Inter-Set Blood-Flow Restriction Increases Peripheral Physiological Stress While Preserving Repeated-Sprint...

Inter-set blood-flow restriction (BFR) may increase the physiological stimulus of repeated-sprint exercise without compromising mechanical output, but evidence in trained athletes is limited. In a randomized crossover design, 26 national-level male badminton players completed three 5 × 5-s cycling sprints (25-s intra-set rest, 3.5-min inter-set recovery). During the first two recoveries, cuffs were inflated to 130 mmHg (BFR) or 20 mmHg (sham-BFR). Outcomes included power output, vastus lateralis muscle oxygenation (SmO₂), heart rate, exercise-related sensations, and vertical jump. Mean and peak power declined across sets with no condition or interaction effects. Sprint decrement scores showed no differences. Muscle oxygenation kinetics revealed time and condition × time effects: recovery SmO₂ was lower with BFR during the first two inter-set recoveries (Δ = 16.04 and 15.50 pp; p ≤ 0.05), whereas this difference reversed during the non-occluded third recovery (Δ = -6.00; p = 0.010). Early SmO₂ resaturation slopes (0-30 s) were slower with BFR in recoveries 1-2 (Δ = +0.250 and + 0.209 pp/s; p < 0.001 and < 0.05), but not recovery 3. Heart rate and breathing difficulty increased across sets, without condition effects. Response showed condition × set interactions, with higher leg discomfort (Set 2) and perceived exertion (Sets 2-3) under BFR. After exercise, countermovement height decreased in BFR (p < 0.001), not in sham-BFR (p = 0.093). Inter-set BFR increased peripheral physiological and perceptual stress and altered muscle oxygenation recovery without compromising repeated-sprint mechanical performance or cardiovascular responses. This strategy may provide a practical method to enhance training stress in trained athletes, although greater post-exercise reductions in jump performance suggest potential neuromuscular fatigue.