Enhanced physiological tremor (EPT) associated with fatiguing static muscle contractions is generally thought to limit continuous muscle work. However, the EPT dies away, allowing the continuous muscle contraction to be maintained at low-level workload. Here, we report a case study of a 22-year-old male volunteer who performed static plantar flexion at 30% maximal voluntary contraction (MVC) for 66 min with repeated EPT events. Comparative analysis of 1 min pre- and post-EPT phases revealed lower electromyographic (EMG) activity, heart rate, and blood pressure levels during the post-EPT phases, while the popliteal artery blood-flow volume and vascular conductance were raised. EPT may therefore be a mechanism for removing factors that inhibit continuous muscle contraction. This unique case report provides new insight into the functional significance of EPT during prolonged static muscle contractions.
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