Coupling phenomena during asynchronous submaximal two-hand, multi-finger force production tasks in humans.
We studied asynchronous two-hand multi-finger force production at submaximal levels. Subjects produced constant levels of force with one hand (F(REF)), and started ramp force production with the other hand (F(RAMP)) 3 s later. The zero-maximal force-zero ramp lasted 10 s. Visual feedback was provided only for F(REF) during the first 3 s and only for F(RAMP) during the rest of the trial. The initiation of F(RAMP) induced a transient overshoot by F(RAMP) and a drop in F(REF); both scaled with F(REF). Later into the trial, F(REF) dropped slowly, while F(RAMP) undershot maximal force by about 15%. Two regimes of bimanual interaction are hypothesized, 'strong interaction' when an effector is added to a one-hand task, and 'weak interaction' during two-hand force production.
D000328:Adult; D005260:Female; D005385:Fingers / Q000502:physiology*; D007839:Functional Laterality / Q000502:physiology*; D018737:Hand Strength / Q000502:physiology*; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D008297:Male; D009048:Motor Skills / Q000502:physiology; D018763:Muscle Fatigue / Q000502:physiology