Rejc Enrico, di Prampero Pietro Enrico, Lazzer Stefano, Grassi Bruno, Simunic Bostjan, Pisot Rado, Antonutto Guglielmo, Narici Marco
Department of Medical and Biological Sciences, University of Udine, P.le Kolbe 4, 33100, Udine, Italy,
Eur J Appl Physiol. 2015 Feb;115(2):429-36. doi: 10.1007/s00421-014-3024-5. Epub 2014 Oct 26.
Microgravity leads to a decline of muscle power especially in the postural muscles of the lower limb. Muscle atrophy primarily contributes to this negative adaptation. Nutritional countermeasures during unloading were shown to possibly mitigate the loss of muscle mass and strength. The aim of this study was to investigate the effects of different diet energy intakes during prolonged inactivity on body composition and lower limbs power output.
The effects of lower or higher diet energy intake on the decline of maximal explosive power of the lower limbs, as determined on a sledge ergometer before and after 35 days of bed rest, were investigated on two matched groups of young healthy volunteers. Body composition and lean volume of the lower limb were also measured.
After bed rest, fat mass increased (+20.5 %) in the higher energy intake group (N = 9), while it decreased (-4.8 %) in the lower energy intake group (N = 10). Also, the loss of body fat-free mass and lean volume of the lower limb was significantly greater in the higher (-4.6 and -10.8 %, respectively) as compared to the lower (-2.4 and -3.7 %, respectively) diet energy intake group. However, the loss of maximal explosive power was similar between the two groups (-25.2 and -29.5 % in the higher and lower energy intake group, respectively; P = 0.440).
The mitigation of loss of muscle mass by means of a moderate caloric diet restriction during prolonged inactivity was not sufficient for reducing the loss of maximal explosive power of the lower limbs.
微重力会导致肌肉力量下降，尤其是下肢的姿势肌。肌肉萎缩是造成这种负面适应的主要原因。研究表明，在失重期间采取营养对策可能会减轻肌肉质量和力量的损失。本研究的目的是调查长期不活动期间不同饮食能量摄入对身体成分和下肢功率输出的影响。
在两组匹配的年轻健康志愿者中，研究了较低或较高饮食能量摄入对卧床休息35天前后在雪橇测力计上测定的下肢最大爆发力下降的影响。还测量了身体成分和下肢的瘦体积。
卧床休息后，高能量摄入组（N = 9）的脂肪量增加（+20.5%），而低能量摄入组（N = 10）的脂肪量减少（-4.8%）。此外，与低饮食能量摄入组（分别为-2.4%和-3.7%）相比，高饮食能量摄入组（分别为-4.6%和-10.8%）的无脂肪体重和下肢瘦体积的损失明显更大。然而，两组之间最大爆发力的损失相似（高能量摄入组和低能量摄入组分别为-25.2%和-29.5%；P = 0.440）。
在长期不活动期间，通过适度限制热量饮食来减轻肌肉质量的损失，不足以减少下肢最大爆发力的损失。
