Understanding movement control in infants through the analysis of limb intersegmental dynamics.
Understanding movement control in infants through the analysis of limb intersegmental dynamics.
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通过分析肢体节间动力学了解婴儿的运动控制。
DOI：
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发表时间：
1990
影响因子：
1.4
通讯作者：
Esther Thelen
中科院分区：
文献类型：
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作者：
Klaus Schneider;Ronald F. Zernicke;Beverly D. Ulrich;Jody L. Jensen;Esther Thelen
理解肢体运动控制的一个重要组成部分是中枢神经系统如何处理不仅由肌肉动作，而且由重力和与肢体节段运动相关的被动反应产生的联力和扭矩。在这项研究中，我们询问婴儿的神经运动系统如何控制一系列主动和被动的力量，以产生刻板印象的、无意的运动。我们具体分析了仰卧位3个月大的婴儿在不同强度的自发性周期性腿部运动(踢)中的肢体节间动力学。使用逆动力学，我们计算了髋关节、膝关节和踝关节的主动(肌肉)和被动(运动相关和重力)扭矩分量在三维肢体运动学中的贡献。为了计算关节扭矩，需要准确估计肢体的人体测量参数，我们使用人体模型来确定这些参数。我们对肢体节段间动力学的分析明确地量化了主动和被动力量的复杂相互作用，产生了3个月大婴儿常见的简单、非自愿的踢腿动作。我们的结果表明，在非剧烈踢腿中，髋关节反转是由于重力引起的伸肌扭矩的结果，而不是肌肉扭矩和总的运动相关扭矩的屈肌效应的综合作用。在更有力的踢腿中，总的运动相关扭矩作为髋屈肌扭矩增加；伸肌扭矩是抵消总运动相关扭矩的屈肌影响所必需的，在大运动范围的情况下，屈肌重力扭矩也是如此。因此，随着连接节段的运动引起的被动扭矩影响的变化，肌肉扭矩被调整以产生净扭矩来反转踢腿运动。因此，尽管每一次踢腿的强度、运动范围、协调性和运动背景都有相当大的异质性，但平滑的轨迹是由肌肉扭矩产生的，不仅抵消和补充了重力，而且还抵消和补充了连接的节段运动产生的依赖于运动的扭矩。
One important component in the understanding of the control of limb movements is the way in which the central nervous system accounts for joint forces and torques that may be generated not only by muscle actions but by gravity and by passive reactions related to the movements of limb segments. In this study, we asked how the neuromotor system of young infants controls a range of active and passive forces to produce a stereotypic, nonintentional movement. We specifically analyzed limb intersegmental dynamics in spontaneous, cyclic leg movements (kicking) of varying intensity in supine 3-month-old human infants. Using inverse dynamics, we calculated the contributions of active (muscular) and passive (motion-dependent and gravitational) torque components at the hip, knee, and ankle joints from three-dimensional limb kinematics. To calculate joint torques, accurate estimates were needed of the limb's anthropometric parameters, which we determined using a model of the human body. Our analysis of limb intersegmental dynamics explicitly quantified the complex interplay of active and passive forces producing the simple, involuntary kicking movements commonly seen in 3-month-old infants. our results revealed that in nonvigorous kicks, hip joint reversal was the result of an extensor torque due to gravity, opposed by the combined flexor effect of the muscle torque and the total motion-dependent torque. The total motion-dependent torque increased as a hip flexor torque in more vigorous kicks; an extensor muscle torque was necessary to counteract the flexor influences of the total motion-dependent torque and, in the case of large ranges of motion, a flexor gravity torque as well. Thus, with changing passive torque influences due to motions of the linked segments, the muscle torques were adjusted to produce a net torque to reverse the kicking motion. As a consequence, despite considerable heterogeneity in the intensity, range of motion, coordination, and movement context of each kick, smooth trajectories resulted from the muscle torque, counteracting and complementing not only gravity but also the motion-dependent torques generated by movement of the linked segments.
爪子抖动反应期间膝盖和脚踝处的惯性和肌肉力矩的对比作用。
影响因子：
2.5
作者：
Hoy,MG;Zernicke,RF;Smith,JL
通讯作者：
Smith,JL
影响因子：
2.4
作者：
HOY, MG;ZERNICKE, RF
通讯作者：
ZERNICKE, RF