Ventilatory threshold during incremental running can be estimated using EMG shorts

The present study examined whether shorts with textile electromyographic (EMG) electrodes can be used to detect second ventilatory threshold (VT2) during incremental treadmill running. Thirteen recreationally active (REC) and eight endurance athletes were measured for EMG, heart rate, blood lactate and respiratory gases during VO2max test (3 min ramps, 1 km ⋅ h−1 increments). VT2, onset of blood lactate accumulation (OBLA) and EMG threshold (EMGT) were determined. In athletes, OBLA occurred at 56 ± 6 mL ⋅ kg−1 ⋅ min−1, VT2 occurred at 59 ± 6 mL ⋅ kg−1 ⋅ min−1, and EMGT at 62 ± 6 mL ⋅ kg−1 ⋅ min−1 without significant differences between methods (analysis of variance: ANOVA). In REC participants, OBLA occurred at 40 ± 10 mL ⋅ kg−1 ⋅ min−1, VT2 occurred at 43 ± 7 mL ⋅ kg−1 ⋅ min−1, and EMGT at 41 ± 9 mL ⋅ kg−1 ⋅ min−1 without significant differences between methods (ANOVA). For the entire group, correlation between EMGT and VT2 was 0.86 (P < 0.001) and 0.84 (P < 0.001) between EMGT and OBLA. Limits of agreement between EMGT and VT2 were narrower in athletes than in REC participants. Thus, it is concluded that estimation of VT2 using EMGT in athletes is more valid than in REC participants. In practice, experienced runners could use online feedback from EMG garments to monitor whether their running intensity is near VT2.