Figure 2.

CV distributions in the FM and MCG groups: beginning and ending at 60% MVC. CV distributions in the FM (top) and MCG group (bottom) shown as two-second epochs at the beginning and end of a 60% MVC. Mean CV distribution values and skewnesses were significantly higher in the FM group (p < 0.001, Kolmogorov-Smirnov test). The numbers of identified MUAPs are also shown. MCG = matched control group; FM = fibromyalgia; s-EMG = surface electromyography; MVC = maximal voluntary contraction; MNF = mean power frequency of the spectrum; CV = conduction velocity; MPQ-SF = McGill Pain Questionnaire Short Form; FFS = Fibrofatigue Scale; ARV = average rectified value; CC = correlation coefficient; MUAP = motor unit action potential; MU = motor unit; DD = double differential.