Upper trapezius muscle conduction velocity during fatigue in subjects with and without work-related muscular disorders: a non-invasive high spatial resolution approach

摘要: The development of fatigue at the muscle fibre level can be assessed in terms a decrease conduction velocity (CV). present study aimed to investigate if work-related muscular disorders occupations characterised by static loads long duration affect resistance painful muscle. A group eight secretaries suffering from bilateral chronic pain shoulder/neck region was compared healthy subjects. upper trapezius studied under isometric contractions, holding arm horizontal plane up endurance point. Changes CV estimated motor unit were investigated using non-invasive high spatial resolution electromyographic (EMG) approach. In addition, number potentials per second (PPS), and root mean square (RMS) bipolar signals assessed, results reported as standard error for each value. Subjects with showed less pronounced changes respect No differences between subjects without encountered PPS RMS. findings on indicate an increased fatigue-related recruitment MUs fact that this is not reflected RMS estimates might due fatigue-induced firing rate and/or de-recruitment fatigued MUs. Furthermore, methodological limitations adopted method estimation ‘global’ parameters such have considered.