They were also asked to describe any lower extremity injuries. All questions were asked in either Rarámuri or Spanish, and then translated into English. Arch height and stiffness were assessed using an arch height index measurement system43 that measures total foot length, the length of the foot from the back of the heel to the first metatarsophalangeal joint (TFL), and the height of the dorsum of the foot at 50% of foot length (DH). Participants were measured both sitting and standing with 13 mm thick boards placed under the heel and the phalanges and metatarsal heads to enable the arch to move.

Navicular height was measured by having Apoptosis Compound Library individuals stand on a hard flat surface (a concrete floor or a wooden board), placing a small ink mark on the navicular tuberosity, and then measuring the vertical distance between the ground and the PD-1 antibody inhibitor mark using a rigid steel ruler accurate to 1 mm. Following Zifchock and colleagues,43 the arch height index (AHI) was calculated as DH/TFL both standing and seated; the arch stiffness index (ASI) was calculated as (body mass × 0.4)/(AHIseated − AHIstanding). Participants were asked to wear whatever

footwear they normally use, and to wear shorts or skirts that could be rolled up to reveal the knee. Reflective tape markers were placed on the following locations on one side of the body: greater trochanter, the center of the knee (in between the lateral femoral epicondyle and the lateral tibial plateau), the lateral malleolus, the lateral surface of the 5th metatarsal head, and the lateral aspect of the tuber calcaneus. Participants were then photographed with a scale in lateral and frontal position with a numeric identification. All participants were then instructed to run around

an open field for approximately 5 min Beta-glucuronidase at a pace they would choose when running a long distance. After the participant settled into a comfortable gait, step frequency was measured using an adjustable metronome (Matrix, New Market, VA, USA) fitted with an earpiece. Preferred step frequency was considered to be the frequency attained once the cadence stayed constant for at least 1 min. Repeated measurements from the same subjects indicate that step frequency measurements are accurate to approximately 4 steps/min. Once each subject had warmed up, his or her running kinematics were then immediately recorded in lateral view on a trackway, approximately 15 m in length set up an a flat, grass-free and rock-free area, typical of the surfaces on which the Tarahumara normally walk and run in terms of surface hardness. A high-speed video camera (Casio EX-ZR100; Casio USA, Dover, NJ, USA) was positioned at 0.