High cycling cadence reduces carbohydrate oxidation at given low intensity metabolic rate

作者：Beneke R^*; Alkhatib A

来源：Biology of Sport, 2015, 32(1): 27-33.

DOI：10.5604/20831862.1126325

• pedaling rate
• lactate
• respiratory exchange ratio
• aerobic

Cycling cadence (RPM)-related differences in blood lactate concentration (BLC) increase with increasing exercise intensity, whilst corresponding divergences in oxygen uptake ((V) over dotO(2)) and carbon dioxide production ((V) over dotCO(2)) decrease. Aim of the present study was to test whether a higher RPM reduces the fraction (%) of the (V) over dotO(2) 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, (V) over dotO(2) and (V) over dotCO(2) were measured. At respiratory exchange ratios (RER) < 1, relCHO were calculated and the constant determining 50% relCHO (k(CHO)) was approximated as a function of the BLC. At submaximal workload (V) over dotO(2), (V) over dotCO(2), and relCHO were lower (all p < 0.002; eta(2) > 0.209) at 50 than at 100 RPM. No differences were observed in (V) over dotO(2)peak (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; eta(2) = 0.680) at 50 than at 100 RPM irrespective of cycling intensity. At 50 RPM, k(CHO) (4.2 +/- 1.4 (mmol . l(-1))(3)) was lower (p = 0.043; eta(2) = 0.466) than at 100 RPM (5.9 +/- 1.9 (mmol . l(-1))(3)). This difference in k(CHO) 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.

• 出版日期2015-3