Fig. 2.

Maximum ankle dorsiflexion during walking and climbing. For industrialized human populations, maximum dorsiflexion during walking ranges from 15.0° to 20.0° (55–57), and gross injury or microfilament damage occurs at a mean angle of 44.0° (hashed line) ± 10.9° (SD; red shaded region) (54). For Twa men (n = 7 individuals; filled circles), maximum dorsiflexion ranged from 34.4 to 47.0° during vertical climbing (photograph by George H. Perry, reproduced with permission). The average maximum dorsiflexion of wild chimpanzees (photograph by Jeremy DeSilva; reproduced from ref. 3) occurred at a mean angle of 45.5° (filled square) ± 7.1° (SD; whiskers) (3).