When we think stiffness, we think “bad,” but that isn’t necessarily the case. In fact, some stiffness can be good. For example, tight hamstrings help many ball players jump higher. So how do you know when your stiffness is good or bad? Here are some things to consider.

It depends…
Eric Cressey, trainer and author of Functional Stability Training: Optimizing Movement, says the difference between good and bad stiffness depends on the person. This is particularly true for people who carry a lot of stress and tension in the body. This kind of stiffness leads to inflammation and limits range of motion. Working with a trainer or therapist can help to realign the body to create stiffness in one place with the goal of releasing stiffness or tension, and improving range of motion, in another place like the shoulders for example. Stiffness here is probably related to activation of the sympathetic nervous system. This is our fight or flight response that keeps us tense and ready for battle – even when there is no danger. The goal is to activate the parasympathetic nervous system, or rest and digest. Here the nervous system feels safe and calm – muscles respond accordingly.

Good stiffness can come when the parasympathetic nervous system is activated
Trainer Tony Gentilcore offers his thoughts on the benefits of stiffness. This is a gem from his post, Stiff hamstrings can affect the ability to flex and extend the hips. However, more importantly, the ASLR (active straight leg screen) is about teaching people to get into better positions – improving stiffness in other areas – to “trick” the CNS (central nervous system) into turning off the emergency breaks.
When people are in more optimal positions (better alignment) what presented as “tight” or stiff is no longer the case.
Good stiffness
Stiffness is good when it helps to improve alignment, strength, mobility, and dynamic motor control. As an example, Gentilcore offers that stiffness in the anterior core promotes posterior pelvic tilt thus improving (rather than limiting) range of motion in the hips. Stiffness in the lats may improve efficiency with deadlifts.

Bad stiffness
Pain and limited range of motion often signal stiffness. This kind of stiffness is often caused by or leads up to an injury such as a sprain or tear, not to mention an increased likelihood of faulty movement patterns up and down the kinetic chain, says Gentilcore. The problem with bad stiffness is that it may indicate overactivation of the nervous system. This increased sensitivity can impede performance in everything from lifting, to jumping and running.

What can help
Yoga is helpful for getting in a more flexion based approach (ball player LeBron James practices yoga). Good stiffness can improve biomechanics and reduce the likelihood of injury from bad stiffness. Physical therapy and working with a trainer can also help. According to Cressey, even taking a deep breath can relieve tightness.

Regardless of the kind of stiffness you have, stop if you feel pain.