Fig. 5. The comparison of attachment performances between commercial array and MEAP.

a, e Photographs of CA and MEAP attachment, illustrating the difference when recording from muscle and muscle-tendon junction of biceps brachii. b, f sEMG signals recorded using CA and MEAP on muscle and muscle-tendon junction of biceps brachii. Four typical channels were picked for each recording. c, g Spatial SNR performance map for each channel of CA and MEAP for the first and last muscle contraction. SNR_f: SNR of the first contraction; SNR_l: SNR of the last contraction. d, h Statistical analysis of performances of CA and MEAP, including baseline noise level of CA before and after one or three muscle contractions, as well as after reattachment; baseline noise level of MEAP before and after ten muscle contractions; baseline noise change rates before and after muscle contractions; SNR performance of the last muscle contraction recorded by each of the CA and MEAP channels (n = 64 for each measurement). The box plots show the mean (centre square), median (centre line), the 25th to 75th percentiles (box) and the smallest and largest value that is ≤1.5 times the interquartile range (the limits of the lower and upper whiskers, respectively) Significance was determined by one-sided t test (*P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001).