Reliability of a simple method for determining muscle fiber conduction velocity

This study evaluated the reliability of muscle fiber conduction velocity (MFCV) measurement. Methods: Forty healthy, young participants performed isometric dorsiflexion of the foot on 3 non‐consecutive days. The reliability of force, root‐mean‐square (RMS) amplitude of the surface electromyographic (sEMG) signal, and MFCV were evaluated using the intraclass correlational analysis of variance technique. Results: The means across test days for all measures exhibited slight changes (<5%) and were considered stable. All measures exhibited remarkable consistency within subjects as indicated by high intraclass correlation coefficients (0.83–0.98). Conclusions: The procedures resulted in highly reliable MFCV values, and included: (1) electric identification of motor points prior to electrode placement; (2) twitch identification of muscle fiber orientation to guide initial electrode placement; (3) rotation of electrodes clockwise or counter‐clockwise to maximize the similarity and delay of compound muscle action potentials across all detection surfaces; and (4) minimization of synergistic activity during voluntary contractions. Muscle Nerve, 2012