Electromyogram as an indicator of neuromuscular fatigue during incremental exercise

摘要: This study analysed the changes in electromyographic activity (EMG) of vastus lateralis muscle (VL) during an incremental maximal oxygen uptake test on a treadmill. A breakpoint integrated electromyogram (iEMG)-velocity relationship has already been interpreted two ways: either as sign neuromuscular fatigue or expression iEMG-velocity characteristics. The aim this was to method distinguishing effects from those due increases exercise power. Eight well-trained male runners took part study. They completed running protocol consisting 4-min stages increments power output. Between each stage (about 15 s after start minute at rest), subjects had maintain standard effort: 10-s isometric leg extension contraction [50% voluntary (IMVC)]. EMG recorded and protocols, change signal being considered fatigue. relationships were strongly fitted by second-order polynomial function for data taken both (r = 0.98) end stage. Based stability 50%IMVC-iEMG noted between stages, start-iEMG identified expressing without which end-iEMG increased significantly more steeply than iEMG threshold simultaneous with ventilatory equivalent carbon dioxide threshold. parallel ventilation would suggest existence common regulation stimuli linked effort intensity and/or metabolic conditions. fall intracellular [K+] discussed one main factors regulating ventilation.