We talk so much about neuromuscular reprogramming, usually addressing the neural side because this aspect of movement are the first changes a body makes to a training session. In fact, your nervous system can make huge improvements after just one workout. However, what about the muscle structure these nerves supply, the meat itself? These improvements take time, weeks to sometimes months, but are well worth the wait.
To begin, we’ll lay out a couple basic structural aspects, fascicle length and muscle pennation. To avoid a longer discussion, we’ll just define fasicle length as the length of a bunch of muscle fibers bound together. And muscle pennation is the angle at which these fascicles are oriented relative to the tendon to which they attach. Think of it like a feather, where these fibers all attach to a central quill. A 2011 Study out of the Edith Cowan University in Western Australia specifically looked at these structures and their role in one of the more basic, athletic movements, jumping.
These authors, and previous research, have found that longer fascicles increase the potential contractile velocity and the ability to produce force at higher velocities. It’s like giving your car a higher gear in order to drive faster, and the quality we call, FORCE.
Another major finding was that the muscles with more pennation were better able to resist forces due to the increased surface area to distribute impacts, like landing from a jump or stopping to change running direction. This ability we call RATE, referring to the athlete’s capacity to decelerate movements quickly.
So to improve your FORCE, or your fascicle length, higher velocity movements are your best option as exercises like sprinting or jumping are more associated with these muscular changes. Pennation angle, the major structure associated with increases in RATE, is improved by heavier movements like weightlifting. The bonus is that these heavier lifts have also been shown to improve fascicle length, so do not pursue just one avenue of either speed or strength as both pursuits will ultimately affect FORCE and RATE, just in different proportions.
You won’t necessarily see these changes in pennation or fascicle length, but you’ll be able to drive faster and stop sooner.