Jaw Muscle Electromyographic Response to Whole-Body Postural Perturbation

Area of Science:

• Biomechanics
• Sensorimotor control
• Human physiology

Background:

• Whole-body postural control relies on sensorimotor integration.
• The specific role of jaw muscle activity in postural stability is not well understood.

Purpose of the Study:

• To investigate the relationship between jaw muscle activity and whole-body postural stability.
• To measure jaw muscle activity and postural sway during predictable and unpredictable postural perturbations.

Main Methods:

• Twelve healthy adults experienced vertical perturbations while holding a bar.
• Jaw-opening (anterior suprahyoid) and jaw-closing (masseter) muscle activity were measured via surface electromyography (EMG).
• Whole-body postural sway was assessed using motion capture and a force plate.

Main Results:

• Greater vertical bar displacement occurred during uncued (unpredictable) perturbations compared to cued (predictable) ones.
• Jaw-opening muscle activity exceeded baseline in significantly more uncued trials than cued trials.
• Center-of-foot-pressure (COP) displacement increased when jaw muscle activity exceeded baseline during uncued perturbations.

Conclusions:

• Increased activation of jaw-opening muscles during unpredictable perturbations suggests their recruitment for postural control.
• These findings support the involvement of jaw muscles in maintaining whole-body stability.