Intersegmental Coordination During Human Locomotion: Does Planar Covariation of Elevation Angles Reflect Central Constraints?

Abstract

Hicheur, Halim, Alexander V. Terekhov, and Alain Berthoz. Intersegmental coordination during human locomotion: does planar covariation of elevation angles reflect central constraints? J Neurophysiol 96: 1406 -1419, 2006. First published June 21, 2006 doi:10.1152/jn.00289.2006. To study intersegmental coordination in humans performing different locomotor tasks (backward, normal, fast walking, and running), we analyzed the spatiotemporal patterns of both elevation and joint angles bilaterally in the sagittal plane. In particular, we determined the origins of the planar covariation of foot, shank, and thigh elevation angles. This planar constraint is observable in the three-dimensional space defined by these three angles and corresponds to the plane described by the three time-varying elevation angle variables over each step cycle. Previous studies showed that this relation between elevation angles constrains lower limb coordination in various experimental situations. We demonstrate here that this planar covariation mainly arises from the strong correlation between foot and shank elevation angles, with thigh angle independently contributing to the pattern of intersegmental covariation. We conclude that the planar covariation of elevation angles does not reflect central constraints, as previously suggested. An alternative approach for analyzing the patterns of coordination of both elevation and joint (hip, knee, and ankle) angles is used, based on temporal cross-correlation and phase relationships between pairs of kinematic variables. We describe the changes in the pattern of intersegmental coordination that are associated with the changes of locomotor modes and locomotor speeds. We provide some evidence for a distinct control of thigh motion and discuss the respective contributions of passive mechanical factors and of active (arising from neural control) factors to the formation and the regulation of the locomotor pattern throughout the gait cycle.

Planar covariation of limb elevation angles during bipedal locomotion in common quails (Coturnix coturnix)

“…The correlation between foot and shank elevation angles was significantly smaller in quail bipedal locomotion (0.76-0.83) than in both macaque (0.88-0.91) and human (0.94-0.97) bipedal locomotion (P<0.001 for all combinations), indicating that the strong correlation between foot and shank elevation angles observed in humans (Hicheur et al, 2006) was not observed in quails. However, the correlation between thigh and foot elevation angles was significantly larger in quail (0.85-0.95) and macaque (0.76-0.92) bipedal locomotion than in human bipedal locomotion (0.24-0.58; P<0.001 for all combinations), and the correlation between shank and thigh elevation angles was significantly larger in quail (0.61-0.87) and macaque (0.77-0.82) bipedal locomotion than in human bipedal locomotion (0.49-0.69; P<0.001 for all combinations).…”

“…changes in the orientation of these segments with respect to the vertical axis, covary to form a regular loop within a single plane in three-dimensional space (Borghese et al, 1996;Bianchi et al, 1998;Grasso et al, 1998;Ivanenko et al, 2002;Ivanenko et al, 2005;Ivanenko et al, 2007;Ivanenko et al, 2008;Hicheur et al, 2006;Barliya et al, 2009;Dominici et al, 2010;Ogihara et al, 2012;Sylos-Labini et al, 2013). In humans, the plane can account for more than 99% of the total variance in the elevation angles (Borghese et al, 1996).…”

Planar covariation of limb elevation angles during bipedal walking in the Japanese macaque

“…Further details of the calculation method employed in this study have been described elsewhere [1,4,8]. To evaluate similarities between pairs of elevation angles, we calculated correlation coefficients as described previously [9]. We also approximated elevation angle profiles using the first Fourier decomposition harmonics to quantify phase shifts between pairs of elevation angles [2,10].…”

“…However, biomechanical constraints may also play a part in emergence of the planar law. For example, Hicheur et al [9] suggested that the planar law arises mainly due to the strong coupling of foot and shank movements resulting from a restricted range of ankle joint movement. Barliya et al [10] argued that biomechanical constraints due to biarticular muscles and passive coupling of limb segments may also play a role, although the inter-segmental plane may not emerge only from such biomechanical factors.…”

Planning of spatially-oriented locomotion following focal brain damage in humans: A pilot study

“…We used heel strike and toe off events to define steps [24]. These events were derived from the time course of heel and toe Z position profiles and corresponded to the local minima of these two signals.…”