The purpose of the present investigation was to compare the electromyographic (EMG) responses and the estimated physical working capacity at the
fatigue threshold (PWC(FT)) values recorded from
electrode arrangements placed: (1) parallel to the muscle fiber pennation angle (
MFPA), (2) parallel to the long axis of the femur, and (3) over the innervation zone (IZ) during incremental cycle ergometry. Thirteen college-aged males and females (mean age ± SD=22.4 ± 3.4 years) performed an incremental test to exhaustion on a cycle ergometer. A linear
electrode array was utilized to determine the
MFPA and location of the IZ of the vastus lateralis (VL). For determination of the PWC(FT) values, EMG signals were recorded from three bipolar
electrode arrangements at different locations over the VL. The results of a one-way repeated measures ANOVA indicated there were no significant (p<0.05) mean differences in PWC(FT) values among the
electrode arrangements (parallel to the
MFPA=190 ± 36 W; parallel to the long axis of the femur=194 ± 40 W; and over the IZ=199 ± 51 W) or the EMG amplitude and MPF values at the common power outputs. There were also significant correlations (r=0.75-0.91) among the three
electrode arrangements for PWC(FT) values. These findings suggested that the PWC(FT), like absolute EMG amplitude and MPF, is robust to the influence of
electrode placement over the IZ as well as the orientation with respect to the
MFPA during cycle ergometry.