International journal of sports physiology and performance最新文献

Purpose: The aim of this study was to investigate the effects of repeated-sprint training in hypoxia (RSH) versus in normoxia (RSN) in female national-level rugby union players.

Methods: In a randomized, controlled, and crossover study, 8 female rugby union players performed 5 sessions of repeated sprints either in normobaric hypoxia (RSH, simulated altitude: 3000 m; FiO2 = 14.5%) or in normoxia (RSN, terrestrial altitude: 165 m; FiO2 = 20.5%). Before (Pre) and after (Post) training, repeated-sprint ability (6 × 10-s "all-out" sprints and 20-s recovery) was evaluated on a cycle ergometer.

Results: From Pre to Post, peak power output was improved in RSH (602 [98] vs 704 [92] W; P = .007) but not in RSN (661 [91] vs 673 [76] W; P = .560). Similarly, mean power output was enhanced in RSH (445 [63] vs 532 [51] W; P = .013) but not in RSN (499 [88] vs 509 [63] W; P = .557). Sprint decrement did not change in either RSH (24.5 [8.9] vs. 24.0% [5.7%]; P = .819) or RSN (22.7 [5.9] vs 24.3% [4.8%]; P = .336).

Conclusion: As few as 5 sessions of RSH were beneficial for improving peak and mean power outputs during repeated-sprint exercise in female national-level rugby union players compared with the same training in normoxia.

Purpose: This study explored the acute physiological effects of different eccentric tempos, explosive speed (EXP), volitional speed, and 4-second tempo during 5 sets of velocity-based squat training.

Methods: Twelve healthy males performed parallel squats under 3 eccentric conditions using a randomized crossover design. Each session included 5 sets at a relative load, initiated with a concentric mean velocity of 0.70 m·s-1, continuing until 20% velocity loss, with 300-second rest intervals. Blood lactate concentration was measured preexercise and postexercise each set, while changes in muscle tissue saturation index, deoxygenated hemoglobin, oxygenated hemoglobin, and total hemoglobin were continuously monitored during training using near-infrared spectroscopy.

Results: The 4-second eccentric tempo resulted in significantly greater increase in lactate than EXP (3.82 [1.0] vs 2.89 [0.8] mmol·L-1, P = .002) and a higher area under the curve of lactate (4 s: 112.9 [22.8] vs EXP: 93.8 [25.1] mmol·L-1·min, P = .003, d = 1.02). Changes in tissue saturation index, deoxygenated hemoglobin, and oxygenated hemoglobin and time under tension were significantly higher in the 4-second trial than in the EXP and volitional speed trials (P < .05). No significant differences were observed in the changes in total hemoglobin, number of repetitions, training volume, mean velocity, mean power, or subjective perceptions (P > .05).

Conclusions: A 4-second eccentric tempo induces greater metabolic and oxygenation responses under identical velocity-loss conditions while preserving power output and subjective perceptions. These findings highlight eccentric velocity as a key variable in velocity-based training, particularly for optimizing metabolic stress and training adaptations.

Purpose: This study examined the effects of cluster sets (CS) versus traditional sets (TRAD) on performance and perceptual responses during pneumatic chest press (CP) and leg press (LP). Exercise-specific differences and the influence of sex and strength were also explored.

Methods: Forty-seven recreationally resistance-trained young adults (23 male and 24 female) performed CP and LP at 70% 1-repetition maximum in either CS (4 × [2 × 5], 30-s intraset rest, 150 s between sets) or TRAD (4 × 10, 180-s rest between sets) in randomized order. Mean concentric velocity (MCV), MCV loss, rating of perceived exertion (RPE), and estimated repetitions to failure were recorded. Repeated-measures analyses of variance were used for statistical comparisons, with sex and strength included as exploratory variables.

Results: MCV was higher (P < .001, partial η2 = .272), RPE was lower (P < .001, partial η2 = .246), and estimated repetitions to failure was higher (P < .001, partial η2 = .429) in CS than TRAD, with no exercise-specific differences. Although MCV loss was lower in CS (P < .001, partial η2 = .364), post hoc analyses revealed that this benefit was only significant during CP and among males. However, the sex-related effect did not remain significant after adjusting for strength. While sex- and strength-related interactions emerged for MCV, they were limited to higher-order interactions involving repetitions but did not alter the overall CS benefit.

Conclusions: CS effectively maintained MCV, reduced RPE, and increased estimated repetitions to failure compared with TRAD across CP and LP using pneumatic-resistance devices. The benefit of CS in attenuating MCV loss differed by exercise and sex, with the sex effect moderated by strength.

Purpose: This study explored the association between strength and power capacities and bat speed in female cricketers to inform strength and conditioning practices.

Methods: Twenty-nine professional female cricketers volunteered for 3 testing sessions. Day 1: participant information, grip strength, medicine-ball push for maximum velocity, 10/5 Reactive Strength Index Hop Test. Day 2: isometric midthigh pull, vertical jump, 1-repetition-maximum (1RM) bench pull, and maximum-repetition body-weight push-up. Day 3: maximal bat speed for 4 cricket shots-cut (BScut), drive (BSdrive), pull (BSpull), and slog (BSslog)-versus 3 delivery types (off-spin, medium, and fast). Statistical analysis (α = .05) included Pearson r, multiple linear regression (R-squared), and 1-way repeated-measures analysis of variance with Tukey HSD analysis.

Results: Overall bat speed was associated with absolute 1RM bench pull (r = .70, P < .0001), dominant medicine-ball push for maximum velocity (r = .65, P < .0001), nondominant medicine-ball push for maximum velocity (r = .60, P < .0001), and absolute isometric midthigh pull (r = .47, P = .01). Physical capacities regression modeling explained 52.7% of variance in bat speed overall (adjusted R-squared = .5267, standard error of estimate = 2.40, P < .0001). BScut was slower than all shots (P < .0001). BScut (P < .0001), BSdrive (P < .0001), and BSpull (P < .0001) were slower during fast versus off-spin deliveries.

Conclusions: Absolute upper-body pulling strength, dominant rotational power, and absolute total-body isometric strength are critical qualities for power-hitting training in female cricketers. Practitioners may include these findings in their program design to better support female athletes.

Purpose: Applying a backstroke ledge (BSL) during the backstroke start reportedly enhances starting performance; however, whether different BSL heights improve start performance remains unclear. We aimed to examine the effect of different BSL heights on flight distance, entry posture, and time to reach 5 m during backstroke start.

Methods: Eleven male backstroke swimmers performed a 15-m backstroke under 3 different starting conditions, with BSL heights set at +0.04 m (High), 0 m (Medium), and -0.04 m (Low) trials relative to the water surface. One 60-Hz and two 120-Hz video cameras were used to analyze whole-body kinematics, including center-of-mass (CM) height and horizontal velocity at takeoff, flight distance, whole-body posture, and time to reach 5 m.

Results: The high trial significantly reduced the time to reach 5 m compared with that of the Low trial (P = .013). Additionally, CM height (P < .001) and horizontal velocity (P = .042) at takeoff were higher in the High trial than in the Low trial; hence, the flight distance was extended (P = .032). While upper-body water-entry posture improved with higher BSL (P < .043), whole-body posture did not differ significantly (P > .090).

Conclusion: Setting a BSL higher than the water surface enhances flight distance by increasing CM vertical position and horizontal velocity at takeoff, thereby improving backstroke start performance. Athletes are encouraged to familiarize themselves with higher BSL settings to enhance their start performance.

Purpose: This study aimed to evaluate the impact of auditory deprivation on tennis-stroke accuracy and perceived exertion among tennis players, with a focus on understanding how auditory inputs affect sport performance.

Methods: A total of 77 active tennis players participated in this controlled trial, which involved playing tennis under standard auditory conditions and with auditory deprivation using noise-isolation devices. Data were collected using a Zepp Tennis Smart Sensor 2 to assess hit accuracy, and the Borg Rating-of-Perceived-Exertion (RPE) scale was used to measure exertion levels.

Results: Players demonstrated significantly lower accuracy in hitting the center of the racket under auditory deprivation compared with standard auditory conditions (OR: 0.71, 95% CI, 0.68 to 0.75, P < .001). Additionally, auditory deprivation resulted in higher reported exertion levels, with 75% of participants reporting increased RPE compared with standard conditions (95% CI, 64% to 84%, P < .001).

Conclusions: Auditory deprivation negatively impacts both the accuracy of tennis strokes and the subjective experience of exertion in players. These findings highlight the importance of auditory cues in sport performance and suggest that integrating sensory feedback can enhance athletic training and performance strategies. This study supports further exploration of sensory inputs' role in sport and their potential in training regimens.

Purpose: To determine the recovery kinetics of performance, muscle damage, and neuromuscular fatigue following 2 speed-endurance maintenance training (SEMT) protocols in soccer.

Methods: Ten well-trained male soccer athletes randomly completed 3 trials: work-to-rest ratio SEMT/1:3, SEMT/1:1, and a control trial. Training load during SEMT was monitored using a global positioning system and heart-rate monitors. Isokinetic strength of knee extensors and flexors; repeated-sprint ability (RSA); speed 10-, 30-m, countermovement jump (CMJ); and muscle damage (delayed-onset muscle soreness [DOMS] and creatine kinase) markers were evaluated at baseline and at 0, 24, 48, and 72 hours posttraining. Maximal voluntary contraction of knee extensors and flexors was additionally assessed at 1, 2, and 3 hours posttraining.

Results: Strength (eccentric torque) and speed performance (RSA, 10-m and 30-m sprint times) were reduced (P < .05) following the SEMT/1:3 for up to 72 and 48 hours, respectively, and following SEMT/1:1 for up to 48 and ≤24 hours, respectively. Eccentric torque and RSA deterioration was greater in SEMT/1:3 compared to SEMT/1:1 at 72 hours and immediately postexercise, respectively (P < .05). Indicators of neuromuscular fatigue (CMJ and maximal voluntary contraction) declined in SEMT/1:3 at 24 and 2 hours postexercise (P < .05) and in SEMT/1:1 immediately and at 2 hours postexercise (P < .05). Muscle damage (DOMS) in the knee flexors was elevated in both SEMT protocols for up to 48 hours (P < .05).

Conclusions: SEMT/1:3 induces short-term neuromuscular fatigue; provokes a decrease of strength (48-72 h), speed and RSA (48 h), and jump height (24 h); and is related with an elevation of knee flexors' DOMS (48 h). Increased work-to-rest ratio causes higher levels of exercise-induced muscle damage.

Maximal aerobic exercise tests (MAET) are essential in sports and clinical settings for assessing fitness and guiding treatments. Encouragement strategies play a crucial role in ensuring maximal effort, thereby enhancing test validity. This scoping review aimed to examine the effects of various encouragement strategies on performance outcomes during MAET. This review followed the Guidelines and Preferred Reporting Items for Systematic Reviews and Meta-Analysis Extension for Scoping Reviews protocols. A comprehensive search was conducted across multiple databases (Google Scholar, PubMed, PsycINFO, SURF, SPONET, and Taylor & Francis) using a combination of keywords related to MAET and encouragement strategies. Studies were eligible if they assessed the effects of MAET with at least 1 motivational strategy and were published in English in peer-reviewed journals. Data were extracted independently by 2 reviewers, with disagreements resolved through a third reviewer. Forty-nine studies were included in this review. The studies assessed various encouragement strategies including music (41%), verbal encouragement (12%), self-talk (21%), competition (10%), and attentional focus (16%) across both open- and closed-ended MAET. Music and sound consistently improved performance in open-ended tests (no predetermined end), whereas their effects in closed-ended tests (defined start and end point) were inconsistent. Verbal encouragement, particularly when frequent and personalized, generally enhanced performance. Positive effects were also observed for motivational self-talk and competitive conditions. However, the effects of attentional focus strategies remained inconclusive. This review highlights the potential of different encouragement strategies in enhancing performance during MAET. However, gaps remain in understanding their mechanisms, and future research should focus on combining strategies and standardizing protocols.

Purpose: This study aimed to determine the level of agreement between critical power (CP) and the second lactate threshold in rowers, examine their respective relationships with rowing performance, and assess the accuracy of the CP model in predicting 2000-m rowing time.

Methods: Previously collected data were retrieved from well-trained, national or international standard male (n = 20) and female (n = 18) rowers who underwent testing at their respective clubs administered by a sport scientist. The second lactate threshold was determined using the modified Dmax (ModDmax) and LogPoly-modified Dmax (LogPoly) methods via an incremental rowing ergometer test. Time-trial tests consisted of a 2000-m performance trial, with the remaining tests (500 m and either 5000 m or 6000 m) used to determine CP and work above CP (W') via the linear 1/time model.

Results: Associations between CP, ModDmax, and LogPoly were moderate to strong (r2 = .49-.70); however, power output at CP (311 [67] W) was lower (P < .001) than at ModDmax (324 [68] W) and LogPoly (323 [67] W). Of the 3 methods, CP achieved the highest association with rowing performance (r2 = -.81; P < .001), followed by ModDmax and LogPoly (both r2 = -.75; P < .001). The inclusion of W' in the full CP model predicted 2000-m time that was highly correlated (male r2 = .92 and female r2 = .81, P < .001) with actual time.

Conclusions: Although agreement in absolute power output between CP, ModDmax, and LogPoly was not confirmed, associations between them were strong, and all had moderate to high correlations with 2000-m rowing performance.