Bell Martin P, Ferguson Richard A
Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, United Kingdom.
J Appl Physiol (1985). 2009 Sep;107(3):763-9. doi: 10.1152/japplphysiol.91654.2008. Epub 2009 Jul 9.
The effect of elevated muscle temperature on mechanical efficiency was investigated during exercise at different pedal frequencies in young and older women. Eight young (24 +/- 3 yr) and eight older (70 +/- 4 yr) women performed 6-min periods of cycling at 75% ventilatory threshold at pedal frequencies of 45, 60, 75, and 90 rpm under control and passively elevated local muscle temperature conditions. Mechanical efficiency was calculated from the ratio of energy turnover (pulmonary O(2) uptake) and mechanical power output. Overall, elevating muscle temperature increased (P < 0.05) mechanical efficiency in young (32.0 +/- 3.1 to 34.0 +/- 5.5%) and decreased (P < 0.05) efficiency in older women (30.2 +/- 5.6 to 27.9 +/- 4.1%). The different effect of elevated muscle temperature in young and older women reflects a shift in the efficiency-velocity relationship of skeletal muscle. These effects may be due to differences in recruitment patterns, as well as sarcopenic and fiber-type changes with age.
在年轻女性和老年女性以不同踏板频率进行运动期间，研究了肌肉温度升高对机械效率的影响。八名年轻女性（24±3岁）和八名老年女性（70±4岁）在对照条件和局部肌肉温度被动升高的条件下，以45、60、75和90转/分钟的踏板频率，在通气阈值的75%下进行6分钟的骑行。机械效率由能量转换（肺氧摄取量）与机械功率输出的比值计算得出。总体而言，升高肌肉温度使年轻女性的机械效率提高（P<0.05）（从32.0±3.1%提高到34.0±5.5%），而使老年女性的效率降低（P<0.05）（从30.2±5.6%降至27.9±4.1%）。年轻女性和老年女性中肌肉温度升高的不同影响反映了骨骼肌效率-速度关系的转变。这些影响可能归因于募集模式的差异，以及随着年龄增长出现的肌肉减少症和纤维类型变化。
