Figure 3. The duty times of the masseter of animal #5. (A) The hourly 5% duty time of the superficial masseter during the third (thick line) and fourth (thin line) experimental days. The bar above the curves indicates the day (open) and night (solid) periods. The 5% (B), 20% (C), and 50% duty times (D) for the superficial (open) and deep (solid) masseter regions as recorded during all experimental days. Note that, at all activity levels and for the entire experimental period (7 days), the deep masseter region was more active than the superficial muscle.