Authors: David Stewart Andrea Macaluso Giuseppe De Vito
Publish Date: 2003/02/28
Volume: 89, Issue: 6, Pages: 509-513
Abstract
The effect of an active warmup on maximal voluntary contraction MVC maximal instantaneous power output and surface EMG sEMG parameters was studied Eight volunteers mean SD 22 4 years completed two trials on the same day one control CO and the other preceded by an active cycling warmup WU at 70 ventilatory threshold determined by the ventilatory equivalent method Quadriceps muscle temperature measured from vastus lateralis with a flexible thermistor was 338 04°C in CO compared to 368 05°C in WU P005 Aural temperature measured by an infrared tympanic thermistor was not different between conditions Experimental trials consisted of three kneeextension maximum voluntary contractions at a 90° angle with simultaneous recording of sEMG from the vastus lateralis followed by three squat jumps performed on a force platform SEMGs were analysed in the frequency domain as median frequency MDF and in the time domain as root mean square RMS MDF was 592 141 Hz in CO compared to 672 118 Hz in WU P005 while RMS was higher in CO compared to WU 065 028 mV vs 056 019 mV P005 MVC was not different 4657 1076 N vs 4901 1172 N whilst instantaneous power output during the squat jump was significantly higher in the WU trial 3324 866 W vs 3569 919 W P005 These data show MDF to be altered with an active warmup which would relate to a greater conduction velocity This may translate into faster activation of the muscle fibres thus partly explaining the increase in power output
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