The prevalence of pediatric obesity continues to increase worldwide,bringing with it various metabolic,functional,social,and psychological complications.1 Both the prevention and treatment of childhood obesity must be...The prevalence of pediatric obesity continues to increase worldwide,bringing with it various metabolic,functional,social,and psychological complications.1 Both the prevention and treatment of childhood obesity must be based on multidisciplinary approaches combining nutrition,physical activity(PA),and psychological support.2 As an essential element of these multicomponent strategies,regular physical activity has been acknowledged as having beneficial effects on children's and adolescents,body composition,physical fitness,and metabolic profile,as well as on their health-related quality of life,social and psychological health,and academic achievement.3,4 Given that only a relatively small proportion of children and adolescents meet the public health recommendations for PA,5 and given that weight loss exercise-based interventions suffer from a high attrition rate,there is a clear need for appropriate PAs.展开更多
Purpose:The aim of this study was to review,systematically,evidence concerning the link between the ACTN3 R577X polymorphism and the rates and severity of non-contact injuries and exercise-induced muscle damage in ath...Purpose:The aim of this study was to review,systematically,evidence concerning the link between the ACTN3 R577X polymorphism and the rates and severity of non-contact injuries and exercise-induced muscle damage in athletes and individuals enrolled in exercise training programs.Methods:A computerized literature search was performed in the electronic databases PubMed,Web of Science,and SPORTDiscus,from inception until November 2020.All included studies compared the epidemiological characteristics of non-contact injury between the different genotypes of the ACTN3 R577X polymorphism.Results:Our search identified 492 records.After the screening of titles,abstracts,and full texts,13 studies examining the association between the ACTN3 genotypes and the rate and severity of non-contact injury were included in the analysis.These studies were performed in 6 different countries(Spain,Japan,Brazil,China,the Republic of Korea,and Italy)and involved a total participant pool of 1093 participants.Of the studies,2 studies involved only women,5 studies involved only men,and 6 studies involved both men and women.All the studies included were classified as highquality studies(≥6 points in the Physiotherapy Evidence Database(PEDro)scale score).Overall,evidence suggests there is an association between the ACTN3 R577X genotype and non-contact injury in 12 investigations.Six studies observed a significant association between A CTN3 R577X polymorphism and exercise induced muscle damage:2 with non-contact ankle injury,3 with non-contact muscle injury,and 1 with overall non-contact injury.Conclusion:The present findings support the premise that possessing the ACTN3 XX genotype may predispose athletes to a higher probability of some non-contact injuries,such as muscle injury,ankle sprains,and higher levels of exercise-induced muscle damage.展开更多
Background:Components of Self,completed with the perceived social support determine the individual differences in theevaluation of a stressor and the behavioral responses toward it,such as health-related anxiety.The s...Background:Components of Self,completed with the perceived social support determine the individual differences in theevaluation of a stressor and the behavioral responses toward it,such as health-related anxiety.The study set as a goal theanalysis of associations between the components of Self,such as self-evaluation,sense of coherence,perceived social support,and reported health-related anxiety in an adult sample.Methods:147 adults from the 18–73 age group(mean age 37.5)voluntarily completed the questionnaire through Qualtrics online platform containing the Short Health Anxiety Inventory,Core Self-Evaluation Scale,Social Support Assessing Scale,and one Health Self-Evaluation Item.Results:ANOVA foundrelevant differences in total scores and subscales’scores of the health anxiety scale depending on the positive self-evaluation.Linear regression shows that the analyzed variables were responsible for the prediction of a higher value on the“Perceivedprobability of becoming ill”subscale in a proportion of 45.6%and for the“Perceived consequence of illness”subscale in aproportion of 20.2%The predictive value of the linear regression model for the total score on the health anxiety scale was46.3%.Our findings show that negative Core Self-Evaluation is linked with perceived health anxiety.Conclusions:Selfevaluation,sense of coherence and perceived social support influence the perceived health and can explain the differences inthe reported health-related anxiety.展开更多
Background:Low levels of antioxidant paraoxonase 1(PON 1)enzyme activity,PON1-Q192R polymorphism(a glutamine(Q)to arginine(R)substitution at position 192),PON1-L55M polymorphism(a leucine(L)to methionine(M)substitutio...Background:Low levels of antioxidant paraoxonase 1(PON 1)enzyme activity,PON1-Q192R polymorphism(a glutamine(Q)to arginine(R)substitution at position 192),PON1-L55M polymorphism(a leucine(L)to methionine(M)substitution at position 55),and oxidized low-density lipoprotein(oxLDL)are risk factors for coronary heart disease.Aerobic exercise improves PON1 activity,but the effects of hypoxic exercise are yet unclear.The aim of this study was to determine the effects of hypoxic underwater rugby training on PON1 activity and oxLDL levels and the role of the mentioned polymorphisms.Methods:Serum PON1 and arylesterase activities(ARE),PON1,PON3,and oxLDL protein levels(by using the enzyme-linked immunosorbent assays)were determined in an athletic group(42 trained male underwater rugby players;age=21.7±4.2 years,mean±SD)and a control group(43 sedentary men;age=23.9±3.2 years).The polymorphisms were determined from genomic DNA samples.Results:PON1 activity(25.1%,p=0.052),PON3(p<0.001),and oxLDL(p<0.001)of the athletic group,including most genotype groups,were higher than those of the control group.In comparison to the controls,PON1 activity levels(p=0.005)of the PON1-Q192R homozygote QQ genotype group and PON1 activity levels(30%,p=0.116)of the PON1-L55M homozygote LL genotype group were higher,whereas ARE activity values of athletic R allele carrier(Rc=QR+RR)(p=0.005)and LL group(p=0.002)were lower than the control genotype groups related to their polymorphisms.Conclusion:Hypoxic training can cause(1)significant oxidative stress,including oxLDL,and an antioxidant response(increase in PON1 activity and PON3),(2)differences in the activity of PON1 and ARE,which are modified by PON1-Q192R and PON1-L55M polymorphisms,respectively,and(3)improvements in PON1 activity of QQ and LL groups.However,hypoxic training can cause a disadvantage of LL and Rc groups for ARE.展开更多
The biathlon, an Olympic sporting discipline that combines cross-country skiing with rifle marksmanship, entails considerable physiological demands, as well as fine motor control while shooting after intense exercise ...The biathlon, an Olympic sporting discipline that combines cross-country skiing with rifle marksmanship, entails considerable physiological demands, as well as fine motor control while shooting after intense exercise and under mental pressure. Although much of our knowledge about cross-country skiing is probably also applicable to the biathlon, carrying the rifle and shooting under stress make this discipline somewhat unique. The present review summarizes and examines the scientific literature related to biathlon performance, with a focus on physiological and biomechanical factors and shooting technique, as well as psychophysiological aspects of shooting performance. We conclude with suggestions for future research designed to extend our knowledge about the biathlon, which is presently quite limited.展开更多
The Beijing 24th 2022 Winter Olympic Games present a unique opportunity to promote the spirit and values of the Olympic Games in relation to their impact on physical activity and global health,sports medicine,and spor...The Beijing 24th 2022 Winter Olympic Games present a unique opportunity to promote the spirit and values of the Olympic Games in relation to their impact on physical activity and global health,sports medicine,and sports performance.The 2022 Winter Olympic Games mark the 98th year since the first Winter Games were held in Chamonix,France,in 1924.The inaugural Winter Olympic Games sponsored 16 events,and 250 athletes from 16 nations participated.1 In contrast,the Beijing 2022 Winter Olympic Games will sponsor 109 events.展开更多
Purpose:This study aimed to assess the effectiveness and time course for improvements in explosive actions through resistance training(RT)vs.plyometric training(PT)in prepubertal soccer players.Methods:Thirty-four mal...Purpose:This study aimed to assess the effectiveness and time course for improvements in explosive actions through resistance training(RT)vs.plyometric training(PT)in prepubertal soccer players.Methods:Thirty-four male subjects were assigned to:a control group(n=11);an RT group(5 regular soccer training sessions per week,n=12);a PT group(3 soccer training sessions and 2 RT sessions per week,n=11).The outcome measures included tests for the assessment of muscle strength(e.g.,1 repetition maximum half-squat test),jump ability(e.g.,countermovement jump,squat jump,standing long jump,and multiple 5 bounds test),linear speed(e.g.,20m sprint test),and change of direction(e.g.,Illinois change of direction test).Results:The RTG showed an improvement in the half-squat(△=13.2%;d=1.3,p<0.001)and countermovement jump(△=9.4%;d=2.4,p<0.001)at Week 4,whereas improvements in the 20-m sprint(△=4.2%;d=1.1,p<0.01);change of direction(CoD)(△=3.8%;d=2.1,p<0.01);multiple 5 bounds(△=5.1%;d=1.5,p<0.05);standing long jump(△=7.2%;d=1.2,p<0.01);squat jump(△=19.6%;d=1.5,p<0.01);were evident at Week 8.The PTG showed improvements in CoD(△=2.1%;d=1.3,p<0.05);standing long jump(△=9.3%;d=1.1,p<0.01);countermovement jump(△=16.1%;d=1.2,p<0.01);and squat jump(△=16.7%;d=1.4,p<0.01);at Week 8 whereas improvements in the 20-m sprint(△=4.1%;d=1.3,p<0.01);and multiple 5 bounds(△=7.4%;d=2.4,p<0.001);were evident only after Week.The RT and PT groups showed improvements in all sprint,CoD,and jump tests(p<0.05)and in half-squat performance,for which improvement was only shown within the RTG(p<0.001).Conclusion:RT and PT conducted in combination with regular soccer training are safe and feasible interventions for prepubertal soccer players.In addition,these interventions were shown to be effective training tools to improve explosive actions with different time courses of improvements,which manifested earlier in the RTG than in the PTG.These outcomes may help coaches and fitness trainers set out clear and concise goals of training according to the specific time course of improvement difference between RT and PT on proxies of athletic performance of prepubertal soccer players.展开更多
Background: Artificial turf is considered a feasible global alternative to natural turf by many sports governing bodies. Consequently, its ability to provide a safe and consistent playing surface regardless of climate...Background: Artificial turf is considered a feasible global alternative to natural turf by many sports governing bodies. Consequently, its ability to provide a safe and consistent playing surface regardless of climate becomes essential. The aims of this study were to determine the effects of artificial surface temperature on:(1) mechanical properties of the turf and(2) the kinematics of a turf-sport related movement.Methods: Two identical artificial turf pitches were tested: one with a cold surface temperature(1.8°C–2.4°C) and one with a warm surface temperature(14.5°C–15.2°C). Mechanical testing was performed to measure the surface properties. Four amateur soccer players performed a hurdle jump to sprint acceleration movement, with data(contact time, step length and hip, knee and ankle kinematics) collected using CODASport(200 Hz).Results: The temperature difference had a significant influence on the mechanical properties of the artificial turf, including force absorption,energy restitution, rotational resistance, and the height where the head injury criterion was met. Both step length(p = 0.008) and contact time(p = 0.002) of the initial step after the landing were significantly longer on the warm surface. In addition, significant range of motion and joint angular velocity differences were found.Conclusion: These findings highlight different demands placed on players due to the surface temperature and suggest a need for coaches,practitioners, and sports governing bodies to be aware of these differences.展开更多
Purpose This study aimed to investigate whether there is a systematic change of leg muscle activity,as quantified by surface electromyography(EMG),throughout a standard running footwear assessment protocol at a predet...Purpose This study aimed to investigate whether there is a systematic change of leg muscle activity,as quantified by surface electromyography(EMG),throughout a standard running footwear assessment protocol at a predetermined running speed.Methods Thirty-one physically active adults(15 females and 16 males)completed 5 testing rounds consisting of overground running trials at a speed of 3.5 m/s.The level of muscle activity from 6 major leg muscles was recorded using surface EMG.The variables assessed were the EMG total intensity as a function of time and the cumulative EMG overall intensity.Systematic effects of the chronological testing round(independent variable)on the normalized EMG overall intensity(dependent variable)were examined using Friedman analysis of variates and post hoc pairwise Wilcoxon signed-rank tests(α=0.05).Results There was a systematic reduction in overall EMG intensity for all 6 muscles over the time course of the running protocol(p<0.001)until the fourth testing round when EMG intensities reached a steady state.The one exception was the biceps femoris muscle,which showed a significant reduction of EMG intensity during the stance phase(p<0.001)but not the swing phase(p=0.16).Conclusion While running at a predetermined speed,the neuromuscular system undergoes an adaptation process characterized by a progressive reduction in the activity level of major leg muscles.This process may represent an optimization strategy of the neuromuscular system towards a more energetically efficient running style.Future running protocols should include a familiarization period of at least 7 min or 600 strides of running at the predetermined speed.展开更多
Winter sports, including those with a focus on gliding with skis on snow, have become extremely complex in the last few decades. During the Olympic Games held in Pyeongchang,
Background:Postural control has been associated with the functional impairment in persons with multiple sclerosis(pwMS).However,there is a need for reliable methods to assess postural control in early stages of the di...Background:Postural control has been associated with the functional impairment in persons with multiple sclerosis(pwMS).However,there is a need for reliable methods to assess postural control in early stages of the disease,when subtle changes can be difficult to detect.The aims of this study were to assess the absolute and relative reliability of a standing and a sitting posturographic protocol in minimally(Expanded Disability Status Scale≤2)and moderately(2.5≤Expanded Disability Status Scale≤4)impaired pwMS,and to analyze relationships among postural control and functional mobility and gait performance.Methods:To assess postural control in an upright stance,14 minimally and 16 moderately impaired pwMS performed six 70 s trials in tandem stance,3 with their weaker leg behind(TSWL)and 3 with their stronger leg behind(TSSL).Additionally,participants completed five 70 s trials using an unstable sitting protocol(US)to assess trunk stability.The mean radial errors of TSWL,TSSL,and US trials were calculated as postural control indexes.Furthermore,participants performed the Timed Up and Go test(TUG)and the Timed 25-foot Walk test(T25FW)to measure their functional mobility and gait speed,respectively.Reliability was evaluated using the intraclass correlation coefficient(ICC3,1)and the standard error of measurement(SEM).Analyses of variances were carried out to assess between-group differences.Hedges’g index(dg)was used to estimate the effect size of differences.Pearson correlation analyses(r)were performed to examine the relationships among the postural control and the functional tests.Results:Posturographic tests showed a high reliability in both minimally(0.87≤ICC≤0.92;9.32%≤SEM≤11.76%)and moderately(0.80≤ICC≤0.92;10.33%≤SEM≤15.33%)impaired pwMS.Similarly,T25FW and TUG displayed a high consistency in minimally(0.89≤ICC≤0.94;3.43%≤SEM≤5.17%)and moderately(0.85≤ICC≤0.93;5.57%≤SEM≤6.56%)impaired individuals.Minimally impaired pwMS showed a better performance on the TUG,T25FW,and TSWL than moderately impaired individuals(p<0.05;dg≥0.8).The TSWL,TSSL,and US variables correlated with TUG scores(0.419≤r≤0.604;p<0.05),but TSWL also correlated with T25FW scores(r=0.53;p<0.01).Furthermore,US scores correlated with both tandem stance parameters(TSWL:r=0.54,p<0.01;TSSL:r=0.43,p<0.05).Conclusion:Tandem and sitting posturographic tests provide reliable measures of postural control in pwMS,even in individuals with a homogeneous disease profile.Gait speed,functional mobility,and weaker leg status seem decisive in assessing the degree of physical activity limitation in pwMS.Finally,although trunk stability does not seem to be so affected by the course of the disease,it remains relevant for postural control and functional capacity.展开更多
In this study, we investigated the effect of sodium bicarbonate (NaHCO3) supplementation at a dose of 0.2 g·kg−1 40 min before an exercise on intermittent endurance performance and gastrointestina...In this study, we investigated the effect of sodium bicarbonate (NaHCO3) supplementation at a dose of 0.2 g·kg−1 40 min before an exercise on intermittent endurance performance and gastrointestinal distress. The participants were six healthy male students of a university. The Yo-Yo intermittent recovery test level 2 (Yo-Yo IR2) was used for the evaluation of intermittent endurance. The participants ingested water (Cont) or NaHCO3 independently at three timings. After drinking water, the Yo-Yo IR1 was performed for 2 min as warm-up. After resting for 5 min, the Yo-Yo IR2 was initiated. The measurement items were exercise distance, nutrition intake, biochemical test results, and blood gas analysis findings. The participants who ingested NaHCO3 had a 14% extended distance than those who ingested Cont, and 2/3 of those who took NaHCO3 showed a better motor performance. No significant difference was observed between the participants who took Cont and NaHCO3 in terms of pH level at baseline, and the NaHCO3 level was significantly higher during pre- and post-exercise (p 3 in terms of bicarbonate ion level at baseline, and the NaHCO3 level was significantly higher during pre- and post-exercise (p 3 at a low dose (0.2 g·kg−1), their exercise ability during an intermittent endurance test has improved. Furthermore, when digestive absorption is considered, eating a meal in advance may be able to suppress the onset of gastrointestinal distress.展开更多
The aim of the study was to investigate associations between psychological and biological changes due to resistance training in people with impaired glucose tolerance (IGT). Subjects were randomized into maximal (MRT)...The aim of the study was to investigate associations between psychological and biological changes due to resistance training in people with impaired glucose tolerance (IGT). Subjects were randomized into maximal (MRT) versus endurance resistance training (ERT) groups. Intervention periods lasted four months. All subjects had blood work that suggested IGT at the initial screening. The ERT acted as a wait-list control group when the MRT performed their training. Baseline scores on general life satisfaction (LISAT) and sense of humor (SHQ-6: a positive coping resources) were obtained. Potential differences between groups (types of intervention and intervention versus control) were investigated by analysis of variance (one-way ANOVA). Correlations were calculated in each group to estimate the degree of covariance between biological and psychological changes from pre- to post-intervention by Pearson and Spearman coefficients. Sense of humor tended to be correlated with a positive reduction of insulin following MRT as well as with reduction in body fat following ERT. Differences across the intervention groups in changes from pre- to post-training in biological variables (glucose, insulin, muscle mass, and corrected percentage of fat) as well as psychological variables (general life satisfaction and sense of humor) were not significant, whereas differences in BMI and weight were significant. By investigating the intervention groups separately in comparison to the control group, the MRT revealed significant improvement by reduction in insulin, percentage of fat, BMI and weight. The ERT caused significant improvements for insulin and percentage of fat, while general life satisfaction had a significant negative development.展开更多
Motile cells of the green alga, Ulva fasciata respond to the quantity and quality of irradiance simultaneously. The specific responses of motile cell types (gametes and spores) by irradiance influence migration behavi...Motile cells of the green alga, Ulva fasciata respond to the quantity and quality of irradiance simultaneously. The specific responses of motile cell types (gametes and spores) by irradiance influence migration behavior in coastal water environment. Gametes maximally aggregated at the highest white light intensity (250 μmol·m-2·s-1), while spores maximally aggregated in the dark (0 μmol m-2·s-1) of this study. Gametes maximally aggregated in green irradiance over blue, red and dark while spore maximally aggregated in the dark. The results of quantity are spectral responses are likely to be underline the ecological success and physiological strategies in varied irradiance environments includes: 1) gametes respond to specific quantities and spectral irradiance;2) spores respond negatively to quantity and quality of irradiance to enhance the probability of finding substratum;and 3) populations of adults that come from these motile cells behaviors. The specific quantities and spectral qualities of irradiance responses show specific ecological migration that can be attributed to photosynthesis under limiting irradiance in coastal waters for the motile cells of U. fasciata.展开更多
This study aimed to determine the appropriate nutritional intakes and dietary habits of high school-aged cross-country skiers and speed skaters. The subjects, all high school students from N Prefecture, included 18 ma...This study aimed to determine the appropriate nutritional intakes and dietary habits of high school-aged cross-country skiers and speed skaters. The subjects, all high school students from N Prefecture, included 18 male cross-country skiers, 5 male speed skaters, 10 female cross-country ski players and 4 female speed skaters. Physical measurements, food intake frequency survey results, bone mineral density and exercise stress test outcomes, and lactic acid measurements were evaluated. Female athletes in both sports had higher body fat percentages relative to the average range stated for female athletes. Male speed skaters had a significantly higher maximum oxygen in-take than that male cross-country skiers did. By contrast, this parameter did not differ significantly among female athletes. A negative correlation was observed between the fat free mass and muscle mass, and a positive correlation was observed among the body fat percentage, fat percentage, and fat mass. Both male and female athletes had protein intake ratios within the reference ranges. All athletes except male speed skaters had lipid energy ratios that were higher than the upper limit of the reference value. Both male and female athletes also reported carbohydrate energy ratios within the reference ranges, but had cereal energy ratios below the reference values. Athletes should pay attention to the ingestion of various nutrients to ensure a sufficient energy intake. Accordingly, adolescent athletes should consume daily meals containing a good balance of staple foods, main dishes, side dishes, milk and other dairy products, and fruits.展开更多
Background:Evidence supports the anti-inflammatory effect of exercise-based cardiac rehabilitation(CR)in patients with cardiovascular disease(CVD).Nonetheless,the influence of training variables on the effects of exer...Background:Evidence supports the anti-inflammatory effect of exercise-based cardiac rehabilitation(CR)in patients with cardiovascular disease(CVD).Nonetheless,the influence of training variables on the effects of exercise training is debateable.Therefore,this systematic review with meta-analysis aims to i)estimate the effects of exercise-based CR on the circulating levels of inflammatory biomarkers in patients with CVD based on the type of exercise,and ii)analyse the influence of other potential moderator variables.Methods:Electronic searches were performed in PubMed,Scopus,and Web of Science databases up to October 2022.A random-effects models of standardised mean difference(SMD)were used.Subgroup analyses and meta-regressions were used to carry out heterogeneity analyses.Results:Aerobic exercise diminished the levels of C-reactive protein compared with the control group in patients with CVD(SMD+=-0.33[95%CI=-0.47,-0.20),as well as the levels of tumor necrosis factor-alfa exclusively in patients with chronic heart failure(SMD+=-0.38[95%CI=-0.59,-0.17]).Moreover,heterogeneity analyses showed that the effect of aerobic exercise on vascular cell adhesion molecule-1 is higher in studies that carried out a CR programme based exclusively on exercise,as well as in studies that performed a shorter intervention period or carried out a lower number of exercise sessions(P≤0.05).Conclusion:Our findings support the anti-inflammatory effect of aerobic exercise in patients with CVD.The low number of studies testing interventions using resistance or combined exercise precludes a definitive answer about their anti-inflammatory effects in this patient population.展开更多
Regular physical activity(PA)promotes healthy aging,and activities aiming to increase muscular strength(i.e.,resistance exercise(RE))are important PA modalities for achieving health benefits.Previous meta-analyses dem...Regular physical activity(PA)promotes healthy aging,and activities aiming to increase muscular strength(i.e.,resistance exercise(RE))are important PA modalities for achieving health benefits.Previous meta-analyses demonstrated that both RE^(1) and muscular strength^(2) were associated with mortality benefits,even when RE was performed above the PA targets recommended by current guidelines^(1,3).展开更多
Purpose: The aims of this study were to assess differences of limb symmetry index(LSI) in strength-and coordination-related tasks between high-level, competitive, noninjured ski racers of different age-related perform...Purpose: The aims of this study were to assess differences of limb symmetry index(LSI) in strength-and coordination-related tasks between high-level, competitive, noninjured ski racers of different age-related performance levels and to prospectively assess limb differences as a possible risk factor for traumatic and overuse injury in youth ski racers.Methods: The study(Study 1) included 285 high-level competitive ski racers(125 females, 160 males) of 3 age-related performance levels and based on the school system: 95 youth(10à14 years, secondary modern school), 107 adolescent(15à19 years, grammar school), and 83 elite athletes(20à34 years). To investigate the second aim(Study 2), 67 of the 95 youth athletes were included and any traumatic or overuse injuries were prospectively recorded over 2 seasons. All athletes performed 4 unilateral tests(strength related: one-leg counter movement jump(OL-CMJ) and one-leg isometric/isokinetic press strength test(OL-ILS); coordination related: one-leg stability test(OL-ST) and one-leg speedy jump test(OL-SJ)). The LSI was calculated by dividing the dominant leg by the nondominant leg and multiplying by 100. Kruskal-Wallis H tests and binary logistic regression analyses were conducted.Results: There were significant differences between the LSI of the 3 age-related performance-level groups only in the strength-related tests: the OL-CMJ(x2(2, 285) = 9.09; p = 0.01) and the OL-ILS(x2(2, 285) = 14.79; p < 0.01). The LSI for OL-ILS was found to be a significant risk factor for traumatic injury in youth ski racers(Wald = 7.08; p < 0.01). No significant risk factors were found for overuse injuries.Conclusion: Younger athletes display slightly greater LSI values only in the strength-related tests. The cut-off value of limb differences of <10%for return to sport decisions seems to be appropriate for elite athletes, but for youth and adolescent athletes it has to be critically discussed. It seems to be necessary to define thresholds based on specific performance tasks(strength vs. coordination related) rather than on generalizations,and age-related performance levels must be considered. Limb differences in unilateral leg extension strength represent a significant injury risk factor in youth ski racers.展开更多
文摘The prevalence of pediatric obesity continues to increase worldwide,bringing with it various metabolic,functional,social,and psychological complications.1 Both the prevention and treatment of childhood obesity must be based on multidisciplinary approaches combining nutrition,physical activity(PA),and psychological support.2 As an essential element of these multicomponent strategies,regular physical activity has been acknowledged as having beneficial effects on children's and adolescents,body composition,physical fitness,and metabolic profile,as well as on their health-related quality of life,social and psychological health,and academic achievement.3,4 Given that only a relatively small proportion of children and adolescents meet the public health recommendations for PA,5 and given that weight loss exercise-based interventions suffer from a high attrition rate,there is a clear need for appropriate PAs.
文摘Purpose:The aim of this study was to review,systematically,evidence concerning the link between the ACTN3 R577X polymorphism and the rates and severity of non-contact injuries and exercise-induced muscle damage in athletes and individuals enrolled in exercise training programs.Methods:A computerized literature search was performed in the electronic databases PubMed,Web of Science,and SPORTDiscus,from inception until November 2020.All included studies compared the epidemiological characteristics of non-contact injury between the different genotypes of the ACTN3 R577X polymorphism.Results:Our search identified 492 records.After the screening of titles,abstracts,and full texts,13 studies examining the association between the ACTN3 genotypes and the rate and severity of non-contact injury were included in the analysis.These studies were performed in 6 different countries(Spain,Japan,Brazil,China,the Republic of Korea,and Italy)and involved a total participant pool of 1093 participants.Of the studies,2 studies involved only women,5 studies involved only men,and 6 studies involved both men and women.All the studies included were classified as highquality studies(≥6 points in the Physiotherapy Evidence Database(PEDro)scale score).Overall,evidence suggests there is an association between the ACTN3 R577X genotype and non-contact injury in 12 investigations.Six studies observed a significant association between A CTN3 R577X polymorphism and exercise induced muscle damage:2 with non-contact ankle injury,3 with non-contact muscle injury,and 1 with overall non-contact injury.Conclusion:The present findings support the premise that possessing the ACTN3 XX genotype may predispose athletes to a higher probability of some non-contact injuries,such as muscle injury,ankle sprains,and higher levels of exercise-induced muscle damage.
文摘Background:Components of Self,completed with the perceived social support determine the individual differences in theevaluation of a stressor and the behavioral responses toward it,such as health-related anxiety.The study set as a goal theanalysis of associations between the components of Self,such as self-evaluation,sense of coherence,perceived social support,and reported health-related anxiety in an adult sample.Methods:147 adults from the 18–73 age group(mean age 37.5)voluntarily completed the questionnaire through Qualtrics online platform containing the Short Health Anxiety Inventory,Core Self-Evaluation Scale,Social Support Assessing Scale,and one Health Self-Evaluation Item.Results:ANOVA foundrelevant differences in total scores and subscales’scores of the health anxiety scale depending on the positive self-evaluation.Linear regression shows that the analyzed variables were responsible for the prediction of a higher value on the“Perceivedprobability of becoming ill”subscale in a proportion of 45.6%and for the“Perceived consequence of illness”subscale in aproportion of 20.2%The predictive value of the linear regression model for the total score on the health anxiety scale was46.3%.Our findings show that negative Core Self-Evaluation is linked with perceived health anxiety.Conclusions:Selfevaluation,sense of coherence and perceived social support influence the perceived health and can explain the differences inthe reported health-related anxiety.
基金Science and Technology Centre unit of Ege University for its financial support(No.33.102.2014.0001)。
文摘Background:Low levels of antioxidant paraoxonase 1(PON 1)enzyme activity,PON1-Q192R polymorphism(a glutamine(Q)to arginine(R)substitution at position 192),PON1-L55M polymorphism(a leucine(L)to methionine(M)substitution at position 55),and oxidized low-density lipoprotein(oxLDL)are risk factors for coronary heart disease.Aerobic exercise improves PON1 activity,but the effects of hypoxic exercise are yet unclear.The aim of this study was to determine the effects of hypoxic underwater rugby training on PON1 activity and oxLDL levels and the role of the mentioned polymorphisms.Methods:Serum PON1 and arylesterase activities(ARE),PON1,PON3,and oxLDL protein levels(by using the enzyme-linked immunosorbent assays)were determined in an athletic group(42 trained male underwater rugby players;age=21.7±4.2 years,mean±SD)and a control group(43 sedentary men;age=23.9±3.2 years).The polymorphisms were determined from genomic DNA samples.Results:PON1 activity(25.1%,p=0.052),PON3(p<0.001),and oxLDL(p<0.001)of the athletic group,including most genotype groups,were higher than those of the control group.In comparison to the controls,PON1 activity levels(p=0.005)of the PON1-Q192R homozygote QQ genotype group and PON1 activity levels(30%,p=0.116)of the PON1-L55M homozygote LL genotype group were higher,whereas ARE activity values of athletic R allele carrier(Rc=QR+RR)(p=0.005)and LL group(p=0.002)were lower than the control genotype groups related to their polymorphisms.Conclusion:Hypoxic training can cause(1)significant oxidative stress,including oxLDL,and an antioxidant response(increase in PON1 activity and PON3),(2)differences in the activity of PON1 and ARE,which are modified by PON1-Q192R and PON1-L55M polymorphisms,respectively,and(3)improvements in PON1 activity of QQ and LL groups.However,hypoxic training can cause a disadvantage of LL and Rc groups for ARE.
文摘The biathlon, an Olympic sporting discipline that combines cross-country skiing with rifle marksmanship, entails considerable physiological demands, as well as fine motor control while shooting after intense exercise and under mental pressure. Although much of our knowledge about cross-country skiing is probably also applicable to the biathlon, carrying the rifle and shooting under stress make this discipline somewhat unique. The present review summarizes and examines the scientific literature related to biathlon performance, with a focus on physiological and biomechanical factors and shooting technique, as well as psychophysiological aspects of shooting performance. We conclude with suggestions for future research designed to extend our knowledge about the biathlon, which is presently quite limited.
文摘The Beijing 24th 2022 Winter Olympic Games present a unique opportunity to promote the spirit and values of the Olympic Games in relation to their impact on physical activity and global health,sports medicine,and sports performance.The 2022 Winter Olympic Games mark the 98th year since the first Winter Games were held in Chamonix,France,in 1924.The inaugural Winter Olympic Games sponsored 16 events,and 250 athletes from 16 nations participated.1 In contrast,the Beijing 2022 Winter Olympic Games will sponsor 109 events.
文摘Purpose:This study aimed to assess the effectiveness and time course for improvements in explosive actions through resistance training(RT)vs.plyometric training(PT)in prepubertal soccer players.Methods:Thirty-four male subjects were assigned to:a control group(n=11);an RT group(5 regular soccer training sessions per week,n=12);a PT group(3 soccer training sessions and 2 RT sessions per week,n=11).The outcome measures included tests for the assessment of muscle strength(e.g.,1 repetition maximum half-squat test),jump ability(e.g.,countermovement jump,squat jump,standing long jump,and multiple 5 bounds test),linear speed(e.g.,20m sprint test),and change of direction(e.g.,Illinois change of direction test).Results:The RTG showed an improvement in the half-squat(△=13.2%;d=1.3,p<0.001)and countermovement jump(△=9.4%;d=2.4,p<0.001)at Week 4,whereas improvements in the 20-m sprint(△=4.2%;d=1.1,p<0.01);change of direction(CoD)(△=3.8%;d=2.1,p<0.01);multiple 5 bounds(△=5.1%;d=1.5,p<0.05);standing long jump(△=7.2%;d=1.2,p<0.01);squat jump(△=19.6%;d=1.5,p<0.01);were evident at Week 8.The PTG showed improvements in CoD(△=2.1%;d=1.3,p<0.05);standing long jump(△=9.3%;d=1.1,p<0.01);countermovement jump(△=16.1%;d=1.2,p<0.01);and squat jump(△=16.7%;d=1.4,p<0.01);at Week 8 whereas improvements in the 20-m sprint(△=4.1%;d=1.3,p<0.01);and multiple 5 bounds(△=7.4%;d=2.4,p<0.001);were evident only after Week.The RT and PT groups showed improvements in all sprint,CoD,and jump tests(p<0.05)and in half-squat performance,for which improvement was only shown within the RTG(p<0.001).Conclusion:RT and PT conducted in combination with regular soccer training are safe and feasible interventions for prepubertal soccer players.In addition,these interventions were shown to be effective training tools to improve explosive actions with different time courses of improvements,which manifested earlier in the RTG than in the PTG.These outcomes may help coaches and fitness trainers set out clear and concise goals of training according to the specific time course of improvement difference between RT and PT on proxies of athletic performance of prepubertal soccer players.
文摘Background: Artificial turf is considered a feasible global alternative to natural turf by many sports governing bodies. Consequently, its ability to provide a safe and consistent playing surface regardless of climate becomes essential. The aims of this study were to determine the effects of artificial surface temperature on:(1) mechanical properties of the turf and(2) the kinematics of a turf-sport related movement.Methods: Two identical artificial turf pitches were tested: one with a cold surface temperature(1.8°C–2.4°C) and one with a warm surface temperature(14.5°C–15.2°C). Mechanical testing was performed to measure the surface properties. Four amateur soccer players performed a hurdle jump to sprint acceleration movement, with data(contact time, step length and hip, knee and ankle kinematics) collected using CODASport(200 Hz).Results: The temperature difference had a significant influence on the mechanical properties of the artificial turf, including force absorption,energy restitution, rotational resistance, and the height where the head injury criterion was met. Both step length(p = 0.008) and contact time(p = 0.002) of the initial step after the landing were significantly longer on the warm surface. In addition, significant range of motion and joint angular velocity differences were found.Conclusion: These findings highlight different demands placed on players due to the surface temperature and suggest a need for coaches,practitioners, and sports governing bodies to be aware of these differences.
基金The authors would like to acknowledge Jordyn Vienneau,Aimee(Smith)Mears,Christian Meyer,and Antonio Blago for their support in collecting data for this study.The authors would like to thank Adidas(Herzogenaurach,Germany)for providing the test shoes.
文摘Purpose This study aimed to investigate whether there is a systematic change of leg muscle activity,as quantified by surface electromyography(EMG),throughout a standard running footwear assessment protocol at a predetermined running speed.Methods Thirty-one physically active adults(15 females and 16 males)completed 5 testing rounds consisting of overground running trials at a speed of 3.5 m/s.The level of muscle activity from 6 major leg muscles was recorded using surface EMG.The variables assessed were the EMG total intensity as a function of time and the cumulative EMG overall intensity.Systematic effects of the chronological testing round(independent variable)on the normalized EMG overall intensity(dependent variable)were examined using Friedman analysis of variates and post hoc pairwise Wilcoxon signed-rank tests(α=0.05).Results There was a systematic reduction in overall EMG intensity for all 6 muscles over the time course of the running protocol(p<0.001)until the fourth testing round when EMG intensities reached a steady state.The one exception was the biceps femoris muscle,which showed a significant reduction of EMG intensity during the stance phase(p<0.001)but not the swing phase(p=0.16).Conclusion While running at a predetermined speed,the neuromuscular system undergoes an adaptation process characterized by a progressive reduction in the activity level of major leg muscles.This process may represent an optimization strategy of the neuromuscular system towards a more energetically efficient running style.Future running protocols should include a familiarization period of at least 7 min or 600 strides of running at the predetermined speed.
文摘Winter sports, including those with a focus on gliding with skis on snow, have become extremely complex in the last few decades. During the Olympic Games held in Pyeongchang,
文摘Background:Postural control has been associated with the functional impairment in persons with multiple sclerosis(pwMS).However,there is a need for reliable methods to assess postural control in early stages of the disease,when subtle changes can be difficult to detect.The aims of this study were to assess the absolute and relative reliability of a standing and a sitting posturographic protocol in minimally(Expanded Disability Status Scale≤2)and moderately(2.5≤Expanded Disability Status Scale≤4)impaired pwMS,and to analyze relationships among postural control and functional mobility and gait performance.Methods:To assess postural control in an upright stance,14 minimally and 16 moderately impaired pwMS performed six 70 s trials in tandem stance,3 with their weaker leg behind(TSWL)and 3 with their stronger leg behind(TSSL).Additionally,participants completed five 70 s trials using an unstable sitting protocol(US)to assess trunk stability.The mean radial errors of TSWL,TSSL,and US trials were calculated as postural control indexes.Furthermore,participants performed the Timed Up and Go test(TUG)and the Timed 25-foot Walk test(T25FW)to measure their functional mobility and gait speed,respectively.Reliability was evaluated using the intraclass correlation coefficient(ICC3,1)and the standard error of measurement(SEM).Analyses of variances were carried out to assess between-group differences.Hedges’g index(dg)was used to estimate the effect size of differences.Pearson correlation analyses(r)were performed to examine the relationships among the postural control and the functional tests.Results:Posturographic tests showed a high reliability in both minimally(0.87≤ICC≤0.92;9.32%≤SEM≤11.76%)and moderately(0.80≤ICC≤0.92;10.33%≤SEM≤15.33%)impaired pwMS.Similarly,T25FW and TUG displayed a high consistency in minimally(0.89≤ICC≤0.94;3.43%≤SEM≤5.17%)and moderately(0.85≤ICC≤0.93;5.57%≤SEM≤6.56%)impaired individuals.Minimally impaired pwMS showed a better performance on the TUG,T25FW,and TSWL than moderately impaired individuals(p<0.05;dg≥0.8).The TSWL,TSSL,and US variables correlated with TUG scores(0.419≤r≤0.604;p<0.05),but TSWL also correlated with T25FW scores(r=0.53;p<0.01).Furthermore,US scores correlated with both tandem stance parameters(TSWL:r=0.54,p<0.01;TSSL:r=0.43,p<0.05).Conclusion:Tandem and sitting posturographic tests provide reliable measures of postural control in pwMS,even in individuals with a homogeneous disease profile.Gait speed,functional mobility,and weaker leg status seem decisive in assessing the degree of physical activity limitation in pwMS.Finally,although trunk stability does not seem to be so affected by the course of the disease,it remains relevant for postural control and functional capacity.
文摘In this study, we investigated the effect of sodium bicarbonate (NaHCO3) supplementation at a dose of 0.2 g·kg−1 40 min before an exercise on intermittent endurance performance and gastrointestinal distress. The participants were six healthy male students of a university. The Yo-Yo intermittent recovery test level 2 (Yo-Yo IR2) was used for the evaluation of intermittent endurance. The participants ingested water (Cont) or NaHCO3 independently at three timings. After drinking water, the Yo-Yo IR1 was performed for 2 min as warm-up. After resting for 5 min, the Yo-Yo IR2 was initiated. The measurement items were exercise distance, nutrition intake, biochemical test results, and blood gas analysis findings. The participants who ingested NaHCO3 had a 14% extended distance than those who ingested Cont, and 2/3 of those who took NaHCO3 showed a better motor performance. No significant difference was observed between the participants who took Cont and NaHCO3 in terms of pH level at baseline, and the NaHCO3 level was significantly higher during pre- and post-exercise (p 3 in terms of bicarbonate ion level at baseline, and the NaHCO3 level was significantly higher during pre- and post-exercise (p 3 at a low dose (0.2 g·kg−1), their exercise ability during an intermittent endurance test has improved. Furthermore, when digestive absorption is considered, eating a meal in advance may be able to suppress the onset of gastrointestinal distress.
文摘The aim of the study was to investigate associations between psychological and biological changes due to resistance training in people with impaired glucose tolerance (IGT). Subjects were randomized into maximal (MRT) versus endurance resistance training (ERT) groups. Intervention periods lasted four months. All subjects had blood work that suggested IGT at the initial screening. The ERT acted as a wait-list control group when the MRT performed their training. Baseline scores on general life satisfaction (LISAT) and sense of humor (SHQ-6: a positive coping resources) were obtained. Potential differences between groups (types of intervention and intervention versus control) were investigated by analysis of variance (one-way ANOVA). Correlations were calculated in each group to estimate the degree of covariance between biological and psychological changes from pre- to post-intervention by Pearson and Spearman coefficients. Sense of humor tended to be correlated with a positive reduction of insulin following MRT as well as with reduction in body fat following ERT. Differences across the intervention groups in changes from pre- to post-training in biological variables (glucose, insulin, muscle mass, and corrected percentage of fat) as well as psychological variables (general life satisfaction and sense of humor) were not significant, whereas differences in BMI and weight were significant. By investigating the intervention groups separately in comparison to the control group, the MRT revealed significant improvement by reduction in insulin, percentage of fat, BMI and weight. The ERT caused significant improvements for insulin and percentage of fat, while general life satisfaction had a significant negative development.
文摘Motile cells of the green alga, Ulva fasciata respond to the quantity and quality of irradiance simultaneously. The specific responses of motile cell types (gametes and spores) by irradiance influence migration behavior in coastal water environment. Gametes maximally aggregated at the highest white light intensity (250 μmol·m-2·s-1), while spores maximally aggregated in the dark (0 μmol m-2·s-1) of this study. Gametes maximally aggregated in green irradiance over blue, red and dark while spore maximally aggregated in the dark. The results of quantity are spectral responses are likely to be underline the ecological success and physiological strategies in varied irradiance environments includes: 1) gametes respond to specific quantities and spectral irradiance;2) spores respond negatively to quantity and quality of irradiance to enhance the probability of finding substratum;and 3) populations of adults that come from these motile cells behaviors. The specific quantities and spectral qualities of irradiance responses show specific ecological migration that can be attributed to photosynthesis under limiting irradiance in coastal waters for the motile cells of U. fasciata.
文摘This study aimed to determine the appropriate nutritional intakes and dietary habits of high school-aged cross-country skiers and speed skaters. The subjects, all high school students from N Prefecture, included 18 male cross-country skiers, 5 male speed skaters, 10 female cross-country ski players and 4 female speed skaters. Physical measurements, food intake frequency survey results, bone mineral density and exercise stress test outcomes, and lactic acid measurements were evaluated. Female athletes in both sports had higher body fat percentages relative to the average range stated for female athletes. Male speed skaters had a significantly higher maximum oxygen in-take than that male cross-country skiers did. By contrast, this parameter did not differ significantly among female athletes. A negative correlation was observed between the fat free mass and muscle mass, and a positive correlation was observed among the body fat percentage, fat percentage, and fat mass. Both male and female athletes had protein intake ratios within the reference ranges. All athletes except male speed skaters had lipid energy ratios that were higher than the upper limit of the reference value. Both male and female athletes also reported carbohydrate energy ratios within the reference ranges, but had cereal energy ratios below the reference values. Athletes should pay attention to the ingestion of various nutrients to ensure a sufficient energy intake. Accordingly, adolescent athletes should consume daily meals containing a good balance of staple foods, main dishes, side dishes, milk and other dairy products, and fruits.
文摘Background:Evidence supports the anti-inflammatory effect of exercise-based cardiac rehabilitation(CR)in patients with cardiovascular disease(CVD).Nonetheless,the influence of training variables on the effects of exercise training is debateable.Therefore,this systematic review with meta-analysis aims to i)estimate the effects of exercise-based CR on the circulating levels of inflammatory biomarkers in patients with CVD based on the type of exercise,and ii)analyse the influence of other potential moderator variables.Methods:Electronic searches were performed in PubMed,Scopus,and Web of Science databases up to October 2022.A random-effects models of standardised mean difference(SMD)were used.Subgroup analyses and meta-regressions were used to carry out heterogeneity analyses.Results:Aerobic exercise diminished the levels of C-reactive protein compared with the control group in patients with CVD(SMD+=-0.33[95%CI=-0.47,-0.20),as well as the levels of tumor necrosis factor-alfa exclusively in patients with chronic heart failure(SMD+=-0.38[95%CI=-0.59,-0.17]).Moreover,heterogeneity analyses showed that the effect of aerobic exercise on vascular cell adhesion molecule-1 is higher in studies that carried out a CR programme based exclusively on exercise,as well as in studies that performed a shorter intervention period or carried out a lower number of exercise sessions(P≤0.05).Conclusion:Our findings support the anti-inflammatory effect of aerobic exercise in patients with CVD.The low number of studies testing interventions using resistance or combined exercise precludes a definitive answer about their anti-inflammatory effects in this patient population.
文摘Regular physical activity(PA)promotes healthy aging,and activities aiming to increase muscular strength(i.e.,resistance exercise(RE))are important PA modalities for achieving health benefits.Previous meta-analyses demonstrated that both RE^(1) and muscular strength^(2) were associated with mortality benefits,even when RE was performed above the PA targets recommended by current guidelines^(1,3).
文摘Purpose: The aims of this study were to assess differences of limb symmetry index(LSI) in strength-and coordination-related tasks between high-level, competitive, noninjured ski racers of different age-related performance levels and to prospectively assess limb differences as a possible risk factor for traumatic and overuse injury in youth ski racers.Methods: The study(Study 1) included 285 high-level competitive ski racers(125 females, 160 males) of 3 age-related performance levels and based on the school system: 95 youth(10à14 years, secondary modern school), 107 adolescent(15à19 years, grammar school), and 83 elite athletes(20à34 years). To investigate the second aim(Study 2), 67 of the 95 youth athletes were included and any traumatic or overuse injuries were prospectively recorded over 2 seasons. All athletes performed 4 unilateral tests(strength related: one-leg counter movement jump(OL-CMJ) and one-leg isometric/isokinetic press strength test(OL-ILS); coordination related: one-leg stability test(OL-ST) and one-leg speedy jump test(OL-SJ)). The LSI was calculated by dividing the dominant leg by the nondominant leg and multiplying by 100. Kruskal-Wallis H tests and binary logistic regression analyses were conducted.Results: There were significant differences between the LSI of the 3 age-related performance-level groups only in the strength-related tests: the OL-CMJ(x2(2, 285) = 9.09; p = 0.01) and the OL-ILS(x2(2, 285) = 14.79; p < 0.01). The LSI for OL-ILS was found to be a significant risk factor for traumatic injury in youth ski racers(Wald = 7.08; p < 0.01). No significant risk factors were found for overuse injuries.Conclusion: Younger athletes display slightly greater LSI values only in the strength-related tests. The cut-off value of limb differences of <10%for return to sport decisions seems to be appropriate for elite athletes, but for youth and adolescent athletes it has to be critically discussed. It seems to be necessary to define thresholds based on specific performance tasks(strength vs. coordination related) rather than on generalizations,and age-related performance levels must be considered. Limb differences in unilateral leg extension strength represent a significant injury risk factor in youth ski racers.
