Journal of science and medicine in sport最新文献

Objectives: To determine if circulating mitochondrial deoxyribonucleic acid levels increase after sport activity involving blows to the head, such as boxing, and if it could play a role in inflammatory cascade regulation in response to trauma.

Design: Observational, longitudinal.

Methods: We measured mitochondrial deoxyribonucleic acid levels and integrity in ten non-professional male boxers before and after three weekly sparring matches. We set up a protocol to separate three different plasma fractions enriched in mitochondria-containing vesicles, mitochondrial deoxyribonucleic acid bound to proteins and naked mitochondrial deoxyribonucleic acid. We quantified the levels of the main cytokines involved in inflammatory response and the levels of neurofilament light, a well-known marker of brain damage.

Results: Circulating mitochondrial deoxyribonucleic acid levels increased after each match. In the second fraction, we also observed an increase over the weeks. Mitochondrial deoxyribonucleic acid is less intact after each match if compared with pre-match integrity, especially the naked form which is not protected within vesicles or mitochondria. Circulating levels of interleukin-6, interleukin-1beta and interleukin-10 increased after each match linking traumatic brain injuries to inflammatory state. Neurofilament light chain showed a similar trend to mitochondrial deoxyribonucleic acid.

Conclusions: As mitochondrial deoxyribonucleic acid displays an inflammatory effect and neurofilament light chain is more specific for brain injury, we concluded that the simultaneous analysis of these two parameters could be helpful to monitor the effects of traumatic brain injury in contact sports, and that mitochondrial deoxyribonucleic acid is a promising candidate biomarker to study the inflammatory state of patients who suffered repeated traumatic brain injuries.

Objectives: Female athletes have a lower risk of hamstring strain injuries than males. The variations in oestradiol and progesterone concentrations happening during the menstrual cycle and oral contraceptive use may influence muscle mechanical properties, potentially affecting muscle injury risk. However, to date, no study has combined an assessment of hamstring muscles' mechanical properties spread over the full knee range of motion with rigorous hormonal control of the menstrual cycle, electromyographic monitoring and inclusion of oral contraceptive users. The present study aims to be the first to rigorously evaluate the association between menstrual cycle, oral contraceptive use and hamstring muscles' mechanical properties.

Design: Cross-sectional study with repeated measures.

Methods: Shear wave elastography measurements were performed at three different times during the menstrual and oral contraceptive cycle. Hormonal assessment and electromyographic monitoring were also carried out.

Results: No difference in hamstring muscles' shear wave speed, anatomical cross-sectional area, knee joint musculoarticular stiffness and maximal range of motion were observed along the menstrual cycle despite the presence of the expected variations in ovarian steroid hormones concentrations. No difference in these parameters was also reported throughout the oral contraception use.

Conclusions: No differences in the mechanical properties of the hamstring muscles were observed, whether the concentrations of ovarian steroid hormones fluctuate with the menstrual cycle or remain stable with oral contraceptive use, despite the notable effects of these hormones on the muscle composition.

Objectives: Fat tissue does not directly contribute to an increase in propulsive force in swimming, though it has the potential to indirectly enhance swimming performance by reducing active drag as the specific gravity of fat tissue is lower than that of water. However, the relationship between body composition and active drag has not been elucidated. This study aimed to evaluate how body composition relates to active drag during arms-only front crawl swimming.

Design: Cross-sectional study.

Methods: Twenty-two male collegiate swimmers (height, 1.73 ± 0.06 m; body mass, 67.6 ± 6.0 kg) performed arms-only front crawl swimming using a measuring active drag-system. Active drag was evaluated at 1.20, 1.50 m/s, and maximum swimming velocity. Body composition data, fat mass, fat-free mass, and the percentage of fat mass relative to body mass (%fat mass) were measured using dual-energy X-ray absorptiometry. The associations between body composition data and active drag were evaluated using Pearson's correlation coefficients.

Results: The results indicated that %fat mass was negatively correlated with active drag at 1.20 and 1.50 m/s, whereas fat-free mass was positively correlated with active drag at 1.50 m/s.

Conclusions: In male swimmers with %fat mass between 6.3 and 12.0 %, a higher %FM, reflecting lower body density, had lower active drag at submaximal swimming velocities. These findings suggest that swimmers and their coaches should consider the balance of fat mass and fat-free mass from the perspective of active drag rather than unnecessarily decreasing fat mass or increasing fat-free mass to enhance swimming performance.

Objectives: To explore the potential association between rapid weight changes and self-reported injury status (presence or absence of injury) 7 days following competitive events among male and female combat sports competitors.

Design: A 14-month study of 24 events.

Methods: A weight management questionnaire was completed 1-day post-competition, and an injury questionnaire was completed 7 days post-competition. These online questionnaires provided data on body mass and injury status. Mixed effects logistic regression models were used to analyse the odds ratios of rapid weight change variables and their impact on athletes' self-reporting as injured or non-injured.

Results: There were 172 responses (155 athletes) to both questionnaires (37 females (24 %) and 118 males (76 %)); 88 athletes (51 %) reported no injury, and 84 (49 %) reported injury. Rapid weight loss 7 days (RWL -7 days) and 24 h (RWL -24 h) before weigh-ins was 4.9 % ± 3.4 % and 2.6 % ± 2.1 % for females, and 6.1 % ± 3.2 % and 3.0 % ± 1.9 % for males. Mixed effects logistic regression models returned the highest odds ratio for male RWL -24 h (odds ratio: 1.20, 95 % confidence interval: 1.00-1.43, p = 0.044). This indicates that for a 1 % increase in male RWL -24 h before official weigh-ins, the likelihood of reporting an injury increases by a factor of 1.2.

Conclusions: Male RWL -24 h before weigh-ins is associated with reporting an injury at 7 days post-competition. Therefore, athletes and coaches should carefully consider and aim to limit pre-competition rapid weight loss to minimise the likelihood of injury.

Objectives: This study aimed to evaluate the dose-response relationship between different exercise types and the alleviation of motor symptoms in Parkinson's Disease patients.

Design: A systematic review and network meta-analysis were conducted to compare the effects of 12 exercise types on motor symptoms in Parkinson's Disease patients using randomized controlled trials.

Methods: A systematic search was conducted across PubMed, Medline, Embase, PsycINFO, Cochrane Library, and Web of Science until September 10, 2024. A total of 81 trials involving 4596 patients were included. Mean differences with 95 % credible intervals were calculated, and evidence quality was assessed using Confidence in Network Meta-Analysis. The Minimum Clinically Important Difference was used to assess clinical efficacy.

Results: The optimal exercise dose for overall motor symptom improvement was 1300 MET-min/week (mean difference: -6.07, 95 % credible intervals: -8.10 to -4.01). Dance at 850 MET-min/week provided the greatest improvement (mean difference: -11.18, 95 % credible intervals: -16.01 to -6.22). Significant improvements were seen with doses as low as 60-100 MET-min/week for body weight support training, dance, resistance training, and sensory exercise. The Minimum Clinically Important Difference was achieved with doses exceeding 670 MET-min/week for overall exercise, and at lower doses for specific types: aerobic exercise (1100 MET-min/week), body weight support (420 MET-min/week), and dance (230 MET-min/week).

Conclusions: The optimal exercise dose for alleviating motor symptoms in Parkinson's Disease patients is 1300 MET-min/week, with dance being most effective at 850 MET-min/week. These findings provide evidence-based recommendations for Parkinson's Disease management.

Objectives: Knee braces were introduced to sports 30 years ago. However, knee brace use for non-contact anterior cruciate ligament injury prevention intervention remains contentious due to concerns about performance hindrances. Since knee brace use is a potential modifiable risk factor, we aimed to investigate the effect of discounting and continued functional knee brace (FKB) on lower extremity power-vertical jump (VJ), acceleration, speed, and agility performance.

Design: Prospective cohort crossover study.

Methods: Twenty-seven healthy male athletes performed seven tests, over six days of 12 test sessions (S), during three test conditions (non-braced, braced, and removed brace or continued brace use). This study focuses on VJ, acceleration, speed, and agility performance during S12 when athletes were randomly selected to remove the FKB after 17.5 h or continue using the FKB for 21.0 h.

Results: After brace removal, nonsignificant performance levels improved in the VJ (2.7 %; 95 % CI 52.5-62.8; Cohen's effect size (ES) = trivial), acceleration (1.8 %; 95 % CI 0.500-0.562; ES = small), and agility (0.5 %; 95 % CI 9.25-10.13; ES = trivial), while a nonsignificant slower speed was recorded (0.5 %; 95 % CI 1.81-1.95; ES = trivial). Continued brace use led to a nonsignificant performance improvement in all tests; VJ (3.1 %; 95 % CI 53.5-60.2; ES = small), acceleration (1.5 %; 95 % CI 0.511-0.561; ES = trivial), speed (1.0 %; 95 % CI 1.83-1.95; ES = trivial), and agility (1.8 %; 95 % CI 9.26-10.04; ES = trivial).

Conclusions: Removal of FKB led to improved performance in three performance tests, while continued brace use improved performance in all four tests.

Objectives: To quantify the direct and indirect costs associated with injuries in professional men's cricket from 2015/16 to 2021/22 and to report the association between the cost of injuries and team success.

Design: Retrospective cohort study.

Methods: Injury insurance claims were obtained for cricket-related injuries to determine direct costs. Player's salary cost whilst injured was calculated from total salary expenditure, number of players, seasonal days and days lost to injury from prospective injury recording. A linear mixed model was used to assess the association between team success (County Championship points) and cost of injury.

Results: The average annual total cost of injuries per team was £167,447 (±£20,678), comprising £38,127 (±£24,000) injury insurance costs, £40,007 (±£23,977) injured players salary costs and £89,243 medical staff costs. Hand injuries incurred the highest number of claims and lumbar spine injuries accounted for the largest cost. Approximately 7 % of players' annual salary was earned whilst injured. The cost of injury was negatively associated with team success in Division 1; those with a two SD higher injury cost (£58,561) accrued 28 fewer points (95 % CI -54, -2) on average. The association in Division 2 teams was unclear (two SD increase (£53,339): +15 points [95 % CI: -10, 41]).

Conclusions: These data support the implementation of effective injury prevention measures for lumbar spine, hand and knee injuries to reduce injury rates and subsequent costs. Highlighting the financial and team performance costs of injuries may help to engage key stakeholders in injury prevention initiatives.