I’m studying different exercise compensations and the associated underactive and overactive muscles that might be contributing to the problem… I really want to be able to think about the problem and apply it, not just memorize answers. Some just don’t make sense to me (even after looking at muscle insertions, origins, & actions). For example, the book states a knee moving inward on a single leg squat, overactive muscles = biceps fem(s.h.), lateral gastroc, and vastus lateralis. That doesn’t make sense to me given its actions. Can someone maybe help me find a different way to look at it so it makes better sense to me? Thx!
here is my understanding of it, using our example of the SL squat:
In the ideal world, a person doing a SL squat would do it in a way that the knees are tracking over the toes. That’s when all the major muscles involved have the correct postural starting point and none of them are lengthened or shortened before movement begins.
When you see this kind of compensation, it indicates that the gluteus medius is too weak to counteract the actions of the others, and thus the knee moves towards the mid-line. It does not mean that the ‘overactive’ muscles are super-strong but that the whole relationship between the muscles is off. Prolonged sitting can cause this chronic shortening for example.
That is the reason for the recommendation of doing SMR for the ‘overactive’ muscles followed by stretching to restore the proper relationship between muscles.
Does that help?
Hello Eileen Bochsler,
Karin Singleton explains this very well.
Another way to say it: the overactive are working more than the under active. The overactive are overpowering the under active.
It is like pairing new and old rubber bands with each other or tying something down with a new and old bungee cord. It can be like using a new rubber resistance on one arm and an old stretched rubber resistance on the other arm. Things are out of balance.
Look at the body to see what is in or out of balance or alignment.
I give you much credit for wanting to understand over memorize. Your future clients thank you and you will make a great trainer. Keep up that great attitude.
Natalie aka NAPS 2 B Fit.
I’m not sure if you are a subscriber of NASM’s monthly insider but NASM just sent an article last week about Overactive and Underactive muscles.
Great info, take a look at the link below.