Rapid aiming movements are typically used to study upper limb motor control and development. Despite the large corpus of work in this area, few studies have examined kinematic manual asymmetries in children who have just started formal schooling and until now, none have characterized how children coordinate their joints to complete these movements (i.e., interjoint coordination). In the present study, manual asymmetries in kinematics and interjoint coordination in strongly right-handed 6-year-old children were investigated when reaching for ipsilateral and contralateral targets with their dominant right arm and the non-dominant left arm. Overall, manual asymmetries in interjoint coordination are apparent for both 6-year-old children and young adults, although young children completed the task by adopting a different strategy than adults. Also, control strategies employed by 6-year-old children were influenced by both the location of the target as well as the arm used to perform the task. Specifically, compared to all other conditions, children’s trajectories were more curved when performing contralateral movements with the non-dominant left arm, which were driven by smaller shoulder excursions combined with larger elbow excursions for this condition. Based on these results, we argue that the differences in interjoint coordination reflect the stage of development of 6-year-old children, the origin of which derives from maturational (e.g., hand dominance) and environmental factors (e.g., school-based experience).

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6 岁儿童的运动运动学和关节间协调受目标位置和手臂的影响

快速瞄准运动通常用于研究上肢运动控制和发展。尽管在该领域有大量的工作，但很少有研究检查刚开始接受正规教育的儿童的运动学手动不对称，直到现在，还没有研究描述儿童如何协调关节以完成这些运动（即关节间协调）。在本研究中，研究了 6 岁右利手儿童在用惯用的右臂和非惯用的左臂触及同侧和对侧目标时的运动学不对称和相互协调。总体而言，6 岁儿童和年轻人在交互协调中的手动不对称性都很明显，尽管幼儿通过采用与成人不同的策略来完成任务。还，6 岁儿童采用的控制策略受到目标位置以及用于执行任务的手臂的影响。具体而言，与所有其他条件相比，儿童在用非优势左臂进行对侧运动时的轨迹更弯曲，这是由较小的肩部偏移和较大的肘部偏移驱动的。基于这些结果，我们认为相互协调的差异反映了 6 岁儿童的发展阶段，其起源源于成熟（例如，手优势）和环境因素（例如，基于学校的经验） . 与所有其他情况相比，儿童在用非惯用左臂进行对侧运动时，其轨迹更弯曲，这是由较小的肩部偏移和较大的肘部偏移所驱动的。基于这些结果，我们认为相互协调的差异反映了 6 岁儿童的发展阶段，其起源源于成熟（例如，手优势）和环境因素（例如，基于学校的经验） . 与所有其他情况相比，儿童在用非惯用左臂进行对侧运动时，其轨迹更弯曲，这是由较小的肩部偏移和较大的肘部偏移所驱动的。基于这些结果，我们认为相互协调的差异反映了 6 岁儿童的发展阶段，其起源源于成熟（例如，手优势）和环境因素（例如，基于学校的经验） .