Angulo-Barroso Rosa, Ferrer-Uris Blai, Jubany Júlia, Busquets Albert
Institut Nacional d'Educació Física de Catalunya (INEFC), Universitat de Barcelona (UB), Barcelona, Spain.
Department of Kinesiology, California State University, Northridge, CA, United States.
Front Psychol. 2022 Dec 2;13:982467. doi: 10.3389/fpsyg.2022.982467. eCollection 2022.
Landing is a critical motor skill included in many activities performed in the natural environment by young children. Yet, landing is critically relevance to ensure proper stability and reduce injury. Furthermore, landing is an integral part of many fundamental motor skills which have been linked to greater physical activity, sport participation, and perceived competence in children. Our aim was to examine the drop-landing strategies of young children focusing on the lower extremity with a multi-variant approach.
Forty-four children divided into four age groups (G1:3-4.5 y, G2:4.5-6 y, G3:6-7.5 y, G4:7.5-9 y) performed 20 drop-land trials in four different conditions: predictable stationary landing, running to the left, to the right, and stay in place. Fifteen reflective markers, two force plates, and ten surface electromyography (sEMG) sensors were used to collect data. MANOVAs (Group x Condition) were conducted separately for the kinematic, kinetic, and sEMG variables.
Only significant group effects were found (kinematic MANOVA = 0.039, kinetic MANOVA = 0.007, and sEMG MANOVA = 0.012), suggesting that younger groups (G1, G2) differed to the older groups (G3, G4). G1 showed less knee flexion and slower ankle dorsi-flexion during the braking phase compared to G3, while G2 presented smaller ankle dorsi-flexion at the braking phase and smaller ankle range of motion than G3. Overall kinetic variables analysis showed a group difference but no group differences for any single kinetic variable alone was found. Regarding sEMG, G1 during the flight phase exhibited longer tibialis anterior and hamstrings activity than G3 and G3 & G4, respectively; and an earlier start of the hamstrings' impact burst than G4. In addition, distal to proximal control was primarily used by all groups to coordinate muscle activity (in response to impact) and joint motion (after impact).
Perhaps a developmental critical point in landing performance exists at 4-5 years of age since G1 presented the largest differences among the groups. This suggests that to improve landing strategies could start around this age. Future studies should examine if playground environments that include equipment conducive to landing and practitioners in the kindergarten schools are adequate vehicles to empower this type of intervention.
落地是幼儿在自然环境中进行的许多活动所包含的一项关键运动技能。然而，落地对于确保适当的稳定性和减少受伤至关重要。此外，落地是许多基本运动技能的一个组成部分，这些技能与儿童更多的身体活动、体育参与和感知能力有关。我们的目的是采用多变量方法研究幼儿的下落着地策略，重点关注下肢。
44名儿童被分为四个年龄组（G1：3 - 4.5岁，G2：4.5 - 6岁，G3：6 - 7.5岁，G4：7.5 - 9岁），在四种不同条件下进行20次下落着地试验：可预测的静止着地、向左跑、向右跑和原地停留。使用15个反光标记、两个测力板和10个表面肌电图（sEMG）传感器收集数据。对运动学、动力学和sEMG变量分别进行多因素方差分析（组×条件）。
仅发现显著的组效应（运动学多因素方差分析 = 0.039，动力学多因素方差分析 = 0.007，sEMG多因素方差分析 = 0.012），表明较年轻的组（G1、G2）与较年长的组（G3、G4）存在差异。与G3相比，G1在制动阶段膝关节屈曲较少，踝关节背屈较慢，而G2在制动阶段踝关节背屈较小，踝关节活动范围比G3小。总体动力学变量分析显示存在组间差异，但单独任何一个动力学变量均未发现组间差异。关于sEMG，G1在飞行阶段胫前肌和腘绳肌的活动时间分别比G3以及G3和G4更长；腘绳肌冲击爆发的起始时间比G4更早。此外，所有组主要采用从远端到近端的控制来协调肌肉活动（对冲击的反应）和关节运动（冲击后）。
由于G1在各年龄组中表现出最大差异，或许4 - 5岁是落地表现的一个发育关键点。这表明改善落地策略可从这个年龄左右开始。未来的研究应考察幼儿园学校中包含有助于落地的设备的操场环境以及从业者是否是促进这类干预的合适途径。
