It remains unclear whether the rhythmic processes of chewing and gait synchronize during concurrent execution in humans. To evaluate the entrainment of chewing rhythm by gait speed, we measured electromyography from the masseter and tibialis anterior muscles during chewing at a habitual rhythm while walking on a linear treadmill in 12 healthy volunteers. Vertical movement of the head was also measured using an accelerometer. Each 5-min session included gait tasks using a treadmill at three speeds: Auto: the participant's self-selected gait speed, High: Auto × 1.3, and Low: Auto ÷ 1.3. Electromyography from the masseter muscles were also measured during chewing while stationary (Chew-Only). Chewing rhythm during walking was the same as that for head movement, occurring at twice the speed of the walking rhythm, in nine participants (Low), eight participants (Auto), and eight participants (High). For these participants, chewing rhythm in the Auto and High conditions differed significantly from that in the Chew-Only condition. Significant differences in chewing rhythm were also observed among gait speeds　(Low vs. Auto vs. High). Our findings demonstrate that entrainment of habitual chewing rhythm to gait speed is a significant phenomenon, and that the dominant ratio of chewing-walking-head movement rhythms is 2:1:2.

中文翻译：

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人类跑步机行走时步态速度对咀嚼节奏的影响

目前尚不清楚咀嚼和步态的节奏过程在人类并发执行期间是否同步。为了评估步态对咀嚼节奏的影响，我们测量了 12 名健康志愿者在线性跑步机上行走时以习惯节奏咀嚼期间咬肌和胫骨前肌的肌电图。头部的垂直运动也使用加速度计测量。每个 5 分钟的会话包括使用跑步机以三种速度进行的步态任务：自动：参与者自行选择的步态速度，高：自动 × 1.3，和低：自动 ÷ 1.3。在静止（仅咀嚼）咀嚼期间还测量了来自咬肌的肌电图。步行时的咀嚼节奏与头部运动的咀嚼节奏相同，以步行节奏的两倍速度发生，在 9 名参与者中（低），八名参与者（自动）和八名参与者（高）。对于这些参与者，自动和高条件下的咀嚼节奏与仅咀嚼条件下的咀嚼节奏有显着差异。在步态速度（低与自动与高）之间也观察到咀嚼节奏的显着差异。我们的研究结果表明，习惯性咀嚼节律对步态速度的影响是一个显着的现象，咀嚼-行走-头部运动节律的主导比例为 2:1:2。