Journal of Sports Medicine and Physical Fitness最新文献

Background: Non-contact anterior cruciate ligament injuries are common in soccer and volleyball, occurring during changes of direction and landings. This study aimed to investigate kinematic differences between soccer and volleyball players in single-planar and multiplanar landing tasks, simulating sport-specific injury mechanisms. Since the anterior cruciate ligament injury rate in soccer is higher than in volleyball, we hypothesized that volleyball players would adopt safer landing strategies, especially in single-planar landing tasks.

Methods: Twenty-two soccer and 19 volleyball players performed single-leg drop landing, drop jump in vertical, 45°-medial and 45°-lateral directions. Box height and jump length were adapted to the subject's height and performance level, respectively. A 9-camera motion capture system provided lower limb kinematics. Two mixed multivariate analyses of covariance (sport, task, sex as covariate) were used to compare soccer and volleyball players' initial contact and peak kinematics (α=0.05).

Results: Task had significant effects on lower limb initial contact and peak angles, as expected. Sport and task × sport interaction had no significant effects on kinematics.

Conclusions: Soccer and volleyball players' landing strategies were thus similar in each task, in opposition to initial hypotheses. We might speculate that the higher anterior cruciate ligament injury rate in soccer may be more related to non-predictable factors than the isolated landing kinematics.

Background: Alterations caused by face masks on physiological responses vary among different population groups. This study aimed to investigate whether physically active and sedentary individuals respond differently to face mask use during exercise.

Methods: Sixteen healthy college students were divided into two groups: Physically active group (N.=10; 26.50±2.80 years) and Sedentary group (N.=6; 26.33±2.81 years). They performed three maximal cardiopulmonary exercise test (CPET)s following the Bruce protocol: one without a face mask (NON), one with a surgical mask (SUR) and one with a cloth mask (CLO). Cardiorespiratory parameters and heart rate were monitored continuously during the test. Blood pressure, oxygen saturation and lactate level were measured immediately before and after exertion.

Results: Significant differences were found between the Physically active and the Sedentary group in peak VO2 (VO2peak) in NON (P=0.030). However, this difference disappeared when the face masks were used. Furthermore, VO2/kg (P=0.002) and METs (P=0.002) decreased significantly at the respiratory compensation point (RCP) only in the Physically active group with face masks. No significant differences were found between the two groups for exercise time, lactate level and dyspnea (P>0.05).

Conclusions: The decrease in exercise tolerance and cardiorespiratory responses, particularly VO2peak, due to face mask use was greater in physically active individuals compared to sedentary individuals. Population group characteristics should be considered when adapting face masks to daily life.

Background: This study aimed to describe the nutrition knowledge, food security risk and eating disorder risk of development male rugby league players.

Methods: Sixty athletes from one Australian professional rugby league club volunteered. A cross sectional online survey questionnaire consisted of three sections (Eating Disorders Inventory (EDI-3), Nutrition Knowledge and Food Security). All athletes completed the online survey without assistance using a personal electronic device.

Results: The mean total knowledge score was 65.7±13.1%. There was a positive relationship between age and knowledge score, P=0.050, r²=0.06. The majority of players had breakfast everyday (N.=45, 73.8%), took pack lunches (N.=33, 55.0%), and had homemade evening meals (N.=55, 91.7%). The majority of players ate more than 1 hour before training (N.=45, 75%) and all players (n=60, 100%) ate within half an hour of training finishing. The majority of participants agreed that nutrition could influence physical and cognitive aspects of nutrition however, skill-based activities were perceived by fewer participants to be influenced by nutrition. The majority (N.=38, 63.3%) had high food security, six (10.0%) had marginal food security, whereas 10 (16.7%) and six (10.0%) had low and very low security respectively.

Conclusions: These results show a concerning levels of eating disorder risk, food insecurity and poor nutrition knowledge amongst male development rugby league players. However, it does show that they believe nutrition can impact their health and performance, and they do mostly appear to adhere to the nutrition principals for optimising health and performance.

Background: The prevalence of a history of exercise-associated muscle cramping (hEAMC) among ultramarathon runners is high. While the Comrades is one of the most popular mass community-based participation ultramarathons (90 km) globally, research on the epidemiology, clinical characteristics, and risk factors of entrants' lifetime hEAMC are scarce. This research aimed to describe the epidemiology, clinical characteristics, and risk factors of hEAMC among Comrades Marathon entrants.

Methods: This was a retrospective, cross-sectional study in which 10973 race entrants of the 2022 Comrades Marathon participated. Entrants completed a prerace medical screening questionnaire that included questions related to the lifetime prevalence (%; 95% CI), severity, treatment and risk factors (demographics, training/racing variables, chronic disease/allergies, injury) for EAMC.

Results: One thousand five hundred eighty-two entrants reported hEAMC in their lifetime (14.4%; 95% CI: 13.77-15.09). There was a significantly (P<0.01) higher prevalence of male (16.10%; 95% CI:15.34-16.90) than female (8.31%; 95% CI: 7.27-9.50) entrants with hEAMC (PR=1.94; 95% CI:1.68-2.23). The prevalence of hEAMC was highest in entrants with a: 1) 1 disease increase in composite disease score (PR=1.31; 95% CI:1.25-1.39); 2) history of collapse (PR=1.87; 95% CI 1.47-2.38); 3) past chronic musculoskeletal (MSK) injury (PR=1.71; 95% CI 1.50-1.94); and 4) MSK injury in the previous 12 months (PR=2.38;95% CI: 2.05-2.77). Training-related risk factors included an increase of 10 km weekly running distance (PR=0.97; 95% CI:0.95-0.99) and a training pace increase of 1min/ km (slower) (PR=1.07; 95% CI:1.03-1.12).

Conclusions: Future research should investigate the causal relationship between risk factors identified and hEAMC in ultramarathon runners. Findings from this study could assist in effective anticipation and adequate planning for treating EAMC encounters during community-based mass participation events.

Introduction: The anaerobic threshold (AT) is an important physiological index used as a parameter for predicting performance and evaluating adaptations induced by training. The aim of this study was to carry out a systematic literature review to survey the randomized studies that compared the effects of high-intensity interval training (HIIT) with the effects of moderate intensity continuous training (MICT) on the anaerobic threshold of highly trained athletes in endurance sports.

Evidence acquisition: The following databases were searched: MEDLINE, Embase, Cochrane Wiley, PubMed, SPORTDiscus, Web of Science, and ProQuest for randomized trials. The search terms covered the areas of HIIT and MICT. This study was registered in the International Prospective Register of Systematic under the number CRD42020155474.

Evidence synthesis: Three studies were included for the qualitative and quantitative synthesis, totaling 72 participants, of whom 28 belonged to the MICT group and 44 to the HIIT group.

Conclusions: The summary result showed that HIIT promotes greater adaptation in the AT of highly trained athletes compared to continuous training (ES=0.73; 95% CI: 0.25-1.21); however, the certainty of evidence evaluated by the GRADE method is low and heterogeneity is high (I2=82%; P<0.01).

First rib stress fractures are uncommon in athletes and diagnosis requires a high degree of clinical suspicion. Diagnostic delay may increase risk of poor healing and long-term complications. Case reports and series describe these injuries primarily in overhead athletes; proposed contributing factors include anatomic susceptibility to stress and repetitive opposing muscular forces. We describe an ice hockey goalie with acute-on-chronic thoracic back pain who was found to have a first rib stress fracture, which to our knowledge is the first reported in this sport. We hypothesize that biomechanical stress from new stick positioning contributed to the injury. Our patient recovered symptomatically with conservative treatment; however, imaging suggested nonunion of the fracture site and possible pseudoarthrosis.

Background: Abdominal pressure is important for athlete performance and conditioning, and lung function is implicated in running performance and economy. We aimed to determine the synergistic effects of trunk muscle strength training on abdominal pressure and lung function in university student runners.

Methods: A total of 18 healthy male runners participated in the study. Abdominal pressure was measured against air pressure applied by a cuff belt wrapped around the trunk. Forced expiratory volume in 1 second (FEV1) and FEV in 6 seconds (FEV6) were measured. Trunk muscle strength training was performed for 8 weeks, and abdominal pressure and lung function were compared preintervention as well as at 8 weeks and 6 months postintervention. Correlations between the preintervention abdominal pressure and FEV1 and FEV6, as well as the rate of change (Δ) of each item at each time point, were examined.

Results: Preintervention correlations between abdominal pressure and lung function were significant for abdominal pressure and FEV1 (r=0.475, P=0.047) and abdominal pressure and FEV6 (r=0.473, P=0.047). Significant correlations were found between Δabdominal pressure and ΔFEV1 (r=0.489, P=0.040) and Δabdominal pressure and ΔFEV6 (r=0.478, P=0.045) between preintervention and 8 weeks postintervention. Significant correlations were found between Δabdominal pressure and ΔFEV6 (r=0.557, P=0.016) between 8 weeks and 6 months postintervention.

Conclusions: The trunk muscle strength training intervention improved abdominal pressure and lung function, and the rate of change was also positively correlated, suggesting a synergistic effect between the two.

Background: While numerous studies have explored age and playing position effects on fitness levels in male adolescent soccer players, research on female players in this context is lacking. The purpose of this study was to examine the effects of age and playing position on field-based physical fitness measures in adolescent female soccer players, with consideration for maturity.

Methods: This cross-sectional study involved 284 females aged 12.0-15.9 years. Participants performed the 20-m multi-stage fitness test (20MSFT) to assess estimated maximum oxygen uptake (VO2max), 10-m and 20-m sprints, 505 Test to evaluate change of direction speed (CODS), the medicine ball chest throw (MBCT) and countermovement vertical jump (CMVJ) to assess muscle power. For data analysis, participants were separated into age groups (12, 13, 14, and 15 years), and playing position (forward, midfielder, defender, and goalkeeper). Age at peak height velocity was considered a covariate to account for maturity status.

Results: Players aged 14 years demonstrated faster CODS compared to 15 years old (P=0.014), while superior MBCT performance was noted at both ages compared to younger ages (P<0.001). Goalkeepers exhibited lower VO2max than midfielders and defenders (P<0.05). Defenders and goalkeepers exhibited greater hip circumference and body mass compared to midfielders (P≤0.01), along with a larger waist circumference for defenders compared to midfielders (P=0.003). Age and position interactions were absent. When analyses were run without controlling for maturity, all results were the same except for CODS where no age effect was found.

Conclusions: This study suggests that upper body power, and flexibility may be impacted by age and playing position in adolescent female soccer players, regardless of maturity status. The CODS appears to be influenced by age only when controlling for maturity.

Introduction: Passive time, during the post-warmup and half-time, decreases athletes' performance and increases injury risk factors in the active phases of the soccer match. Objective. This narrative review aims to research and synthesize existing evidence to identify brief re-warmup strategies that may find applicability in the post-warmup and half-time of a soccer match.

Evidence acquisition: The analysis was conducted on PubMed, Web of Science, PEDro, SPORTDiscus and Google Scholar. Due to the lack of evidence, no temporal time was established, preferring most up-to-date articles. The data were synthesized in relation to the objectives, following the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines.

Evidence synthesis: Our research yielded a total of 753 studies, 463 related to re-warmup, 136 articles on re-warmup in soccer, and 154 articles on re-warmup during half-time. Of these, 26 met the inclusion objectives and were included in this research. Our findings confirm that a re-warmup can mitigate the decremental effect of static rest on performance. From the studies considered, we have identified a work that emphasizes how a 1-minute warmup of high-intensity exercise at speed corresponding to 90% of VO2max can prevent decreases related to passive time, in sprint performance and muscle strength, as well as improve muscle temperature. These results could apply to both post-warmup and half-time scenarios of a soccer match.

Conclusions: From this narrative review, it has been possible to highlight a one-minute high-intensity re-warmup that improved sprint performance, increased core temperature, and enhanced muscle activation, not leading to additional physiological or psychological fatigue.