dislocates or banded pull aparts during their warm up.

Neuromuscular efficiency refers to having the right muscle fire at the right time and in the right plane. There is a significant neuromuscular influence with respect to mobility training. Flexibility training has minimal neuromuscular influence.

When we are working on our flexibility this usually involves only one or two joints. Picture raising the leg to the ceiling with a straight knee while on your back. Here the hip joint is the key one involved. Compare this to hinging back at the hips while reaching forward with the hands. Now there is involvement of the ankle, hip, t-spine and shoulder.

Fascia helps connect the body. When we stretch focussing on just one joint there is minimal involvement of the fascia. For this example, imagine wearing a tight fitting wetsuit. When on your back on the ground you won't feel the stretch of the wetsuit through the back and shoulders. If you stood up and touched your toes you'd feel the stretch of the wetsuit on every part of the back of the wetsuit.

When assessing flexibility this can be done on the ground, unloaded with a goniometer to measure the angles between joints. Mobility can be assessed with various movements such as a toe touch or a squat. As well, mobility needs to be re-assessed as it has a significant neuromuscular influence and is facilitated with strength and power. As young athletes, develop, mature and get stronger we should changes in their mobility.

In terms of when we should perform flexibility training this is best done after training or outside of training sessions. When performed before training this results in lower power outputs and a poorer training experience. This occurs because static stretching, which flexibility training is, makes the musculotendinous unit more compliant. The joint will then yield more to the external force and result in an energy leak. Mobility training has the opposite effect and enhances power outputs. This is partly due to the significant neuromuscular influence on mobility training. Plyometrics, sprints and med ball work don't necessarily make us stronger or fitter but they do help us develop force more quickly which has to do with our nervous system.

Going forward keep in mind how flexibility and mobility differ. Mobility training can and should be incorporated into a training sessions whereas addressing flexibility should be done outside of training. Not only is mobility work facilitated by strength and power, it can also be used in between sets to address muscular imbalances and lead to better results.

Brooks, T., & Cressey, E. (2013). Mobility training for the young athlete. Strength & Conditioning Journal, 35(3), 27-33.