Abt. Medizin, Training und Gesundheit, Inst. Sportwissenschaft und Motologie, Philipps Universität Marburg, Germany.
Academy of Sport and Sport & Physical Activity, Sheffield Hallam University, United Kingdom.
Biol Sport. 2015 Mar;32(1):27-33. doi: 10.5604/20831862.1126325. Epub 2014 Oct 28.
Cycling cadence (RPM)-related differences in blood lactate concentration (BLC) increase with increasing exercise intensity, whilst corresponding divergences in oxygen uptake ([Formula: see text]O2) and carbon dioxide production ([Formula: see text]CO2) decrease. Aim of the present study was to test whether a higher RPM reduces the fraction (%) of the [Formula: see text]O2 used for carbohydrate oxidation (relCHO) at a given BLC. Eight males (23.9 ± 1.6 yrs; 177 ± 3 cm; 70.3 ± 3.4 kg) performed incremental load tests at 50 and 100 RPM. BLC, [Formula: see text]O2 and [Formula: see text]CO2 were measured. At respiratory exchange ratios (RER) < 1, relCHO were calculated and the constant determining 50 % relCHO (kCHO) was approximated as a function of the BLC. At submaximal workload [Formula: see text]O2, [Formula: see text]CO2, and relCHO were lower (all p < 0.002; η(2) > 0.209) at 50 than at 100 RPM. No differences were observed in [Formula: see text]O2peak (3.96 ± 0.22 vs. 4.00 ± 0.25 l · min (-1)) and RERpeak (1.18 ± 0.02 vs. 1.15 ± 0.02). BLC was lower (p < 0.001; η(2) = 0.680) at 50 than at 100 RPM irrespective of cycling intensity. At 50 RPM, kCHO (4.2 ± 1.4 (mmol · l (-1))(3)) was lower (p = 0.043; η(2) = 0.466) than at 100 RPM (5.9 ± 1.9 (mmol · l (-1))(3)). This difference in kCHO reflects a reduced CHO oxidation at a given BLC at 100 than at 50 RPM. At a low exercise intensity, a higher cycling cadence can substantially reduce the reliance on CHO at a given metabolic rate and/or BLC.
随着运动强度的增加，与踏频（RPM）相关的血乳酸浓度（BLC）增加差异，而相应的氧气摄取量 ([Formula: see text]O2) 和二氧化碳产生量 ([Formula: see text]CO2) 减少差异。本研究的目的是测试在给定的 BLC 下，较高的 RPM 是否会降低碳水化合物氧化（relCHO）所消耗的氧气百分比（%）。8 名男性（23.9 ± 1.6 岁；177 ± 3 厘米；70.3 ± 3.4 千克）以 50 和 100 RPM 进行递增负荷测试。测量 BLC、[Formula: see text]O2 和 [Formula: see text]CO2。在呼吸交换率（RER）<1 时，计算 relCHO，并将确定 50% relCHO 的常数（kCHO）近似为 BLC 的函数。在亚最大工作负荷下，[Formula: see text]O2、[Formula: see text]CO2 和 relCHO 均低于 50 RPM（所有 p<0.002；η(2)>0.209）。在[Formula: see text]O2peak（3.96 ± 0.22 与 4.00 ± 0.25 l·min(-1))和 RERpeak（1.18 ± 0.02 与 1.15 ± 0.02）之间未观察到差异。无论骑行强度如何，BLC 均低于 50 RPM（p<0.001；η(2)=0.680）。在 50 RPM 时，kCHO（4.2 ± 1.4（mmol·l(-1))(3)）低于 100 RPM（5.9 ± 1.9（mmol·l(-1))(3)）（p=0.043；η(2)=0.466）。这种 kCHO 的差异反映了在给定 BLC 下，100 RPM 比 50 RPM 时的 CHO 氧化减少。在低运动强度下，较高的踏频可以在给定的代谢率和/或 BLC 下，显著减少对 CHO 的依赖。
