INTRODUCTION:
Ischemic preconditioning (IPC) may serve as an ergogenic aid in sport and health. There is, however, less known regarding potential pressure-specific effects and/or the influence of muscle size and strength on exercise performance following IPC. The purpose of this investigation was to examine the acute effects of various IPC pressures on repetitions to failure (RTF) and if muscle size and/or strength are associated with RTF.
METHODS:
Twenty-one males (21.4 ± 2.2 years; 177.4 ± 8.6 cm; 80.6 ± 12.5 kg) visited the laboratory on four separate visits. The first visit consisted of baseline measurements of muscle size (cross-sectional area [CSA]) and strength (one-repetition maximum [1RM]) of the dominant leg. The next three visits consisted of IPC randomly implemented at low (SHAM [20 mmHg]), moderate (80% of total arterial occlusion pressure [TAOP]), and high (220 mmHg) pressures. A total of three cycles, consisting of pressure applied for five minutes followed by five minutes of rest, was completed with a pneumatic cuff placed most proximally on the dominant leg. Following IPC, participants completed one-set of unilateral, isotonic leg extension muscle actions to volitional failure at 30% of their 1RM. A one-way ANOVA was performed to determine mean differences in RTF while separate stepwise linear regressions were performed to determine the associations of CSA and 1RM on RTF for each IPC pressure.
RESULTS:
There was no significant main effect for Pressure (p = 0.059) on RTF. The stepwise linear regression indicated that 1RM was a significant (p < 0.001) predictor for RTF in the low (r = 0.68; R2 = 0.46), moderate (r = 0.71; R2 = 0.51), and high conditions (r = 0.69; R2 = 0.48), while the addition of CSA did not significantly (p = 0.879 to 0.972; R2 change = 0.00 to 0.024) improve the model.
CONCLUSION:
There was no ergogenic effect of IPC on RTF. Instead, RTF was positively related to muscle strength which explained approximately 50% of the variance in RTF. Thus, improving fatigue resistance may be accomplished through resistance exercise.