Singh Tarkeshwar, Koh Michael
Physical Education and Sports Science, National Institute of Education, Nanyang Technological University, Singapore.
J Biomech. 2009 Apr 16;42(6):736-42. doi: 10.1016/j.jbiomech.2009.01.035. Epub 2009 Mar 9.
Backpack load carriage increases ground reaction forces and increases the stiffness in the upper extremity that can cause transmission of higher amount of forces from the lower extremity to the head. This study investigated the effect of load carriage and placement of load on the back on the shock transmission mechanisms amongst children. Fifteen primary school boys with mean age 10.01 (+/-1.31) years, mean height 136.40 (+/-10.08)cm and mean mass 31.83 (+/-7.13)kg completed the study. Subjects carried 10%, 15% and 20% bodyweight (BW) loads on two locations on the back, namely upper and lower. Results showed a significant reduction in pelvic and trunk rotation in the transverse plane and an increase in the upper body stiffness for loads exceeding 15% of BW. The lower limb results showed a reduction in the first peak force and cadence and a significant change in the walking velocity and time to the first peak force for 20% load. No significant differences were found for the load configuration but the upper configuration showed slightly higher shock transmission. The changes in the lower limb dynamics indicated that there are locomotion mechanisms in place amongst children to modulate shock transmission to the head.
背负背包会增加地面反作用力，并增加上肢的刚度，这可能导致更多的力从下肢传递到头部。本研究调查了背负负荷以及负荷在背部的位置对儿童冲击传递机制的影响。15名小学男生完成了这项研究，他们的平均年龄为10.01（±1.31）岁，平均身高为136.40（±10.08）厘米，平均体重为31.83（±7.13）千克。受试者在背部的两个位置，即上部和下部，背负10%、15%和20%体重（BW）的负荷。结果显示，当负荷超过体重的15%时，骨盆和躯干在横平面上的旋转显著减少，上半身刚度增加。下肢结果显示，20%负荷时，第一个峰值力和步频降低，步行速度和到达第一个峰值力的时间有显著变化。负荷配置方面未发现显著差异，但上部配置显示出略高的冲击传递。下肢动力学的变化表明，儿童存在调节向头部冲击传递的运动机制。
