De Looze M P, Toussaint H M, Commissaris D A, Jans M P, Sargeant A J
Department of Health Science, Faculty of Human Movement Sciences, Vrije Universiteit, Amsterdam, The Netherlands.
J Appl Physiol (1985). 1994 Jul;77(1):420-6. doi: 10.1152/jappl.1994.77.1.420.
Determining the separate energy costs of the positive and negative mechanical work in repetitive lifting or lowering is quite complex, as a mixture of both work components will always be involved in the up- and downward motion of the lifter's body mass. In the current study, a new method was tested in which coefficients specifically related to the positive and negative work were estimated by multiple regression on a data set of weight-lifting and weight-lowering tasks. The energy cost was obtained from oxygen uptake measurements. The slopes of the regression lines for energy cost and mechanical work were steeper for positive than for negative work. The cost related to the negative work was approximately 0.3-0.5 times the cost of the positive work. This finding is well in line with data obtained directly from other isolated activities of either positive or negative work (e.g., ladder climbing vs. descending). However, the intercept values of the regression lines were not significantly different from zero or were even negative. This was most likely due to the metabolic energy not related to processes that yield mechanical work (e.g., isometric muscle actions) that was not constant among trials.
确定重复提举或放下过程中正向和负向机械功各自的能量消耗相当复杂，因为在举重者身体质量的上下运动中，这两种功的成分总是混合存在的。在当前研究中，测试了一种新方法，即通过对一组举重和放重任务的数据集进行多元回归，来估计与正向和负向功具体相关的系数。能量消耗通过摄氧量测量获得。正向功的能量消耗和机械功回归线的斜率比负向功的更陡。与负向功相关的消耗约为正向功消耗的0.3 - 0.5倍。这一发现与直接从其他正向或负向功的孤立活动（如爬梯子与下梯子）获得的数据非常吻合。然而，回归线的截距值与零无显著差异，甚至为负。这很可能是由于与产生机械功的过程（如等长肌肉动作）无关的代谢能量在各试验中并不恒定。
