Active Relative to Passive Ischemic Preconditioning Enhances Intense Endurance Performance in Well-Trained Men

This study tested the hypothesis of whether ischemic exercise preconditioning (IPC-Ex) elicits a better intense endurance exercise performance than traditional ischemic preconditioning at rest (IPC-rest) and a SHAM procedure. Twelve men (average V˙O2max ∼61 mL·kg-1·min-1) performed 3 trials on separate days, each consisting of either IPC-Ex (3 × 2-min cycling at ∼40 W with a bilateral-leg cuff pressure of ∼180 mm Hg), IPC-rest (4 × 5-min supine rest at 220 mm Hg), or SHAM (4 × 5-min supine rest at .09) or cycling efficiency (P ≥ .24). Eight subjects anticipated IPC-Ex to be best for their performance. Four subjects favored SHAM. Performance in a 4-minute maximal test was better following IPC-Ex than IPC-rest and tended to be better than SHAM. The IPC procedures did not affect blood potassium, while pH was transiently elevated only by IPC-Ex. The performance-enhancing effect of IPC-Ex versus IPC-rest may be attributed to a placebo effect, improved pH regulation, and/or a change in the perception of effort.