Resistance Training With Or Without Load Promotes Similar Changes In Electromyography Activity But Not In Blood Lactate

Abstract

PURPOSE: to comparison the changes in peak electromyography (EMG) activity and levels of blood lactate (mmol/L) during a specific resistance exercise by three different moments, with extra load (TL), no load (TWL) and no load but with visual feedback (TLF). METHODS: twenty healthy men (age: 26.5±4.8 height: 1.77±0.1 weight: 80.6±12.9) volunteered to participate in the study. Participants were scheduled in two visits on laboratory, a) 10 repetition maximum test (10-RM test) and b) performance of three aleatory and different situations of a knee extension (1 - extra load, 2 - no load and 3 - no load with visual feedback) with movement velocity of a 2-second to concentric and eccentric phase (controlled by a mobile app metronome) and 10 minutes of rest between then. Blood lactate was measure before and after each situation. EMG activity was evaluated on vastus medialis (VM), vastus lateralis (VL) and rectus femoris (RF). A significance level of p≤0.05 was adopted for all statistical. tests. RESULTS: There were an increase in blood lactate after all the moments when compared to before exercise performance (p<0.05) and the blood lactate was higher in post situation TL (p<0.05) when comparison TWL and TLF (8.2±2.9, 4.2±1.8, 4.3±1.7, respectively). Additionally, significant difference was found between in all moments (p<0,05). The significant difference on EMG activity (p<0.05) only occurred on rectus femoris in TL set when compared to TWL (775.9±325.1, 492.7±262.5, respectively), but not significant difference (p>0.05) in the TLF situation (573.2±219.7). CONCLUSIONS: Performing exercise using no load can be efficient to promote increase in EMG activity and metabolic responses being an important training strategy when extra load is not possible.FIGURE