Adaptability in infant walking

项目总结 功能性运动技能的一个特点是适应性--根据身体或环境的变化调整动作。 拟议的项目重点是婴儿走路的适应性，因为婴儿必须在中间学习走路 他们身体和环境的持续变化。身体的变化(由于身体的生长，携带 物品、鞋类等)和环境(不同的地面、障碍物等)改变生物力学 平衡、推进和制动方面的限制。此外，走路是一项基本的运动技能，在 日常活动，以及临床评估和干预的中心。 中心假设是婴儿通过日常行走体验获得适应能力。也就是说，婴儿 学习如何在不断变化的环境中调整行走模式(脚步和关节角度) 在一个不断变化的身体里的环境。一个世纪的研究表明，婴儿的年龄和日常行走 经验(从步行开始以来经过的时间)预测了他们赤脚在平地上行走的技能。但很少 这项工作检查了婴儿改变行走模式(速度、步长、关节角度等)的能力。应付 他们身体或环境的变化。因此，拟议的项目填补了科学知识的经验空白。 这是发展理论的基础。 这项拟议的实验测试了日常步行经验在儿童智力发展中的作用 婴幼儿走路的适应性。由于年龄和行走经验被混淆，拟议的实验 采用受试者内、年龄恒定的设计-所有14个月大的婴儿在走路时控制年龄 经验(0-4个月)自由变化。婴儿将在基线条件下进行测试(赤脚在平地上行走 人行道)和4种需要适应性的新条件-2身体条件(在平坦的人行道上行走 穿着脚趾向上倾斜10°或向下倾斜10°的鞋子)；以及2种环境条件(赤脚在 坡道向上倾斜10°或向下倾斜10°)。鞋的状况影响婴儿的平衡；坡度状况 影响平衡、推进和刹车。时空足迹测量、关节角度和步态干扰将 描述婴儿如何改变他们的走路方式以应对新的挑战。 目的1测试婴儿在每种情况下是否表现出不同的行走模式，以及是否有行走体验 与图案的类型和多样性有关。目标2评估在不同条件下行走的相似性 并测试行走经验是否会放大不同条件之间的相似或不同。 这两个目标都利用机器学习分析(密度峰值聚类和相似矩阵)的能力来 充分描述婴儿在环境中和在环境中行走的特征。受试者内，年龄恒定的设计， 创新的身体环境测试条件和分析技术提供了强大的长期测试 目的：了解经验在婴幼儿运动技能适应性发展中的作用。发现 承诺告知早期干预做法，以支持儿童的运动发育。

PROJECT SUMMARY A hallmark of functional motor skill is adaptability—tailoring movements to changes in the body or environment. The proposed project focuses on adaptability in infant walking because infants must learn to walk in the midst of continual changes in their bodies and environments. Changes in the body (due to physical growth, carrying objects, footwear, etc.) and environment (varying ground surfaces, obstacles, etc.) alter the biomechanical constraints on balance, propulsion, and braking. Moreover, walking is a foundational motor skill, endemic in everyday activity, and central to clinical assessment and intervention. The central hypothesis is that infants acquire adaptability via everyday walking experience. That is, infants learn strategies for modifying their walking patterns (footfalls and joint angles) as they navigate an ever-changing environment in a continually changing body. A century of research shows that infants’ age and everyday walking experience (elapsed time since walk onset) predict their skill when walking barefoot over flat ground. But little work examined infants’ ability to modify their walking patterns (speed, step length, joint angles, etc.) to cope with changes in their body or environment. Thus, the proposed project fills an empirical gap in scientific knowledge that is fundamental to developmental theory. The proposed experiment tests the role of everyday walking experience in the development of adaptability in infant walking. Because age and walking experience are confounded, the proposed experiment uses a within-subjects, age-held-constant design—all 14-month-old infants to control for age while walking experience (0-4 months) varies freely. Infants will be tested in a baseline condition (walking barefoot over a flat walkway) and in 4 novel conditions that require adaptability—2 body conditions (walking over a flat walkway wearing shoes that tilt their toes 10° up or 10° down); and 2 environment conditions (walking barefoot over a sloping walkway tilted 10° up or 10° down). The shoe conditions affect infants’ balance; the slope conditions affect balance, propulsion, and braking. Spatiotemporal footfall measures, joint angles, and gait disruptions will characterize how infants modify their walking to cope with the novel challenges. Aim 1 tests whether infants display different walking patterns in each condition, and whether walking experience is related to the type and diversity of patterns. Aim 2 assesses the similarity in walking between conditions for each infant, and tests whether walking experience amplifies the similarity or dissimilarity between conditions. Both aims leverage the power of machine learning analyses (density peak clustering and similarity matrices) to fully characterize infants’ walking within and across conditions. The within-subjects, age-held-constant design, innovative body-environment test conditions, and analytic techniques provide a strong test of the long-term objective: to understand the role of experience in the development of adaptability in infant motor skill. Findings promise to inform early intervention practices to support children’s locomotor development.