Published in:
01-11-2003 | Short Communication
Occurrence of electromyographic and ventilatory thresholds in professional road cyclists
Authors:
F. Hug, D. Laplaud, B. Savin, L. Grélot
Published in:
European Journal of Applied Physiology
|
Issue 5-6/2003
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Abstract
The temporal relationship between the electromyographic (EMG) and ventilatory thresholds was investigated during incremental exercise performed by eight professional road cyclists. The exercise, performed on a cycloergometer, started at 100 W with successive increments of 26 W·min−1 until exhaustion. Gas exchange and the root mean square value of EMG (RMS) from eight lower limb muscles were examined throughout the exercise period. Professional cyclists achieved a maximal oxygen consumption, i.e. V̇O2max, of 5.4 (0.5) l·min−1 [74.6 (2.5) ml·min−1·kg−1, range: 67.8–82.4 ml·min−1·kg−1] and a maximum power (W
max) of 475 (30) W (range: 438–516 W). Our results showed at least the occurrence of a first EMG threshold (EMGTh1) in 50% (gastrocnemius lateralis) of the subjects and a second EMG threshold (EMGTh2) in 63% (gastrocnemius medialis). EMGTh1 occurred significantly before the first ventilatory threshold (VT1), i.e. at 52 (2)% and 62 (9)% of W
max, respectively. Inversely, no significant difference was observed between the occurrence of EMGTh2 and the second ventilatory threshold (VT2), i.e. at 86 (1)% and 89 (7)% of W
max, respectively. These results suggest that the use of EMG may be a useful non-invasive method for detecting the second ventilatory threshold in most of the muscles involved in cycling exercise.