Cettolo Valentina, Ferrari Marco, Biasini Vincenzo, Quaresima Valentina
Department of Science and Biomedical Technologies, University of L'Aquila, L'Aquila, Italy.
Med Sci Sports Exerc. 2007 Nov;39(11):1949-59. doi: 10.1249/mss.0b013e3181453476.
The purpose of this study was to investigate, in heavy-resistance strength-trained (N = 10) and untrained (N = 10) subjects, the vastus lateralis muscle oxyhemoglobin (O2Hb) desaturation time course in response to a brief, maximal, voluntary isometric contraction.
The two groups were not statistically different physically. Mean (+/- SD) age, height, and body mass of all the subjects were 28.0 +/- 6.3 yr, 1.8 +/- 0.1 m, and 77.8 +/- 9.9 kg, respectively. Each subject performed five trials. Every trial consisted of 1) a 1-min rest period, 2) a leg press exercise of 2-4 s, and 3) a 5-min recovery period. Leg press exercise consisted of a static maximal voluntary contraction performed using the dominant leg only. Leg press strength was recorded using a load cell. Muscle O2Hb saturation (SmO2) was measured noninvasively by near-infrared spectroscopy (0.17-s sampling time).
Rate of force development was higher in the trained subjects than in the untrained ones (6897 +/- 1654 vs 5515 +/- 1434 N x s(-1); P < 0.05). Once the exercise began, the time to the onset of SmO2 decrease was consistently shorter in the untrained than in the trained subjects (2.81 +/- 0.40 vs 3.91 +/- 0.67 s, P < 0.01). In all the trained subjects and in two of the untrained ones, SmO2 started to decrease once the exercise was stopped. After the end of the exercise, SmO2 transiently decreased and reached its minimum value in 15.0 +/- 3.8 and 10.1 +/- 1.3 s in the trained and untrained subjects, respectively (P < 0.01).
These data suggest that the vastus lateralis muscle of heavy-resistance strength-trained subjects could have a late activation of the oxidative metabolic system, or greater stored oxygen available, during a very fast, short, isometric maximal contraction.
本研究旨在调查重阻力力量训练组（N = 10）和未训练组（N = 10）受试者在进行一次短暂、最大强度的自愿等长收缩时，股外侧肌氧合血红蛋白（O2Hb）去饱和的时间进程。
两组受试者在身体状况上无统计学差异。所有受试者的平均（±标准差）年龄、身高和体重分别为28.0±6.3岁、1.8±0.1米和77.8±9.9千克。每位受试者进行5次试验。每次试验包括：1）1分钟的休息期；2）2 - 4秒的腿部推举练习；3）5分钟的恢复期。腿部推举练习仅使用优势腿进行静态最大自主收缩。使用测力传感器记录腿部推举力量。通过近红外光谱法（采样时间为0.17秒）无创测量肌肉O2Hb饱和度（SmO2）。
训练组受试者的力量发展速率高于未训练组（6897±1654对5515±1434牛·秒⁻¹；P < 0.05）。运动开始后，未训练组受试者SmO2开始下降的时间始终比训练组受试者短（2.81±0.40对3.91±0.67秒，P < 0.01）。在所有训练组受试者和两名未训练组受试者中，运动停止后SmO2开始下降。运动结束后，训练组和未训练组受试者的SmO2分别在15.0±3.8秒和10.1±1.3秒时短暂下降并达到最小值（P < 0.01）。
这些数据表明，在非常快速、短暂的等长最大收缩过程中，重阻力力量训练受试者的股外侧肌可能具有氧化代谢系统的延迟激活，或者有更多的储存氧可用。
