Sports Medicine - Open最新文献

Fitness has been dominantly defined in terms of physical conditioning components. Under such definition, males tend to outperform females in strength, speed, aerobic or anaerobic capacity when compared at the same age and training status. However, females have a higher life expectancy, which in humans is related to higher biological fitness. Using the paradox of sex differences in fitness-where males have higher physical fitness but do not have a higher life expectancy-the aim of this opinion paper is to (a) highlight the multidimensionality of fitness, and (b) redefine health-related fitness, drawing on key fitness goals in biology: adaptability and survival. The redefinition of health-related fitness as the "adaptive ability to foster survival possibilities" encompasses synergies across physical, mental, psychological, emotional, social and subjective dimensions, while embracing the diversity of human characteristics, including sex, gender, age, somatotype, vital state, disability, disease and wellbeing, among others.

Background: Providing runners with injury prevention suggestions from a biomechanical perspective is crucial in light of the increased incidence of running-related injuries forecasted with the rising popularity of the half-marathon. Previous research has demonstrated associations between running injuries and patterns of lower extremity biomechanics, as well as indicating that inadequate rest between training sessions can result in injuries and underperformance. However, whether half-marathon running elicits lower extremity biomechanical changes and the recovery time remains largely unclear. This study aimed to investigate the acute changes (pre-run and immediately post-run) and the time course of recovery (pre-run, day 1, and day 2) in neuromuscular function, landing strategies, and lower extremity joint mechanics of recreational runners following a simulated half-marathon protocol on a treadmill.

Results: Compared to pre-half-marathon measurements, we observed significant reductions in concentric (Flexors: Pre: 1.49 ± 0.50Nm/kg, Post: 1.34 ± 0.54Nm/kg, p < 0.001; Extensors: Pre: 2.19 ± 0.73Nm/kg, Post: 2.00 ± 0.82Nm/kg, p < 0.001) and eccentric (Flexors: Pre: 1.67 ± 0.68Nm/kg, Post: 1.34 ± 0.62Nm/kg, p < 0.001; Extensors: Pre: 2.44 ± 0.13Nm/kg, Post: 1.96 ± 0.12Nm/kg, p < 0.001) torques of the knee flexors and extensors, reductions in eccentric knee flexor to concentric knee extensor torque ratios (Pre: 0.78 ± 0.27, Post: 0.68 ± 0.22, p < 0.001), and impaired knee (Pre: 1.6 ± 0.1°, Post: 3.0 ± 0.2°, p < 0.001) and hip (Pre: 1.5 ± 0.2°, Post: 2.6 ± 0.2°, p < 0.001) joint position sense immediately post running. Additionally, we observed an increase in contact time (p = 0.006), decreases in peak vertical ground reaction force (p < 0.001) and impulse (p < 0.001), and changes in lower extremity joint kinematics and kinetics during the stance phase of running immediately after the half-marathon. Most measured parameters recovered within one day, except hip joint position sense, which was restored within two days. By the second day, we also observed super-compensation in thigh muscle torques.

Conclusion: The study revealed that simulated treadmill half-marathon induces alterations to neuromuscular function, impacts landing strategies, and elicits changes in lower extremity joint mechanics. However, these effects are temporary and resolve within two days post-run. These findings provide valuable insights to optimize training responses and prevent overtraining in recreational runners.

Background: Various exercise thresholds have been evaluated to predict athlete performance. However, a systematic review of the literature assessing the association between lactate-based exercise thresholds and 2000 m rowing ergometer performance is still lacking. These may have utility in the prediction of 2000 m rowing ergometer performance due to the close relationship between metabolic parameters and development of endurance capacity. The aim of the present study is to review and assess the extent, quality, and reliability of lactate-based exercise testing and methodologies in their association with 2000 m rowing ergometer performance, and to discuss the potential implications for performance prediction.

Methods: The systematic review was performed following PRISMA 2020 guidelines. The databases searched were EMBASE, MEDLINE and SPORTDiscus. The initial search took place in July 2022, with an update search performed in September 2023, and again in August 2024. Studies which reported a lactate test and its correlation to 2000 m ergometer performance were included. No meta-analysis was performed.

Results: Twenty-four studies comprising 797 athletes (513 male, 257 female, 27 not stated) met the eligibility criteria for inclusion in the review. The most commonly used testing protocol involved the use of incremental step-tests. A range of exercise intensity parameters, lactate-based exercise thresholds and interpretation methodologies were employed. Of these, the power or velocity at a blood lactate concentration of 4 mmol l^-1 was the most common test, with correlation coefficients ranging from 0.53 to 0.96 suggesting that 28-92% of the variance in rowing performance can be explained by this metric. Six studies that rated as GOOD on the risk of bias assessment found very strong correlations > 0.85 (p < 0.05).

Conclusions: This systematic review found that there is good evidence that the power generated at a blood lactate concentration of 4 mmol l^-1 correlates strongly to 2000 m rowing ergometer performance and may have useful predictive power. However, the review also identified the varying quality of the available literature, with a variety of parameters, exercise protocols, testing methods, and performance metrics being used to report performance making it difficult to compare results between studies. Other tests such as $\dot{V}{O}_2$ at a blood lactate concentration of 4 mmol l^-1 and power at the initial non-linear inflection blood lactate threshold merit further investigation as the extent and reliability of the available data is currently insufficient to draw firm conclusions.

Protocol registration: The protocol was registered on Open Science Framework on 17/11/2022. https://doi.org/10.17605/OSF.IO/D8YCE.

Background: The Rating-of-Fatigue (ROF) scale is a validated tool to measure changes in perceived fatigue in sports and everyday contexts; thus, this study aimed to translate and validate the Portuguese version of the ROF scale. For this, the study was composed of three phases. Phase 1 involved a comprehensive translation of the ROF scale into Portuguese, followed by a back-translation and a consolidation process to obtain the final version of the ROF scale in Portuguese. In phase 2, the face validity of the scale was assessed. Seventy-three native Portuguese speakers responded to a series of Likert scale items designed to evaluate the purpose of the scale and assess whether it accurately measured the intended construct. In the final phase, the convergent and divergent validity of the scale was assessed during an incremental cycling test to exhaustion, followed by 10 min of passive recovery and a subsequent repetition of the initial 5 min of the test. The study was conducted between October 2023 and June 2024 in Portugal.

Results: The results from phase 1 indicated a high level of comparability and interpretability between the original and back-translated versions, with only minor adjustments made to finalize the Portuguese version of the ROF scale. In phase 2, a high level of face validity was observed. The median score for the item "measures fatigue" was (median [IQR]) was 3.0 [3.0, 4.0] out of 4. After participants were provided with the scale instructions, the face validity score improved significantly (4.0 [3.0, 4.0]; p = 0.001). In phase 3, during the incremental test, very large correlations were observed between ROF, and key physiological and performance indicators, including rating of perceived exertion (RPE), heart rate, oxygen consumption, and power output. Discriminant validity between ROF and RPE was found during the recovery.

Conclusions: The present study indicates that the Portuguese version of the ROF maintains the properties of the original version and can be used effectively in the Portuguese language.

Background: Recent data show a dramatic increase in non-communicable diseases in developing countries, including cardiovascular disease, obesity and diabetes. Most of these diseases may be preventable and to some extent treatable by alterations in physical activity. We investigated the correlations of physical activity levels, according to energy expenditure [measured in metabolic equivalent minutes per week (METs x min/week)] with fasting glycaemia levels, blood pressure, body compositions and anthropometric variables in participants from Bissau, Guinea-Bissau.

Method: The International Physical Activity Questionnaire was used to assess levels of physical activity, by calculating METs x min/week. These were subsequently divided into low, moderate or high physical activity categories in a healthy group of participants. Fasting glucose, arterial blood pressure, body mass index and body fat were also assessed. Data was analyzed using the SPSS statistical software.

Results: 429 participants were included from sports and health facilities around the country. Of these, 187 were highly active (> 3000 MET × min/ week or at least 1500 METs × min/week) and had a mean age of 26.8 ± 7.5 years. 76% (327/429) were male and 24% were female (102/429). The mean energy expenditure was 4866.7 ± 1241.2 METs × min/week and the mean fasting glucose was 94.0 ± 14.1 mg/dl. 4.1% (18/429) of the participants had diabetes and 12.8% (55/429) had hypertension. A significant negative correlation was found between blood glucose and total physical activity (r_s = - 0.117, p = 0.015). Sedentary participants had the highest proportion (5.1%) of diabetes and higher rates of hypertension (15.8%). These participants had the highest obesity (10.1%) and overweight prevalence (23.7%). In addition, they also presented the highest percentage (5.1%) of body fat, with 55% of them showing high or very high visceral fat% content. In the sedentary group, a significant positive correlation, was found, indicating a low moderate association, between systolic blood pressure and weekly sitting time, r_s(175) = 0.205, p = 0.006.

Conclusion: While high levels of physical activity had a significant impact on glycaemia control, physical activity had no significant impact on blood pressure. However, weekly sitting time may increase blood pressure.

Background: Prolonged sitting induces fatigue in deep trunk muscles, thereby decreasing spinal support and increasing stress on the spine. Core exercises effectively facilitate recovery from trunk muscle fatigue based on evidence from subjective outcomes; however, there is a lack of systematic investigation into localized muscle activity specifically related to prolonged sitting. Therefore, this scoping review summarizes the evidence on the effects of core exercises in alleviating trunk muscular fatigue induced by prolonged sitting, focusing on objective outcomes such as electromyography (EMG) and tensiomyography.

Methods: Articles published between January 2010 and February 2024 were sought in PubMed, Scopus, Web of Science, MEDLINE, and Cochrane Library, as well as Elsevier, SpringerLink, and Google Scholar. The findings were reported following the guidelines provided by the PRISMA-ScR checklist.

Results: Out of 106 papers initially identified, eight met the inclusion criteria. During core exercises, fatigued trunk muscles exhibit an increase in EMG root mean square (RMS) values. In the post-intervention (from 9 days to 8 weeks), tensiomyography outcomes of the erector spinae muscles significantly improved, whilst EMG results were insignificant. The contraction times of both the left and right erector spinae balanced out, indicating a harmonizing effect of the exercise. Regarding the recovery of other trunk muscles, only the transversus abdominis and internal oblique muscles exhibited a significant increase in the EMG median frequency that decreased over prolonged sitting.

Conclusions: Core exercises are effective in alleviating muscular fatigue caused by prolonged sitting. This can be observed from significant changes in EMG and tensiomyography parameters during exercise and after the training protocol. Intervention studies have primarily targeted the recovery of the erector spinae muscles, with less attention on other trunk muscles. Although significant improvements in tensiomyography results for the erector spinae can be observed after core exercise intervention, the impact on EMG remains uncertain.

Key points: 1. Core exercises have an acute effect on reducing muscle fatigue caused by prolonged sitting. 2. Core exercise intervention studies, primarily targeting the erector spinae muscles, significantly improve tensiomyography outcomes, but evidence for electromyography outcomes is lacking. In addition, few studies have analyzed the electromyography mean frequency and root mean square values, which are crucial in assessing muscle fatigue and recovery. 3. Only a few studies have investigated the effectiveness of core exercises in restoring other trunk muscles, such as the transversus abdominis and multifidus, following prolonged sitting fatigue.

Background: Injury and illness prevention practices in competitive snow sports must be better understood among stakeholders. In particular, there is a need for a greater understanding of what context-specific stakeholders require for prevention. Therefore, this study surveyed stakeholders' current practices, needs, responsibilities and knowledge dissemination preferences related to injury and illness prevention in competitive snow sports and described the main commonalities and differences between stakeholder groups.

Methods: We conducted a cross-sectional study that used an online survey developed using Kipling's principle (the "5W1H" method) and targeted athletes, coaches, team staff, ski racing suppliers, and representatives from all competition levels and all competitive snow sports governed by the International Ski and Snowboard Federation. The data were analysed following both quantitative and qualitative descriptive analyses.

Results: Most of the 436 respondents believed in and reported needing more information on injury and illness prevention. The participants stated that the main goal of prevention was to avoid injuries and minimise their time away from being on snow, and they stressed their different underlying motivations. Despite the differences across subgroups, participants highlighted knee and head injuries and concussions as their primary injury prevention targets and priorities for additional information. Respiratory and cardiovascular illnesses were reported as their main targets of illness prevention, but more information on all illnesses was reported. Current practices and priorities for additional information fell under athlete-, equipment-, snow/environment-, and course-related prevention areas. Moreover, stakeholders highlighted their need for more information on mental health and training. Shared responsibilities were identified across the development, dissemination, and implementation of prevention, along with stakeholders' preferred communication channels.

Conclusions: Our study provides meaningful insights across athlete, equipment-, snow/environment-, and course-related prevention areas related to snow sports, roles, and competition levels. These insights may inform the development, dissemination and further implementation of any tailored and context-driven preventive measure by better addressing end-users' needs. These findings may support successful future preventive interventions by providing key elements and a clear path to improve athletes' health and safety.

Background: To best simulate armed combat-related emergencies, military personnel undergo operational training that attempts to recreate multiple physical stressors. Understanding the specific aspects of physical performance degradation after operational training helps to better inform future training practices, as these declines translate to real-world operations. The purpose of this meta-analysis was to investigate the effects of operational trainings on physical performance metrics in military personnel.

Methods: Six electronic databases were searched for studies that investigated physical performance metrics in active-duty military personnel before and after multiple-day operational training. Sample sizes, means and standard deviations were extracted from included studies, and random-effects meta-analyses were conducted using standardized mean differences (Hedge's g) with 95% confidence intervals (p ≤ 0.05).

Results: Seventeen studies (N = 1592 participants) were included for final review and grouped by physical performance metric. Meta-analyses revealed a large pre-to-post decline in lower body jump power (n = 4, g = 0.87, 95% CI [0.28, 1.47]), and small declines in short-duration lower body power-jump distance (n = 5, g = 0.39, 95% CI [0.16, 0.63]), upper body endurance (n = 4, g = 0.40, 95% CI [0.09, 0.71]), and core endurance (n = 2, g = 0.46, 95% CI [0.10, 0.82]). Substantial heterogeneity was observed in the included studies (I² = 0-91%).

Conclusions: Military operational training temporarily diminishes lower body performance to a greater extent than other constructs. The most consistent findings showed reductions in power production (large magnitude) and muscular endurance (small magnitude), which appear to have implications for military training and risk reduction. In real-world operational applications, reduced power- and endurance-generating capabilities may be detrimental to meeting tactical requirements, making these metrics valuable for military leadership to focus on during personnel training.

Background: Enhancing youth's physical fitness levels during childhood and adolescence through prior training programs can significantly optimize their athletic performance. The integrative neuromuscular training (INT) model is designed to improve neuromuscular function and prevent athletic injuries, and is superior to the traditional physical training method. This systematic review and meta-analysis aims to compare the effects of INT versus traditional physical fitness training (PT) on physical performance-related outcomes in young athletes.

Methods: Six online databases (PubMed, MEDLINE, Embase, SPORTDiscus, Web of Science, PsycINFO) searched from inception through 15 January 2024. Meta-analysis was performed when data were available from two or more trials. Physical performance-related outcomes were analyzed using standardized mean differences (SMDs) and mean differences (MDs) with 95% confidence intervals (CIs). The certainty of evidence and quality of the included studies were rated using the GRADE scale and the revised Cochrane risk-of-bias tool respectively.

Results: Seventeen randomized controlled trials with 649 young athletes were included in the systematic review. Of those, 1 study showed a low risk of bias, 1 showed a high risk, and 15 showed some concerns. Compared to the PT group, INT significantly improved dynamic balance (MD = 7.29%, 95%CI 3.31 to 11.28, p < 0.001, I² = 64.7%), static balance (SMD = -0.54, 95%CI -0.84 to -0.24, p < 0.001, I² = 0.0%), jumping performance (SMD = 0.53, 95%CI 0.32 to 0.73, p < 0.001, I² = 0.0%), sprinting capacity (SMD = -0.76, 95%CI -1.13 to -0.39, p < 0.001, I² = 57.6%) and maximal strength (SMD = 1.01, 95%CI 0.35 to 1.67, p = 0.002, I² = 81.9%%). No significant between-group differences were identified for agility and flexibility.

Conclusion: Our findings suggest that INT has the potential to be an effective training method to improve physical performance in young athletes. Moreover, further research is needed to determine the effects and associated doses for young athletes of different age groups.

Background: Imbalances between muscle strength and tendon stiffness influence the mechanical demand on the tendon (i.e., tendon strain) and may increase tendon injury risk. The purpose of this study was to identify muscle-tendon imbalances and to promote a more balanced musculotendinous adaptation through a personalized assessment and exercise prescription concept in female adolescent handball athletes (13-16 years).

Methods: At four measurement time points during a competitive season, we used dynamometry and ultrasonography to assess knee extensor muscle strength, patellar tendon stiffness and strain. Tendon micromorphology was assessed with a peak spatial frequency (PSF) analysis of proximal tendon ultrasound images. Muscle-tendon imbalances were identified based on tendon strain during maximum voluntary contractions. A control group (n = 15) followed their usual training. In the intervention group, athletes with a deficit in tendon stiffness (strain ≥ 9%; n = 6) or no muscle-tendon imbalances (strain between 4.5% and 9%; n = 15) performed exercises (3x/week for 32 weeks) with a personalized load to reach ~ 6.2% tendon strain to predominantly promote tendon or both muscle and tendon adaptation. Individuals with a muscle strength deficit (strain ≤ 4.5%; n = 1) trained with submaximal loads to failure to promote muscle strength.

Results: In the intervention group we found lower fluctuations of maximum tendon strain (p = 0.005) and a decrease in tendon strain over time (p = 0.010), which was more pronounced in individuals with initially high tendon strain. While there were no systematic changes in muscle strength or tendon stiffness at the group level (p > 0.05), the marked decrease in tendon strain in individuals with a deficit in tendon stiffness was caused by a predominant increase in tendon stiffness. Overall, the prevalence of muscle-tendon imbalances was reduced in the intervention group, while it temporarily increased in the control group. PSF did not differ between groups at baseline but decreased significantly in the intervention group (p = 0.013).

Conclusions: The findings suggest that the personalized concept is suitable to promote a more uniform adaptation of knee extensor muscle strength and patellar tendon stiffness and to reduce the prevalence of musculotendinous imbalances in female adolescent athletes, which may have important implications for tendon injury prevention.

Trial registration: DRKS, DRKS00035110. Registered 20 September 2024-retrospectively registered, https://drks.de/search/de/trial/DRKS00035110 .