where α is the pennation angle (Kumagai et al., 2000).Thus, fascicles were assumed straight and the model did not account for fascicle curvature. The error involved with this technique has been shown to be reasonably low(~2.3%) in contracted Tibialis Anterior (Reeves and Narici, 2003), where fascicle curvature is significant.Given that fascicles in the relaxed muscle are relatively
straight (see Figure 1; right), we estimated that our error would be somewhat smaller.