부산대학교 도서관

Purpose: Whilst pre-exercise ischaemic preconditioning (IPC) can improve lower-body exercise performance, its impact on upper-limb performance has received little attention. This study examines the influence of IPC on upper-body exercise performance and oxygen uptake (V̇O2) kinetics. Methods: Eleven recreationally-active males (24 ± 2 years) completed an arm-crank graded exercise test to exhaustion to determine the power outputs at the ventilatory thresholds (VT1 and VT2) and V̇O2peak (40.0 ± 7.4 ml·kg−1·min−1). Four main trials were conducted, two following IPC (4 × 5-min, 220 mmHg contralateral upper-limb occlusion), the other two following SHAM (4 × 5-min, 20 mmHg). The first two trials consisted of a 15-minute constant work rate and the last two time-to-exhaustion (TTE) arm-crank tests at the power equivalents of 95% VT1 (LOW) and VT2 (HIGH), respectively. Pulmonary V̇O2 kinetics, heart rate, blood-lactate concentration, and rating of perceived exertion were recorded throughout exercise. Results: TTE during HIGH was longer following IPC than SHAM (459 ± 115 vs 395 ± 102 s, p =.004). Mean response time and change in V̇O2 between 2-min and end exercise (ΔV̇O2) were not different between IPC and SHAM for arm-cranking at both LOW (80.3 ± 19.0 vs 90.3 ± 23.5 s [p =.06], 457 ± 184 vs 443 ± 245 ml [p =.83]) and HIGH (96.6 ± 31.2 vs 92.1 ± 24.4 s [p =.65], 617 ± 321 vs 649 ± 230 ml [p =.74]). Heart rate, blood-lactate concentration, and rating of perceived exertion did not differ between conditions (all p ≥.05). Conclusion: TTE was longer following IPC during upper-body exercise despite unchanged V̇O2 kinetics. Highlights Whilst pre-exercise ischaemic preconditioning can improve lower-body exercise performance and alter V̇O2 kinetics, its impact on upper-limb performance has received little attention. An acute bout of ischaemic preconditioning prior to arm-crank ergometry exercise significantly improved time to exhaustion compared to a sham control condition. V̇O2 kinetics in response to ischaemic preconditioning remained unchanged, suggesting alternative mechanisms may explain performance improvements. [ABSTRACT FROM AUTHOR]