The physiological effects of low-intensity NMES on short-term recovery from supra-maximal exercise bouts in trained male triathletes

Inadequate recovery from high-intensity exercise bouts can limit sporting performance [1]. Previous research using various recovery intervention protocols have generally found positive results compared to passive recovery [2,3]. A recent study showed that NMES during recovery lowered blood lactate (Bla) compared to passive recovery [4]. The aim of this study was to determine the acute effects of NMES on BLa and performance parameters in trained male tri-athletes. Methods On three separate days, 13 trained male triathletes (31 ± 5 yrs; 182.8 ± 6.9 cm; 78.1 ± 8.4 kg) performed six 30 sec Wingate tests (30WanT) on a cycle ergometer. Each session consisted of 3 x 30WanT (bouts 1-3) interspersed by 4 min recovery (80 Watts @ 80 rev.min-1), followed by a randomly assigned 30 min recovery intervention of either: i) passive (seated), ii) active (cycling @ 30% VO2max) or iii) NMES (1 Hz / 500 μs - ON:OFF 2:6 s). The 3 x 30WanT bouts were then repeated (bouts 4-6) and compared to bouts 1-3 for peak power (PP), mean power (MP) and fatigue index (FI). BLa and heart rate (HR) were recorded at designated time points throughout. Data were analysed using repeated measures ANOVA with Tukey’s HSD post hoc test. Results BLa decreased significantly faster during the active recovery intervention compared to both the NMES and passive interventions (P < 0.05). There were no significant differences between interventions for PP (P = 0.710), MP (P = 0.928) and FI (P = 0.814) when the post intervention bouts (4-6) where compared to the pre intervention bouts (1-3). Discussion NMES during recovery was not more effective than active, or surprisingly, passive recovery for improving subsequent performance. Despite Bla clearing at a significantly faster rate for the active recovery intervention, PP, MP or FI did not improve significantly compared to NMES and passive. This supports the belief that lactate is not a major cause of muscle fatigue [1]. In conclusion, NMES does not appear to be more effective than traditional methods for enhancing recovery. References 1. Williams C & Ratel S, (2009). Human Muscle Fatigue. Routledge. 2. Gill ND et al., (2006). Effectiveness of post match recovery strategies in rugby players. Br J Sports Med, 42, 260-263. 3. Lane KN & Wenger HA. (2004). Effect of selected recovery conditions on performance of repeated bouts of intermittent cycling separated by 24 hours. J Stren Cond Res, 18, 855-860. 4. Neric FB et al., (2009). Comparison of swim recovery and muscle stimulation on lactate removal after swimming. J Stren Cond Res, 23, 2560-2567.