title: Metabolic and neuromuscular adaptations to endurance training in professional cyclists: a longitudinal study.
abstract: The aim of this longitudinal study was to analyze the changes in several metabolic and neuromuscular variables in response to endurance training during three defined periods of a full sports season (rest, precompetition and competition). The study population was formed by thirteen professional cyclists (age +/- SEM: 24+/-1 years; mean V(O2 max) approximately 74 ml kg(-1) min(-1)). In each testing session, subjects performed a ramp test until exhaustion on a cycle ergometer (workload increases of 25 W min(-1)). The following variables were recorded every 100 W until the tests: oxygen consumption (V(O2) in l min(-1)), respiratory exchange ratio (RER in V(CO2) V(O2)(-1)) and blood lactate, pH and bicarbonate concentration [HCO3(-)]. Surface electromyography (EMG) recordings were also obtained from the vastus lateralis to determine the variables: root mean square voltage (rms-EMG) and mean power frequency (MPF). RER and lactate values both showed a decrease (p<0.05) throughout the season at exercise intensities corresponding to submaximal workloads. In contrast, no significant differences were found in mean pH or [HCO(3-)]. Finally, rms-EMG tended to increase during the season, with significant differences (p<0.05) observed mainly between the competition and rest periods at most workloads. In contrast, precompetition MPF values increased (p<0.05) with respect to resting values at most submaximal workloads but fell (p<0.05) during the competition period. Our findings suggest that endurance conditioning induces the following general adaptations in elite athletes: (1) lower circulating lactate and increased reliance on aerobic metabolism at a given submaximal intensity, and possibly (2) an enhanced recruitment of motor units in active muscles, as suggested by rms-EMG data.
authors.affiliation: Departamento de Ciencias Morfológicas y Fisiología, Universidad Europea de Madrid, Spain. alejandro.lucia@mrfs.cisa.uem.es
authors.forename: A
authors.initials: A
authors.lastname: Lucía
authors.forename: J
authors.initials: J
authors.lastname: Hoyos
authors.forename: J
authors.initials: J
authors.lastname: Pardo
authors.forename: J L
authors.initials: JL
authors.lastname: Chicharro
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D000328:Adult; D001639:Bicarbonates / Q000097:blood; D001642:Bicycling / Q000502:physiology*; D004576:Electromyography; D015444:Exercise / Q000502:physiology; D005080:Exercise Test; D006801:Humans; D006863:Hydrogen-Ion Concentration; D019344:Lactic Acid / Q000097:blood; D008137:Longitudinal Studies; D009046:Motor Neurons / Q000502:physiology; D018482:Muscle, Skeletal / Q000294:innervation / Q000502:physiology; D010101:Oxygen Consumption / Q000502:physiology; D010807:Physical Endurance / Q000502:physiology*; D011659:Pulmonary Gas Exchange / Q000502:physiology
chemical_list: D001639:Bicarbonates; D019344:Lactic Acid