Fig. 4

Associations between practice-related changes in motor performance and EMG duration in healthy subjects extracted from 9 studies. a Data points for the agonist EMG duration (8 studies, 14 data points). b Data points for the antagonist EMG duration (5 studies, 5 data points). The number of data points is larger compared to the number of studies because a few studies studied multiple muscles. Muscles acting as both agonist and antagonist were excluded from data analyses. EMG electromyography, r Pearson’s correlation coefficients, R² coefficient of determination