Spatio-temporal gait characteristics of the hind-limb cycles during voluntary bipedal and quadrupedal walking in bonobos (Pan paniscus)

Abstract

Spatio-temporal gait characteristics (step and stride length, stride frequency, duty factor) were determined for the hind-limb cycles of nine bonobos (Pan paniscus) walking quadrupedally and bipedally at a range of speeds. The data were recalculated to dimensionless quantities according to the principle of dynamic similarity. Lower leg length was used as the reference length. Interindividual variability in speed modulation strategy of bonobos appears to be low. Compared to quadrupedal walking, bipedal bonobos use smaller steps to attain a given speed (differences increase with speed), resulting in shorter strides at a higher frequency. In the context of the ("hybrid") dynamic pattern approach to locomotion (Latach, 1998) we argue that, despite these absolute differences, intended walking speed is the basic control variable which elicits both quadrupedal and bipedal walking kinematics in a similar way. Differences in the initial status of the dynamic system may be responsible for the differences in step length between both gaits. Comparison with data deduced from the literature shows that the effects of walking speed on stride length and frequency are similar in bonobos, common chimpanzees, and humans. This suggests that (at least) within extant homininae, spatio-temporal gait characteristics are highly comparable, and this in spite of obvious differences in mass distribution and bipedal posture.

Locomotor versatility in the white-handed gibbon (Hylobates lar): A spatiotemporal analysis of the bipedal, tripedal, and quadrupedal gaits

“…To allow for comparison of the subjects of different size, we treated the square root of the Froude number as dimensionless velocity (DV), and the SL and SF of the hind limbs were scaled to lower leg length using the formulae provided in Table 2 (Alexander and Jayes, 1983;Aerts et al, 2000). As direct leg length measures were not available and were not allowed under the zoo protocol, we had to estimate them from the video images.…”

“…As direct leg length measures were not available and were not allowed under the zoo protocol, we had to estimate them from the video images. Lower leg length was measured from knee to ankle and was used instead of total hind limb length since it proved to be the most accurate length measure that can be obtained from the video images (Aerts et al, 2000). Lower leg length is proportional to total hind limb length and has proven to be a good dimension for normalization of the variables (Isler and Thorpe, 2003;Alexander, 2004).…”

“…Finally, we included some spatiotemporal data for bipedal walking in bonobos (n ¼ 17) and humans (n ¼ 31), as presented by Aerts et al (2000), and calculated linear regression equations for the DSL and DSF as a function of dimensionless walking speed. The human data were obtained from Alexander (1992) and Adachi et al (1996) and were scaled to lower leg length, assuming a ratio of lower leg length to total hind limb length of 0.54 (Winter, 1991; see also Aerts et al, 2000), to allow for comparison with the gibbon data.…”

“…Recently, efforts have been made to compile a sound quantitative data set of gait variables for great apes (Aerts et al, 2000;D'Août et al, 2002;Isler and Thorpe, 2003;Isler, 2005;Vereecke et al, 2003Vereecke et al, , 2004. The lack of information for gibbon locomotion is unfortunate because insights into their locomotor capacities could add to our understanding of hominoid locomotion and perhaps the evolution of habitual terrestrial bipedalism in humans.…”

“…Finally, bipedal gait characteristics of gibbons were compared to those of bonobos (Pan paniscus) and humans (Homo sapiens). These species are interesting for comparison, in view of their different morphology, their ability to walk bipedally, and their close phylogenetic relationship with gibbons (McHenry and Corruccini, 1981;Goodman, 1999;Aerts et al, 2000;Vereecke et al, 2003;D'Août et al, 2004;Goodman et al, 2005).…”