Motor program concept says that our movements are pre-programmed in an open-loop fashion. Imagine a seed which has a blueprint of what it wants to become in its core. Especially this motor program concept is applied to explain fast movements that are around 100-150 ms. If such were the case, would it then be possible to have programs/engrams stored in our brain for each and every action? Could this immense storage of the motor program in brain feasible? Another question that can come will be for novel movements. What about certain movements that we have never done before? Do you think that program is also imprinted on our brain?
Generalized motor program concept gives a solution for both the storage and the novelty problems. It says that by modifying the parameters such as force and timing of the movement you could have a single motor program that could be customized for different patterns.
A common example would be the walking pattern: you could walk slowly or fast, trot or run slowly or fast. Shapiro (1981) in his experiment showed the ratio of timing of a single step (100%): See the diagram. Now this ratio was unperturbed when the subject was walking or running. What does it mean? In slow walking the timing parameter was slower and for running the timing parameter was faster in the common motor program that oversees both walking & running! Another example to think about is a familiar song one could sing quickly-slowly or loudly-in whispers. You can make out the original song due to its fixed ratio of the timing and note of the song. Here all you have done is changed the parameters of that song with respect to time and audibility. The same thing applies for the handwriting, whether you write in your right or left hand or with foot or manipulating a pen between your teeth. One could make out the unique pattern of an individual’s writing style!
Ref:
Schmidt, R.A. (1988). Motor control and learning: A behavioral emphasis. Champaign: Human Kinetics.
Shapiro, D.C., Zernicke, R.F., Gregor, R.J., & Diestel, J.D. (1981). Evidence for generalized motor programs using gait-pattern analysis. Journal of Motor Behavior, 13, 33-47.
