Reliability and precision of EMG in leg, torso, and arm muscles during running.

Changes in electromyographic (EMG) parameters are used to evaluate timing, amplitude, and fatigue of muscle actions during movement. Little published data describe the reliability and precision of multiple EMG parameters, how these parameters compare to one another, and how these parameters vary between muscles. The purpose of this study was to determine the reliability and precision of four EMG parameters recorded from the legs, torso, and arm muscles during running. Fifteen well-trained male runners performed moderate-intensity treadmill running while EMG data were collected from thirteen muscles. Integrated EMG (iEMG), root mean square EMG (RMS), maximum M-wave, and median power frequency (MPF) were calculated for 25 consecutive strides. Intra-class correlation coefficients (ICC) and standard error of measurement (SEM) for each parameter were calculated for each muscle. Seven muscles displayed good reliability (ICC>0.80) for all parameters studied. MPF was the most reliable variable, with 12 muscles having ICC>0.80 and <6% normalized SEM. Reliability and precision differed between muscles of similar function and anatomic region. These data emphasize the need for researchers and clinicians to have reliability and precision measures for all parameters of each muscle, and demonstrates that generalizations must be used cautiously when interpreting EMG data collected during running.