Abstract # 163:

Scheduled for Sunday, September 20, 2009 06:30 PM-09:00 PM: Session 14 (Mission Bay Ballroom CDE) Poster Presentation


SPATIO-TEMPORAL AND KINEMATIC CHARACTERISTICS OF BIPEDAL LOCOMOTION WHILE CARRYING A LOAD IN BEARDED CAPUCHIN MONKEYS (CEBUS LIBIDINOSUS)

E. A. Sanches1, M. Duarte1, Q. Liu2, E. Ottoni1, P. Izar1, E. Visalberghi3 and D. Fragaszy2
1University of Sao Paulo, Laboratory of Biophysics, School of Physical Education and Sport, Sao Paulo, Sao Paulo, USA, 2University of Georgia, 3Institute for Science and Technology of Cognition, CNR, Italy
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We describe the spatiotemporal and kinematic characteristics of bipedal locomotion in 5 adult male and 1 adult female Cebus libidinosus in their natural environment. From three dimensional reconstructions of video, we analyzed five strides per monkey (where one stride is defined by two successive right-foot strikes) while the monkey bipedally carried a 930 gm stone and one or more nuts, 15 gm each (totaling 22% to 52% of their body weight) for a 3-meter straight line track. We determined walking speed, length, duration, and duty factor of the stride, and angles of the ankle, knee, and hip joints. On average (±1 SD), the monkeys walked at a speed of 1.3±0.2 m/s with stride durations of 0.46±0.06 s, stride lengths of 4.9±0.8 leg-length, and duty cycles of 0.64±0.05. The dimensionless analysis suggested that the C. libidinosus presented similar walking dynamics as Pan (paniscus & troglodytes) and Homo sapiens. The ankle, knee, and hip joints presented the following average coefficients of variations [±1 SD]: 11.5±1.8%, 11.8±4.6%, and 15.5±3.6%, respectively. The ankle-knee plot showed a simple and consistent relationship, but different than in Homo. The knee-hip plot showed a similar pattern as in Homo, except that the monkeys presented greater flexion of the knee and hip throughout the stride cycle. Bipedal locomotion appears to be consistent and similar to Homo and Pan with respect to kinematic and spatiotemporal characteristics.