MacLellan M J, Catavitello G, Ivanenko Y P, Lacquaniti F
School of Kinesiology, College of Human Sciences and Education, Louisiana State University, 112 Huey P. Long Field House, Baton Rouge, LA, 70803, USA.
Laboratory of Neuromotor Physiology, Santa Lucia Foundation, via Ardeatina 306, 00179, Rome, Italy.
Exp Brain Res. 2017 Nov;235(11):3287-3294. doi: 10.1007/s00221-017-5060-y. Epub 2017 Aug 11.
Habitual quadrupeds have been shown to display a planar covariance of segment elevation angle waveforms in the fore and hind limbs during many forms of locomotion. The purpose of the current study was to determine if humans generate similar patterns in the upper and lower limbs during hand-foot crawling. Nine healthy young adults performed hand-foot crawling on a treadmill at speeds of 1, 2, and 3 km/h. A principal component analysis (PCA) was applied to the segment elevation angle waveforms for the upper (upper arm, lower arm, and hand) and lower (thigh, shank, and foot) limbs separately. The planarity of the elevation angle waveforms was determined using the sum of the variance explained by the first two PCs and the orientation of the covariance plane was quantified using the direction cosines of the eigenvector orthogonal to the plane, projected upon each of the segmental semi-axes. Results showed that planarity of segment elevation angles was maintained in the upper and lower limbs (explained variance >97%), although a slight decrease was present in the upper limb when crawling at 3 km/h. The orientation of the covariance plane was highly limb-specific, consistent with animal studies and possibly related to the functional neural control differences between the upper and lower limbs. These results may suggest that the motor patterns stored in the central nervous system for quadrupedal locomotion may be retained through evolution and may still be exploited when humans perform such tasks.
研究表明，习惯性四足动物在多种运动形式中，其前肢和后肢的节段仰角波形呈现出平面协方差。本研究的目的是确定人类在手足爬行时，上肢和下肢是否会产生类似的模式。九名健康的年轻成年人在跑步机上以1、2和3公里/小时的速度进行手足爬行。分别对上肢（上臂、下臂和手部）和下肢（大腿、小腿和足部）的节段仰角波形进行主成分分析（PCA）。仰角波形的平面度通过前两个主成分解释的方差之和来确定，协方差平面的方向通过与该平面正交的特征向量的方向余弦来量化，并投影到每个节段半轴上。结果表明，上肢和下肢的节段仰角平面度得以保持（解释方差>97%），尽管在以3公里/小时的速度爬行时上肢略有下降。协方差平面的方向具有高度的肢体特异性，这与动物研究一致，可能与上肢和下肢的功能性神经控制差异有关。这些结果可能表明，中枢神经系统中存储的四足运动的运动模式可能通过进化得以保留，并且在人类执行此类任务时仍可能被利用。
