不同体质量幼儿纵跳过程中的生物力学特征

Biomechanical characteristics of children with different body weights during vertical jump

背景:超重和肥胖在幼儿中越来越普遍,有研究表明体质量过大会影响幼儿的基本运动能力,但运用生物力学方法进行分析的研究较少,更加缺乏将仿真运用其中分析其运动过程中肌肉用力情况的研究。目的:运用运动生物力学研究方法分析不同体质量的幼儿在纵跳过程中的运动学、动力学以及动作过程中下肢肌肉力值,比较这些数据的差异。方法:在北京某幼儿园采取随机抽样的方法抽取四五岁幼儿52名,按体质量指数分为正常体质量组20名、超重组16名和肥胖组16名。运用BTS三维红外动作捕捉系统和Kistler三维测力台以及VIXTA录像解析系统同步采集幼儿纵跳过程中的运动学和动力学数据;运用AnyBody 7.1.2仿真建模软件计算下肢肌肉力指标。结果与结论:①正常组的纵跳高度、膝关节变化量高于超重组和肥胖组(P<0.05,P<0.01);正常组膝屈曲最小值、躯干角大于肥胖组(P<0.05);②正常组比目鱼肌外侧头、腓肠肌外侧头、臀中肌前束小于超重组(P<0.05);③正常组比目鱼肌外侧头、腓肠肌外侧头、腓骨长肌、股内侧肌下束、臀中肌前束小于肥胖组(P<0.05);④正常组半腱肌、臀小肌前束大于肥胖组(P<0.05),正常组上下孑孓肌、闭孔内肌大于超重组(P<0.05);⑤肥胖组腓骨短肌大于正常组和超重组(P<0.05);⑥肥胖组臀小肌后束小于正常组和超重组(P<0.05);⑦结果提示:超重和肥胖幼儿纵跳高度低于同年龄段正常体质量幼儿,且表现出初期纵跳阶段的运动学特征;在落地缓冲阶段超重和肥胖幼儿在前后方向和左右方向产生的地面反作用力更大;幼儿在完成纵跳动作时主要发力肌肉是比目鱼肌外侧头、腓肠肌外侧头、腓骨短肌、腓骨长肌、股四头肌、臀中肌、臀大肌及大收肌;超重组和肥胖组幼儿股四头肌以及活动髋关节的标准化之后的相关肌肉力相比于同年龄段正常体质量幼儿更低。

BACKGROUND:Overweight and obesity are becoming more and more common in young children.Studies have shown that excessive body mass affects the fundamental movement competence of young children.However,there are fewer studies using biomechanical methods for analysis,and there is a lack of researches on using simulation to analyze the muscle force during exercise.OBJECTIVE:To analyze the kinematics,dynamics and lower limb muscle strength of children of different weights during vertical jump using sports biomechanics research methods,and compare the differences in these data.METHODS:Totally 52 children aged 4-5 years old were selected from a kindergarten in Beijing using a random sampling method.According to the body mass index,they were divided into a normal body mass group(n=20),an overweight group(n=16)and an obesity group(n=16).The BTS three-dimensional infrared motion capture system,the Kistler three-dimensional force plate and the VIXTA video analysis system were used to synchronously collect the kinematics and dynamics data of the children during the vertical jump.AnyBody7.1.2 simulation modeling software was used to calculate the lower limb muscle strength indicators.RESULTS AND CONCLUSION:(1)The vertical jump height and knee changes in the normal body mass group were higher than those in the overweight group and the obesity group(P<0.05,P<0.01).The minimum knee flexion and the trunk angle were greater in the normal body mass group than those of the obesity group(P<0.05).(2)The soleus lateralis,gastrocnemius lateralis,and gluteus medius anterior in the normal body mass group were smaller than those in the overweight group(P<0.05).(3)The soleus lateralis,gastrocnemius lateralis,peroneus longus,inferior funicle of vastus medialis,and anterior funicle of gluteus medius in normal body mass group were smaller than those in the obesity group(P<0.05).(4)The semitendinosus and the anterior funicle of gluteus minimus in the normal body mass group were larger than those in the obesity group(P<0.05).The inferior and superior of gemellus and obturator internus in the normal body mass group were larger than those in the overweight group(P<0.05).(5)Peroneal brevis muscle was larger in the obesity group than that in the normal body mass group(P<0.05)and overweight group(P<0.05).(6)Posterior funicle of gluteus minimus was smaller in the obesity group than that in the normal group(P<0.05)and overweight group(P<0.05).(7)The results showed that the vertical jump height of overweight and obese children was lower than that of normal-weight children of the same age,and showed the kinematic characteristics of the initial vertical jump stage.During the landing stage,overweight and obese children have greater ground reaction forces in the front and rear and left and right directions.The main muscles that children use when they complete the vertical jump are the soleus lateralis,the gastrocnemius lateralis,the peroneus brevis,the peroneus longus,and the quadriceps,gluteus medius,gluteus maximus muscle,and adductor magnus muscles.The normalized muscle strength of the quadriceps femoris and the active hip joint of the overweight and obese children was lower than that of the normal weight children of the same age.