Abstract
Previous authors indicate that females perform with more precision while males demonstrate larger force and rate of force development during manual goal-directed actions. The locus of these sex differences is currently contextualized under evolutionary (e.g., Hunter-Gatherer Hypothesis) and socio-cultural models (e.g., Sex-Specific Response Style Hypothesis). We investigated sex differences in the regulation of chuck-grip force using a submaximal force production task while measuring EMG and Force. 30 right hand dominant people participated (16 female; 18-30 years). Participants completed maximal contractions (MVCs) before and after the experimental trials. Using a chuck-grip (i.e., thumb in opposition to index and middle finger), participants pinched a force transducer to match force-profiles which contained three square-target pulses. Within the experimental trials, the three target pulses were either constant (i.e., 3x 45N), or variable (i.e., 1 each of 30N, 45N, and 60N in different orders). Males produced higher peak force (PF) in the MVC trials. During the experimental trials, participants had a lower peak rate of force development and a larger undershoot of PF for the first pulse. Females had a larger undershoot in PF during the constant force-target trials. Participants initiated force closer to the target time as the pulses progressed during a trial. During the constant force-target trials, males initiated force earlier than females for the first and second pulses. Results are evaluated in the context of modern models of the control of goal-directed action. Outcomes indicate the need to examine sex as a factor in the neurological functioning of the human sensory-motor system.
