Dimensions of model variations. The model of the average athletes’ dimensions was varied to investigate the effects of proximal aponeurosis width and muscle width on internal muscle tissue strain. For proximal aponeurosis width and muscle width variations, width was varied at each superior–inferior location and over the range of measurements. Widths were set to the minimum dimensions, the average minus one standard deviation, the average plus one standard deviation and the maximum dimensions. The average model corresponds to the average dimensions across all athletes. All other dimensions in the model variations remained at the values listed in Table 1. apo: aponeurosis.