Sports Medicine - Open最新文献

There is a growing body of literature on sex-differences in human performance, particularly in the context of endurance sports. However, several mechanisms (e.g., higher type 1 fibres proportion; lesser neuromuscular fatigue; higher metabolic flexibility etc) have been previously proposed and suggest an advantage to females over ultra-endurance competitions on flat terrain. However, in mountain ultramarathon, the percent sex difference between male and female records appears to be larger than on various road/track running distances on flat terrain, suggesting that additional factors related to the specific mountainous conditions may be at play. In this Current Opinion, we point to three specific factors that are likely to influence and widen sex differences in ultra-distance running events performed in the mountains (i.e., uphill- downhill locomotion, altitude, and changes in extreme ambient temperatures).First, the sex differences in uphill endurance performance are approximately two times larger than those in events primarily performed on flat terrain (i.e., 18-22% vs. 9-12%, respectively), mainly due to the detrimental influence of the lower lean mass to fat mass ratio and lower fast twitch/type II fibre type proportion in females).At altitude, the ventilatory response to exercise emerges as one of the most sex-sensitive factors that may modify reactions to hypoxia. A diffusive mechanism appears to be involved in the larger hypoxemia commonly reported in females.Finally, responses to cold environments are also sex-dependent, with females exhibiting lower muscle mass, which limits thermogenic heat production, a higher body surface area-to-mass ratio, and a greater prevalence of Raynaud's phenomenon.Altogether, these specific factors must be further understood when analyzing sex-differences in mountain ultra-trail performance. Don't forget to look at the scenery!

Background: It is recommended to prescribe sets to volitional muscular failure (e.g., 4 sets) or a fixed repetition scheme of 75 repetitions (1 × 30, 3 × 15) in low-load resistance exercise with blood flow restriction (BFR-RE). While prior studies suggest both protocols may elicit similar muscular adaptations, the extent to which this is explained by matched exercise volume remains unclear.

Objectives: This systematic review and meta-analysis evaluated the number of repetitions performed during four sets of low-load BFR-RE to volitional muscular failure and compared these with the fixed 75-repetition scheme. The goal was to determine whether the two protocols yield similar total and per-set repetition volumes.

Methods: On 10/31/2024, two databases (PubMed^® and Scopus) were used to identify studies that applied a protocol of four sets to volitional muscular failure in BFR-RE with a load of ≤ 50% of one repetition maximum (1RM), regardless of the outcome investigated. Mean repetition data were pooled using a random-effects meta-analysis. One-sample t-tests compared per-set and total volumes to the reference scheme (1 × 30, 3 × 15).

Results: Across 25 studies (47 means; n = 678), the estimated total repetitions performed to failure was 73.1 (95% CI: 61.1 to 85.2). Per-set means were 36.0 (95% CI: 30.5 to 41.4), 14.7 (95% CI: 12.2 to 17.1), 11.5 (95% CI: 9.2 to 13.8), and 10.4 repetitions (95% CI: 8.1 to 12.7) for sets 1 through 4, respectively.

Conclusion: Four sets of BFR-RE to volitional muscular failure produce similar total repetition volume compared to the commonly implemented fixed 75-repetition scheme, though the distribution of repetitions per set differs. These findings provide insight into the mechanical equivalence of two widely used BFR-RE prescriptions.

Background: Resistance training (RT) coaches regularly instruct their trainees to terminate a set when the repetition velocity drops below a certain threshold, aligned with the principles of velocity loss in velocity-based training (VBT). However, absent of a velocity-tracking device, coaches are required to detect velocity loss through observation-a topic that has never been studied. Here, we assess the accuracy of RT coaches in detecting when trainees reach specific repetition velocity loss thresholds.

Methods: Twenty RT coaches participated in a single experimental session. They observed videos of two trainees completing sets of the barbell bench press and barbell back squat exercises, using three loads (45%, 65%, and 85% of 1 repetition-maximum [1RM]), and recorded from two views (front and side). We asked them to detect when repetition velocity dropped below two velocity loss thresholds (20% and 40% relative to their first repetition). We examined whether load, velocity loss threshold, view, mental fatigue, and gaze strategy (bar or no-bar tracking) influenced accuracy. We compared outcomes using a negative binomial generalized mixed-effects model.

Results: The average absolute error across all conditions was 2.6 repetitions. Coaches improved their accuracy (negative estimates indicate reduced error) when observing a higher velocity loss threshold (40% vs 20%; - 1.8, 95%CI [- 2.3, - 1.3]); observing heavier loads (- 0.8, 95% CI [- 1.5, - 0.1] for 65% 1RM, and - 3, 95%CI [- 3.4, - 2.6] for 85% 1RM compared to 45% 1RM); and employing a bar tracking gaze strategy compared to a no-bar strategy (- 1.7, 95%CI [- 2.7, - 0.4]). In contrast, point of view and mental fatigue had a negligible effect.

Conclusions: While coaches detect velocity loss with some degree of accuracy, their error rates vary depending on the threshold, load, and gaze strategy. These factors should be considered when using perceived velocity loss in practice.

Background: Physical inactivity and prolonged sedentary behavior represent significant public health concerns that can be addressed to achieve considerable health benefits. However, it is unknown whether starting to exercise in later life is an effective intervention for promoting health and longevity in older adults who have not exercised previously. The study aimed to explore whether starting to exercise in later life could offer survival benefits for older adults (≥ 65 years), particularly focusing on the impact of exercise duration on survival.

Methods: A total of 23,889 older participants (median age: 91.0 [IQR: 82.0-100.0], 8760 males) from the Chinese Longitudinal Healthy Longevity Survey were included. Participants comprised non-exercisers who never exercised and regular exercisers who started to exercise regularly after age 65 for at least one year. The exposure was exercise duration, which was self-reported and categorized into four groups: non-exercise (0 years), 1 to < 10 years, 10 to < 20 years, and ≥ 20 years. The study outcome was overall survival. Accelerated failure time models were used to investigate the association between exercise duration and outcomes.

Results: During a follow-up period totaling 101118.9 person-years, there were 18,751 recorded deaths (78.5%). Overall, regular exercisers had longer survival time than non-exercisers, with an adjusted time ratio (TR) of 1.07 (95% CI: 1.03-1.11, p < 0.001). When compared to non-exercisers, the adjusted TRs for participants with varying exercise durations were as follows: 1.06 (95% CI: 0.99-1.14, p = 0.086) for those exercising between 1 and < 10 years, 1.03 (95% CI: 0.97-1.08, p = 0.382) for those between 10 and < 20 years, and significantly higher at 1.12 (95% CI: 1.05-1.18, p < 0.001) for those with ≥ 20 years of exercise duration. In addition, smooth curve fitting analysis also revealed the survival benefits of exercise were only significant for those with an exercise duration of ≥ 20 years, with an adjusted TR of 1.024 (95% CI: 1.013-1.036, p < 0.001) for each 5-year increase in duration.

Conclusions: Starting to exercise in later life can provide survival benefits for older adults, but only if they maintain exercise for over 20 years. This long latency period may suggest suboptimal exercise efficiency among older adults in real-world contexts; therefore, it is essential not only to emphasize the importance of long-term exercise but also to promote structured exercise within this population.

Background: Mental fatigue (MF) in sports has developed from well-controlled laboratory-based studies to applied studies with greater ecological validity. Ongoing developments in the representativeness of MF inducement approaches, including the broad range of sport-specific motor tasks to simulated real-life scenarios, have shown methodological variability and inconsistent outcomes of effectiveness. Evaluating and comparing these approaches is essential to provide recommendations for designing inducement tasks in future research and considerations for practitioners. Therefore, the systematic review aimed to summarize more ecologically valid MF-inducing tasks in representative sports contexts and to evaluate the MF inducement effectiveness via manipulation check outcomes and potential after effects on subsequent sport-specific performance.

Methods: The review was registered on the PROSPERO database (CRD42024577183). PubMed, Web of Science, PsycINFO, and SPORTDiscus were searched until 21 August 2024 for studies that applied acute, more ecologically valid MF-inducing tasks within sports-specific contexts. The MF inducement task design and effectiveness across representative sports and participants were investigated.

Results: Twelve papers were included. Only a quarter of studies presented an overall low risk of bias. The 20-minute sports-specific motor tasks with cognitive demands and most 30-minute simulated real-life scenarios (i.e., social media use on smartphones, watching tactical videos, sports-themed videogame play) successfully induced MF in differing athlete samples. Ineffective MF inducement was attributed to shorter task duration, passive engagement with sparse cognitive demands, or the involvement of less susceptible participants.

Conclusions: This systematic review evaluated MF inducement methodologies with greater ecological validity to sporting contexts. The inducement effectiveness varied within four task types. Athletes and sports practitioners should carefully manage the modality and content of pre-competition activities to minimize MF. Future research should refine and co-design the MF-inducing task with practitioners based on multifaceted MF evidence from laboratory and real-life settings, create immersive scenarios that can better replicate the inducement process in specific contexts, and improve measurement tools, which will provide comprehensive evaluation and verification of the MF inducement.

Background: The aim of this study was to explore how a metabolomic approach could provide valuable information on changes in the athletes' metabolome during a mountain ultramarathon race. To achieve this goal, we established a longitudinal cohort of athletes enrolled in the TOR des Géants, a 330 km mountain ultramarathon with 24,000 m of elevation gain. Sixteen healthy male athletes (43.9 ± 10.1 years) were recruited, and blood samples were collected at four time points: pre-race, mid-race, post-race and after 72 h recovery. Using a 1H-NMR-based metabolomic approach, we evaluated metabolic changes that occur during both race effort and recovery, and correlated them with functional muscle, cardiac, inflammatory, and renal biomarkers already used in the clinic. The processed data were analyzed using multivariate analysis tools specific to longitudinal study design, and innovative pathway analysis was used for data interpretation.

Results: Mountain ultramarathon running significantly affected the metabolism and physiology of athletes. Multivariate analysis highlighted specific metabolites and functional biomarkers associated with prolonged exercise. Neither metabolite levels nor biomarker concentrations returned to baseline after 3 days of recovery. Finally, innovative pathway analysis shed light on specific metabolic changes resulting from mountain ultramarathon exercise.

Conclusion: In this study, we propose an NMR-based metabolomics strategy to assess exercise-associated metabolic changes during and after events such as the Tor des Géants. Using state-of-the-art data representation methods specific to metabolomics analysis, we demonstrated that such a methodology can provide a unique view of the biology associated with such extreme conditions. As this approach provides unique insights into the biology of extreme exercise, it holds promise for the development of new tools for athlete management.

Background: Physical fitness is a key component in the development of an active lifestyle and a determinant of future health, particularly in childhood. The findings of physical fitness assessments enable evidence-based monitoring and the identification of long-term trends. The COVID-19 pandemic is an additional factor that can be considered in the analysis, as its influence is already known. The aim of our analysis was to comprehensively investigate secular trends with respect to the physical fitness of children before and during the pandemic. This study also serves to test whether Citizen Science projects can deliver results comparable to those obtained using traditional assessment formats while also documenting certain limitations of this approach.

Methods: Data on annual assessments conducted in the German federal state of Baden-Wuerttemberg were pooled from 12 cohorts starting in 2012. The analyses are based on 25,580 6-10 year-old children (M = 7.56, SD = 1.21 years; 12,575 girls) in our analysis. We estimated the effects of the COVID-19 pandemic using a regression discontinuity design within a linear mixed model. This enabled us to estimate pre-pandemic and pandemic trends, and to adjust for age, sex, and body constitution fixed-effect covariates and child and region as random factors.

Results: For the pre-pandemic cohorts, we found significant trends only slightly negative or positive trends in six of eight items. This suggests that the declining trend in physical fitness in children has been slowing down. The COVID-19 pandemic affected physical fitness negatively for six items (i.e., shift at critical date: 6 min Run, Jumping Sideways, Sit-Ups, Push-Ups; negative change from pre-pandemic to pandemic trends: 20 m Sprint, Standing Long Jump). There was no evidence for pandemic changes in balancing backwards and stand-and-reach items. Effects of age, sex, and body constitution replicated previous results.

Conclusions: Continuous monitoring of children's physical fitness is essential, especially in the context of the COVID-19 pandemic. Such monitoring identifies positive and negative trends and provides evidence for the need of strategies and actions. It is particularly important to initiate systematic initiatives during childhood to promote physical fitness and reduce deficits, as this is the time when the foundations for an active and healthy lifestyle are laid.

Background: This is a post-hoc secondary analysis of a randomized controlled trial whose purpose was to analyze the effect of a supervised-combined aerobic and resistance exercise (concurrent exercise) training program during pregnancy on 1-month infant neuromotor skills based on maternal pre-pregnancy body mass index (BMI).

Methods: Ninety-four pregnant women participated in this study, which was conducted at East Carolina University (Greenville, North Carolina, USA) between 2015 and 2018, and were allocated into concurrent exercise (n = 42) or stretching and breathing group (n = 52). The exercise group followed a 50-min 3 days/week moderate intensity concurrent exercise training program from the 16th gestational week until birth. Infant neuromotor skills were assessed with the Peabody Developmental Motor Scales, 2nd edition (PDMS-2).

Results: Per protocol analyses showed that infants from the exercise group and whose mothers were normal-weight, had higher PDMS-2 Stationary, Locomotion (borderline) and Gross Motor Quotient (GMQ) percentiles than infants of stretching and breathing participants (p = 0.022, ηp2 = 0.20; p = 0.054, ηp2 = 0.15; p = 0.022, ηp2 = 0.20, respectively). No differences between groups were found in infants whose mothers were normal-weight in reflexes percentiles in the adjusted model, or those infants whose mothers were overweight/obese in any of the outcomes (all p ≥ 0.05).

Conclusions: Concurrent exercise training during pregnancy improves neuromotor skills in infants at 1 month of age in normal-weight women. Further studies are needed to understand the influence of concurrent exercise training during pregnancy on infants whose mothers are overweight or obese, and the potential mechanism behind the role of maternal BMI in the development of infant neuromotor skills.

Clinical trial registration: ClinicalTrials.gov Identifier: NCT03838146.

Background: Head impacts, particularly, non-concussive impacts, are common in sport. Yet, their effects on the brain remain poorly understood. Here, we investigated the acute effects of non-concussive impacts on brain microstructure, chemistry, and function using magnetic resonance imaging (MRI) and other techniques.

Results: Fifteen healthy male soccer players participated in a randomised, controlled, crossover pilot trial. The intervention was a non-concussive soccer heading task ('Heading') and the control was an equivalent 'Kicking' task. Participants underwent MRI scans ~ 45 min post-task which took ~60 min to complete. Blood was also sampled, and cognitive function assessed, pre-, post-, 2.5 h post-, and 24 h post-task. Brain chemistry: Heading increased total N-acetylaspartate (p = 0.012; g = 0.66) and total creatine (p = 0.010; g = 0.77) levels in the primary motor cortex (but not the dorsolateral prefrontal cortex) as assessed via proton magnetic resonance spectroscopy. Glutamate-glutamine, myoinositol, and total choline levels were not significantly altered in either region. Brain structure: Heading had no significant effects on diffusion weighted imaging metrics. However, two blood biomarkers expressed in brain microstructures, glial fibrillary acidic protein and neurofilament light, were elevated 24 h (p = 0.014; g = 0.64) and ~ 7-days (p = 0.046; g = 1.19) post-Heading (vs. Kicking), respectively. Brain Function: Heading decreased tissue conductivity in 11 clusters located in the white matter of the frontal, occipital, temporal and parietal lobes, and cerebellum (p's < 0.001) as assessed via electrical properties tomography. However, no significant differences were identified in: (1) connectivity within major brain networks as assessed via resting-state functional MRI; (2) cerebral blood flow as assessed via pseudo continuous arterial spin labelling; (3) activity within electroencephalography frequencies (infra-slow [0.03-0.06 Hz], theta [4-8 Hz], alpha [9-12 Hz], or beta [13-25 Hz]); or (4) cognitive (memory) function.

Conclusions: This study identified chemical, microstructural and functional brain alterations in response to an acute non-concussive soccer heading task. These alterations appear to be subtle, with some only detected in specific regions, and no corresponding cognitive deficits observed. Nevertheless, our findings suggest that individuals should exercise caution when performing repeated non-concussive head impacts in sport. Trial registration ACTRN12621001355864. Date of registration: 7/10/2021. URL: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=382590&isReview=true .