Effects of different cycling cadences (revolutions/min [rpm]) on metabolic rate, blood lactate concentration (BLC), and reliance on carbohydrate (CHO) defined as the fraction of oxygen uptake used for CHO oxidation (relCHO) are highly individual. Whether this depends on the individually maximal achievable rpm obtained at minimized cycling resistance (rpmmax) is unknown. The authors tested the hypotheses that the individual freely chosen rpm in an incremental cycle-ergometer test (ILT) and relCHO at given BLC levels both depend on rpmmax. Seven master cyclists and 8 not specifically trained leisure athletes performed an ILT at individually freely chosen rpm and an rpmmax test. Respiratory data and BLC were measured; relCHO was plotted as a function of the BLC for the determinations of the individual BLC at relCHO of 75% and 95% (BLC75% and BLC95%). With 16.7%, the between-subjects variability of individual rpm was high but independent from rpmmax. In the master athletes, rpmmax explained 59.3% and 95.2% of BLC75% (P = .043) and BLC95% (P = .001), respectively. Irrespective of cycling experience, the individually preferred average rpm at submaximal stages of an ILT is highly variable and independent of rpmmax. In experienced cyclists, carbohydrate management defined as the ratio between substrate availability as indicated by BLC and relCHO depends on rpmmax.
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- Author: Renate M. Leithäuser x
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Ralph Beneke, Tobias G.J. Weber, and Renate M. Leithäuser
Ralph Beneke, Hermann Heck, Helge Hebestreit, and Renate M Leithäuser
The value of blood lactate concentration (BLC) measured during incremental load tests in predicting maximal lactate-steady-state (MLSS) workload has rarely been investigated in children. In 17 children and 18 adults MLSS was 4.1 ± 0.9mmol 1.1. Workload at BLC of 3.0mmol 1.1 determined during an incremental load test explained about 80% of the variance (p < .001) and best predicted MLSS workload independent of age. This was despite the increase in power per time related to maximum incremental load test power being higher (p < .001) in children than in adults. The BLC response to given exercise intensities is faster in children without affecting MLSS.
Renate M. Leithäuser, Dieter Böning, Matthias Hütler, and Ralph Beneke
Relatively long-lasting metabolic alkalizing procedures such as bicarbonate ingestion have potential for improving performance in long-sprint to middle-distance events. Within a few minutes, hyperventilation can induce respiratory alkalosis. However, corresponding performance effects are missing or equivocal at best.
Purpose:
To test a potential performance-enhancing effect of respiratory alkalosis in a 30-s Wingate Anaerobic Test (WAnT).
Methods:
10 men (mean ± SD age 26.6 ± 4.9 y, height 184.4 ± 6.1 cm, body-mass test 1 80.7 ± 7.7 kg, body-mass test 2 80.4 ± 7.2 kg, peak oxygen uptake 3.95 ± 0.43 L/min) performed 2 WAnTs, 1 with and 1 without a standardized 15-min hyperventilation program pre-WAnT in randomized order separated by 1 wk.
Results:
Compared with the control condition, hyperventilation reduced (all P < .01) pCO2 (40.5 ± 2.8 vs 22.5 ± 1.6 mm Hg) and HCO3 − (25.5 ± 1.7 vs 22.7 ± 1.6 mmol/L) and increased (all P < .01) pH (7.41 ± 0.01 vs 7.61 ± 0.03) and actual base excess (1.4 ± 1.4 vs 3.2 ± 1.6 mmol/L) pre-WAnT with an ergogenic effect on WAnT average power (681 ± 41 vs 714 ± 44 W) and total metabolic energy (138 ± 12 vs. 144 ± 13 kJ) based on an increase in glycolytic energy (81 ± 13 vs 88 ± 13 kJ).
Conclusion:
Hyperventilation-induced respiratory alkalosis can enhance WAnT cycling sprint performance well in the magnitude of what is seen after successful bicarbonate ingestion.
