Effects of altering pedal frequency on the slow component of pulmonary VO2 kinetics and EMG activity.
Int J Sports Med
; 31(8): 529-36, 2010 Aug.
Article
en En
| MEDLINE
| ID: mdl-20432199
ABSTRACT
This study investigated the effects of pedal frequency on the slow component of pulmonary oxygen uptake ( V O(2)) kinetics during heavy exercise at the same relative intensity. We hypothesized that higher pedal frequency (expected to enhance fast-twitch muscle fiber recruitment) would be associated with greater slow component amplitude (A' (s)), surface electromyography (normalized root mean square; RMS) and blood lactate concentration ([lactate]). Eight subjects performed square-wave transitions to heavy exercise at 35 and 115 rpm. Furthermore, alternated cadences square-wave transitions (35-115 rpm) were performed to examine the potential effects of additional fast-twitch muscle fiber recruitment on the slow component. Significance was accepted when P<0.05. The A' (s) was greater at higher cadences (0.58+/-0.08 and 0.70+/-0.09 L.min (-1) at 115 and 35-115 rpm, respectively) than at 35 rpm (0.35+/-0.04 L.min (-1)). Greater EMG increase over time (DeltaRMS ((10-3 min))) and [lactate] were observed at 115 and 35-115 rpm compared with 35 rpm. There was a significant correlation between A' (s) and overall DeltaRMS ((10-3 min)) for all pedal frequencies combined (r=0.63; P=0.001). Pedal frequency had no effect on time constants or time delays. These findings are consistent with the concept that progressive recruitment of muscle fibers is associated with the V O(2) slow component.
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1
Base de datos:
MEDLINE
Asunto principal:
Consumo de Oxígeno
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Ciclismo
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Prueba de Esfuerzo
Límite:
Adult
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Humans
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Male
Idioma:
En
Revista:
Int J Sports Med
Año:
2010
Tipo del documento:
Article
País de afiliación:
Brasil