Re: Is it possible to isolate pinky finger movement?

Training Muscles for New Tasks

You reference an answer to previous question, where I outlined that muscle tendons sometimes fuse so that they act upon more than one joint at the same time (in this case the joints of the fourth and fifth fingers). You ask specifically if a muscle can be taught a new movements that it would not naturally perform.

It seems like all my Mad Scientist answers are the same – “It depends.” The way you phrase the question – teaching a muscle to act in a way that is not natural – means that a strict answer to your question is no. If a muscle does not cross a joint, it cannot act upon that joint. So, if this is the reason why the muscle does not act in the way you ask, then no amount of training will change that.

But, of course, it is rarely that simple. The organs that we call muscles are actually collections of individual motor units (muscle fibers) that tend to work together, but they don’t have to. If muscle fibers are available that are mechanically capable of performing the action in question, then it is theoretically possible to selectively activate just those muscle fibers. In this case the possibility is dependent upon neural control. Is there a nerve fiber that can selectively activate just those muscle fibers? If the answer is no, then those muscle fibers cannot be activated independently. If the answer is yes, than it should be possible to develop a training regime that will take advantage of that unique neuromuscular connection. In fact, some aspects of rehabilitation therapy are based upon this relationship. After neural damage, rehabilitation therapy teaches a person to make greater use of the neuromuscular connections that are left behind.