%0 Journal Article %T Application of Biomechanics in Treating the Athlete: The All Important Measurements of Relaxed Calcaneal Stance Position, Achilles Flexibility, and First Ray Range of Motion. %A Blake RL %J Clin Podiatr Med Surg %V 40 %N 1 %D Jan 2023 %M 36368850 %F 0.769 %R 10.1016/j.cpm.2022.07.007 %X Biomechanics is a crucial component of treating lower extremity pathology. The relaxed calcaneal stance position, the Achilles flexibility, and the first ray motion and position tests are demonstrated and should be mastered. The relaxed calcaneal stance position is crucial in children's flat feet treatment, adult acquired flat feet, and all pronatory symptoms. The Achilles flexibility measurement demonstrates normality, tightness, or overflexibility. Tightness and overflexibility denote weakness owing to the contractile properties of the tendon. The first ray motion and position examination elucidates whether the first ray is normal or part of a pronatory problem or a supinatory problem.