Covert muscle excitation is outflow from the central generation of motor imagery

Two studies were conducted in an attempt to examine inflow and outflow processing by examining covert muscle excitation during motor imagery (MI) and its correlation with motor task performance. Examining 80 novice dart throwers in Experiment 1, MI produced greater levels of covert excitation at the dominant biceps in comparison to control imagery (CI). In addition, covert excitation correlated significantly with imagery ability and imagery vividness. This excitation, however, did not predict motor task acquisition or retention. Experiment 2 attempted to manipulate pre-imagery relaxation states by giving 104 novice dart performers a relaxation task or a distraction task before imagery sessions. MI resulted in improved task retention and resulted in significantly greater covert muscle excitation at the frontalis in comparison to CI. The relaxation condition, however, did not yield greater levels of muscular relaxation in comparison to the distraction condition, and did not yield greater imagery vividness or motor performance. Finally, covert muscle excitation did not predict motor acquisition or retention error. Results suggest that covert excitation is a byproduct of the central generation of the image that does not relate meaningfully to motor skill acquisition or retention gains.