Effects of health locus of control and health value upon EMG biofeedback training

Subjects who scored highly internal or external on a health locus of control scale and who scored high or low on the value each attached to good health were each given two sessions of frontalis EMG biofeedback training in accordance with a 2 x 2 x 2 factorial design. It was predicted that both internality and high health value would be positively associated with ability to control EMG and that these influences would combine additively. The predictions were not supported but a significant interaction between internality and health value was found. This interaction could be explained by assuming that both internality and high health value increased drive which in turn produced greater muscle tension, the relationship between drive and muscle tension being an ascending sigmoid function.