Idiosyncratic Control of the Center of Mass in Expert Climbers

Abstract

We studied posture and movement coordination adopted by expert climbers. The investigation of such expertise might be of particular interest to gain understanding about the mechanisms underlying the biomechanical control of vertical quadrupedal locomotion. A novel custom setup was developed to analyze the dynamic distribution of vertical reaction forces under the feet and the motion of the center of body mass (COM) during vertical climbing in nine Elite Climbers (EC) and nine control subjects. Two adaptive features were found in EC. First, unexpectedly they tended to maintain larger COM distances from the wall relative to controls subjects, during both the static and dynamic phases of vertical body motion. Second, while the control subjects tended to restrain the lateral motion of the COM, all EC demonstrated systematic COM oscillations associated with significant alternating dynamic redistribution of the body weight between the limbs during the double support phase. The latter phenomenon likely reflects an adopted basic climbing strategy in experts. The results will be discussed in the context of the biomechanical control of vertical quadrupedal locomotion. Furthermore, a convergence of the optimal solution towards a more diagonal climbing strategy in EC may shed light on the origin of the diagonal gait in primates and early hominids habituated to quadrupedal vertical locomotion.