Temporal Organization in a Repetitive Speed Skill

Abstract

The investigation sought to recognize the strategies of effector organization used by the human operator, from a detailed multi-level analysis of the response in a repetitive speed skill, hand cranking. In the experiment motion photography, a strain gauge record of the force exerted on the handle of the crank, and an electromyographic analysis of the activity of the principal agonist and antagonist muscles about the wrist, elbow and shoulder joints of the arm were employed to record the details of the on-going response.

Effector organization was evaluated in terms of serial timing and positional timing. The serial timing of the response units involves (i) the sequencing or ordering of these units and (ii) the phasing or temporal structuring of these ordered response units. Positional timing is the relationship between the occurrence of the response and an external event or signal.

The analysis of the results showed that phasing is of central importance in the organization of the response by effector processes. This form of temporal structuring appears to be more significant than positional timing. There was some evidence that the faster subjects were also the more consistent in the temporal organization of the response. It is suggested that the skilled performer establishes a relatively stable motor programme in which the instructions initiating the principal events are ordered into a well defined temporal sequence which operates in part in an open-loop fashion.