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The relationship between structural changes in the cerebral gray matter and diminished balance control performance in patients with chronic ankle instability (CAI) has remained unclear. This paper aimed to assess the difference in gray matter volume (GMV) between participants with CAI and healthy controls (HC) and to characterize the role of GMV in the relationship between disease duration and balance performance in CAI. 42 participants with CAI and 33 HC completed the structural brain MRI scans, one‐legged standing test, and Y‐balance test. Regional GMV was measured by applying voxel‐based morphometry methods. The result showed that, compared with HC, participants with CAI exhibited lower GMV in multiple brain regions (familywise error [FWE] corrected p < 0.021). Within CAI only, but not in HC, lower GMV in the thalamus (β = −0.53, p = 0.003) and hippocampus (β = −0.57, p = 0.001) was associated with faster sway velocity of the center of pressure (CoP) in eyes closed condition (i.e., worse balance control performance). The GMV in the thalamus (percentage mediated [PM] = 32.02%; indirect effect β = 0.119, 95% CI = 0.003 to 0.282) and hippocampus (PM = 33.71%; indirect effect β = 0.122, 95% CI = 0.005 to 0.278) significantly mediated the association between the disease duration and balance performance. These findings suggest that the structural characteristics of the supraspinal elements is critical to the maintenance of balance control performance in individuals suffering from CAI, which deserve careful consideration in the management and rehabilitation programs in this population. [ABSTRACT FROM AUTHOR]

Introduction: Heavy‐load strength training (HLT) is generally considered the Gold Standard exercise modality for inducing gains in skeletal muscle strength. However, use of heavy external exercise loads may be contraindicative in frail individuals. Low‐load resistance exercise combined with partial blood‐flow restriction (LL‐BFR exercise) may offer an effective alternative for increasing mechanical muscle strength and size. The aim of this study was to compare the effect of LL‐BFR training to HLT on maximal muscle strength gains. Prospero registration‐id (CRD42014013382). Materials and methods: A systematic search in six healthcare science databases and reference lists was conducted. Data selected for primary analysis consisted of post‐intervention changes in maximal muscle strength. A random‐effects meta‐analysis with standardized mean differences (SMD) was used. Results: Of 1413 papers identified through systematic search routines, sixteen papers fulfilled the inclusion criteria, totalling 153 participants completing HLT and 157 completing LL‐BFR training. The magnitude of training‐induced gains in maximal muscle strength did not differ between LL‐BFR training and HLT (SMD of −0.17 (95% CI: −0.40; 0.05)). Low between‐study heterogeneity was noted (I2 = 0.0%, Chi2P = 9.65). Conclusion: Low‐load blood‐flow‐restricted training appears equally effective of producing gains in maximal voluntary muscle strength compared to HLT in 20‐ to 80‐year‐old healthy and habitually active adults. [ABSTRACT FROM AUTHOR]

The main aim of the Swedish physical activity and fitness cohort study ( SPAF-1958) was to describe physical fitness, physical activity, health, and lifestyle across part of the lifespan, and to assess the influences on these factors from the environment, personal factors, and genetics. There is inevitable dropout from longitudinal studies, and it may be systematic. The aim of this first paper of the second follow-up of SPAF-1958 was to provide a dropout analysis to consider to what extent the participants, at 52 years of age, remain a representative sample of the original adolescent study population. Additional aims were to provide an overview of the study protocol and the ongoing study population. Ongoing study participants in SPAF born in 1958 were, at the second follow-up at the age of 52, still representative of the study cohort in terms of sex, adolescent geographical area, upper secondary school program, adolescent body composition, muscular strength, and muscular endurance. However, a higher physical activity and, among women, a higher aerobic capacity in adolescence decreased the risk for dropout. It is important when interpreting results from longitudinal studies to adjust for the systematic dropout that could bias the conclusions drawn from the results. [ABSTRACT FROM AUTHOR]

Across two studies, we tested the proposition that interdependence structures (i.e., task interaction among teammates during competition, competition against teammates, presence of a collective outcome) influence interdependence perceptions among teammates as well as perceptions of group cohesion, competitiveness, and satisfaction. Study 1 was a paper-and-pencil survey completed by 210 individual sport athletes from 12 university- and college-level teams. Multiple mediation analyses demonstrated that participants who had to work alongside teammates during competition reported increased interdependence perceptions that were, in turn, associated with increased cohesion and satisfaction as well as decreased competitiveness. There were no differences according to whether participants competed in the same event as all of their teammates or not. Study 2 involved a weekly e-mail survey with 17 university-level individual sport athletes who reported interdependence perceptions on a continual basis over the course of their competitive season. Interdependence perceptions were higher during weeks that were close in time to competitions with a collective group outcome. These studies reveal how interdependence structures shape the group environment and support applied efforts that consider ways to structure teammate interdependencies in ways to optimize group functioning and promote member satisfaction. [ABSTRACT FROM AUTHOR]

In this paper, we report survival estimates for male and female Olympic medal winners and for male and female finalists at the British and U S national tennis championships. We find a consistent longevity advantage of Olympic medal-winning female athletes over Olympic medal-winning male athletes competing separately in the same events since 1900 and for female finalists over male finalists competing separately in the finals of the national tennis championships of Britain and of the United States since the 1880s. This is the case for sample mean comparisons, for Kaplan-Meier survival function estimates, including life expectancy, and for Cox proportional hazard estimates, which show statistically significant lower hazard rates for women with birth year and other variables constant. The female longevity advantage over males is similar in the early period samples (birth years before1920) and in the full period samples, and is 5-7 years. [ABSTRACT FROM AUTHOR]

The aim of the present study was twofold: first, to determine the meeting all three 24‐h movement guidelines in Colombian preschool‐aged children, and second, to explore the associations between different socio‐ecological correlates and the meeting of these guidelines. This was a cross‐sectional study with data from the Encuesta Nacional de Situación Nutricional (ENSIN‐2015) in Colombia, 2015–2016. The sample comprised 3002 low‐income preschoolers (3–4 years old, 50.7% boys). Data on physical activity, screen time, and sleep time were collected using the Cuestionario para la Medición de Actividad Física y Comportamiento Sedentario, reported by their parents. In total, 18 potential correlates (individual, interpersonal, organizational, and community level) were analyzed. Backward binary logistic regression analysis was performed with the potential correlates as independent variables and meeting all three 24‐h movement guidelines as dependent variables. The prevalence of preschoolers meeting all three 24‐h movement guidelines or none was 4.8% and 16.6%, respectively. In the final model, boys (odds ratio [OR] = 1.87, 95% confidence interval [CI] 1.00–3.50) and those who do not have television in their bedroom (OR = 2.09, 95%CI 1.05–4.14) were more likely to meet all three 24‐h movement guidelines compared to with girls and those who have television, respectively. In conclusion, strategies to promote adherence to all 24‐h movement guidelines among low‐income preschoolers are warranted, and should focus on actions considering the importance of sex and home environment changes to support these movement behaviors. [ABSTRACT FROM AUTHOR]

Introduction: At the pandemic's beginning, significant concern has risen about the prevalence of myocardial involvement after SARS‐CoV‐2 infection. We assessed the cardiovascular burden of SARS‐CoV‐2 in a large cohort of athletes and identified factors that might affect the disease course. We included 633 athletes in our study on whom we performed extensive cardiology examinations after recovering from SARS‐CoV‐2 infection. More than half of the athletes (n = 322) returned for a follow‐up examination median of 107 days after the commencement of their infection. Results: Troponin T positivity was as low as 1.4% of the athletes, where the subsequently performed examinations did not show definitive, ongoing myocardial injury. Altogether, 31% of the athletes' rapid training rebuild was hindered by persistent or reoccurring symptoms. Female athletes reported a higher prevalence of return to play (RTP) symptoms than their male counterparts (34% vs. 19%, p = 0.005). The development of long COVID symptoms was independently predicted by increasing age and acute symptoms' severity in a multiple regression model (AUC 0.75, CI 0.685–0.801). Athletes presenting with either or both cough and ferritin levels higher than >150 μg/L had a 4.1x (CI 1.78–9.6, p = 0.001) higher odds ratio of developing persistent symptoms. Conclusion: While SARS‐CoV‐2 rarely affects the myocardium in athletes, about one in three of them experience symptoms beyond the acute phase. Identifying those athletes with a predisposition to developing long‐standing symptoms may aid clinicians and trainers in finding the optimal return‐to‐play timing and training load rebuild pace. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the association between individual and school characteristics associated with the number of school days children comply with moderate-to-vigorous physical activity ( MVPA) recommendations. Sample comprises 612 Portuguese children, aged 9-11 years, from 23 schools. Time spent in MVPA was measured by accelerometry, while individual-level correlates were obtained by anthropometry and questionnaires. School-level variables were collected by questionnaire, and accelerometer wear time and season were also considered. Maximum likelihood estimates of model parameters were obtained via a multilevel analysis with children as level-1, and school as level-2. Children who spent more time in sedentary activities and girls were less likely to comply with MVPA/daily. More mature children and those who use active transportation to school were more likely to attain the PA recommendation. Furthermore, greater accelerometer wear time and spring season increased the chance to achieve the recommended MVPA. In terms of school-level correlates, a greater number of available facilities was negatively associated with children MVPA compliance. Given the set of variables, our results showed that individual characteristics seem to be more relevant for children's compliance rates with PA/day than school context variables, which should be taken into account in the implementation of school policies and practices. [ABSTRACT FROM AUTHOR]

Deficits in muscles of the lumbo-pelvic region, such as a relatively small multifidus muscle, have been used to predict lower limb injuries in professional football players. Results have been less consistent for the size of the quadratus lumborum ( QL) muscle. Changes in size of the multifidus and QL muscles could be functionally related to each other, and modeling this relationship could improve prediction of lower limb injuries. Ultrasound imaging examinations were performed on male elite football players at the start of the Australian Football League ( AFL) pre-season and playing season. Injury data were obtained from records collected by each club. Results indicated that the cross-sectional area of the multifidus muscle was related to the occurrence of an injury in the pre-season (odds ratio [ OR] = 2.08/cm2 decrease below the mean; OR for dichotomized measure = 12.2) and in the season ( OR = 2.43/cm2). The size of the QL muscle was significantly related to an injury in the pre-season ( OR = 2.12/cm2 increase above the mean; OR for dichotomized measure = 7.26) but not in the season. A significant link was found between the ratio of the multifidus and QL muscles, and the incidence of pre-season ( OR = 14.71) and season injuries ( OR = 5.29). The sensitivity and specificity of the model in the pre-season were 75% and 85.7%, respectively; values for the playing season were 88.4% and 62.5%. A model was developed for prediction of lower limb injuries in football players. Combining size measurements of the multifidus and QL muscles improved predictive power. This information may have clinical implications for injury screening and prevention. [ABSTRACT FROM AUTHOR]

The objective of this study was to estimate the incidence and prevalence of injury and illness among elite junior tennis players. A cohort of 73 players (11-14 years) in the 2012-2013 Dutch national high-performance program was followed for 32 weeks; all participants completed the study. The OSTRC Questionnaire on Health Problems was used to record self-reported injuries and illnesses and to record training and match exposure. Main outcome measures were average prevalence of overuse injury and illness and incidence density of acute injury. On average, players practiced 9.1 h/week ( SD 0.6; range 2.3-12.0) and had 2.2 h of match play ( SD 0.6; range 2.3-12.0). During the course of the study, 67 players reported a total of 187 health problems. The average weekly prevalence of all health problems was 21.3% (95% CI: 19.2-22.9), of which 12.1% (95% CI: 10.9-13.3) constituted overuse injuries and 5.8% (95% CI: 4.6-6.9) illnesses. The incidence of acute injuries was 1.2/1000 h of tennis play (95% CI: 0.7-1.7). The high occurrence of overuse injuries among elite junior tennis players suggests that an early focus on preventative measures is warranted, with a particular focus on the monitoring and management of workload. [ABSTRACT FROM AUTHOR]

To determine the 1-year self-reported incidence of overuse and traumatic sport injuries and risk factors for injuries in children participating in a summer sports camp representing seven different sports. 4363 children, 11 to 15 years old participating in a summer camp in seven different sports answered a questionnaire. Injury in this cross-sectional study was defined as a sport-related trauma or overload leading to pain and dysfunction preventing the person from participation in training or competition for at least 1 week. A number of risk factors for injury were investigated such as sex, age, number of hours spent on training in general, and on resistance training with weights. Nearly half [49%, 95% confidence interval ( CI) 48-51%] of the participants had been injured as a result of participation in a sport during the preceding year, significantly more boys than girls (53%, 95% CI 50-55% vs 46%, 95% CI 43-48%; P < 0.001). Three factors contributed to increased incidence of sport injuries: age, sex, and resistance training with weights. Time spent on resistance training with weights was significantly associated with sport injuries in a logistic regression analysis. In children age 11 to 15 years, the risk of having a sport-related injury increased with age and occurred more often in boys than in girls. Weight training was the only modifiable risk factor that contributed to a significant increase in the incidence of sport injuries. [ABSTRACT FROM AUTHOR]

Physical activity is favorable for peak bone mass but if the skeletal benefits remain and influence fracture risk in old age is debated. In a cross-sectional controlled mixed model design, we compared dual X-ray absorptiometry-derived bone mineral density ( BMD) and bone size in 193 active and retired male elite soccer players and 280 controls, with duplicate measurements of the same individual done a mean 5 years apart. To evaluate lifetime fractures, we used a retrospective controlled study design in 397 retired male elite soccer players and 1368 controls. Differences in bone traits were evaluated by Student's t-test and fracture risk assessments by Poisson regression and Cox regression. More than 30 years after retirement from sports, the soccer players had a Z-score for total body BMD of 0.4 (0.1 to 0.6), leg BMD of 0.5 (0.2 to 0.8), and femoral neck area of 0.3 (0.0 to 0.5). The rate ratio for fracture after career end was 0.6 (0.4 to 0.9) and for any fragility fracture 0.4 (0.2 to 0.9). Exercise-associated bone trait benefits are found long term after retirement from sports together with a lower fracture risk. This indicates that physical activity in youth could reduce the burden of fragility fractures. [ABSTRACT FROM AUTHOR]

The aim of this investigation was to give insights into the impact of endurance training on oral health, with regard to tooth erosion, caries, and salivary parameters. The study included 35 triathletes and 35 non-exercising controls. The clinical investigation comprised oral examination, assessment of oral status with special regard to caries and erosion, saliva testing during inactivity, and a self-administered questionnaire about eating, drinking, and oral hygiene behavior. In addition, athletes were asked about their training habits and intake of beverages and sports nutrition. For saliva assessment during exercise, a subsample of n = 15 athletes volunteered in an incremental running field test ( IRFT). Athletes showed an increased risk for dental erosion ( P = 0.001). No differences were observed with regard to caries prevalence and salivary parameters measured during inactivity between athletes and controls. Among athletes, a significant correlation was found between caries prevalence and the cumulative weekly training time ( r = 0.347, P = 0.04). In athletes after IRFT and at maximum workload, saliva flow rates decreased ( P = 0.001 stimulated; P = 0.01 unstimulated) and saliva pH increased significantly ( P = 0.003). Higher risk for dental erosions, exercise-dependent caries risk, and load-dependent changes in saliva parameters point out the need for risk-adapted preventive dental concepts in the field of sports dentistry. [ABSTRACT FROM AUTHOR]

Sports injuries could be highly detrimental to the career of a physical education teacher education ( PETE) student. To enable the development of future sports injury prevention programs, sports injuries in 128 first-year academic bachelor PETE students were registered prospectively during one academic year. Common risk factors for sports injuries, taken from the literature, were also evaluated by means of logistic regression analysis. We found an incidence rate of 1.91 and an injury risk of 0.85, which is higher than generally found in a sports-active population. Most injuries involved the lower extremities, were acute, newly occurring injuries, and took place in non-contact situations. More than half of all injuries lead to an inactivity period of 1 week or more and over 80% of all injuries required medical attention. A major part of these injuries happened during the intracurricular sports classes. Few differences were seen between women and men. A history of injury was a significant risk factor ( P = 0.018) for the occurrence of injuries, and performance of cooling-down exercises was significantly related to a lower occurrence of ankle injuries ( P = 0.031). These data can inform future programs for the prevention of sports injuries in PETE students. [ABSTRACT FROM AUTHOR]

This study aimed to observe the incidence rates of hamstring strain injuries ( HSIs) across different competition levels and ages during the Penn Relays Carnival. Over a 3-year period, all injuries treated by the medical staff were recorded. The type of injury, anatomic location, event in which the injury occurred, competition level, and demographic data were documented. Absolute and relative HSI (per 1000 participants) were determined, and odds ratios ( ORs) were calculated between sexes, competition levels, and events. Throughout the study period 48 473 athletes registered to participate in the Penn Relays Carnival, with 118 HSIs treated by the medical team. High school girls displayed lesser risk of HSI than high school boys ( OR = 0.55, P = 0.021), and masters athletes were more likely than high school- ( OR = 4.26, P < 0.001) and college-level ( OR = 3.55, P = 0.001) athletes to suffer HSI. The 4 × 400-m relay displayed a greater likelihood of HSI compared with the 4 × 100-m relay ( OR = 1.77, P = 0.008). High school boys and masters-level athletes are most likely to suffer HSI, and there is higher risk in 400-m events compared with 100-m events. [ABSTRACT FROM AUTHOR]

This study aimed to compare objectively recorded physical activity ( PA) levels and walking steps among pregnant women. Cross-sectional data from a multiethnic cohort ( n = 823) of pregnant women consisting of 44% from Western countries, 24% from South Asia, 14% from Middle East, and 18% from other countries. PA and steps were recorded by the activity monitor SenseWear™ Pro3 Armband. A total of 678 women were included in the analysis. Western women walked significantly more steps and had higher moderate-to-vigorous-intensity physical activity ( MVPA) levels compared with South Asian women per weekday and weekend day. Interaction terms ( P = 0.008) between ethnicity ( Western vs South Asian) and parity, and education, respectively, were identified: having ≥1 children was positively associated with steps during weekends in South Asians in contrast to Western women. Having <12 years education was associated with more MVPA time among South Asians in contrast to Western women. South Asian women are prone to low levels of PA during pregnancy and South Asian women without children and with higher education may have an elevated risk for an inactive lifestyle during pregnancy. [ABSTRACT FROM AUTHOR]

The purpose of this review was to determine whether very elderly muscle (>75 years) hypertrophies in response to physical training. The databases MEDLINE; EMBASE; CINAHL Plus and SPORTDiscus were systematically literature searched with reference lists of all included studies and relevant reviews. Controlled trials (inactive elderly control group) involving healthy elderly participants over 75 years participating in an intervention complying with an established definition of physical training were included. Data extraction and quality assessment were performed using the PEDro scale. Data analysis was performed on muscle size and strength using Rev Man (software version 5.1). Four studies were included of which four of four measured changes in gross muscle size. Training induced increases in muscle size from 1.5%-15.6% were reported in three of four studies, and one of four studies reported a decrease in muscle size (3%). The greatest gain in muscle mass was observed in a study of whole body vibration training. Meta-analysis of three studies found an increase of thigh muscle cross-sectional area (mean difference 2.31 cm2 or 0.2%, 95% confidence interval ( CI): 0.62 to 4.00; P = 0.008) and muscle strength (standardized mean difference 1.04, 95% CI: 0.65 to 1.43; P < 0.001). Physical training when delivered as resistance training has the ability to elicit hypertrophy and increase muscle strength in very elderly muscle. [ABSTRACT FROM AUTHOR]

Clinical outcomes of anterior cruciate ligament ( ACL) reconstruction with double-bundle and single-bundle techniques are still controversial. We therefore performed a systematic review to compare postoperative outcomes between the two techniques. Randomized control trials comparing the outcomes between the two techniques were identified from Medline and EMBASE since inception to April 27, 2011. Data were independently extracted by two reviewers. Thirteen of 318 studies were eligible; 9, 11, 7, and 8 studies were pooled for rotation, translation, function, and complication outcomes, respectively. The double-bundle technique was approximately four times (95% CI: 2.65, 11.99) and two times (95% CI: 1.16, 5.21) more likely to show a normal pivot shift and normal International Knee Documentation Committee ( IKDC) grading compared with the single-bundle technique. However, there were nonsignificant differences in KT grading ( OR = 1.66, 95% CI: 0.77, 3.82), IKDC score (0.29, 95% CI: −1.17, 1.75), Lysholm knee score (−0.87, 95% CI: −2.66, 0.93), Tegner activity score (0.37, 95% CI: −0.05, 0.79), and complications ( OR = 1.11, 95% CI: 0.48, 2.57). Heterogeneity was present in some outcomes but there was no evidence of publication bias for any outcome. The double-bundle may be better than the single-bundle ACL reconstruction technique in rotational stability but not for function, translation, and complications. [ABSTRACT FROM AUTHOR]