by Dave Rohe
To understand the title of this Physio Talks better, it may help to know a bit about the neurological principle stated eloquently in the phrase ‘the brain knows movement, not muscles.’ Like many succinct phrases that is an over simplification. But the essence is still true, the brain and spinal cord organise movements using many highly coordinated muscle contractions and relaxations to accomplish a movement task. The brain does not organise one muscle at a time, but many muscles whose interactions are timed to make a coordinated movement. When more strength is needed, more of some muscles become involved, while others need to dampen their efforts and others start to contract to make sure the joints involved are protected and move in the proper direction. It’s rather marvellous to think about, actually.
So, when someone requires rehabilitation, or wants to get stronger at doing something, or just become more coordinated at doing something, the best way to go about it is to repeatedly perform the needed motions against resistance. The traditional way to go about retraining, or advanced training, which is rapidly disappearing from PT as a treatment method, is to decide which muscle or muscles are the main ones responsible for the movement(s) under consideration and then to develop an exercise program for each muscle to make it stronger, longer or whatever. So, if someone has difficulty rising from a chair because his/her thighs seem weak, the traditional exercise regime has the person sitting on the edge of a table and doing knee straightening exercise against resistance to make the quadriceps on the front of the thigh stronger, because they are the primary knee straighteners - everyone knows that strength of knee straightening is very important to rising from a chair.
Will this exercise help the person rise from the chair more easily? Eventually, yes. But if the person needs to improve rising more quickly, or if the person must not only rise but walk away as quickly as possible, exercise specificity must be applied to the problem. So, rising from the chair used as the exercise will not only involve knee muscles, but also trunk, hip, and ankle muscles. To make it easier at the beginning of training, because the person wouldn’t need the physio if it was easy already, we might start from a higher seat, then lower the seat to increase the effort as the person gains strength, until we could have the person on a regulation chair height holding addition weight in their hands to increase the effort more. They would then be strengthening everything needed to stand in a faster, easier and more coordinated fashion.
This example is just that, an example. But it works for many necessary exercises. It even works with professional athletes, who are perfectly healthy but need to perform at a higher level in order to win. You will see pictures of athletes running with parachutes attached behind, or pushing against weighted sleds, or swinging leaded bats, or throwing weighted balls, all using the required motions to accomplish the coordinated act while repeatedly doing the activity against higher than usual resistance. Exercise specificity.
So, the next time you find yourself needing to perform some activity better, either because of injury, disuse over time or wanting to compete at a higher level, consider the motion rather than the muscle.
These comments are general in nature. Be sure to check with your physio or doctor if you are not sure whether they apply to your situation.
by Dave Rohe