Orofacial and Hand Force Dynamics in Neurotypical Children

Currently, there has not been sufficient research conducted regarding fine force muscle control in the face and hands of neurotypical children, specifically finger-thumb grip and lower lip compression. Additional research regarding fine force muscle control in neurotypical children would provide further knowledge about biomechanics and force dynamics in children, as well as help establish normative data and a more complete picture of lifespan neurodevelopment for fine motor control. This knowledge has applications in treatment and diagnostics in a clinical setting. Using the ForceWIN10 system, this study examined muscle force dynamics using a series of voluntary ‘ramp-and-hold’ muscle contractions in the lower face (lower lip elevation) and hand (thumb-index finger grip). Four target forces were tested (ranging from 0.25N to 2.00N), using visually guided force targets. This study found main effects related to age, sex, and muscle group tested. The younger children had lesser degrees of end-point accuracy and greater inconsistency in force peaks and hold-phase stability when compared with older children. Males overall exhibited larger maximum voluntary contraction forces (MVCF) than females across muscle groups. The lower lip showed slower reaction times, lower MVCF, and greater hold-phase variability and standard deviation than the fingers