Specificity

Specificity means that changes in your body are specific to the type and focus of training. If one performs strengthening exercises for the arms, one gains strength in the arms. Such an exercise may have some benefit for the entire body, but strength training the arms has limited aerobic benefits, since the primary purpose of the exercise is to provide muscular resistance. The concept of specificity also applies within a class of exercise, such as cardiovascular exercises. Someone who walks regularly may quickly be out of breath when swimming a lap at the pool. Walking moves the legs and arms in a particular way, with the legs doing most of the work. Swimming motions are entirely different; one primarily uses the arms. Any cardiovascular exercise has some crossover benefits; your choice of training activity may be affected by what your problematic joints can tolerate.

I briefly addressed specificity in chapter 1, when I discussed measuring your baseline. I suggested that you select a cardiovascular measure that would reflect the activity you are doing or plan to do. If you choose a different activity from the one that you used for a baseline measure, you may not see as much improvement as is actually occurring. Functional activities are quite specific, which is why they are good components of a training program. That very attribute, however, also limits their benefits. Remember the lady with the shoulder problem who practiced lifting her hand to her head as part of her rehabilitation. If she had done only that, with no other strengthening and flexibility exercises, she probably would not have been able to do other activities such as putting objects away in an overhead cupboard. Specificity, then, is one of the reasons you need a balanced program with cardiovascular, strength, and flexibility exercises.