Thorstensson A
Eur J Appl Physiol Occup Physiol. 1986;55(6):569-74. doi: 10.1007/BF00423198.
The effects of moderate external loading on the aerobic demand of submaximal running were studied in habitually active adult men (29-37 yrs) and 10 year-old boys. The load was symmetrically placed around the trunk and adjusted to correspond to 10% of body weight. Running was performed on a treadmill at 8, 10 and 11 km X h-1 (2.2, 2.8 and 3.1 m X s-1). A small, but consistent decrease in net oxygen uptake (gross oxygen uptake in ml X kg-1 X min-1 minus calculated basal metabolic rate) with load was observed in both groups at all speeds, except for the men at 8 km X h-1. The decrease was larger for the boys and tended to enhance with speed. The boys had a higher net oxygen uptake than the adults at all unladen running velocities, whereas the difference in the loaded condition was significant only at the highest speed. The decrease in net oxygen uptake with load could not be directly correlated with differences in body weight or step frequency. It is hypothesized that a difference in the utilization of muscle elastic energy could underlie part of the age and load dependent changes observed in running economy.
在习惯性运动的成年男性（29 - 37岁）和10岁男孩中，研究了适度外部负荷对次最大强度跑步有氧需求的影响。负荷对称地置于躯干周围，并调整至相当于体重的10%。在跑步机上以8、10和11 km·h⁻¹（2.2、2.8和3.1 m·s⁻¹）的速度跑步。在所有速度下，两组均观察到净摄氧量（每千克体重每分钟毫升数的总摄氧量减去计算出的基础代谢率）随负荷出现小幅但持续的下降，但8 km·h⁻¹速度下的成年男性除外。男孩的下降幅度更大，且有随速度增加的趋势。在所有无负荷跑步速度下，男孩的净摄氧量均高于成年人，而在有负荷情况下，仅在最高速度时差异显著。净摄氧量随负荷的下降与体重或步频差异无直接关联。据推测，肌肉弹性能量利用的差异可能是跑步经济性中观察到的部分年龄和负荷依赖性变化的基础。
