What if you just FEEL more flexible?

Today I am going to geek out on you a little bit with some great info I got from a research article I recently read dealing with stretching and changes in flexibility.  When you do a flexibility program like the goalie’s Ultimate Guide for Durable and Flexible Hips, you see your range of motion improve.  You find you can get deeper into your splits without discomfort.  Can you tell me why?

You might think your muscles are getting longer.  How are they getting longer?  Is it a viscoelastic stretch where your muscles, like a rubber band, lengthen when they are stretched, but return to a normal resting length once the stretch force is removed?

Is it due to a plastic deformation where the stretch exceeds the elastic component of the muscles and connective tissue resulting in a permanent plastic deformation of the muscle?

With sustained stretching programs will your body actually add extra contractile units (sarcomeres) to individual muscle fibers, which adds length to the muscle based on the chronic demands on the muscle?

Other theories suggest that the protective stretch reflex becomes downgraded.  This is a protective reflex, which causes a muscle to contract when over stretched to reduce the risk of the muscle becoming overstretched and damaged.

Or is it due to a sensory change that occurs with the goalie-stretching program?  In other words, when researchers evaluate the effects of stretching programs on flexibility, they will often cue the research subject to stretch to the point of pain, discomfort, stretch, resistance or stiffness.  Could it be that with regular stretching the subject becomes accustomed to the sensation of stretch and can put more stress on the muscle, resulting in more range of motion, before experiencing what they interpret as discomfort or stretch.

As you can imagine it is very difficult to distinguish the exact mechanism that leads to the outstanding flexibility that comes with a consistent stretching routine.  Researchers cannot physically measure the muscle length, plastic deformation, number of sarcomeres or reflex activity following a stretching intervention.  Nor can they measure the sensory experience of the athlete.

For now, I want you to have an appreciation that there is very little understanding of how stretching improves flexibility, but as a goalie, the ‘how’ is none of your concern.  What matters to you is the fact that working consistently on your flexibility will result in more mobility.

If you are a bit of a science geek and want to learn more details about the concepts discussed in this post, then check out this great article from the Physical Therapy JournalIncreasing Muscle Extensibility: A Matter of Increasing Length or Modifying Sensation? Cynthia Holzman Weppler and S. Peter Magnusson.  2010; 90:438-449

Happy training!  Cheers,