Effects of combined strength and power training on physical performance and interlimb asymmetries in adolescent female soccer players

Purpose: This study examined the effects of an 8-week combined strength and power training (CSPT) intervention on physical performance and inter-limb asymmetries in adolescent female soccer players. Methods: Thirty-seven adolescent female soccer players (age: 16.1±1.1 yrs) were randomly assigned to a control (CG, n = 18) and experimental group (EG, n = 19). EG performed CSPT twice a week, which consisted of strength and power exercises that trained the major muscles of the lower body and trunk musculature. Pre- and post-intervention tests included unilateral and bilateral horizontal and countermovement jump tests, a 40-m sprint test (10 and 30-m split times), a 10-m sprint with a 180º change of direction (COD) test and a multiple COD test (V-cut test). Asymmetries were also analyzed in the unilateral tests. Results: Significant group by time interaction of the improvement between pre and post-tests were observed for speed (Effect size (ES): -1.30 to -1.16) and COD tests (ES: -0.62 to -0.61) but not in jumping (ES: -0.09 to 0.28) and inter-limb asymmetries tests (ES: -0.13 to 0.57). Conclusions: The short-term in-season CSPT program induced greater speed and COD performance improvements compared to soccer training alone in adolescent female soccer players

Determining the reliability and usability of change of direction speed tests in adolescent female soccer players: a systematic review

INTRODUCTION: This review aimed 1) to describe the most common tests used for assessing change of direction (COD) performance; 2) to detail the reliability of current COD tests; 3) to provide an overview of current intervention strategies used to improve COD performance in adolescent female soccer players. EVIDENCE ACQUISITION: A computerized search was conducted in the PubMed, Cochrane Plus and Web of Science (from 1995 to January 2020) for English and Spanish language and peer-reviewed investigations. EVIDENCE SYNTHESIS: A total of 221 studies were identified, with only 16 meeting the specific search criteria. The main findings were that eleven different tests have been used to assess COD performance with intraclass correlation coefficient and coefficient of variation values between 0.72-0.99 and 1-10.6%, respectively. The number of CODs performed during each test ranged from 1 to 9 within a range of 45º to 180º and with a duration 10 s. CONCLUSIONS: Findings indicate that the reliability of the COD tests seems to depend on: the equipment used, the surface tested on and the technical level of the soccer player. These results should be interpreted with caution as they may be influenced by the period of growth and maturation, the playing position of the player and the period of the soccer season. Finally, strength and power drills could be considered as appropriate to improve COD performance

Association of physical activity levels and prevalence of major degenerative diseases: Evidence from the national health and nutrition examination survey (NHANES) 1999–2018

Objectives: Degenerative diseases are associated with lower healthy life expectancy and higher mortality. Physical activity (PA) has demonstrated a fundamental role in the prevention and control of several pathologies associated to the aging process. The aim of this study was to analyze the association of PA with the prevalence of sarcopenia, osteoporosis and osteoarthritis in non-institutionalized American population. Methods: Cross-sectional study carried out in participants aged ≥50 years from the 1999–2018 National Health and Nutrition Examination Survey (NHANES). Sarcopenia was defined using appendicular lean mass adjusted for body mass index (ALM:BMI; men 1800 MET-min/week was associated with reduced odds for osteoporosis; and performing 150–1800 MET-min/week of PA was associated with reduced odds for osteoarthritis after adjust the results by several confounders. Conclusions: The benefits of PA in sarcopenia, osteoporosis, and osteoarthritis prevention are evident among Americans aged ≥50 years

Swimming training repercussion on metabolic and structural bone development; benefits of the incorporation of whole body vibration or pilometric training; the RENACIMIENTO project

Introduction: Enviromental factors such as exercise participation and nutrition have often been linked to bone improvements. However, not all sports have the same effects, being non-osteogenic sports such as swimming defined as negative or neutral sports to practice regarding bone mass by some authors, similarly exercise-diet interaction in especific groups is still not clear. Objective: To present the methodology of the RENACIMENTO project that aims to evaluate body composition and more specifically bone mass by several techniques in adolescent swimmers and to observe the effects and perdurability of whole body vibration (WBV) and jumping intervention (JIN) on body composition and fitness on this population and explore posible diet interactions. Design: Randomized controlled trial. Methods: 78 swimmers (12-17 y) and 26 sex- and age-matched controls will participate in this study. Dual energy X-ray, peripheral Quantitative Computed Tomography, Quantitative Ultrasound, Bioelectrical Impedance Analysis, and anthropometry measurements will be performed in order to evaluate body composition. Physical activity, nutrition, pubertal development and socio-economical status may act as confounders of body composition and therefore will also be registered. Several fitness factors regarding strength, endurance, performance and others will also be registered to evaluate differences with controls and act as confounders. A 7-month WBV therapy will be performed by 26 swimmers consisting of a training of 15 minutes 3 times per week. An 8 month JIM will also be performed by 26 swimmers 3 times per week. The remaining 26 swimmers will continue their normal swimming training. Four evaluations will be performed, the first one in order to describe differences between swimmers and controls. The second one to describe the effects of the interventions and the third and fourth evaluations to describe the perdurability of the effects of the WBV and JIN. Conclusion: The RENACIMIENTO project will allow to answer several questions regarding body composition, fitness, bone mass and interaction with diet of adolescent swimmers, describe swimming as a positive, negative or neutral sport to practice regarding these parameters and elucidate the effects and perdurability of WBV and JIM on body composition

Some Reflections on Age Discrimination, Referees’ Retirement Ages and European Sports (Law)

Introduction: This paper is the first in a series of reflections on the relationship between discrimination, sport and the law, a body of work that has been motivated in part by the potential impact of the 2000 Equalities Directive upon European sports law, but also by developments in human rights jurisprudence and in the domestic laws of several jurisdictions. The phenomenon of age discrimination in sport, and the social and economic impact thereof, has been far less widely considered than is the case with other forms of sports discrimination (although the literature would miraculously emerge if the subject-matter were more directly concerned with men’s professional football). In contrast, free movement and competition law have impacted significantly upon sports provisions that discriminate on the basis of nationality; it is equally evident that age discrimination in the context of sports employment has not been considered with anything approaching the degree of sophistication that pervades our understanding of discrimination in occupation or employment on the grounds of disability, sexual orientation and religion/belief (the other discriminatory forms that are covered by the 2000 Directive); and our poor understanding of age-related sports discrimination generally stands in marked contrast to our appreciation of how challenges to discrimination on the grounds of sex and race have precipitated far-reaching changes to sports practices. Throughout the EU, with the possible exception of the Irish Republic, age discrimination law is far less advanced than is the case with discrimination which takes any of those other forms, the remedies are weaker and fewer people are aware of them. However, this state of affairs will undoubtedly change under the impact of the Equalities Directive, and even though the provisions themselves (and member states’ transposing of them) attract legitimate criticism, some longstanding practices of sports bodies are now open to challenge

A global risk assessment of primates under climate and land use/cover scenarios

Primates are facing an impending extinction crisis, driven by extensive habitat loss, land use change, and hunting. Climate change is an additional threat, which alone or in combination with other drivers, may severely impact those taxa unable to track suitable environmental conditions. Here, we investigate the extent of climate and land use/cover (LUC) change‐related risks for primates. We employed an analytical approach to objectively select a subset of climate scenarios, for which we then calculated changes in climatic and LUC conditions for 2050 across primate ranges (N=426 species) under a best‐ and a worst‐case scenario. Generalised linear models were used to examine whether these changes varied according to region, conservation status, range extent, and dominant habitat. Finally, we reclassified primate ranges based on different magnitudes of maximum temperature change, and quantified the proportion of ranges overall and of primate hotspots in particular that are likely to be exposed to extreme temperature increases. We found that, under the worst‐case scenario, 74% of Neotropical forest‐dwelling primates are likely to be exposed to maximum temperature increases up to 7°C. In contrast, 38% of Malagasy savanna primates will experience less pronounced warming of up to 3.5°C. About one quarter of Asian and African primates will face up to 50% crop expansion within their range. Primary land (undisturbed habitat) is expected to disappear across species’ ranges, whereas secondary land (disturbed habitat) will increase by up to 98%. With 86% of primate ranges likely to be exposed to maximum temperature increases >3°C, primate hotspots in the Neotropics are expected to be particularly vulnerable. Our study highlights the fundamental exposure risk of a large percentage of primate ranges to predicted climate and LUC changes. Importantly, our findings underscore the urgency with which climate change mitigation measures need to be implemented to avert primate extinctions on an unprecedented scale

Effects of active video games on health-related physical fitness and motor competence in children and adolescents with overweight or obesity: Systematic review and meta-Analysis

Background: Childhood obesity is one of the most important public health problems. Active video games (AVGs) have been proposed as an attractive alternative to increase energy expenditure and are being investigated to determine their effectiveness against childhood obesity. Objective: The aim of this study is to summarize the existing research and draw conclusions about the effects of AVGs on health-related physical fitness and motor competence in children and adolescents with overweight and obesity. Methods: The search strategy was applied to PubMed, MEDLINE, Web of Science, and SPORTDiscus, including randomized and nonrandomized controlled trials investigating the effects of AVG programs on health-related physical fitness and motor competence in children and adolescents with overweight and obesity. To measure the risk of bias in randomized and nonrandomized controlled trials, 2 different quality assessment tools were used. In total, 15 articles met the inclusion criteria, and the variables of interest were BMI, body fat percentage, cardiorespiratory fitness (CRF), waist circumference, fat-free mass, muscular fitness, and motor competence. A meta-Analysis was performed. Results: Positive effects were found for BMI and body fat percentage, favoring the AVG group compared with a control group with no intervention (mean difference-0.209; 95% CI-0.388 to-0.031 vs mean difference-0.879; 95% CI-1.138 to-0.602). Positive effects seem to be observed for CRF. The effects of AVG interventions on muscular fitness, fat-free mass, waist circumference, and motor competence are unclear. Conclusions: AVG programs showed positive effects on BMI, body fat percentage, and CRF. AVG could be a good strategy to combat childhood obesity. © 2021. KJMIR Publications Inc.. All right reserved

Effects Of Playing Surfaces On Volumetric Bone Mineral Density In Adolescent Male Soccer Players

It has been well recognized that impact loading in sporting activity is highly associated with bone accretion. Recently, Carmona et al. showed that bone mass accretion was similar bone in prepubescent soccer players independently of the playing surface (artificial turf vs. non-grass ground surface). However, the osteogenic effects on volumetric bone mineral density (vBMD) generated by four different playing surfaces of the same sport are unknown. PURPOSE: to investigate the effects over a soccer season in vBMD of male soccer players by playing surface. METHODS: A total of 71 male soccer players (12.7±0.6 y) volunteered to participate in the study. 26 participants were training and playing on 2nd generation artificial turf, 16 on a 3rd generation artificial turf, 10 on a non-grass ground surface and 19 on natural grass (NG). vBMD, at 4 and 38% of the non-dominant tibia, was measured before and after season by peripheral quantitative computed tomography (Stratec XCT-2000 L pQCT scanner). Analysis of variance for repeated measures×2 (time) were performed to determine the effects of playing surface on vBMD controlling for pubertal status. Effect size were calculated according to the methods proposed by Cohen (small (f=0.1), medium (f=0.2), or large (f=0.4)). RESULTS: A group by time interaction was found for vBMD at 38% of the distal tibia (p=0.029 and f=0.38). When pairwise comparisons were carried out, NG showed group by time interactions compared to 2nd generation artificial turf (782 to 804 mg/cm3 vs. 790 to 798 mg/cm3; p=0.007 and f=0.50), and to 3rd generation artificial turf (782 to 804 mg/cm3 vs. 784 to 788 mg/cm3; p=0.027 and f=0.35). CONCLUSION: Soccer players training and playing in NG pitch showed better values in vBMD acquisition than those on 2nd and 3rd generation artificial turf. Despite previous studies presented no differences on bone mass accretion independently of the playing surface. Our results suggest that NG is the most recommended playing surface to improve vBMD in the non-dominant tibia

Resonance locking in giant planets indicated by the rapid orbital expansion of Titan

Saturn is orbited by dozens of moons, and the intricate dynamics of this complex system provide clues about its formation and evolution. Tidal friction within Saturn causes its moons to migrate outwards, driving them into orbital resonances that pump their eccen- tricities or inclinations, which in turn leads to tidal heating of the moons. However, in gi- ant planets, the dissipative processes that determine the tidal migration timescale remain poorly understood. Standard theories suggest an orbital expansion rate inversely pro- portional to the power 11/2 in distance1, implying negligible migration for outer moons such as Saturn’s largest moon, Titan. Here, we use two independent measurements ob- tained with the Cassini spacecraft to measure Titan’s orbital expansion rate. We find Titan rapidly migrates away from Saturn on a timescale of roughly 10 Gyr, corresponding to a tidal quality factor of Saturn of Q ≃ 100, which is more than a hundred times smaller than most expectations. Our results for Titan and five other moons agree with the predic- tions of a resonance locking tidal theory2, sustained by excitation of inertial waves inside the planet. The associated tidal expansion is only weakly sensitive to orbital distance, motivating a revision of the evolutionary history of Saturn’s moon system. In particular, it suggests Titan formed significantly closer to Saturn and has migrated outward to its current position