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Visa fullständig version : Laktat och sEMG vid benpress med olika knävinklar


King Grub
2011-07-30, 08:48
The purpose of this study was to examine the changes in peak power output, blood lactate concentrations and surface electromyographic activity (sEMG) of the agonist [vastus lateralis (VL) and vastus medialis (VM)] and the antagonist [biceps femoris (BF)] muscles at two angular positions intervals (90-67° and 23-0° of knee flexion), during a set of 10 repetitions leading to failure of bilateral leg press exercise. Fatiguing exercise resulted in increased blood lactate concentrations, the agonist mean rectified voltage (MRV) at 90-67° of flexion, the antagonist average MRV at 23-0° of flexion and the spectral parameter proposed by Dimitrov (FI(nsm5)) (P < 0.01-0.05). Significant decreases (P < 0.01-0.05) were observed in power output, median frequency (F(med)) of the agonist muscles at both angular position intervals and of the antagonist muscle at 90-67° of flexion. No changes were observed in the antagonist/agonist MRV activation ratio. The present data suggest that the shift of frequency spectrum to lower frequencies and the accumulation of lactate and/or H(+), but not the antagonist/agonist MRV activation ratio, may be relevant independent factors associated with fatigue.

Eur J Appl Physiol. 2011 Jul 29. Blood lactate and sEMG at different knee angles during fatiguing leg press exercise.