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Abstract:
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The purpose of this study was to determine the effects of eccentric and concentric muscle contractions on the frequency and amplitude of EMG , torque , blood lactate , and the amount of work done . Ten college -aged males performed either four sets of twenty eccentric or concentric maximal contractions to induce muscle fatigue . Pre - and post -fatigues measurements of torque , EMG , blood lactate and work done were recorded . A 2 x 2 repeated measures ANOVA was used to test for differences in condition (concentric , eccentric ) and time (pre , post ) for the following dependent variables : total work done , average torque , change in lactate concentrations VL EMG , RF EMG and VM EMG . Significant pre - post differences were found for torque , blood lactate and EMG median frequency . There was a significant interaction between time and condition for VL EMG amplitude . In the concentric condition VL EMG amplitude decreased due to fatigue , and increased due to fatigue in the eccentric condition . For work done the third and fourth sets were significantly lower than the first set for both the eccentric and concentric conditions . |