squat

<p>Blood flow restriction (BFR) training is commonly prescribed with fixed repetition targets or sets to volitional failure, but these approaches may not individualize repetition exposure. This study compared strength and jump responses to the distinct working-set repetition volumes produced by two session-reference peak-velocity-decline thresholds and volitional failure during low-load BFR full back squat training. Forty-five resistance-trained males (22.9 ± 0.7 years) were allocated to a 10% peak-velocity-decline condition (VL10%), a 40% condition (VL40%), or volitional failure (FAIL; n = 15 each). All groups trained twice weekly for 8 weeks at 30% of the current one-repetition maximum (1RM) with BFR; the assigned set-termination strategy determined working-set repetition volume. Primary outcomes were full back squat 1RM and isometric mid-thigh pull net peak force; jump height and standing broad-jump distance were secondary outcomes. The strategies produced distinct working-set repetition volumes (55.91 ± 0.61, 74.26 ± 0.89, and 94.08 ± 0.93 repetitions per session in VL10%, VL40%, and FAIL, respectively; all adjusted p < 0.001). No statistically significant between-group difference was detected between VL40% and FAIL for the primary strength outcomes, while VL40% involved lower repetition volume and perceived exertion. VL10% reduced repetition volume further and showed favorable changes in countermovement-jump height and standing broad-jump distance, but smaller strength-oriented adaptations than VL40%. Under this low-load BFR protocol, no statistically significant differences were detected between VL40% and FAIL for the primary strength outcomes, whereas VL10% showed smaller improvements in both primary strength outcomes than VL40% and FAIL. Jump responses were outcome-specific: both VL10% and VL40% showed greater CMJ improvements than FAIL, VL40% showed greater SJ improvement than both VL10% and FAIL, and VL10% showed greater SBJ improvement than FAIL.</p>

matched text: “squat”

Background/Objectives: Repeated sprint performance is typically reduced during the morning because of circadian-related changes in physiological function and muscle strength. Acute caffeine supplementation may attenuate these decrements; however, evidence remains inconsistent. This is partly because of inadequate control of chronobiological and methodological confounders. This study investigated the effects of acute morning caffeine ingestion on repeated sprint performance, physiological responses, strength, power and mood under rigorously standardized chronobiological conditions. Methods: Seventeen recreationally active, low habitual caffeine-consumer males completed six laboratory visits comprising three familiarization sessions and three experimental trials in a performance grouped, randomized for starting condition, counterbalanced, double-blind, placebo-controlled, crossover design. Participants ingested either caffeine (CAFF; 300 mg, 2.5–5.3 mg·kg−1), placebo (PLAC) or no-pill control (NoPill) 60 min before testing (07:30 h). Experimental sessions included assessments of mood, caffeine withdrawal symptoms, intra-aural temperature, grip strength, squat jump, countermovement jump and a 10 × 20 m repeated sprint protocol. Heart rate, ratings of perceived exertion (RPE), thermal comfort, blood lactate and blood glucose were assessed throughout the protocol. Data were analyzed using repeated-measures general linear models. Results: Caffeine did not significantly improve repeated sprint performance compared with PLAC or NoPill, although a trend towards faster 20 m sprint times was observed (3.39 ± 0.19 s vs. 3.43 ± 0.18 s and 3.41 ± 0.19 s, respectively; p = 0.070). Caffeine significantly reduced RPE (p = 0.029) but did not alter heart rate, blood lactate, blood glucose, thermal comfort, intra-aural temperature, mood, sleepiness, caffeine withdrawal symptoms nor lower-body power outcomes. Conclusions: Acute morning ingestion of 300 mg caffeine reduced perceived exertion but did not produce a clear ergogenic effect on repeated sprint performance under rigorously standardized chronobiological conditions. These findings suggest that, in low habitual caffeine users, the central perceptual effects of caffeine are insufficient to overcome the physiological constraints limiting morning repeated sprint performance and highlight the importance of rigorous chronobiological standardization when evaluating nutritional ergogenic aids.

matched text: “squat”