Sports Health-A Multidisciplinary Approach最新文献

Background: Preseason training plays a pivotal role in preparing athletes for the competitive season and reducing the risk of hamstring strain injuries (HSI). This study evaluated the protective effect of preseason running workload on the risk of in-season HSI in elite soccer players.

Hypothesis: Higher preseason sprint-related metric is associated with reduced risk of in-season HSI in elite soccer players.

Study design: Cohort study.

Level of evidence: Level 3.

Methods: Global positioning system data and HSI records from 67 elite Japanese soccer players between 2021 and 2023 were analyzed. Variables included internal workload, total distance, high-speed distance, sprint distance, sprint count, and acceleration/deceleration count. Multivariable logistic regression analysis determined the association between workload metrics and HSI risk.

Results: A total of 17 HSI incidents were recorded during the study period. Increased preseason sprint distance was associated significantly with a reduced risk of in-season HSI (odds ratio [OR], 0.896; 95% CI, 0.822-0.976; P = 0.01), even after adjustment (model 1: OR, 0.892; 95% CI, 0.814-0.979; P = 0.02, model 2: OR, 0.899; 95% CI, 0.822-0.983; P = 0.02). Higher sprint count was associated with decreased HSI risk (OR, 0.761; 95% CI, 0.633-0.916; P = 0.004), with consistent findings after adjustments (model 1: OR, 0.755; 95% CI, 0.623-0.916; P = 0.004, model 2: OR, 0.763; 95% CI, 0.631-0.923; P = 0.005). The area under the curve values for sprint distance and sprint count were 0.721 and 0.739, respectively.

Conclusion: Preseason training marked by higher sprint distances and counts demonstrates a protective effect against in-season HSI in elite soccer players, supporting comprehensive preseason running workload as an essential strategy for reducing injury risk and enhancing season readiness.

Clinical relevance: Incorporating sprint-focused training during the preseason may reduce HSI incidence and minimize injury-related absences in elite soccer players.

Background: The aims of this study were to analyze match demands and perceptual responses of cerebral palsy soccer national team players. Specifically, to identify whether variations in match demands exist between playing positions and between halves.

Hypothesis: Differences between playing positions exist and match demands differ from first to second half.

Study design: Cohort study.

Level of evidence: Level 3.

Methods: An observational, longitudinal study was conducted over the 2022-2023 season. Electronic performance and tracking systems collected physical output, whereas perceptual responses were collected through ratings of perceived exertion postmatch.

Results: Playing position significantly affected all variables (F_(4,66) = 4.05-73.31; P < .001; η_p² = 0.20-0.82). Midfielders had the greatest average physical output in all variables, except for high-intensity accelerations per minute (forwards = ~0.19 count/min) and maximum velocity (full-backs = ~28.87 km/h). Match half had no significant effect on any variable (F_(4,66) = 0.00-1.38; P > .05; η_p² = 0.00-0.02), except for distance per minute, which was usually greater in the first half than second half (F_(1,66) = 7.15; P = .01; η_p² = 0.10). Regarding perceptual response, playing position had a significant effect, with goalkeepers having significantly lower ratings of perceived exertion compared with the other positions (P < .05).

Conclusion: Playing position significantly affected all variables, with goalkeepers showing the lowest demands, followed by central defenders. Midfielders had the highest physical output across most variables, except for high-intensity accelerations per minute (forwards) and maximum velocity (full-backs). Match half had no significant effect on any variable, except for distance per minute.

Clinical relevance: Understanding match demands and positional differences in cerebral palsy soccer helps coaches plan tailored training sessions and drills to meet specific physical outputs. This knowledge supports training periodization, optimal player performance, and recovery. Insights into physical challenges for each position assist in scouting and adjusting training intensity.

Background: High-speed actions constitute an important mechanism of hamstring strain injuries (HSIs) in football. These actions have a strong supraspinal base, and changes in brain activity have been noted in other musculoskeletal injuries; however, there is a lack of information about changes in brain-muscle coupling in footballers with HSI history. Therefore, this study aimed to determine whether movement speed and brain-muscle activity differ between players with and without HSI history during a high-speed knee movement task.

Hypothesis: Footballers with previous HSI will show decreased knee movement rate and associated neurophysiological inhibition.

Study design: Cross-sectional study.

Level of evidence: Level 3.

Methods: A total of 108 male footballers (39 with HSI history) performed a maximum-speed knee flexion-extension task over eight 10-second blocks. During this task, brain and muscle activity of knee flexors and extensors were recorded using electroencephalography (EEG) and electromyography (EMG), respectively, and the movement rate was measured.

Results: Footballers with HSI history moved at a higher rate in the first half of the task. This was accompanied by higher theta and decreasing alpha EEG activity, lower rectus femoris and biceps femoris activity, and less flexor-extensor co-contraction. Conversely, there were no differences in corticomuscular coherence (CMC) between groups, but the biceps femoris showed a significantly lower CMC than all other muscles.

Conclusion: The task was able to differentiate players with and without HSI history; in addition, those with previous HSI showed EEG activity patterns associated with increased task load and use of attentional resources for sensorimotor integration. EMG findings indicated players with HSI history were able to perform better despite showing overall reduced activity, especially in the rectus femoris and biceps femoris.

Clinical relevance: Neurocognitive factors may be involved in HSIs and persist even after rehabilitation, suggesting the relevance of including these factors in rehabilitation.

Background: Studies of National Collegiate Athletic Association (NCAA) athletes have been concerning for rates of athletes reporting playing while symptomatic with a concussion and of athlete nondisclosure of concussion symptoms.

Purpose/hypothesis: This study's primary aim was to determine whether application of a brief and validated scale for concussion reporting expectation (CR-E) is an effective screening tool for collegiate athletes. It was hypothesized that 20% of athletes would be considered high risk for nondisclosure of concussion symptoms using this screening tool.

Study design: Cross-sectional.

Level of evidence: Level 2B.

Methods: NCAA Division I athletes (n = 358) from 18 teams who presented for preparticipation physical examinations (PPEs) in the 2023 fall season were queried with the CR-E and concussion history questions. The time to complete the CR-E was recorded, and providers recorded whether the screening results warranted additional concussion counseling or education. We report survey responses for all athletes stratified by sex and sport. Power analysis study population was based on NCAA collegiate athletes.

Results: The CR-E required an average of 2 minutes for athletes to complete during their PPE. Of 238 of 358 athletes who completed the CR-E questionnaire, 2 in 3 were determined to benefit from concussion education. Overall, athletes felt "neutral" about their agreement on a Likert scale to report concussion symptoms in 4 scenarios described on the CR-E. Water polo, volleyball, women's soccer, gymnastics, and football represented sports with higher rates of counseling, below average agreement to report concussion symptoms for 4 scenarios queried, and most frequent nonreporting histories.

Conclusion: The CR-E questionnaire represents an impactful screening tool with high utility and feasibility for collegiate athletes.

Clinical relevance: Our study supports a brief screening tool to guide concussion counseling for athletes. Based on our data, there appears to be room for improvement in athlete concussion education overall.

Background: Tracking systems have revolutionized the analysis of physical demands in professional soccer. Monitoring external load parameters through global positioning systems is crucial for monitoring fatigue, technical-tactical factors, and preventing injuries, especially during disruptions such as COVID-19 and midseason tournaments.

Hypothesis: The FIFA World Cup Qatar 2022 would lead to significant changes in external load parameters among LaLiga players, either positively or negatively, when comparing pre- and post-tournament match performance.

Study design: Retrospective observational study.

Level of evidence: Level 3.

Methods: External load metrics (ie, minutes of game, accelerations, decelerations, sprints, and high-speed running [HSR]) were analyzed to compare performance in 8 pre- versus postleague tournament matches in those soccer players who competed in FIFA World Cup Qatar 2022. The sample consisted of players from the Spanish LaLiga elite soccer league who participated in the Qatar 2022 World Cup.

Results: FIFA World Cup Qatar 2022 did not negatively impact external load variables. Post-tournament values showed improvements in (1) number and distance covered at HSR, (2) distance and number of sprints, (3) number of high-intensity actions performed, and (4) number and distance covered at high-intensity deceleration, without significant differences in total distance covered or maximal speed reached during matches.

Conclusion: FIFA World Cup Qatar 2022 did not negatively affect the performance of Spanish LaLiga players. On the contrary, several external load metrics such as HSR, sprinting, accelerations, and decelerations showed improved performance post-tournament.

Clinical relevance: These results may help clarify the effects of future in-season league stoppages due to international competitions.

Context: Manipulation of resistance training variables influences the structural and functional adaptations of muscle, having a great impact on sport performance and hamstring injury prevention.

Objective: To analyze how the main resistance training variables affect the biceps femoris long head architecture in soccer players.

Data sources: Five databases were searched from inception to January 2024.

Study selection: Studies that included training intervention groups and measured muscle architecture adaptations before and after the training program in soccer players were included.

Study design: Systematic review with meta-analysis.

Level of evidence: Level 2.

Data extraction: Muscle thickness, fascicle length, and pennation angle were extracted from included studies as main outcomes.

Results: Six studies and 12 training groups (168 participants) were analyzed. The effects of Nordic hamstring exercise (NHE) against soccer interventions, volume of training, and frequency of training as independent variables were analyzed. NHE significantly improved biceps femoris long head fascicle length (P = 0.01). Training twice a week did not show significant differences compared with training once a week. Higher volumes of training (ie, >290 repetitions) in a period of 6 to 12 weeks with 57 repetitions per week demonstrated significant effects.

Conclusion: NHE lengthens the fascicle, especially if a sufficient volume (ie, >290 repetitions) and 2 days per week are performed. It is still unknown how the programming of some fundamental variables such as intensity, degree of effort, or exercise selection affects the muscle architecture of the biceps femoris long head.

Background: Exertional heat illnesses (EHIs) affect thousands of high school athletes each year. Although there are clear risk patterns for fatal EHIs based on player characteristics, there is less information on these associations for nonfatal EHIs.

Hypothesis: Prediction of nonfatal EHI risk in American high school football participants can be determined using commonly available data on body mass index (BMI) values and/or player position.

Study design: Epidemiological study.

Level of evidence: Level 3.

Methods: Participants from 22 high schools in the state of Georgia in the United States were used for this study. Player demographics including height, weight, BMI, and player position were considered. EHI occurrences from 2012 to 2014 were recorded and analyzed to determine EHI risk. These data were collected as part of normal practice/competition activities, and the researchers did not interact with the subjects of the study. Therefore, approval from the Institution's Internal Review Board was not required for this investigation.

Results: There were 309 EHIs over 163,118 athlete-exposures. The linemen group had over 2.5 to 3 times greater risk of sustaining heat syncope/heat exhaustion (HS/HE) than the backs (relative risk [RR], 2.63; 95% CI, 1.59-4.33) and Specialists (RR, 3.16; 95% CI, 1.52-6.56) groups. Linemen were at lower risk for exercise-associated muscle cramps (EAMCs) compared with backs (RR, 0.63; 95% CI, 0.53-0.76). No differences were found in relative risk among BMI categories.

Conclusion: Our results indicate that field position is a bigger differentiator in EHI risk than BMI.

Clinical relevance: Sports medicine and coaching staff should be educated that American football participants at the linemen position are at greater risk for HS/HE than those at other positions. This supports the use of position-specific training activities to mitigate EHI risk.

Background: Sleep is negatively affected by muscle-damaging exercise, but it remains unknown whether hot environmental conditions further affect sleep.

Hypothesis: Sleep quality would decline, but sleep quantity would be longer after experiencing both heat exposure and EIMD.

Study design: Crossover study.

Level of evidence: Level 3.

Methods: In a randomized, counterbalanced order, 10 healthy males (mean ± SD: age, 23 ± 3 years; body mass, 78.7 ± 11.5 kg; height, 176.9 ± 5 cm; lactate threshold [LT], 9.7 ± 1.0 km h^-1) performed 30 min of downhill running (DHR) at -10% gradient at the LT in control (ambient temperature [T_amb], 20°C; relative humidity [RH], 20%) and hot conditions (T_amb, 35°C; RH, 40%). Seven days later, participants performed a flat 45-min run in the heat at LT. Sleep parameters were collected from a wearable device the night after DHR, the following 6 nights, and the night of the 45-min flat run. Differences in sleep parameters between conditions following DHR, the subsequent 6 nights, and the night of the 45-min run were analyzed using repeated measures analysis of variance (ANOVA).

Results: Following DHR, total sleep time (6.7 ± 0.7 h vs 5.2 ± 1.8 h; P = 0.040), rapid eye movement (REM; 1.7 ± 0.6 h vs 1.2 ± 0.7 h; P = 0.046), and slow-wave sleep (SWS; 1.6 ± 0.4 h vs 1.2 ± 0.5 h; P = 0.015) were greater in the hot condition. However, REM% and SWS% did not differ (P > 0.05), indicating increases reflected longer sleep duration rather than altered architecture. Sleep efficiency, light sleep, resting heart rate, heart rate variability, and respiratory rate were also unchanged (P > 0.05). No differences were observed across the subsequent 6 nights or after the flat run (P > 0.05).

Conclusion: Sleep duration increased on the night after muscle-damaging exercise in hot conditions, with greater REM and SWS reflecting longer sleep rather than altered architecture.

Clinical relevance: Individuals from various populations, including athletes, military, occupational workers, and the general public may participate in exercise under heat stress, requiring awareness of potential sleep disturbances following exercise in hot conditions.

Background: Blood flow restriction (BFR) training effectively improves strength in muscles directly subjected to occlusion. Secondary effects on distal and contralateral muscles remain underexplored.

Hypothesis: A walking training program plus BFR applied to the upper thigh enhances muscle strength in distal muscles of the lower leg.

Study design: Nonrandomized controlled clinical trial with a within-subject approach.

Level of evidence: Level 1.

Methods: A total of 20 male and 12 female adults (31.1 ± 9.5 years) with ≥10% strength asymmetry in knee extensors completed 3 weekly sessions over 12 weeks. A cuff inflated at 90% of total occlusion pressure was applied to the weaker limb (exercised segment [ES]); the stronger limb served as control segment (CS). Outcomes assessed pre- and postintervention included ankle plantarflexor and dorsiflexor strength and muscle thickness (MT) (medial gastrocnemius [MG] and tibialis anterior [TA]) using isometric testing and ultrasound.

Results: Strength gains were identified after training in the ES and CS for the MG and TA muscles (P < 0.005 pre-to-post comparisons). In the ES, the plantarflexor and dorsiflexor torque increased from 85.6 N·m to 111.7 N·m and from 34.5 N·m to 39.6 N·m, respectively. In the CS, torque increased from 93.1 N·m to 110.5 N·m (plantarflexors) and from 35.5 N·m to 40.3 N·m (dorsiflexors). Relative improvements were greater in the ES (plantarflexor, +30.4%; dorsiflexor, +14.8%) than the CS (plantarflexor, +18.7%; TA, +13.6%), although no interactions were observed (P > 0.05). MT showed nonsignificant variation (P > 0.05). In the ES, the MG changed from 1.93 cm to 2.04 cm and TA from 2.06 cm to 2.33 cm. In the CS, the MG remained stable (1.99 cm to 2.02 cm), and TA varied from 2.12 cm to 2.35 cm.

Conclusion: Walking combined with BFR targeting the upper thigh improves strength in distal muscles of the lower leg, with notable gains in both the occluded and contralateral segments. Neural adaptations likely account for the observed strength increases.

Clinical relevance: BFR walking is an effective, low-impact intervention to enhance lower-limb muscle strength, with potential applications in rehabilitation and training for people with asymmetry or muscle weakness.

Background: Chronic ankle instability (CAI) can induce contralateral limb deficits, influencing interlimb asymmetry during athletic tasks. Understanding the magnitude, direction, and individual thresholds of these asymmetries is critical for effective rehabilitation and performance monitoring.

Hypothesis: CAI-induced contralateral limb deficits significantly influence the magnitude and direction of interlimb asymmetry in jumping and change-of-direction-speed (CODS) tasks.

Study design: Cross-sectional study.

Level of evidence: Level 3.

Methods: Male elite soccer players with (n = 32) and without (n = 38) CAI performed single-leg hop (SLH), single-leg triple hop, modified-505 (Mod505), and 90°-changes-of-direction tests.

Results: Paired-sample t tests revealed small-to-moderate differences between dominant and nondominant limbs in both groups (P < 0.05), moderate-to-large differences between injured and contralateral uninjured limbs (P < 0.05), large differences between injured and matched limbs of healthy players (P < 0.05), and small nonsignificant differences between contralateral uninjured and matched limbs of healthy players (P > 0.05). Independent-sample t test revealed asymmetries were significantly higher in all tests (P < 0.05) except for SLH (P > 0.05) in players with CAI. Kappa coefficient showed substantial-to-perfect agreements for players with CAI (κ = 0.71-1.00), and moderate-to-substantial agreements for healthy players (κ = 0.51-0.73), indicating asymmetries favored same limb. Agreement percentages for similar identifications of asymmetry patterns based on individual thresholds derived from intralimb variability revealed that injured players adopted similar patterns in CODS (81.25%), while healthy players adopted similar patterns between SLH and mod505 (76.32%).

Conclusion: CAI-induced contralateral limb deficits influenced magnitude and direction of asymmetry, potentially underestimating asymmetry. Asymmetry consistently favors the same limb due to injury and functional similarities; thresholds derived from intralimb variability identify real asymmetry.

Clinical relevance: These findings highlight the importance of considering contralateral limb deficits when interpreting interlimb asymmetries in players with CAI. Rehabilitation programs should address these deficits to optimize performance and reduce injury risk.