Details on Subjects and Experimental Trials used for Regression Fits.

<p>: Body weight (kg), and : Body height (m),</p><p> and : Minimum and maximum gait speed (m/s)</p><p> and : Minimum and maximum hip quasi-stiffness in extension stage (Nm/rad)</p><p> and : Minimum and maximum hip quasi-stiffness in flexion stage (Nm/rad)</p><p> and : Minimum and maximum hip excursion in extension stage (deg)</p><p> and : Minimum and maximum hip excursion in flexion stage (deg)</p><p>: Average of the linear fit on moment-angle curve in extension stage</p><p>: Average of the linear fit on moment-angle curve in flexion stage</p><p>‡Data collected at Human PoWeR Lab, NC State University <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0081841#pone.0081841-Farris1" target="_blank">[16]</a></p><p>†Data collected at Biomechanics Lab, East Carolina University <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0081841#pone.0081841-Hortobgyi1" target="_blank">[55]</a></p><p>•Data collected at Laboratory of Biomedical Technologies at Politecnico Di Milano.