Kulas Anthony, Zalewski Paul, Hortobagyi Tibor, DeVita Paul
Department of Health Education and Promotion, East Carolina University, 249 Ward Sports Medicine Building, Greenville, NC 27858, USA.
J Biomech. 2008;41(1):180-5. doi: 10.1016/j.jbiomech.2007.06.027. Epub 2007 Aug 3.
Although both trunk mass and trunk position have the potential to affect lower extremity biomechanics during landing, these effects are not well understood. Our overall hypothesis stated that both trunk mass and trunk position affect lower extremity biomechanics in landing. Thus, our purpose was to determine the effects of an added trunk load and kinematic trunk adaptation groups on lower extremity joint kinematics, kinetics, and energetics during drop-landings. Twenty-one recreationally active subjects were instrumented for biomechanical analysis. Subjects performed two sets of eight double-limb landings with and without 10% body weight added to the trunk. On lower extremity dependent variables, 2(condition: no load, trunk load)x2(group: trunk extensors vs. trunk flexors) ANOVAs were performed. Condition by group interactions at the hip showed differing responses to the added trunk load between groups where the trunk extensor group decreased hip extensor efforts ( downward decrease 11-18%) while the trunk flexor group increased hip extensor efforts ( upward increase 14-19%). The trunk load increased biomechanical demands at the knee and ankle regardless of trunk adaptation group. However, the percent increases in angular impulses and energy absorption in the trunk extensor group were 14-28% while increases in the trunk flexor group were 4-9%. Given the 10% body weight added to the trunk, the 14-28% increases at the knee and ankle in the trunk extensor group were likely due to the reduced hip extensor efforts during landing. Overall these findings support our overall hypothesis that both trunk mass and trunk position affect lower extremity biomechanics during vertically oriented landing tasks.
虽然躯干质量和躯干位置都有可能在着陆过程中影响下肢生物力学，但这些影响尚未得到充分理解。我们的总体假设是，躯干质量和躯干位置都会影响着陆时的下肢生物力学。因此，我们的目的是确定增加的躯干负荷和运动学上的躯干适应组对下落着陆过程中下肢关节运动学、动力学和能量学的影响。对21名有休闲运动习惯的受试者进行了生物力学分析。受试者进行了两组，每组八次双下肢着陆，一组在躯干上增加了10%体重，另一组没有增加。对于下肢相关变量，进行了2（条件：无负荷、躯干负荷）×2（组：躯干伸肌组与躯干屈肌组）方差分析。髋关节处的条件×组交互作用显示，两组对增加的躯干负荷有不同反应，躯干伸肌组降低了髋部伸肌的用力程度（向下降低11%-18%），而躯干屈肌组增加了髋部伸肌的用力程度（向上增加14%-19%）。无论躯干适应组如何，躯干负荷都会增加膝关节和踝关节处的生物力学需求。然而，躯干伸肌组的角冲量和能量吸收增加百分比为14%-28%，而躯干屈肌组的增加百分比为4%-9%。考虑到躯干增加了10%的体重，躯干伸肌组膝关节和踝关节处14%-28%的增加可能是由于着陆过程中髋部伸肌用力程度降低所致。总体而言，这些发现支持了我们的总体假设，即躯干质量和躯干位置都会影响垂直定向着陆任务期间的下肢生物力学。
