Can molecular hydrogen supplementation enhance physical performance in healthy adults? A systematic review and meta-analysis.

Background: Physical exertion during exercise often leads to increased oxidative stress and inflammatory responses, significantly affecting physical performance. Current strategies to mitigate these effects are limited by their effectiveness and potential side effects. Molecular hydrogen (H2) has gained attention for its antioxidant and anti-inflammatory properties. Studies have suggested that H2 supplementation contributes to antioxidant potential and anti-fatigue during exercise, but the variance in the observations and study protocols is presented across those studies. Objective: This systematic review and meta-analysis aimed to comprehensively characterize the effects of H2 supplementation on physical performance (i.e., endurance, muscular strength, and explosive power), providing knowledge that can inform strategies using H2 for enhancing physical performance. Methods: We conducted a literature search of six databases (PubMed, Web of Science, Medline, Sport-Discus, Embase, and PsycINFO) according to the PRISMA guidelines. The data were extracted from the included studies and converted into the standardized mean difference (SMD). After that, we performed random-effects meta-analyses and used the I 2 statistic to evaluate heterogeneity. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) was used to assess the quality of the evidence obtained from this meta-analysis. Results: In total, 27 publications consisting of 597 participants were included. The search finally included aerobic endurance, anaerobic endurance, muscular strength, lower limb explosive power, rating of perceived exertion (RPE), blood lactate (BLA), and average heart rate (HRavg) in the effect size (ES) synthesis. The ES of H2 on aerobic endurance, including V̇O2max (SMD = 0.09, p = 0.394; I 2 = 0%) and aerobic endurance exercise (SMD = 0.04, p = 0.687; I 2 = 0%), were not significant and trivial; the ES of H2 on 30 s maximal anaerobic endurance (SMD = 0.19, p = 0.239; I 2 = 0%) was not significant and trivial; the ES of H2 on muscular strength (SMD = 0.19, p = 0.265; I 2 = 0%) was not significant and trivial; but the ES of H2 on lower limb explosive power (SMD = 0.30, p = 0.018; I 2 = 0%) was significant and small. In addition, H2 reduces RPE (SMD = -0.37, p = 0.009; I 2 = 58.0%) and BLA (SMD = -0.37, p = 0.001; I 2 = 22.0%) during exercise, but not HRavg (SMD = -0.27, p = 0.094; I 2 = 0%). Conclusion: These findings suggest that H2 supplementation is favorable in healthy adults to improve lower limb explosive power, alleviate fatigue, and boost BLA clearance, but may not be effectively improving aerobic and anaerobic endurance and muscular strength. Future studies with more rigorous designs are thus needed to examine and confirm the effects of H2 on these important functionalities in humans. Systematic review registration: http://www.crd.york.ac.uk/PROSPERO.

Polyphenol supplementation boosts aerobic endurance in athletes: systematic review.

In recent years, an increasing trend has been observed in the consumption of specific polyphenols, such as flavonoids and phenolic acids, derived from green tea, berries, and other similar sources. These compounds are believed to alleviate oxidative stress and inflammation resulting from exercise, potentially enhancing athletic performance. This systematic review critically examines the role of polyphenol supplementation in improving aerobic endurance among athletes and individuals with regular exercise habits. The review involved a thorough search of major literature databases, including PubMed, Web of Science, SCOPUS, SPORTDiscus, and Embase, covering re-search up to the year 2023. Out of 491 initially identified articles, 11 met the strict inclusion criteria for this review. These studies specifically focused on the incorporation of polyphenols or polyphenol-containing complexes in their experimental design, assessing their impact on aerobic endurance. The methodology adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, and the risk of bias was evaluated using the Cochrane bias risk assessment tool. While this review suggests that polyphenol supplementation might enhance certain aspects of aerobic endurance and promote fat oxidation, it is important to interpret these findings with caution, considering the limited number of studies available. Systematic Review Registration: https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42023453321.

Stroke-Specific Swimming Critical Speed Testing: Balancing Feasibility and Scientific Rigour.

This study aimed to assess the reliability of a two-distance critical speed protocol in the specialist strokes of national-level swimmers and understand the practical feasibility of extending the protocol to increase its validity. Thirty-two national-level swimmers (butterfly n = 7; backstroke n = 8; breaststroke n = 7; front crawl n = 10) swum three 200-m and three 400-m performance trials over a three-week period. Critical speed and supra-critical speed distance capacity were computed from the linear modelling of the distance-time relationship. Swimmers were subsequently asked whether they felt they could or would want to complete an 800-m trial as part of a three-distance critical speed protocol to enhance validity. Both 200-m and 400-m performances (coefficient of variation of < 2%) and derived critical speed (typical error of ≤ 0.04 m·s-1; coefficient of variation of < 4%) were reliable for all strokes, while supra-critical speed distance capacity (typical error from 4 to 9 m; coefficient of variation from 13 to 45%) was not reliable. Response rates to the follow-up questions were 100%. Few butterfly swimmers said they felt they could complete an 800-m performance trial (39%), with more positive responses for breaststroke (71%), backstroke (100%), and front crawl swimmers (100%). Butterfly swimmers were significantly less likely to say they could or would want to complete an 800-m trial than backstroke and front crawl swimmers (p < 0.05). Including a third distance 800-m trial to increase critical speed validity would not be acceptable to butterfly swimmers, would be challenging to breaststroke swimmers, but would be acceptable to front crawl and backstroke swimmers.

Medical Rehabilitation of Patients with Post-COVID-19 Syndrome-A Comparison of Aerobic Interval and Continuous Training.

INTRODUCTION: Post-COVID-19 syndrome (PCS) is a multisystemic disorder marked by impaired physical performance as one lead symptom. Since it has been suggested that endurance training as part of medical rehabilitation may be effective in improving physical performance capacity in PCS, this study aimed to compare different modes of aerobic endurance training. METHODS: A total of 110 PCS patients (49.3 ± 11.8 years; 38% women; time after infection = 260.2 ± 127.5 days) underwent detailed clinical screening including symptom-limited cardiopulmonary exercise testing at admission and after 4-6 weeks of inpatient medical rehabilitation. Questionnaires were used to assess disease perception. Patients performed controlled isocaloric cycle ergometer training (3-5 sessions/week; 18 min) as either continuous training (CT) at 50% of maximal workload or as interval training (IT; load = 60%, relief = 30%). Outcomes of PCS patients were compared to coronary artery disease patients (CAD; n = 96) to evaluate overall training effectiveness. RESULTS: Training participation was comparable between the groups, with no indication of training-specific exercise-induced fatigue. Overall, PCS patients improved significantly by a mean of 6.8 ± 12.1% for W at VT1; 3.1 ± 10.0% for VO2 at VT1; 5.5 ± 14.7% for O2 pulse at VT1; 7.5 ± 15.0% for W at VO2peak; 2.7 ± 11.0% for VO2peak and 4.6 ± 12.4% for O2 pulse at VO2peak (all p < 0.05) with no significant differences between groups (p > 0.05). Both groups showed reduced levels of fatigue, anxiety, and depression as well as improved quality of life and wellbeing (all p < 0.05). Compared to guideline-based cardiac rehabilitation, PCS patients showed a similar improvement in workload and oxygen uptake compared to CAD patients. CONCLUSION: PCS patients benefit from aerobic endurance training performed as moderate continuous or interval training as part of a medical rehabilitation program in terms of improved physical exercise capacity and disease perception. The results for PCS patients are comparable to the guideline-based rehabilitation of CAD patients.

Short-Term Speed Variability as an Index of Pacing Stochasticity in Athletic Running Events.

We aimed to compare differences in performance and pacing variability indices between 5000 m heats and finals during major championships in men and women. Data with 100 m time resolution were used to compare overall pacing variability (standard deviation of 100 m section times, SD; and coefficient of variation, CV%) and short-term pacing variability (root mean square of successive differences between 100 m section times, RMSSD). The changes in performance and pacing indices differed between races and competitions. For instance, the men's final in Beijing 2008 was quicker than the heat (p < 0.01) while the CV% was reduced (p = 0.03) and RMSSD increased (p < 0.01). For women, the heats and the final exhibited a similar mean time in London 2017 (p = 0.33) but with CV% (p < 0.001) and RMSSD (p < 0.001) showing opposite trends. Individual analyses of men's and women's champions revealed highly individual variability metrics. The use of RMSSD can complement overall variability indices for better characterization of pacing stochasticity.

Impact of (long) COVID on athletes' performance: a prospective study in elite football players.

OBJECTIVES: To investigate possible persistent performance deficits after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in elite athletes. METHODS: A prospective cohort study in three Belgian professional male football teams was performed during the 2020 - 2021 season. Participants were submitted to strength, jump, and sprint tests and an aerobic performance test (the Yo-Yo Intermittent Recovery test (YYIR)). These tests were repeated at fixed time intervals throughout the season. Assessment of SARS-CoV-2 infection was performed by a polymerase chain reaction (PCR) test before each official game. RESULTS: Of the 84 included participants, 22 were infected with SARS-CoV-2 during follow-up. At the first testing after infection (52.0 ± 11.2 days after positive PCR testing) significantly higher percentages of maximal heart rate (%HRmax) were seen - within the isolated group of infected players- during (p = .006) and after the YYIR (2 min after, p = .013), compared to pre-infection data. This increase in %HRmax was resolved at the second YYIR testing after infection (127.6 ± 33.1 days after positive PCR testing). Additionally, when comparing the first test after infection in formerly infected to non-infected athletes, significantly higher %HRmax were found during (p < .001) and after the YYIR test (p < .001),No significant deficits were found for the jump, muscular strength or sprint tests.Aerobic performance seems compromised even weeks after infection. Simultaneously, anaerobic performance seemed to be spared. Because of the potential detrimental effects on the immune system, caution might be advised with high-intensity exposure until aerobic performance is restored.KEY MESSAGESElite football players' aerobic performance seems to be affected for weeks after they return to sports after a SARS-CoV-2 infection.Similarly, anaerobic performance tests showed no discernible changes between both before and after SARS-CoV-2 infections.Regular YYIR testing is recommended to monitor aerobic performance after SARS-CoV-2 infection.

The Influence of Different SARS-CoV-2 Strains on Changes in Maximal Oxygen Consumption, Ventilatory Efficiency and Oxygen Pulse of Elite Athletes.

PURPOSE: The aim of this study was to evaluate the influence of different SARS-CoV-2 strains on the functional capacity of athletes. METHODS: In total, 220 athletes underwent cardiopulmonary exercise testing (CPET) after coronavirus infection and before returning to sports activities. Eighty-eight athletes were infected by the Wuhan virus, and 66 were infected during the Delta and Omicron strain periods of the pandemic. RESULTS: The CPET results showed significantly decreased maximal oxygen consumption, ventilatory efficiency, and oxygen pulse in athletes who were infected with Wuhan and Delta strains compared to athletes who suffered from Omicron virus infection. An early transition from aerobic to anaerobic metabolic pathways for energy production was observed in the Wuhan and Delta groups but not in athletes who were infected with the Omicron strain. There were no differences in the obtained results when Wuhan and Delta virus variants were compared. CONCLUSION: These results suggest that the Wuhan and Delta virus strains had a significantly greater negative impact on the functional abilities of athletes compared to the Omicron virus variant, especially in terms of aerobic capacity and cardiorespiratory function.

Validity of a new sport-specific endurance test in artistic gymnastics.

Introduction: General and particularly sport-specific testing is an integral aspect of performance optimization in artistic gymnastics. In artistic gymnastics, however, only non-specific field tests have been used to assess endurance performance (e.g., Multistage Shuttle Run Test; Cooper's Test). Methods: This study aimed to examine the validity of a new sport-specific endurance test in artistic gymnastics. Fourteen elite-level gymnasts (i.e., eight males and six females) participated in this study. The newly developed artistic gymnastics-specific endurance test (AGSET) was conducted on two different occasions seven days apart to determine its reliability. To assess the concurrent validity of AGSET, participants performed the multistage shuttle run test (MSRT). Maximum oxygen uptake (VO2max) and respiratory exchange ratio (RER) were directly assessed using a portable gas analyzer system during both protocols. Additionally, the total time maintained (TTM) during the AGSET, maximum heart rate (HRmax), maximal aerobic speed (MAS), and blood lactate concentration (BLa) during the two protocols were collected. Results: The main findings indicated that all variables derived from the AGSET (i.e., VO2max, MAS, HRmax, BLa, and RER) displayed very good relative (all intraclass correlation coefficients [ICC] > 0.90) and absolute (all typical errors of measurement [TEM] < 5%) reliability. Further, results showed that the ability of the AGSET to detect small changes in VO2max, MAS, BLa, and RER was good (smallest worthwhile change [SWC0.2] > TEM), except HRmax (SWC0.2 < TEM). Additionally, results showed a nearly perfect association between the VO2max values derived from the AGSET and MSRT (r = 0.985; coefficient of determination [R²] = 97%) with no statistically significant differences (p>0.05). The mean (bias) ± 95% limits of agreement between the two protocols were 0.28 ± 0.55 mlminkg-1. Discussion: AGSET seems to present very good reliability and concurrent validity for assessing endurance performance in elite artistic gymnastics. In addition, the newly developed protocol presents a good ability to detect small changes in performance.

Economic burden of low cardiorespiratory fitness in Canada.

The objective of this study was to estimate health care and health-related productivity costs associated with low cardiorespiratory fitness (CRF) in Canadian adults. We also estimated costs that would be avoided by a 10 percentage point prevalence reduction in low CRF. A prevalence-based approach was used to estimate the economic costs associated with low CRF. Three pieces of information were used: (1) the pooled relative risk estimates of adverse health outcomes consistently associated with low CRF obtained from meta-analyses of prospective cohort studies; (2) the prevalence of low CRF in Canadian men and women obtained from a nationally representative sample; and (3) the direct (health care) and indirect (lost productivity due to premature mortality) costs of the adverse health outcomes based on the Economic Burden of Illness in Canada data. We estimated the total annual economic burden of low CRF in Canadian adults at CAD$3.6 billion, representing 2.7% of the overall Canadian burden of illness costs in 2021. The three most expensive chronic diseases attributable to low CRF were type 2 diabetes (CAD$1.3 billion), heart disease (CAD$701 million), and depression/anxiety (CAD$565 million). Prescription drug expenditures and hospital care expenditures were the main contributors to the total economic burden. An absolute 10% reduction in the prevalence of low CRF (from 45.5% to 35.5%) would save an estimated CAD$644 million per year in costs. In conclusion, low CRF is an important contributor to the economic burden of illness in Canada. Evidence-based and cost-effective strategies that aim to increase CRF at the population level may help alleviate health care costs and improve health.

[Cardiopulmonary exercise testing for exercise prescription in cardiac rehabilitation]. / Spiroergometrie zur Trainingssteuerung in der kardiologischen Rehabilitation.

Aerobic endurance training is a core component of exercise training (ET) during cardiac rehabilitation (CR). Improvements of cardiopulmonary performance and symptom-free exercise capacity that can be achieved by ET during CR are essential for patient's prognosis and quality of life. Before initiating exercise training in CR, a detailed risk stratification including incremental exercise testing is required in order to ensure safe and effective exercise training conditions. Cardiopulmonary exercise testing (CPX) with measurement of respiratory gases is considered the gold standard of cardiopulmonary performance diagnostics. The oxygen uptake measured at the highest exercise intensity achieved (peakVO2) has strong prognostic implications in primary and secondary prevention of cardiovascular diseases, respectively. The use of CPX with measurement of peakVO2 and determination of ventilatory thresholds (VT) enables a reliable determination of the individual cardiopulmonary performance (peakVO2) and also the aerobic exercise capacity. In addition, CPX is a valuable tool to detect increments in exercise capacity that were achieved by ET during CR. The measurement of peakVO2 and the determination of ventilatory thresholds are basic parameters for an individually tailored exercise prescription. In addition, the targeted control of aerobic endurance training on the basis of CPX parameters increases the effectiveness and safety of the exercise program during CR. In this article, recommendations for an individual exercise prescription, based on the results of CPX, are given for patients with coronary heart disease (CHD), heart failure, as well as for patients with CHD and concomitant type 2 diabetes mellitus.

A VO2max Protocol for Young, Apparently Healthy Adults.

The Bruce and Astrand treadmill protocols are commonly utilized when assessing maximal oxygen consumption (VO2max). However, the steep grade implemented in the protocols often leads to localized muscular fatigue, potentially causing participants prematurely to terminate the test prior to reaching their true VO2max. The purpose of this study was to evaluate a Novel VO2max protocol that may be better suited for young, apparently healthy populations. The Novel protocol starts at a higher speed and lower initial grade to limit lower extremity fatigue. Fifteen participants performed the Bruce, Astrand, and Novel protocols with the following maximal values recorded from each: VO2max, maximal ventilation (VEmax), respiratory exchange ratio (RER), heart rate (HR), rating of perceived exertion (RPE) and time to exhaustion (TTE). The Novel protocol displayed substantial agreement with both criterion protocols. Mean absolute percent error (MAPE) was less than 10% indicating that the Novel protocol is a valid measurement for VO2max values. Bland-Altman analysis revealed that the Novel protocol exhibited a low degree of bias, with tight limits of agreement when compared to the Bruce (bias ±95% LOA = 0.824 ± 3.163) and Astrand protocols (-0.153 ± 3.528) for VO2max. A paired samples t-test revealed no significant differences between Novel and criterion protocols for VO2max. Paired samples t-tests revealed that the Novel protocol had significantly lower TTE when compared to the Bruce and Astrand protocols and produced similar VO2max values to that of the Bruce and Astrand. The Novel protocol may be considered a valid and time-efficient protocol.

An Innovative Approach to Health Promotion and Wellness for University Students with Intellectual and Physical Disabilities: A Case Series.

A university setting offers a unique opportunity to address physical activity for individuals with disabilities. The purpose of this case series was to highlight the development of a formal student-assisted exercise program and examine its impact on the perceived quality of life, exercise confidence, and functional mobility of college-aged individuals with intellectual and physical disabilities. Data from twelve participants was analyzed. Seven participants demonstrated an improvement in scores on the Self-Efficacy to Exercise scale and eight improved in functional measures associated with strength. Thus, a collaborative assisted exercise program in a university setting may positively impact health and physical activity, and exercise participation in young adults with physical and/or intellectual disabilities.

Reliability and validity of field-based tests for assessing physical fitness in gymnasts

Objective: This systematic review aimed at analysing the reliability and validity of field-based tests for assessing physical fitness in gymnasts.MethodThree electronic databases (PubMed, SPORTDiscus, and Scopus) were searched up to March 2022, in order to identify studies that assessed the psychometric properties of field-based physical fitness test among gymnastics.ResultsA total of 16 studies on several gymnastics modalities (artistics n = 11; rhythmic n = 3, artistics and rhythmic n = 1; aerobic n =  1), were analyzed. All studies reported on reliability measured through test-retest design. Validity was reported in only four studies. Regarding specific tests, the split test (ICC = 0.998), and the handstand (ICC= 1) showed the highest test-retest reliability. The greater validity values were achieved by the split test (r2 = 0.52), hanging pikes test (r2 = 0.86), and handstand test (r2 = 0.65).ConclusionA great variety of both specific and non-specific physical fitness tests have been analyzed in the field of gymnastics. The side split test, the handstand test, the vertical jump test, the 20-m run test, the agility test, and the aerobic gymnast anaerobic test could be useful tools to assess flexibility, strength, balance, muscular power, speed, agility, and cardiorespiratory fitness in gymnasts. Further investigations analyzing absolute reliability and criterion validity are needed. (AU)

Effects of hot and humid environments on thermoregulation and aerobic endurance capacity of Laser sailors.

Objectives: The purpose was to investigate the effects of hot and humid environments on thermoregulation and aerobic endurance capacity and whether high skin temperature serves as a more important thermoregulatory factor affecting aerobic exercise capacity. Methods: A randomized cross-over design was applied to this study, in which nine Laser sailors performed the 6 km rowing test (6 km test) in both a warm (ambient temperature: 23 ± 1.4 °C; relative humidity: 60.5 ± 0.7%; wind speed: 0 km/h; WARM) and hot environment (ambient temperature: 31.8 ± 1.1 °C; relative humidity: 63.5 ± 4.9%; wind speed: 3.5 ± 0.7 km/h; HOT). Results: The time for completing 6 km test of HOT group was significantly longer than that of WARM group (P = 0.0014). Mean power of 3-4 km, 4-5 km and 5-6 km were significant lower in HOT group (P = 0.014, P = 0.02, P = 0.003). Gastrointestinal temperature and skin temperature were significantly higher in HOT group during the 6 km test (P = 0.016, P = 0.04). Heat storage at 5 min and 15 min of HOT group were significantly higher than that of WARM group (P = 0.0036; P = 0.0018). Heart rate and physiological strain index of HOT group were significantly higher than that of WARM group during the 6 km test (P = 0.01, P < 0.01). Conclusion: When skin temperature and core temperature both increased, high skin temperature may be the more important thermoregulatory factor that affected the aerobic endurance performance in hot and humid environments. The high skin temperature narrowed the core to skin temperature gradient and skin to ambient temperature gradient, which may result in greater accumulation of heat storage. The greater heat storage led to the lower muscle power output, which contributed to the reduction of the heat production.

Is the maximal lactate steady state concept really relevant to predict endurance performance?

PURPOSE: There is no convincing evidence for the idea that a high power output at the maximal lactate steady state (PO_MLSS) and a high fraction of [Formula: see text]O2max at MLSS (%[Formula: see text]O2_MLSS) are decisive for endurance performance. We tested the hypotheses that (1) %[Formula: see text]O2_MLSS is positively correlated with the ability to sustain a high fraction of [Formula: see text]O2max for a given competition duration (%[Formula: see text]O2_TT); (2) %[Formula: see text]O2_MLSS improves the prediction of the average power output of a time trial (PO_TT) in addition to [Formula: see text]O2max and gross efficiency (GE); (3) PO_MLSS improves the prediction of PO_TT in addition to [Formula: see text]O2max and GE. METHODS: Twenty-one recreationally active participants performed stepwise incremental tests on the first and final testing day to measure GE and check for potential test-related training effects in terms of changes in the minimal lactate equivalent power output (∆PO_LEmin), 30-min constant load tests to determine MLSS, a ramp test and verification bout for [Formula: see text]O2max, and 20-min time trials for %[Formula: see text]O2_TT and PO_TT. Hypothesis 1 was tested via bivariate and partial correlations between %[Formula: see text]O2_MLSS and %[Formula: see text]O2_TT. Multiple regression models with [Formula: see text]O2max, GE, ∆PO_LEmin, and %[Formula: see text]O2_MLSS (Hypothesis 2) or PO_MLSS instead of %[Formula: see text]O2_MLSS (Hypothesis 3), respectively, as predictors, and PO_TT as the dependent variable were used to test the hypotheses. RESULTS: %[Formula: see text]O2_MLSS was not correlated with %[Formula: see text]O2_TT (r = 0.17, p = 0.583). Neither %[Formula: see text]O2_MLSS (p = 0.424) nor PO_MLSS (p = 0.208) did improve the prediction of PO_TT in addition to [Formula: see text]O2max and GE. CONCLUSION: These results challenge the assumption that PO_MLSS or %[Formula: see text]O2_MLSS are independent predictors of supra-MLSS PO_TT and %[Formula: see text]O2_TT.

Validación por especialistas a grupo de ejercicios de resistencia aeróbica para futbolistas Categoría Sub-14

La resistencia aeróbica en el fútbol se considera una capacidad determinante, para lo cual su potenciación es parte indispensable del contenido de la preparación deportiva, siendo útil diseñar modelos especializados para su mejora, los cuales deben someterse en primera instancia a su validación teórica. En tal sentido, se plantea como objetivo de la investigación validar teóricamente a través de expertos nacionales y extranjeros una propuesta sobre un grupo de ejercicios para desarrollar la resistencia aeróbica en futbolistas de la categoría Sub-14. La Investigación es descriptiva-explicativa de orden correlacional, se valida una propuesta de intervención con un grupo de ejercicios de resistencia aeróbica para futbolistas Sub-14 en dos momentos del diseño. Se consultan 5 indicadores evaluativos a 25 especialistas (Nacionales: 14, Extranjeros: 11), se valida teóricamente la futura propuesta de intervención. Entre grupos independientes no se presentaron evaluaciones significativamente diferentes en ninguno de los 5 indicadores. Entre grupos relacionados, se evidenciaron diferencias significativas a favor del postest, tanto en los especialistas nacionales (Integralidad: r=0.001; Asequibilidad: r=0.002; Progresión: p=0.001; Variedad: p=0.001; Especialización Progresiva: p=0.001), como en los extranjeros (Integralidad: r=0.006; Asequibilidad: r=0.004; Progresión: p=0.002; Variedad: p=0.003; Especialización Progresiva: p=0.004). La futura propuesta de intervención presentó una adecuada Integralidad, Asequibilidad, Progresión, Variedad y Especialización Progresiva, mejorando significativamente las evaluaciones de la propuesta en su segundo momento de diseñada. Por otra parte, existe un grado de concordancia adecuado independientemente de las concepciones teóricas y metodológicas de cada grupo independiente, un valor adicional de la propuesta presentada por el autor.

A resistência aeróbica no futebol é considerada uma capacidade determinante, para a qual a sua valorização é uma parte indispensável do conteúdo da preparação desportiva, sendo útil para conceber modelos especializados para o seu aperfeiçoamento, os quais devem ser submetidos, em primeira instância, a uma validação teórica. Neste sentido, o objectivo da investigação é validar teoricamente, através de peritos nacionais e estrangeiros, uma proposta de um grupo de exercícios para desenvolver a resistência aeróbica em jogadores de futebol da categoria sub-14. A investigação é descritiva-explicativa de ordem correlacional, uma proposta de intervenção é validada com um grupo de exercícios de resistência aeróbica para jogadores de futebol sub-14 em dois momentos da concepção. Cinco indicadores de avaliação foram consultados com 25 especialistas (Nacionais: 14, Estrangeiros: 11), e a futura proposta de intervenção foi teoricamente validada. Entre grupos independentes, não houve avaliações significativamente diferentes em nenhum dos 5 indicadores. Entre grupos relacionados, foram evidenciadas diferenças significativas a favor do pós-teste, tanto nos especialistas nacionais (Compreensibilidade: r=0,001; Acessibilidade de preços: r=0,002; Progressão: p=0,001; Variedade: p=0,001; Especialização Progressiva: p=0,001), como nos especialistas estrangeiros (Compreensibilidade: r=0,006; Acessibilidade de preços: r=0,004; Progressão: p=0,002; Variedade: p=0,003; Especialização Progressiva: p=0,004). A futura proposta de intervenção apresentou uma Compreensibilidade, Acessibilidade, Progressão, Variedade e Especialização Progressiva adequadas, melhorando significativamente as avaliações da proposta no seu segundo momento de concepção. Por outro lado, existe um grau de acordo adequado independentemente das concepções teóricas e metodológicas de cada grupo independente, um valor adicional da proposta apresentada pelo autor.

Aerobic endurance in soccer is considered a determining capacity, for which its enhancement is an indispensable part of the content of sports training, being useful to design specialized models for its improvement, which must first be submitted to theoretical validation. In this sense, the objective of the research is to theoretically validate, through national and foreign experts, a proposal on a group of exercises to develop aerobic endurance in soccer players of the U-14 category. The research is descriptive-explanatory of correlational order, an intervention proposal is validated with a group of aerobic endurance exercises for U-14 soccer players in two moments of the design. Five evaluative indicators were consulted to 25 specialists (Nationals: 14, Foreigners: 11), and the future intervention proposal was theoretically validated. Between independent groups, there were no significantly different evaluations in any of the indicators5. Between related groups, significant differences in favor of the posttest were evidenced, both in the national specialists (Comprehensiveness: r=0.001; Affordability: r=0.002; Progression: p=0.001; Variety: p=0.001; Progressive Specialization: p=0.001), and in the foreign specialists (Comprehensiveness: r=0.006; Affordability: r=0.004; Progression: p=0.002; Variety: p=0.003; Progressive Specialization: p=0.004). The future intervention proposal presented adequate Comprehensiveness, Affordability, Progression, Variety and Progressive Specialization, significantly improving the evaluations of the proposal in its second moment of design. On the other hand, there is an adequate degree of agreement regardless of the theoretical and methodological conceptions of each independent group, an additional value of the proposal presented by the author.

Comparison of the Field-Based Intermittent Running Fitness Test 30-15 and the Treadmill Multistage Incremental Test for the Assessment of Cardiorespiratory Fitness in Elite Handball Players.

The aim of the present study was to investigate whether the physiological parameters indicative of cardiorespiratory fitness obtained during the 30-15 intermittent fitness (30-15IFT) test and the multistage laboratory treadmill endurance (TR) test differ. Nineteen elite handball players were recruited for the current study and assigned in a cross-over manner to one of two tests to be performed 48 h apart at each visit to the testing facility. The results showed that VO2max (percentage difference [PC] = 6.1%; p = 0.004) and maximal running velocity (V) (PC = 19.4%; p < 0.001) were significantly higher for the 30-15IFT test than that obtained during the TR test. Furthermore, the onset of blood lactate accumulation was shown to be significantly higher for all measures considered to predict it during 30-15IFT compared to TR as follows: VO2max (PC = 12.6%; p = 0.001), running speed (PC = 33.9%; p < 0.001), and maximal heart rate (PC = 7.5%; p < 0.001). The current study highlights the importance of sport-specific testing, particularly for measuring individual cardiorespiratory fitness in elite handball players, as TR may underestimate crucial variables used for both diagnostics and training prescription.

Relationships Between Maximal Aerobic Speed, Lactate Threshold, and Double Poling Velocity at Lactate Threshold in Cross-Country Skiers.

Purpose: To investigate the relationships between maximal aerobic speed (MAS), lactate threshold in per cent of peak oxygen uptake (LT) and velocity at LT (LTv) in cross-country skiers. Secondly, we aimed to explore the fit of an equation previously used in cyclists and runners in a cohort of well-trained, competitive cross-country skiers for calculation of LTv. Thirdly, we aimed to investigate if a new LTv could still be calculated after a period of regular training only by providing a new MAS. Methods: Ninety-five competitive cross-country skiers (65 males and 30 females) were tested for maximal oxygen uptake (VO2max), peak oxygen uptake in double poling (DP-VO2peak), oxygen cost of double poling (CDP), LT, and LTv. Thirty-five skiers volunteered to be tested 3 months later to evaluate potential changes in LT and LTv. Results: Velocity at LT was mainly determined by MAS (r = 0.88, p < 0.01). LT did not show a significant impact on LTv. The product of MAS·LT precisely predicted LTv at baseline (r = 0.99, SEE = 2.4%), and by only measuring MAS, a new LTv could be accurately calculated (r = 0.92, SEE = 6.8%) 3 months later in a sub-set of the initial 95 skiers (n = 35). Conclusion: The results suggest that LT has minor impact on LTv in DP tested in a laboratory. LTv seemed to be predominantly determined by MAS, and we suggest to put more focus on MAS and less on LT and LTv in regular testing to evaluate aerobic performance capacity in DP.

Prospective analysis of physical activity levels and associated fitness factors amid COVID-19 pandemic and social-distancing rules. A special focus on adolescents.

Objective: Physical activity is a significant health determinant and is likely to be influenced by social-distancing rules imposed by authorities during the COVID-19 pandemic. This study explored gender-based differences in physical activity levels (PALs) and associated factors amid COVID-19 pandemic in adolescents. Methods: In this prospective analysis, 112 healthy adolescents (15.63 ± 1.21 years) participated. They were assessed at the baseline (before the announcement of COVID-19 as a global pandemic) for anthropometry, fitness status, and PALs (baseline-PALs), and next at the follow-up (three months of imposed social-distancing rules) for PALs (follow-up-PALs) over an internet-based platform through the Physical Activity Questionnaire for Adolescents. Results: A significant PALs decline was evidenced for the whole sample (P < .001) and such a decline was predominantly affected by significant PALs reduction among males (P < .001) rather than in females (P = .06). The fitness variables (explosive power, muscle endurance, flexibility, and aerobic endurance) were consistently positively correlated with the baseline- and follow-up-PALs in both genders with particularly prominent associations of PALs with explosive power and aerobic endurance. Conclusion: Physical literacy is necessary for PALs preservation, given the remarkable PALs decreases among adolescents during challenging circumstances such as the COVID-19 pandemic.

Objectif: L'activité physique est un déterminant important de la santé et est susceptible d'être influencée par les règles de distanciation sociale imposées par les autorités pendant la pandémie de COVID-19. Cette étude a exploré les différences basées sur le sexe dans les niveaux d'activité physique (PAL) et les facteurs associés au milieu de la pandémie de COVID-19 chez les adolescents. Méthodes: Dans cette analyse prospective, 112 adolescents en bonne santé (15,63 ± 1,21 ans) ont participé. Ils ont été évalués au départ (avant l'annonce du COVID-19 en tant que pandémie mondiale) pour l'anthropométrie, le statut de forme physique et les PAL (PAL de référence), et ensuite lors du suivi (trois mois de règles de distanciation sociale imposées) pour les PAL (suivi-PAL) sur une plate-forme internet via le questionnaire sur l'activité physique pour adolescents. Résultats: Une baisse significative des PAL a été mise en évidence pour l'ensemble de l'échantillon (p < ,001) et une telle baisse a été principalement affectée par une réduction significative des PAL chez les hommes (p < ,001) plutôt que chez les femmes (p = ,06). Les variables de forme physique (puissance explosive, endurance musculaire, flexibilité et endurance aérobie) étaient constamment corrélées positivement avec les PAL de référence et de suivi chez les deux sexes avec des associations particulièrement importantes de PAL avec la puissance explosive et l'endurance aérobie. Conclusion: La littératie physique est nécessaire pour la préservation des PAL, étant donné les diminutions remarquables des PAL chez les adolescents lors de circonstances difficiles telles que la pandémie de COVID-19.

Cardiorespiratory Fitness Growth in Middle School: Socio-Demographic Factor Associations.

Purpose: The purposes of this study were to (a) examine the three-year longitudinal growth trends of cardiorespiratory fitness among middle school students, and (b) examine the associations between individual and school-level socio-demographic variables and middle school student cardiorespiratory fitness performance. Methods: A longitudinal multilevel analysis design was used. Participants were adolescents (N = 44,801; 48.1% girls) from 33 middle schools in an Eastern U.S. state. The grand mean age for the participants was 12.42 ± 0.98 years old. Individual-level variables included grade (testing year), sex, and the 15-m Progressive Aerobic Cardiovascular Endurance Run (PACER) performance, which was measured annually for 3 years. School-level variables included the percentage of students receiving a free and reduced-price meal, student-faculty ratio for physical education, and school-level academic performance. Results: A three-level hierarchical linear model was used to model the longitudinal performance change across 3 years accounting for individual and school-level factors. A quadratic growth curve was identified in PACER performance changes, with a positive first-order coefficient (ß = 3.05) and a negative second-order coefficient (ß =-0.82) overall. Sex was significantly associated with PACER changes (p < .01), with boys and girls having divergent longitudinal growth curves. School-level academic performance was positively associated with PACER performance; however, the association was not statistically significant. Conclusion: Results indicate that although cardiorespiratory fitness improved across years, on average, performance did not keep up with healthy fitness zone recommendations. In addition, sex-based discrepancies were evident as boys and girls demonstrated different quadratic growth curves in cardiorespiratory fitness.