International journal of sports medicine最新文献

Intermittent hypoxia combined with physical training may enhance performance and health parameters but can impair session quality, limiting adaptations. To address these drawbacks, inter-effort recovery hypoxia has been proposed. This study investigated the effects of a 5-week inter-effort recovery hypoxia protocol followed by a 1-week tapering period in recreational runners. Twenty-four men were allocated to an inter-effort recovery hypoxia group (n = 11) or a normoxia group (n = 13) and assessed for body composition, hematological profile, running economy, maximum velocity, and peak oxygen uptake before training (W0), after training (W6), and after tapering (W8). Training consisted of 3 weekly sessions for 5 weeks: a 5-minute warm-up at 60% of maximum velocity, ten 1-minute effort at 120% (wk 1-3) or 130% (wk 4 and 5) of maximum velocity with 2-minute passive recovery, and 5-minute cool-down at 60% of maximum velocity. The inter-effort recovery hypoxia group inhaled hypoxic air (fraction of inspired oxygen=0.136) during warm-up, recovery bouts, and cool-down. Outcomes were analyzed using generalized linear mixed models. Peak oxygen uptake increased in the inter-effort recovery hypoxia group at W6 (+7%) and W8 (+10%), while the normoxia group improved at W8 (+7%), without group differences; running economy improved in the normoxia group at W8 (+10%). No significant changes occurred in erythropoietin, erythrocytes, hemoglobin, reticulocytes, or body composition. The 5-week inter-effort recovery hypoxia protocol enhanced peak oxygen uptake without hematological changes, indicating a feasible and non-erythropoietic strategy for improving aerobic fitness.

This study examined positional differences in the intermittent nature of efforts during professional football matches and compared two analytical models: one using a fixed metabolic power threshold (Pmet20) and another based on the relationship between oxygen consumption and metabolic power (VO₂-Pmet). Data were collected from 24 First Division players in Cyprus across 50 matches during the 2022-2023 season using GPS technology (WIMU Pro System). High and low metabolic load efforts were analyzed. Results showed significant positional differences in both the duration and intensity of high metabolic load efforts and low metabolic load efforts. Compared to the Pmet20 model, the VO₂-Pmet method identified approximately twice longer high metabolic load effort durations (≈4.1 vs. 2.1 s) and about 70-150% more detected efforts across positions, together with shorter recovery intervals. A notable decline in low metabolic load effort intensity between halves was linked to reduced performance. These findings highlight the dynamic interplay between aerobic and anaerobic systems in football and emphasize the need for position-specific training. Practical applications include designing training programs that reflect the unique intermittent demands of each position, focusing on both high-intensity efforts and recovery. This study provides a robust framework for understanding the football's intermittent nature and offers actionable strategies to enhance player performance through tailored conditioning.

The aim of the present study was to determine the responsiveness of the health-related field-based physical fitness used tests in adults. A total of 62 non-active participants aged 18 to 64 years were randomized into the intervention(n=31) or control group(n=31). The exercise program included 3 sessions/week (60min/session) of multicomponent exercise training for 12 weeks. The control group continued with their usual routines. Pre-post differences were explored with pairwise comparison ANOVA for each group. The proportion of responders/non-responders and the percentage of the population that was expected to respond to the intervention were calculated. None of the tests changed pre-post in the control group (all p>0.05, Cohen's d≤0.2). In the intervention group, overall, all tests were found to be responsive (all p<0.01) after the exercise program with an effects size improvement of moderate to large (all Cohen's d>0.50), except the body weight, waist circumference, and handgrip (Cohen's d≤0.1). The proportion of individual responders was >46%, while the proportion of the population expected to respond was >85% in most of the tests evaluated. All the health-related field-based physical fitness tests were found to be responsive following multicomponent exercise training program, except the anthropometric and handgrip tests, which were less responsive than the others and might require specifically targeted interventions to respond further.

This study investigated the effects of different session volumes on perceptual, performance, morphological changes and their transient responses following the experimental sessions. Thirteen trained males (training experience: 5.1 ± 1.3 years; 10RM Squat: 131 ± 23 kg) completed three counterbalanced experimental sessions consisting of 7, 14, or 21 total sets per session targeting the lower body. A 10 repetition-maximum test (10RM) was used as a performance marker. Anterior thigh muscle thickness (MT) and echo-intensity (EI) were assessed at baseline, immediately post-session, 24, 48, and 72 hours post-experimental session. Perceived recovery status (PRS) was assessed at baseline, 24, 48, and 72 hours post-experimental sessions. Rating of perceived exertion (RPE) was recorded post-session only. The 14 and 21-SETS conditions resulted in greater volume load (VL) (p < 0.05). PRS and RPE were significantly affected by training volume (p < 0.05), particularly in the 21-SETS condition, which induced higher RPE and lower PRS than the other conditions. No condition or condition-by-time effects were observed for MT, EI, or 10RM-VL (p > 0.05). Despite distinct perceptual and VL differences, no sustained muscle swelling or evidence of edema was observed, as MT and EI measurements returned to baseline within 24 hours post-session across all conditions.

The use of a sweat lactate sensor to evaluate the aerobic threshold has not been fully validated in women with low sweat rates. This study aimed to validate aerobic threshold assessment using a sweat lactate sensor in healthy women. Sixteen healthy women who underwent exercise tests using respiratory gas analysis were included. Sweat lactate levels were monitored using a wearable lactate sensor, and the sweat rate was measured using a ventilated capsule perspiration meter. A correlation analysis between the sweat lactate threshold and the ventilatory threshold was performed. The degree of discrepancy between the sweat lactate threshold and the ventilatory threshold was also examined based on sweating dynamics. In all cases, the sweat lactate threshold was detected using a sweat lactate sensor. Although a significant correlation was observed between the sweat lactate threshold and the ventilatory threshold (r _s=0.769), the sweat lactate threshold was significantly delayed compared with the ventilatory threshold, and the difference in the degree of discrepancy between the sweat lactate threshold and the ventilatory threshold increased with increasing thresholds. The onset of sweating was a significant predictor of the discrepancy between the sweat lactate threshold and the ventilatory threshold (r=0.873). Thus, in healthy women, the aerobic threshold assessment using the sweat lactate sensor was feasible. This study demonstrated that late-onset sweating was an important factor in delayed sweat lactate threshold relative to the ventilatory threshold.

The aim of this review was to evaluate the impact of strength training on hamstring muscle strength and physical performance in football players.A systematic review was conducted following the PRISMA guidelines, and the protocol was registered in PROSPERO.A literature search was performed using four electronic databases: Web of Science, SCOPUS, SportDiscuss, and PubMed.Randomized controlled trials conducted with football players aged 15 years or older were included.The studies were grouped according to moderating variables such as training protocol and physical performance outcomes. A total of 20 studies met the inclusion criteria for the review, with 10 studies included in the meta-analysis. Strength training programs demonstrated moderate to large effects on both concentric and eccentric strength of the hamstrings and quadriceps, as well as on physical performance measures such as jumping and sprinting. Eccentric overload training produced the most significant benefits in sprint and jump performance. Strength training, particularly eccentric training, significantly improves both hamstring muscle strength and physical performance in football players of male football players aged 15 years and older, highlighting its importance for injury prevention and sports performance enhancement.However, additional research is needed to evaluate whether similar benefits can be observed in female players and younger age groups.

Soccer requires athletes to exhibit high levels of acceleration and speed, both of which are crucial for optimal performance. The acceleration-speed (A-S) profile is increasingly utilized to assess these sprinting capacities in soccer, providing in situ insights into an athlete's maximal theoretical acceleration (A0) and speed (S0). This study aimed to investigate the association of external load metrics with A0 and S0 across different age groups in elite academy soccer athletes. One hundred thirty-six athletes, ranging from under-14 to B-team, participated in the study. Training sessions and matches were monitored over a season using Global Navigation Satellite System (GNSS) technology to collect data on the A-S profile and external load metrics. Stepwise regression analysis revealed a positive correlation, in several age groups (under-15, -17, -19, and -23 and B-team), between accumulation of sprint distance (Spr. Dist.) and an increased S0 (R ²: 0.30-0.52). However, no significant correlation was found between any external load metric and A0. These findings highlight the necessity of individualized training interventions and the inclusion of Spr. Dist. throughout the planning of the training load of young soccer athletes for the improvement of sprint capacity. It may also suggest that acceleration in youth soccer athletes may be influenced by other factors, such as strength training.

The scapula facilitates the windmill pitching motion, providing a stable base for the shoulder muscles to accelerate the humerus. Given the repetitive range of motion facilitated by the shoulder musculature about the scapula, shoulder overuse injuries are a significant concern in softball pitchers. Therefore, we aimed to provide normative values of scapular kinematics during the windmill pitching motion in high school-aged softball pitchers. Kinematic data from 17 high school-aged softball pitchers (15±1 y; 1.7±0.1 m; 72.3±15.0 kg) throwing fastball pitches at regulation distance 13.1 m (43 ft) were obtained using an electromagnetic tracking system synced with motion analysis. Scapular kinematics throughout the windmill pitching motion indicated that the scapula maintains an anteriorly tilted and internally rotated (protracted) position while moving within 5 and 22° in each plane, respectively. Additionally, on average, the scapula remained upwardly rotated throughout the start and top of the pitch, through foot contact, but moved into downward rotation at ball release. Description of scapular biomechanics during the windmill softball pitch is an area that has not been extensively researched. Our data reinforce the significance of the scapula as a dynamic stabilizer of the shoulder and its critical role in the kinematics and kinetics of the fastpitch softball windmill pitch.

World Aquatics rules require only part of the swimmer's head to break the surface each breaststroke cycle. We aimed to assess the impact of breathing every one or two cycles in breaststroke on energy cost (C) and related bioenergetic variables. Fifteen swimmers completed a 6-week intervention to learn the new breathing pattern, followed by a 5×200-m step test (0.05-m∙s^-1 increments, 30-s rest) in both patterns. Oxygen consumption (VO₂) and blood lactate ([La^-]) were measured to calculate energy expenditure (E _tot) and C. Linear and exponential regressions were computed between E _tot and velocity. Paired t-tests and ANCOVA were applied, controlling for World Aquatics points and age. [La^-] peak, VO₂ peak, E _tot, and C were lower at some intensities when breathing every cycle. Adjusted analyses showed higher E _tot with breathing every two cycles at steps 1, 2, and 5. Linear and exponential regressions showed strong associations for both breathing patterns (r ²=0.74 vs. 0.72, respectively). Individual regressions showed similar patterns in some swimmers, while others differed. Breathing every two cycles elicited higher bioenergetic responses at steps 1, 2, and 5 and did not prove effective during incremental 200-m efforts when compared to the traditional breathing pattern.