School of Sport and Health Sciences, University of Exeter, Exeter, UK.
J Sports Sci. 2011 Jan;29(2):181-9. doi: 10.1080/02640414.2010.526626.
We tested the hypothesis that exercise-induced muscle damage would increase the ventilatory (V(E)) response to incremental/ramp cycle exercise (lower the gas exchange threshold) without altering the blood lactate profile, thereby dissociating the gas exchange and lactate thresholds. Ten physically active men completed maximal incremental cycle tests before (pre) and 48 h after (post) performing eccentric exercise comprising 100 squats. Pulmonary gas exchange was measured breath-by-breath and fingertip blood sampled at 1-min intervals for determination of blood lactate concentration. The gas exchange threshold occurred at a lower work rate (pre: 136 ± 27 W; post: 105 ± 19 W; P < 0.05) and oxygen uptake (VO(2)) (pre: 1.58 ± 0.26 litres · min(-1); post: 1.41 ± 0.14 litres · min(-1); P < 0.05) after eccentric exercise. However, the lactate threshold occurred at a similar work rate (pre: 161 ± 19 W; post: 158 ± 22 W; P > 0.05) and VO(2) (pre: 1.90 ± 0.20 litres · min(-1); post: 1.88 ± 0.15 litres · min(-1); P > 0.05) after eccentric exercise. These findings demonstrate that exercise-induced muscle damage dissociates the V(E) response to incremental/ramp exercise from the blood lactate response, indicating that V(E) may be controlled by additional or altered neurogenic stimuli following eccentric exercise. Thus, due consideration of prior eccentric exercise should be made when using the gas exchange threshold to provide a non-invasive estimation of the lactate threshold.
我们验证了这样一个假设，即运动引起的肌肉损伤会增加递增/斜坡循环运动时的通气（VE）反应（降低气体交换阈值），而不改变血乳酸谱，从而使气体交换和乳酸阈值分离。10 名体能活跃的男性在进行离心运动（包括 100 次深蹲）前（预）和后 48 小时（后）完成了最大递增循环测试。通过呼吸对呼吸测量肺气体交换，并在 1 分钟间隔内从指尖采样血液以确定血乳酸浓度。气体交换阈值出现在较低的工作率（前：136±27 W；后：105±19 W；P<0.05）和氧气摄取量（VO2）（前：1.58±0.26 升·分钟-1；后：1.41±0.14 升·分钟-1；P<0.05）之后的离心运动。然而，乳酸阈值出现在相似的工作率（前：161±19 W；后：158±22 W；P>0.05）和 VO2（前：1.90±0.20 升·分钟-1；后：1.88±0.15 升·分钟-1；P>0.05）之后的离心运动。这些发现表明，运动引起的肌肉损伤使递增/斜坡运动时的 VE 反应与血乳酸反应分离，表明 VE 可能在离心运动后受到额外或改变的神经刺激的控制。因此，在使用气体交换阈值提供非侵入性的乳酸阈值估计时，应该考虑先前的离心运动。
