Stiffness: What You Need To Know

Stiffness is a common concern for athletic performance, injury prevention, and a concern as we age. Lets do a deep dive in what you need to know about stiffness, how to combat it, and how it helps you in performance. 

What exactly is stiffness? 
Stiffness is how much collagen you have and the direction in which it is facing. This creates crosslinks which generates stiffness. When you exercise you increase lysyl oxidase which accumulates more crosslinks.

More Crosslinks = More Stiffness

Less Crosslinks = Less Stiffness

How do we build or break crosslinks?
The speed in which you train has the greatest impact on crosslinks. Fast exercise adds crosslinks (stiffness) Slow exercise breaks crosslinks.

Fast Movements = More Crosslinks = More Stiffness

Slow Movements = Less Crosslinks = Less Stiffness

Stiffness is a necessity 
Stiffness is needed in activities like jumping, sprinting, and pretty much any activity that requires speed and power. An absence of stiffness can potentially increase the risk of injuries especially within the tendons and ligaments. We should think of managing stiffness for the individual instead of erratically eliminating it. 

Injury Prevention & Rehabilitation 
The faster the athlete the more muscle pulls we see because of the crosslinking accompanied with stiffness. Women tend to get less muscle pulls because estrogen inhibits lysyl oxidase so tendons are less stiff, less power, but less muscle pulls. It is the same collagen in knee so they are at a higher risk of ligament injury.

If you have a history of muscle pulls it would benefit you to add slow movements to level out the consistency of your tissue built by crosslinks. The slowest movement is an isometric. While traditionally isometrics are thought of as non-movement like wall-sits we now know that while the joint is not moving there is movement and tension change within the tendon and muscle. 

The key thing with isometrics is not type of isometric but how long you’re holding for. 

Rule of thumb for training stiffness
For health based movements and recovering for sport 30 sec holds are recommended.  After 30 seconds the tension reduces in the tendon while the muscle sheath slides. This is recommended to do 6-8 hours outside of your sport specific training or skill work. 

 0-30%  of max effort done fast can increase stiffness. For high velocity you can’t do as many reps/sets because you can’t maintain the velocity as well so keep that in mind while you program. Quality over quantity. 

Highlighted Expert Keith Baar