Evaluation of the neuromuscular compartments in the peroneus longus muscle through electrical stimulation and accelerometry

BACKGROUND: Muscles are innervated exclusively by a nerve branch and possess definite actions. However, mammalian skeletal muscles, such as the trapezius, the medial gastrocnemius, and the peroneus longus, are compartmentalized. In the peroneus longus muscle, multiple motor points, which innervate individual neuromuscular compartments (NMC), the superior (S-NMC), anteroinferior (AI-NMC), and posteroinferior (PI-NMC), have been described. The contribution of each neuromuscular compartment to the final action of the muscle is fundamental for the rehabilitation of patients afflicted by neurological and muscle dysfunctions. Interventions are often based on electrical principles that take advantage of the physiological characteristics of muscles and nerves to generate therapeutic effects. OBJECTIVE: To compare the effects of stimulating the different neuromuscular compartments (NMCs) of the peroneus longus muscle on the motor threshold (MT) and acceleration of the foot. METHOD: This is a cross-sectional study comprising 37 subjects. The three NMCs of the peroneus longus muscle were stimulated, and the acceleration of the foot and the motor threshold of each NMC were evaluated. A repeated measures analysis of variance with Bonferroni corrections of two intra-subjects factors was performed. RESULTS: The stimulation of the different NMCs did not result in any differences in MT (F=2.635, P=0.079). There were significant differences between the axes of acceleration caused by the stimulation of the different NMCs (F=56,233; P=0.000). The stimulation of the posteroinferior compartment resulted in the greatest acceleration in the X-axis (mean 0.614; standard deviation 0.253). CONCLUSIONS: The posteroinferior compartment primarily contributes to the eversion movement of the foot. NMCs have specific functional roles that contribute to the actions of the muscles to which they belong. .

KINEMATIC ANALYSIS OF AN ANKLE INVERSION SPRAIN − A NEW EVALUATION TECHNIQUE − / 体力科学

The purpose of this study was to measure and analyze peroneus longus reaction time (PRT) as well as ankle movement during ankle sprain simulation. PRT was measured for six control ankles and six unstable ankles with an inversion ankle sprain (1 male and 5 females per group, respectively) using an ankle inverting platform and high speed camera. The unstable group showed a significantly slower PRT (58.8±8.7 ms) than the control group (46.5±8.1 ms). The inversion angular velocity was significantly faster in the unstable group (152.8±62.6 d/s) than the control group (83.2±38.4 d/s). There was no significant difference between the two groups regarding ankle eversion time. Our results indicate that it is important to lead an unstable ankle to reduce inversion angular velocity to prevent recurrent inversion ankle sprain.