International journal of sports medicine最新文献

Thermoregulation is impaired in individuals with a spinal cord lesion (SCI), affecting sweat capacity, heat loss, and core temperature. This can be particularly problematic for athletes with SCI who exercise in hot and humid conditions, like those during the Tokyo 2020 Paralympic Games. Heat acclimation can support optimal preparation for exercise in such challenging environments, but evidence is limited in endurance athletes with SCI. We evaluated whether seven consecutive days of exercise in the heat would result in heat acclimation. Five elite para-cycling athletes with SCI participated (two females, three males, median (Q1-Q3) 35 (31-51) years, four with paraplegia and one with tetraplegia). All tests and training sessions were performed in a heat chamber (30°C and 75% relative humidity). A time-to-exhaustion test was performed on day 1 (pretest) and day 7 (posttest). On days 2-6, athletes trained daily for one hour at 50-60% of individual peak power (P_Peak). Comparing pretest and posttest, all athletes increased their body mass loss (p=0.04), sweat rate (p=0.04), and time to exhaustion (p=0.04). Effects varied between athletes for core temperature and heart rate. All athletes appeared to benefit from our heat acclimation protocol, helping to optimize their preparation for the Tokyo 2020 Paralympic Games.

This study compared lower extremity, trunk, and upper extremity kinematics between tee and front toss hitting in youth baseball athletes. Twenty youth baseball athletes (14.3±2.9 yrs) performed three maximal effort swings off front toss and tee. Kinematic data were collected during the preparatory and acceleration phases. Lower extremity, trunk, and upper extremity kinematics were compared between tee and front toss hitting using 1-dimensional statistical parametric mapping (SPM). There was a significant difference in trunk kinematics between tee and front toss during the preparatory phase (p=.001); the trunk rotated more toward the back side when hitting off a tee compared to front toss (p<0.001). There was also a significant difference in trunk kinematics between tee and front toss for 67% of the acceleration phase; the trunk rotated more towards the back side from 0 to 67% when hitting off the tee (p<0.001). Significant differences were found in trunk kinematics between tee and front toss hitting in youth baseball players, where the trunk is less rotated toward the pitcher in the tee than in the front toss. Coaches utilize various training modalities to enhance hitting performance; however, differences in trunk kinematics should be considered between modalities when developing fundamental hitting techiques in youth baseball athletes.

We compared the effects of different weekly calf training sets on muscle size changes. Sixty-one untrained young women performed a calf training program for 6 weeks, 3 d·wk^-1, with differences in resistance training volume. The participants were randomly assigned to one of the three groups: 6-SET, 9-SET, and 12-SET weekly calf training sets. The calf raise exercise was performed in sets of 15-20 repetitions maximum. The muscle thickness measurements of medial gastrocnemius (MG), lateral gastrocnemius (LG), and soleus (SOL) were taken via B-mode ultrasound. We used the sum of the three-muscle thickness as a proxy for the triceps surae (TS_SUM). The 12-SET group elicited greater increases than the 6-SET in LG (6-SET=+ 8.1% vs. 12-SET=+ 14.3%; P=0.017), SOL (6-SET=+ 6.7% vs. 12-SET=+ 12.7%; P=0.024), and TS_SUM (6-SET=+ 6.9% vs. 12-SET=+ 12.0%; P=0.005), but there was no significant difference in MG changes (6-SET=+ 6.6% vs. 12-SET=+ 9.9%; P=0.067). There were no significant differences when comparing 9-SET vs. 6-SET and 12-SET (P≥0.099). Although all groups experienced calf muscle hypertrophy, our results suggest that the higher dose range may optimize triceps surae muscle size gains.

This systematic review aims to identify the sleep parameters of Olympic athletes and the instruments used to assess and monitor the sleep of these athletes. The search was conducted until February 2023 and was performed in PubMed, Web of Science, and Scopus databases. This systematic review has included studies that investigated at least one of the following sleep parameters: total sleep time (TST), sleep onset latency (SOL), sleep efficiency (SE), awakenings after sleep onset (WASO), quality of sleep, daytime sleepiness, and chronotype; the participants were Olympic athletes. The search returned a total of 280 studies. After screening based on exclusion and inclusion criteria, 11 studies were included. The main results demonstrate that Olympic athletes have TST of 06:10 h, SE of 84%, SOL of 28 min, and WASO of 49 min. The most predominant chronotype is indifferent; over half of the athletes have poor sleep quality and complaints. Furthermore, actigraphy was the most used method to assess sleep. It is concluded that Olympic athletes have TST, SE, and WASO poor than the recommended values. In addition, sleep complaints and poor sleep quality were also observed. Among the objective sleep assessment methods, actigraphy was the method most frequently used in this population.

This study investigated how equipment and sex affect the prediction accuracy of the maximum number of repetitions performed to failure (RTF) using the fastest mean velocity of the set (MV_fastest). Sixteen men and twelve women completed four sessions (two using free-weight equipment and two sessions using the Smith machine). Each session involved three sets of repetitions to failure against the 65%, 75%, and 85% of the one-repetition maximum, interspersed by 10-min of rest. The goodness-of-fit of the individualized RTF-MV_fastest relationships was comparable between both equipment types and sexes (P≥0.510). Moreover, there were not significant differences in the MV_fastest associated with RTF between equipment types (P≥0.258). However, the MV_fastest associated with RTF was higher for men than for women in repetitions 6 to 15 (P≤0.043; ES≥0.69). In addition, the absolute errors when predicting RTF showed no significant differences between equipment types and loads (P<0.444). Specifically, these RTF estimates were within an acceptable range for men (<2 repetitions), but not for women (≥2 repetitions) (main effect of sex: P≤0.018; ES≥0.58). These findings suggest that individualized RTF-MV_fastest equations estimate the RTF with an acceptable precision in men during bench press exercises in both equipment types but exhibit lower precision for women.

The objective of this meta-analysis is to compare the effects on muscle strength and hypertrophy of low and high-intensity aerobic training with BFR (LI-BFR and HI-BFR) versus low and high-intensity aerobic training without BFR (LI and HI). The search was performed in five databases, by two independent researchers, and the terms and keywords used to optimize the searches were related to blood flow restriction and aerobic training. All studies were evaluated for methodological quality using the PEDro scale and for quality of evidence using the GRADE system. Meta-analyses were conducted using RevMan software. After data extraction, 11 studies met all eligibility criteria and were included in the systematic review. The results of the overall analysis between LI-BFR vs. LI showed a significant difference in muscle strength of knee extensors; for hypertrophy, LI was superior to LI-BFR with clinical relevance. Comparing HI-BFR vs. HI there was no superiority for muscle strength. In conclusion, for strength gains very low-quality evidence was found to support no superiority between LI-BFR and HI-BFR compared to LI and HI, respectively. For muscle hypertrophy, superiority of LI was found compared to LI-BFR, with a very low level of evidence.

It is known that female athletes are at risk for eating disorders. It is thought that factors such as pressure and stress experienced by professional athletes may affect emotional eating and body appreciation. In this context, the aim of this study was to evaluate the emotional eating and body appreciation of professional Turkish female athletes. A total of 265 professional female athletes were categorized according to their sport types and nationality. Emotional eating was found to be higher and body appreciation to be lower in athletes competing at the national level. The results of the hierarchical regression analysis, which included variables such as age, body mass index, professional sports background, national level, and sport type show that the most effective factor in explaining emotional eating in professional female athletes is body appreciation. The present study findings support that professional female athletes are at risk in terms of emotional eating and body appreciation. In addition, emotional eating scores were found to be higher and body appreciation scores were lower in national athletes. Psychological factors such as intense stress and pressure have an impact on the eating behavior and body appreciation of national athletes. These results suggest that athletes should be evaluated by nutritionists, doctors, and psychologists from a multidisciplinary perspective.

Our study aimed to examine preoperative differences in strength and balance between dominant foot (DF) and nondominant foot (non-DF) of individuals undergoing ligament stabilization surgery in the general population. Patients with records of preoperative evaluation, including isokinetic dynamometric strength evaluation, Y-balance test (YBT), and Foot and Ankle Outcome Score (FAOS), were included in the study. The DF was the preferred leg for accurately kicking a ball through a goal. Statistical analysis determined the differences between DF and non-DF and the correlations between muscle strength, balance, and FAOS. There was no statistically significant difference between DF and non-DF regarding evertor and invertor muscle strength (p=0.082-0.951). The YBT revealed no significant difference between the two groups (p=0.082-0.951). There was a significant correlation between the evertor peak torque and total work deficits at 30°/s (p=0.022), as well as the evertor peak torque deficit at 120°/s (p=0.048). No significant differences in muscle strength and balance were found between DF and non-DF in nonathletes with chronic ankle instability. Peroneal muscle strength deficit was associated with functional impairment. Tailored interventions are needed to address limb dominance and muscle strength deficits in CAI management.

Biceps femoris long head (BF_LH) aponeurosis size was compared between legs with and without prior hamstring strain injury (HSI) using two approaches: within-group (injured vs. uninjured legs of previous unilateral HSI athletes) and between-group (previously injured legs of HSI athletes vs. legs of No Prior HSI athletes). MRI scans were performed on currently healthy, competitive male athletes with Prior HSI history (n=23;≥1 verified BF_LH injury; including a sub-group with unilateral HSI history; most recent HSI 1.6±1.2 years ago) and pair-matched athletes with No Prior HSI history (n=23). Anonymized axial images were manually segmented to quantify BF_LH aponeurosis and muscle size. Prior unilateral HSI athletes' BF_LH aponeurosis maximum width, aponeurosis area, and aponeurosis:muscle area ratio were 14.0-19.6% smaller in previously injured vs. contralateral uninjured legs (paired t-test, 0.008≤P≤0.044). BF_LH aponeurosis maximum width and area were also 9.4-16.5% smaller in previously injured legs (n=28) from Prior HSI athletes vs. legs (n=46) of No Prior HSI athletes (unpaired t-test, 0.001≤P≤0.044). BF_LH aponeurosis size was smaller in legs with prior HSI vs. those without prior HSI. These findings suggest BF_LH aponeurosis size, especially maximum width, could be a potential cause or consequence of HSI, with prospective evidence needed to support or refute these possibilities.

This study investigated the associations between pre-season and in-season performance with external workload in professional soccer players. Twenty-one players completed hamstring strength, countermovement jump (CMJ), 20-m sprint, and Yo-Yo intermittent recovery tests before (pre-season) and after 8 weeks (in-season). External workload (total distance, high-intensity running distance, number of sprints, and power plays) was quantified during this period, and used to divide the average above and below subgroups outcome by outcome for further analyses. Significance was accepted when P≤0.05. Hamstring strength declined from pre- to in-season [- 6%; p=0.014; effect size (ES): - 0.41], while Yo-Yo performance improved (46%; p=0.001; ES: 1.31). When divided by high-intensity running distance, only the below-average subgroup improved CMJ performance (5%; p=0.030). For minutes played, the above-average subgroup improved Yo-Yo performance (41%; p<0.001), but not the below-average subgroup. Furthermore, playing time correlated with improved Yo-Yo performance (p=0.040; r=0.534). Improved 20-m sprint performance associated with more sprints performed (p=0.045; r=- 0.453). Physical capabilities changed over a competitive season and were related to, and differentiated by, external workload. Because hamstring strength decreased and CMJ only improved in players exposed to less high-intensity external load, practitioners should individualize approaches to counteract these conditions when high external workload is performed over the season.