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We investigated the effect of ischemic preconditioning (IPC) with and without caffeine supplementation on mean power output (MPO) during a 4-min cycling time-trial (TT). In a double-blinded, randomized, crossover-design, 11 trained men performed a TT on 4 days separated by ∼1 week. One hour before TT, participants ingested either caffeine (3 mg kg bw -1 ) or placebo pills, after which femoral blood-flow was either restricted with occlusion cuffs inflated to ∼180 mmHg (IPC), or sham-restricted (0-10 mmHg; Sham) during 3 × 2-min low-intensity cycling (10% of incremental peak power output). Then, participants performed a standardized warm-up followed by the TT. Plasma lactate and K + concentrations and ratings of perceived exertion (RPE) were measured throughout trials. TT MPO was 382 ± 17 W in Placebo + Sham and not different from Placebo + IPC (-1 W; 95% CI: -9 to 7; p = 0.848; d: 0.06), whereas MPO was higher with Caffeine + Sham (+6W; 95% CI: -2 to 14; p = 0.115; d: 0.49) and Caffeine + IPC (+8 W; 95% CI: 2-13; p = 0.019; d: 0.79) versus Placebo + Sham. MPO differences were attributed to caffeine (caffeine main-effect: +7 W; 95% CI: 2-13; p = 0.015; d: 0.54. IPC main-effect: 0 W; 95% CI: -6 to 7; p = 0.891; d: 0.03; caffeine × IPC interaction-effect: p = 0.580; d: 0.17). TT RPE and plasma variables were not different between treatments. In conlcusion, IPC with co-ingestion of placebo does not improve short-term high-intensity performance in trained men versus a double-placebo control (Placebo + Sham) and does not additively enhance performance with caffeine. These data do not support IPC as a useful strategy for athletes prior to competition but confirms caffeine's performance-enhancing effect., (© 2024 The Authors. European Journal of Sport Science published by Wiley‐VCH GmbH on behalf of European College of Sport Science.)

Purpose: We investigated whether 4 weeks of intensified training consisting of speed endurance training (SET) enhanced high-intensity exercise performance in youth national-team ice hockey players., Methods: Utilizing a randomized crossover design, we subjected 17 players to 4 weeks of SET, comprising 6 to 10 × 20 seconds at maximal effort (>95% maximum ice skating speed) with 120-second recovery performed 3 times weekly, or maintenance of regular training (control period). Before and after each period, players completed ice-hockey-specific tests on ice, including a Yo-Yo Intermittent Recovery Level 1 test, a 30-m sprint test, and an agility test. On a separate day, players were assessed for body composition with dual-energy X-ray absorptiometry and performed countermovement jump, maximal voluntary isometric knee extensor contraction, a 15-second maximal sprint test, and a submaximal and incremental test on a bike ergometer in which pulmonary oxygen consumption was determined., Results: Yo-Yo Intermittent Recovery Level 1 test performance increased (P < .001) by 14% (95% CI, 201-496 m) during the SET period. Maximal pulmonary oxygen consumption (P < .05) and time to exhaustion (P < .05) were 4.8% and 6.5% higher, respectively, after the SET period than before. Fat-free mass increased (P < .01) during the SET period by 1.7 kg (95% CI, 1.0-2.5), whereas fat mass remained unchanged. These effects were superior to the control period., Conclusions: These findings underpin the effectiveness of SET for improving on-ice high-intensity performance and highlight that elite ice hockey players can benefit from implementing SET.