Comparison to literature values. Musculotendon measurements for the BFlh were compared to select studies in the literature. If more than one measurement was reported in a literature source, the numbers were averaged. If more than one measurement location was available for the model or literature source (e.g., superior, middle, inferior), the numbers were averaged and the standard deviation is listed. When provided, percentage of the musculotendon unit length is listed in conjunction with the measurements. For the in vivo muscle volume comparison, the BFlh was outlined on all MR images, and muscle volume was calculated as the segmentation area times the slice thickness summed over the muscle’s length (Handsfield et al., 2013). Pennation angle measurements were averaged for the proximal aponeurosis (i.e., deep aponeurosis) and the distal aponeurosis (i.e., superficial aponeurosis). MR: magnetic resonance.