title: Time to exhaustion at maximal lactate steady state is similar for cycling and running in moderately trained subjects.
abstract: We compared time to exhaustion (t(lim)) at maximal lactate steady state (MLSS) between cycling and running, investigated if oxygen consumption, ventilation, blood lactate concentration, and perceived exertion differ between the exercise modes, and established whether MLSS can be determined for cycling and running using the same criteria. MLSS was determined in 15 moderately trained men (30 +/- 6 years, 77 +/- 6 kg) by several constant-load tests to exhaustion in cycling and running. Heart rate, oxygen consumption, and ventilation were recorded continuously. Blood lactate concentration and perceived exertion were measured every 5 min. t (lim) (37.7 +/- 8.9 vs. 34.4 +/- 5.4 min) and perceived exertion (7.2 +/- 1.7 vs. 7.2 +/- 1.5) were similar for cycling and running. Heart rate (165 +/- 8 vs. 175 +/- 10 min(-1); P < 0.01), oxygen consumption (3.1 +/- 0.3 vs. 3.4 +/- 0.3 l min(-1); P < 0.001) and ventilation (93 +/- 12 vs. 103 +/- 16 l min(-1); P < 0.01) were lower for cycling compared to running, respectively, whereas blood lactate concentration (5.6 +/- 1.7 vs. 4.3 +/- 1.3 mmol l(-1); P < 0.05) was higher for cycling. t(lim) at MLSS is similar for cycling and running, despite absolute differences in heart rate, ventilation, blood lactate concentration, and oxygen consumption. This may be explained by the relatively equal cardiorespiratory demand at MLSS. Additionally, the similar t(lim) for cycling and running allows the same criteria to be used for determining MLSS in both exercise modes.
authors: Exercise Physiology, Institute of Human Movement Sciences, ETH Zurich, Zurich, Switzerland. fontana@physiol.biol.ethz.ch
authors: Piero
authors: P
authors: Fontana
authors: Urs
authors: U
authors: Boutellier
authors: Claudia
authors: C
authors: Knöpfli-Lenzin
mesh_terms: D000328:Adult; D001642:Bicycling / Q000502:physiology*; D002320:Cardiovascular Physiological Phenomena; D005080:Exercise Test; D006801:Humans; D019344:Lactic Acid / Q000097:blood*; D008297:Male; D018763:Muscle Fatigue / Q000502:physiology; D010101:Oxygen Consumption / Q000502:physiology; D010807:Physical Endurance / Q000502:physiology; D005082:Physical Exertion / Q000502:physiology*; D010809:Physical Fitness / Q000502:physiology*; D011673:Pulsatile Flow; D012420:Running / Q000502:physiology*; D013997:Time Factors; D055815:Young Adult
chemical_list: D019344:Lactic Acid