International journal of sports physiology and performance最新文献

Purpose: This study examined the effects of low- and high-pressure ischemic preconditioning (LIPC and HIPC) on muscle oxygenation, physiological responses, and performance during repeated 2000-m rowing trials. This was a counterbalanced, repeated-measures crossover study.

Methods: Eleven elite high school rowers were randomly assigned to 1 of 3 warm-up protocols: (1) traditional warm-up (control trial [CON]), (2) LIPC (100-190 mmHg) + traditional warm-up, or (c) HIPC (210-300 mmHg) + traditional warm-up. Measurements were taken before and after warm-up, immediately following two 2000-m rowing efforts, and 10 minutes postexercise. Variables included blood lactate, heart rate, rating of perceived exertion, muscle tissue oxygen saturation (tissue saturation index), mean power output, and total time.

Results: Significantly greater reductions in tissue saturation index of the vastus lateralis during occlusion were observed in LIPC (36.41% [12.03%]) and HIPC (35.05% [14.29%]) compared with CON (10.43% [4.9%], P < .001). No significant group differences were found in blood lactate, heart rate, or rating of perceived exertion, although time effects were noted (P < .001). While first-trial performance was similar, the second 2000-m trial showed significant group differences (P = .009), with HIPC outperforming both CON and LIPC (P < .05). The CON group demonstrated a performance decline, while LIPC and HIPC maintained output. High-pressure ischemic preconditioning also exhibited significantly higher mean power in the second trial compared with CON (P = .04), with consistent pacing.

Conclusions: These findings suggest that ischemic preconditioning, particularly HIPC, may enhance repeated high-intensity rowing performance by improving muscle oxygen extraction and sustaining output, offering practical benefits for endurance athletes.

Purpose: This study investigated the effect of caffeinated chewing gum on sympathetic nerve activity and simulated wrestling performance.

Methods: Sixteen professional male wrestlers (age: 21.8 [1.0] y, height: 168.4 [4.5] cm, mass: 68.2 [8.7] kg) were randomly assigned to either a caffeinated-chewing-gum (CAF) trial or a placebo trial (PL) using a double-blind, randomized crossover study design. Participants warmed up for 15 minutes after chewing CAF containing 3 mg/kg body weight or caffeine-free placebo gum (PL) for 10 minutes. Participants were sequentially tested for grip strength and a specific wrestling performance test (SWPT). Saliva samples were collected when participants arrived at the laboratory and at the end of the SWPT to analyze caffeine and α-amylase concentrations.

Results: Caffeinated chewing gum significantly increased the number of throws in round 1 (CAF: 26.8 [3.3] times, PL: 24.0 [2.7] times; P = .002, Cohen d = 0.92), round 2 (CAF: 22.8 [3.3] times, PL: 20.4 [3.3] times; P = .047, Cohen d = 0.72), and total number of throws (CAF: 49.6 [5.7] times, PL: 44.5 [4.7] times; P = .001, Cohen d = 0.97), as measured by SWPT, compared with the PL. The saliva α-amylase concentrations were higher in the CAF trial than in the PL trial at the end of the SWPT (P = .040, Cohen d = 0.52).

Conclusions: The results of this study provide support that caffeinated chewing gum is effective in improving the number of throws in an SWPT. Increased sympathetic nerve activity may have improved the number of throws.

Purpose: To evaluate whether advanced footwear technology (AFT) reduces the rise in oxygen uptake (V˙O2) and neuromuscular fatigue during extended submaximal running compared with traditional running shoes.

Methods: Fifteen trained distance runners (7 women, 8 men; 23.2 [1.6] y; 65.5 [7.8] kg) completed two 60-minute treadmill runs at ∼75% of critical speed, wearing either control shoes (Saucony Kinvara) or AFT (Saucony Endorphin Pro 3) in a randomized crossover design. V˙O2 was measured continuously using a portable metabolic system, and ground-reaction forces were sampled at minutes 15, 30, 45, and 60. Linear regression was used to quantify V˙O2 drift. Neuromuscular fatigue was assessed via changes in vertical impulse during prerun and postrun vertical jumps.

Results: V˙O2 drift was significantly lower with AFT (0.00056 [0.00060] mL·kg-1·min-1) than with control shoes (0.00088 [0.00071] mL·kg-1·min-1; P = .018). Postrun vertical impulse decreased by only 0.2% in AFT versus 4.9% in control (P = .016), indicating reduced neuromuscular fatigue. No significant differences were found in peak force, stance time, or stride rate between conditions.

Conclusions: AFT reduces the progressive increase in V˙O2 and attenuates neuromuscular fatigue during extended running. These cumulative benefits may enhance endurance performance over time and highlight the importance of evaluating footwear over sustained efforts.

Purpose: A hamstring injury rehabilitation and return-to-play (RTP) individualized approach based on the anatomical structure involved, the location of the injury, and the mechanism of injury is still missing in most studies. RTP criteria should be chosen following the same principles and the complexity of the injury and should receive more attention from the scientific community given that reinjury risk is one of the main challenges associated with hamstring rehabilitation. The available literature is mainly based on articles in which hamstring injuries are treated as a whole without making distinctions for their specific characteristics.

Conclusions: There is a need to improve how we look at RTP criteria for hamstring injuries to improve decision making and help practitioners design the most suitable RTP protocols. We should consider the anatomical structure and the complexity of the injury to determine the importance of lay-off time and healing, understand the implication of the location of injury and the muscle involved on strength-test selection, and knowledge of the mechanism of injury and workload before the injury to assess the ability to activate the muscles in a sport- and mechanism-specific position and prepare the athlete with an appropriate exposure to high-speed running and technical skills.

Background: Achieving a consensus on methods for exercise quantification appears to be a challenging endeavor in sport science. Quantification of exercise enables the description of training in unit doses by coaches and scientists, facilitating subsequent analysis of responses to training.

Purpose: The present manuscript seeks to provide an overview of the merits and limitations of exercise quantification methods based on the product of exercise intensity × duration and those based on maximum tolerable volume.

Results: Intensity × duration methods use parameters to express intensity that are only effective for endurance exercises and could be affected by the possible intermittent format of exercises. In addition, the intensity-duration relationship is not efficiently addressed by these methods, resulting in the overvaluation of prolonged exercises compared with shorter ones. Such limitations do not appear in methods based on maximum volume, which is regarded as an indicator of the maximal dose for a given exercise and can, thus, be used as a reference to quantify the dose of similar exercises.

Conclusion: Because intensity × duration methods inadequately consider the relationship between the variables that constitute the exercise, their use should be restricted to programs that exhibit minimal variation in exercise intensity and type. Conversely, exercise quantification based on maximal duration takes into account the influence of all exercise variables. This way of quantification can be efficient across a wide range of exercise intensities and types; however, it requires knowledge of exercise maxima, which can be challenging to ascertain in a training context.

Background: Accurate assessment of rapid force production is essential for monitoring adaptations to ballistic speed-strength training, a modality central to athletic performance enhancement. Both dynamic (eg, countermovement-jump height or drop-jump reactive strength index) and isometric (eg, rate of force development) tests are commonly used, yet their relative sensitivity to training-induced change remains unclear.

Purpose: To systematically review and analyze the literature to establish whether measures of dynamic or isometric rapid force production were more sensitive to ballistic speed-strength training. In addition, subgroup analysis was performed to evaluate whether the type and temporal aspects of isometric test and associated measures had an impact on the effect.

Methods: A systematic search of databases for eligible articles was conducted up to February 2025. A multivariate random-effects meta-analysis with adjustment for within-study dependencies was employed.

Results: Five studies yielded 15 isometric-dynamic change comparisons, and a total of 82 participants were included in the final analysis. The pooled analysis indicated no significant difference between isometric and dynamic measures following ballistic speed-strength training. Prediction intervals were wide, indicating substantial variability in outcomes across settings. Subgroup analyses similarly revealed no consistent moderating effect.

Conclusions: The magnitude of change in isometric versus dynamic measures of rapid force production can be expected to vary considerably in future practical or experimental settings following ballistic speed-strength training. Practitioners should closely monitor individual responses and avoid assuming uniform training effects for these 2 forms of testing across all athletes.

Purpose: This study investigated the impact of a 6-week sprint interval training (SIT) program conducted either before or after basketball training with a focus on identifying sex differences in the physical performance adaptations of young basketball players. Methods: Twenty-four female and 24 male basketball players volunteered to participate and were randomized to 2 training groups and 1 active control group. The training groups performed SIT before or after basketball practice, which was categorized as follows: females before, females after, female control, males before, males after, and male control, with each group comprising 8 participants. The SIT regimen consisted of 3 sets of 12 repetitions of 5-second all-out sprints, conducted 3 times a week. Results: The females-before, females-after, males-before, and males-after groups showed significant (P = .001) adaptations in the countermovement vertical jump (CMVJ), 20-m sprint, Illinois Change-of-Direction-Speed test, and peak power output (PPO) and mean power output during the Wingate test, as well as in the Yo-Yo Intermittent Recovery Test Level 1. Results revealed no order effects for the female groups (P > .05), whereas among male players, performing SIT before basketball training led to significantly greater improvements in CMVJ, 20-m sprint, and PPO than performing SIT after training (P < .05). In addition, male athletes who performed SIT after basketball training (males after) showed significantly (P < .05) lower improvements in CMVJ, 20-m sprint, and PPO compared with female groups who performed SIT either before (females before) or after (females after) training.

Conclusion: In summary, conducting SIT before basketball training leads to greater improvements in CMVJ, 20-m sprint, and PPO in male athletes. For females, SIT before or after basketball training produces similar performance benefits. Therefore, coaches and practitioners should consider both training order and athlete sex when prescribing SIT, whereby scheduling SIT prior to basketball sessions is recommended to maximize short-duration performance gains in male players, while either timing can be effectively used for female athletes.

Purpose: We investigated the association between training metrics commonly used in soccer and the acute performance decrement (APD) observed after 3 training sessions differing in exercise intensity and duration.

Methods: In separate randomized visits, 16 male soccer players performed a Yo-Yo Intermittent Recovery level 2 test (Yo-Yo IR2) at baseline or 5 minutes after 3 different training sessions consisting of a 10-minute small-sided game (SSG), a 26-minute passing and shooting drill (PSD), or 60 minutes of technical drills (Tech-D). The APD was computed as the percentage reduction in the Yo-Yo IR2 distance from baseline. Training was quantified using metrics of training impulse, a metric based on perceived exertion, movement load, energy expenditure, total distance, and the National Aeronautics and Space Administration Task Load Index (NASA-TLX).

Results: A lower (P < .017) Yo-Yo IR2 distance was covered after SSG and PSD than at baseline and after Tech-D. The APD was higher (P < .022) for SSG (45.6% [19.3%]) than for PSD (31.9% [21.3%]) and Tech-D (9.1% [24.6%]). However, the APD response dissociated from the response of several training metrics recorded. Indeed, higher values (P < .05) were found in Tech-D and/or PSD than in SSG for training impulse, perceived exertion, movement load, energy expenditure, and total distance. Conversely, the response of the NASA-TLX broadly resembled that of APD.

Conclusions: Several training metrics used in soccer dissociate from the APD observed after training sessions differing in intensity and duration, unlike the often-overlooked NASA-TLX. These findings suggest revising the combination of training intensity and duration to improve soccer metrics.

Purpose: Recent investigations have used the term "priming exercise" to describe a bout of low-volume exercise commonly prescribed to enhance same-day performance. Although research has revealed improvements in performance measures following these priming exercise strategies, few studies have explored possible mechanisms behind the performance changes. Nevertheless, investigations have only provided physiological theories for performance outcomes. While testing results may reflect physiological responses, underlying processes likely mediate performance effects. As performance problems are seldom solved using a narrow lens, it may be useful to broaden the scope of discussion to develop more comprehensive hypotheses that can guide future priming exercise research and enhance applied methods.

Conclusion: This article critically evaluates existing explanations and proposes alternative mechanisms that may explain same-day performance effects following priming exercise stimuli.

Purpose: This study aimed to (a) examine the effects of hot-water immersion (HWI) on vertical-jump performance, lower-limb power, and stretch-shortening cycle responses and (b) evaluate temperature-dependent responses by comparing 2 HWI conditions (40 °C vs 42 °C).

Methods: Twenty healthy, physically active participants (12 male and 8 female; age 25.1 (2.7) y; body mass index 22.6 [1.1] kg/m2) completed countermovement-jump (CMJ) and drop-jump assessments before, after, and 15 minutes after a 45-minute water-immersion session at either 34 °C (control), 40 °C, or 42 °C in a randomized order. CMJ outcomes included jump height, peak force, and peak power, while drop-jump outcomes included jump height, reactive strength index, and vertical stiffness.

Results: CMJ height increased following a 45-minute HWI session at both 40 °C and 42 °C (P < .001, d = 1.09; P < .001, d = 1.77), with no differences between the 2 conditions (P = .515). Similar improvements were found for peak power and force. At 15 minutes post-water immersion, all performance measures returned to baseline and did not differ from the control condition. For the drop-jump tests, a main effect of temperature was observed. HWI at 42 °C significantly increased drop-jump height (P = .004; d = 0.71), whereas 40 °C did not (P = .205). Reactive strength index increased following both 40 °C (P = .002; d = 0.74) and 42 °C (P < .001; d = 0.91) conditions. No significant changes were observed in vertical stiffness.

Conclusion: Both HWI conditions, 40 °C and 42 °C, improved CMJ performance (height, force, and power) and reactive strength index, while only HWI at 42 °C enhanced drop-jump height. These effects were transient, returning to baseline within 15 minutes postimmersion.