A Tuning Principle

Muscles get all the glory. They are what we think we are looking at when we see someone physically fit, and they are attributed with all the performance gains made by physically gifted individuals. What if there is another tissue type that is more responsible for these characteristics than meets the eye? What if connective tissue contributes more to movement than we give it credit?

Muscles are comprised largely of fibers that have been broken down into a number of different compartments, all leading to a contractile unit. What has been largely ignored until more recently is the connective tissue surrounding each of the fibers within those compartments, and its role in movement. Every single fiber is surrounded by connective tissue, think of it like a cellophane wrapping that is elastic. Not only that, but muscles are connected to bones by tendons, the rubbery stuff we notice at the end of the meat in our chicken drumstick. If those connective elements are deeply invested in the muscles from end to end and in-between, then what effect might muscles have on their behavior?

It might be that muscles behave like tuners. Their activity, or lack thereof, can effectively tune the connect tissue to act in a particular way. Think of the way you tune a guitar, the amount of tension you put on the strings alters the sound. Muscles may, in fact, do the same thing. They can pre-load the elastic tissues and prepare them for absorbing or releasing energy. The degree to which we place tension or slack on this tissue type could have profound effects on how efficient and effortlessly we move.

Some evidence suggests that the elastic components contribute thirty percent or more of the force production traditionally attributed to a muscle. Muscles may be more than the force producers during high level activities, they may be maximizing the ability of connective tissues to do their part. That might allow for more efficient movement which requires les energetic demands and promotes fluid motion across different types of activities.

Muscles have received much of the attention in the world of performance, with little paid to surrounding tissues and their effects. A more nuanced approach might reveal that the ability to efficiently utilize energy requires elastic mechanisms. Mechanisms stored primarily in connective tissue. We can utilize muscles to tune the guitar strings that create the sound that resonates most.

Austin Ulrich, Physical Therapist