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Featured Application: This work analyzes the current state of the physical rehabilitation field focused on the techniques, devices, and methods used with children and adolescents. Moreover, we present improvements of a gamification-based software prototype for home rehabilitation of young patients, based on this study and a previous experiment. Physical rehabilitation of people who suffer from some motor disability involves an intensive treatment to reduce pain and improve quality of life. Research studies have proven the benefits of technologies based on home-rehabilitation, which complement regular therapy in hospitals. Although there is a significant number of studies that face this challenge when dealing with adults, it has not been explored with young people. In this research article, we focus on this population, since the repetition of physical exercises decreases the youth's motivation, which entails a high risk of dropping out of therapy. That is why we present a systematic mapping study of the techniques, devices, and methods used to address home rehabilitation for children and teenagers. The conclusions indicate that it is essential to use gamification techniques to adopt a plug-and-play metaphor, based on natural interaction mechanisms and on the use of non-intrusive devices, and to customize the rehabilitation process for each individual along with a methodology. We also present the improvements applied to an existing gamification-based software prototype for home rehabilitation. In this system, physical exercises can be customized, laying the foundations to promote precision rehabilitation within the context of young people. [ABSTRACT FROM AUTHOR]

Wearing barefoot-style (minimalist) shoes is suggested as a transition between wearing shoes and barefoot running. Some sources equate wearing Vibram FiveFingers™(VFFs), a brand of barefoot shoes, with running/walking barefoot. Static and dynamic balance exercises are recommended. Little information is available on the effects barefoot shoes may have on dynamic balance. This study's purpose was to examine dynamic balance when participants wore VFFs, athletic shoes, or went barefoot (BF). To test dynamic balance, participants used a modified version of the Star Excursion Balance Test (SEBT), in which the reaching leg followed only three spokes of the test: the anterior, posteromedial and posterolateral. For the timed test, participants touched down as quickly as possible in both directions using all 8 spokes. Thirty participants (ages 24.1+/-3.71 years) without lower extremity injury or experience wearing minimalist shoes were tested using the modified SEBT and a timed test wearing VFFs™, athletic shoes, or BF. Three trials for each footwear were completed for three reaching positions: anterior, posterolateral, posteromedial. The timed test measured (seconds) one counterclockwise and one clockwise direction of the 8-spoke figure. A repeated measures analysis of variance determined if any differences existed between footwear type and studied variables. Anterior reach was significantly greater when wearing shoes than with VFF or BF. Posteromedial reach was greater with shoes than BF. Time trials were not significantly different. Because no difference was found in any measured variables between VFF and BF, the results suggest wearing VFFS™ provided similar dynamic balance as going barefoot. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to examine the convergent validity of the PLAYfun tool, a physical literacy-based measure of movement competence, by examining its association with objectively measured physical activity in a sample of children and youth. Method: Participants included 110 children between the ages of seven to 14 years attending a stratified random sample of 27 afterschool programs across the province of Ontario, Canada. The PLAYfun tool was administered to the participants on one occasion at their afterschool program and then they were asked to wear a pedometer for seven consecutive days to measure their physical activity levels. A series of multiple linear regression models were used to examine the association between PLAYfun scores and physical activity, while controlling for age, sex, and time of year (season) in which the data were collected. Results: On its own, the PLAYfun average score accounted for close to 13% of the variance in physical activity, R = .36, R2 = .13, p < .001. The PLAYfun average score was also a significant independent predictor of physical activity, b (SE) = 145.98 (53.46), p < .01, when controlling for age, sex, and season in which the data were collected, R2 = .30, F (4, 105) = 11.04, p < .001. Conclusion: Results from the present study indicate that the PLAYfun tool is a significant predictor of objectively measured physical activity, supporting the convergent validity of the tool. [ABSTRACT FROM AUTHOR]

Background: Leisure-time physical activity is a term used by physical activity researchers to describe physical activity undertaken during nonwork time. In this study we explore how young people speak about physical activity in relation to leisure. Methods: Eight focus groups and one group interview were conducted with 50 participants aged 16-26 years. Participants included males and females, rural and urban dwellers, and a mixture of active/inactive young people. Focus group transcripts underwent an iterative thematic analysis. Results: Participants found it difficult to recognize leisure time activities in their day to day lives and only rarely mentioned their physical activity involvement when asked about leisure time activities. When discussing physical activity study participants commonly focused on high intensity physical activity such as sport and gym use. Three major themes relating to leisure and physical activity were identified: the meanings ascribed to physical activity, the experience of physical activity, and routines of participation. Conclusion: These findings suggest that the relationship between physical activity and leisure is complex and the term leisure with its associated concepts of satisfaction, relaxation and pleasure may not accurately refect the way young people view their participation in physical activity. [ABSTRACT FROM AUTHOR]

Background: Most children in the United States receive far less physical activity (PA) than is optimal. In rural, under resourced areas of Appalachian Kentucky, physical inactivity rates are significantly higher than national levels. We sought to understand children's perceptions of PA, with the goal of developing culturally appropriate programming to increase PA. Methods: During 11 focus groups, we explored perspectives on PA among 63 Appalachian children, ages 8-17. Sessions were tape recorded, transcribed, content analyzed, and subjected to verification procedures. Results: Several perspectives on PA emerged among these rural Appalachian youth, including the clear distinction between PA (viewed as positive) and exercise (viewed as negative) and an emphasis on time and resource factors as barriers to adequate PA. Additional PA determinants expressed in the focus groups are similar to those of other populations. We include children's recommendations for appealing PA programs. Conclusions: Appalachian and other rural residents contend with the loss of rural health advantages (due to declines in farming/other occupational and a vocational transitions). At the same time, Appalachian residents have not benefitted from urban PA facilitators (sidewalks, recreational facilities, clubs and organized leisure activities). Addressing low PA levels requires extensive community input and creative programming. [ABSTRACT FROM AUTHOR]

Background: This study aimed to examine the relationship between screen time and physical activity (PA) in children and adolescents but also to determine specific elements of PA that were most closely associated with screen time. Methods: We studied a cross-sectional sample of 6176 10.0-15.9 year olds (53% boys, 12.9 ± 1.5 years) who completed the Physical Activity Questionnaire for Children/Adolescents and reported daily screen time. Differences in total PA and specific elements of PA were examined between groups reporting: < 2 h, 2-4 h, and > 4 h daily screen time. Results: There were significant differences between screen time groups in: total PA, number of bouts of PA reported, after school PA, evening PA and weekend PA (P < .0001). There was a graded, negative association between higher screen time and lower free-time PA. Participants reporting < 2 h screen time were also significantly more active during school lunch breaks than those reporting > 2 h. Boys reporting > 4 h screen time were less active during physical education lessons. Conclusions: Screen time is significantly and negatively associated with PA in British youth. Screen time may displace active pursuits out of school but is also associated with lower PA during school. Daily screen time should be limited to < 2 h in line with current recommendations. [ABSTRACT FROM AUTHOR]

Background: Despite frequent use of pedometers in interventions targeting youth PA, there is no literature that addresses the prevalence and reasons for protocol nonadherence. Methods: Adherence behaviors of early adolescents (n = 43; Meanage = 12.3 ± 1.0) in an 8-week, faith-based intervention were monitored/recorded. Students provided reasons for various aspects of protocol breach, which were used to develop a post intervention questionnaire. Analyses included calculations of frequency/percentage as well as cross tabulations/chi square to detect gender/age differences. Results: Over the intervention, recording PA in logs decreased by 85% and was attributed to forgetfulness and lack of time. For pedometers, highest-frequency events included error codes (n = 501), incorrect wear (37%, ≥ 1 day), and shaking (58%-69%, ≥ 1 time). Top reasons for shaking were to make up for lost step opportunities and get further along the route. Of permissible stepping strategies, males used ambulatory activity on the playground and stair usage more, while 6th graders used speed stepping in place more than their respective counterparts. Conclusions: Students admit to basal levels of nonadherence, which should be taken into consideration when designing/implementing interventions. Integrating intervention tasks into the regular curriculum and providing sufficient opportunities to perform them may alleviate some barriers to adherence. Future research should attempt to confirm results in other school types/levels as well as quantify these behaviors in free-living or unstructured settings. [ABSTRACT FROM AUTHOR]

School-community partnerships have shown their potential as incubators for innovations and for contributing to comprehensive physical activity (PA) programs. However, implementation frameworks for school-community partnerships that allow local tailoring of PA programs remain scarce. The present paper aims at documenting the composition of a framework for PA programs within schoolcommunity partnerships. The framework addresses socioecological strategies to promote extracurricular PA opportunities for pupils, which are integrated into five complementary components. To implement and reinforce the five components of the framework, involvement of schools, pupils, family, and community is facilitated by sustainable partnerships between these stakeholders. Partnerships are not only recommended on the school and community level, but also on a broader regional level that covers multiple communities. The development of the framework was an effort to integrate school-community partnerships into a flexible implementation framework for PA promotion. Implications of the framework for research agendas, professional education, and policy are formulated. [ABSTRACT FROM AUTHOR]

Background: Researchers have noted both the utility and limitations of using pedometers to measure physical activity (PA). While these unobtrusive devices are widely accepted for their ability to measure accumulated PA, they have been criticized for their inability to measure exercise intensity. However, recent steps-per-minute (SPM) research provides reasonably accurate measures of intensity allowing users to assess time spent at recommended PA levels. Therefore, the purpose of this study was to determine the SPM taken that are associated with moderate physical activity in 12- to 14-year-old youth. Methods: Ninety-three participants (49 boys and 44 girls; ages 12 to 14) walked on a treadmill for 3 minutes at each of 4 different speeds while wearing a pedometer and a heart rate monitor. Results: On average boys and girls reached their moderate activity intensity threshold at 122 SPM and 102 SPM, respectively. However, individual differences must be taken into account when determining appropriate SPM intensities for youth. Conclusions: The impact of individual differences underscores the need to address SPM for moderate intensity individually rather than with a single guideline for everyone at this age. [ABSTRACT FROM AUTHOR]

Little is known about the prevalence and motives of supplement use among elite young athletes who compete on national and international levels. Therefore, the current survey was performed to assess information regarding the past and present use of dietary supplements among 164 elite young athletes (16.6 ± 3.0 years of age). A 5-page questionnaire was designed to assess their past and present (last 4 weeks) use of vitamins, minerals, carbohydrate, protein, and fat supplements; sport drinks; and other ergogenic aids. Furthermore, information about motives, sources of advice, supplement sources, and supplement contamination was assessed. Eighty percent of all athletes reported using at least 1 supplement, and the prevalence of use was significantly higher in older athletes (p < .05). Among supplement users, minerals, vitamins, sport drinks, energy drinks, and carbohydrates were most frequently consumed. Only a minority of the athletes declared that they used protein/amino acids, creatine, or other ergogenic aids. Major motives for supplement use were health related, whereas performance enhancement and recommendations by others were less frequently reported. Supplements were mainly obtained from parents or by athletes themselves and were mostly purchased in pharmacies, supermarkets, and health-food stores. Among all athletes, only 36% were aware of the problem of supplement contamination. The survey shows that supplement use is common and widespread among German elite young athletes. This stands in strong contrast to recommendations by leading sport organizations against supplement use by underage athletes. [ABSTRACT FROM AUTHOR]

The article presents the current performance capacity in 11-15 year old Dutch adolescents who participated in an incremental cycle test (n = 509) and or in a shuttle run test (N = 1,198). Cycle test results increased significantly with age in both genders, also after normalization to body weight. Shuttle run test results increased significantly with age only in boys. Compared with previous data, the absolute performance capacity in the cycle tests was comparable to data from 15 years ago, whereas the performance capacity normalized to kg body weight and the shuttle run test results seem to be fairly lower compared with the former data. [ABSTRACT FROM AUTHOR]

The aim of this study was to determine if maximal effort, evidenced by peak HR was attained during the 20m shuttle-run test in a naturalistic setting. Shuttle-run test performance and peak HR were measured in 208 volunteers (11-16 years). Peak HR was 196 (95% confidence interval (C.I.) 194-198 bpm). The relationship between test performance and peak HR was assessed by regression. There was a weak, but statistically significant relationship between test performance and peak HR (R² = .029, p = .029) but with such a low coefficient of determination (less than 5% criterion), poor performances were not associated with low peak HR values or underestimation of maximal performance. Peak HR values (196 bpm) were higher than cited criterion values (185 bpm) for maximal effort in laboratory studies. In a naturalistic setting, the 20m shuttle-run test elicits a maximal effort in most children. [ABSTRACT FROM AUTHOR]

Cross-sectional associations between sociocultural factors and objectively-measured physical activity in a sample of 397 children (aged 9) and 213 adolescents (aged 15) were investigated. Associations with children's physical activity were found for mothers' physical activity (β=80, p < .01), parental participation (β=67, p = .01), mother's age (β=-8, p < .01) and, in girls, fathers' physical activity (β=73, p = .045; R² for final model: 10.6%). No sociocultural factors were significantly associated with adolescents' physical activity. Parental factors might be important targets for interventions to increase children's physical activity but other factors may have greater influence. For adolescents' physical activity, factors from other domains may be more important to target. [ABSTRACT FROM AUTHOR]

The age-related decline in physical activity during adolescence is well documented; however, little is known about differences in physical activity among early, average, and late maturing adolescents. The purpose of this study was to examine the relationship between maturity status and physical activity among 167 adolescents who were 13-14 years old. The maturity offset was derived and biological maturity groups were created. Habitual physical activity was determined with a pedometer over a 7-day period. No significant maturity-group differences were found for physical activity. The results of this study did not demonstrate significant differences in physical activity as determined by a pedometer among early, average, and late maturing 13- to 14-year-olds. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate the efficacy of a specific 8-week exercise rehabilitation program as an intervention to treat recurrent nonspecific low back pain in adolescents. A randomized controlled trial involving 54 adolescents (14.6 ± 0.6 years) who suffered from recurrent nonspecific low back pain participated in either the exercise rehabilitation program or a control condition. Pre- and postintervention measures of low back pain status and biological risk indicators were taken. Two-way mixed ANOVA was conducted and significance was set at p < .01. Significant improvement was noted in the exercise rehabilitation group for perceived severity of pain (effect size 1.47) and number of occasions missing physical activity (effect size 0.99). Significant improvement in the exercise rehabilitation group for sit-and-reach performance, hip range of motion, lumbar sagittal mobility (modified Schöber), and number of sit-ups in 60 s were also identified. In conclusion, the specific exercise program appeared to provide positive benefits for adolescents suffering from recurrent nonspecific low back pain. Further evaluation is required to evaluate the effectiveness of the exercise rehabilitation program in relation to other interventions and to assess the long-term effectiveness. [ABSTRACT FROM AUTHOR]

Parents and 531 students (46% males, 78% white) completed equivalent questionnaires. Agreement between student and parent responses to questions about hypothesized physical activity (PA) correlates was assessed. Relationships between hypothesized correlates and an objective measure of student's moderate-to-vigorous physical activity (MVPA) in a subset of 177 students were also investigated. Agreement between student and parent ranged from r = .34 to .64 for PA correlates. Spearman correlations between MVPA and PA correlates ranged from -.04 to .21 for student report and -.14 to .32 for parent report, and there were no statistical differences for 8 out of 9 correlations between parent and student. Parents can provide useful data on PA correlates for students in Grades 7-12. [ABSTRACT FROM AUTHOR]

• IHE appeared to limit the drop in glycemia compared to CME during exercise. • No symptomatic hypoglycemic episode occurred during CME and IHE. • CME transiently reduced level 2 hyperglycemia compared with inactive days. From an early age, exercise is key to managing type 1 diabetes (T1D). However, hypoglycemia around aerobic exercise is a major barrier to physical activity in children. We explore whether intermittent high-intensity aerobic exercise (IHE), designed to mimic spontaneous childhood physical activity patterns, offers better protection against glycemic drop than continuous moderate-intensity exercise (CME). Five boys and 7 girls with T1D (9.8 ± 1.4y) performed ergo cycle-based randomized CME and IHE of identical duration and total mechanical load [50 %PWC 170 vs. 15sec(150 %PWC 170)/30 sec passive recovery; both during two 10-min sets, 5 min in-between]. Capillary glycemia during exercise and interstitial glucose during recovery were compared between exercises and an inactive condition, controlling for baseline glycemia, carbohydrate and insulin. The exercise-induced decrease in capillary glycemia was attenuated by 1.47 mmol·L−1 for IHE vs. CME (P < 0.05). No symptomatic hypoglycemic episodes occurred during exercises. Post-exercise time in hypoglycemia did not differ between conditions. During early recovery, CME reduced time spent > 16.7 mmol·L−1 compared with inactive days (P < 0.05; CME: 0 %; IHE: 16,7 %; INACTIVE: 41,7 %). IHE appeared to limit the glycemic drop compared to CME. Performing 20-min CME or IHE was not associated with increased hypoglycemic risk compared to being inactive. CME appeared even transiently protective against serious hyperglycemia. [ABSTRACT FROM AUTHOR]

The purpose of this study was to document the level of physical activity and sedentary behavior in a representative sample of Singaporean adolescents. A random sample of 1,827 secondary school students from six secondary schools (929 boys, 898 girls, mean age 14.9 ± 1.2 yr) completed the Three-Day Physical Activity Recall (3DPAR) self-report instrument. Approximately 63% of Singaporean high school students met current guidelines requiring 60 min of moderate to vigorous physical activity daily. Just over half (51.6%) met the guideline calling for regular vigorous physical activity. Across all grade levels, boys were consistently more active than girls. More than 70% of Singaporean high school students exceeded the recommended 2 hours per day of electronic media use. Collectively, these findings suggest that a significant proportion of Singaporean adolescents are not sufficiently active and are in need of programs to promote physical activity and decrease sedentary behavior. [ABSTRACT FROM AUTHOR]

This study describes the development, implementation, and evaluation of a structured physical activity intervention designed for high school students (years 11 and 12). A sample of 78 students was randomly allocated to control or intervention conditions for a period of ten weeks. Students in the control group (n = 40) participated in unstructured physical activity in a health and fitness center. Students in the intervention group (n = 38) participated in a ten-week structured health and exercise program based on Bandura's social learning theories. At the initial posttest, a number of statistically significant group differences were found using analysis of covariance. The intervention group reported more physical activity and improved exercise self-efficacy in comparison to the control group. At the 3-month follow-up, no statistically significant differences in physical activity were found. Results from this study suggest that a well-organized exercise-based program can be effective in increasing physical activity behavior of adolescents on a short-term basis. [ABSTRACT FROM AUTHOR]

This study examined the pattern of activity energy expenditure (AEE) among New South Wales (NSW) high school students in relation to age, sex, socioeconomic status (SES), place of residence, cultural background, season, participation in moderate- and vigorous-intensity and in organized and non-organized physical activity. Methods: Cross-sectional survey of a randomly-selected sample (N = 2026). Respondents self-reported their physical activity participation during a usual week in summer and winter. Results: Boys reported greater AEE than girls and, whereas APE was greater among grade 10 than grade 8 boys, the reverse was true for girls. Boys reported the same APE for summer and winter, but girls reported less APE during winter Both boys and girls reported spending the same proportion of their APE in vigorous-intensity (72%) compared with moderate-intensity activity (28%) and in non-organized (60%) compared with organized activity. There was no clear association between urban/rural place of residence and APE. Although APE tended to be positively associated with SES among girls, there was no association among boys. Girls from Asian cultural backgrounds reported much lower AEE than girls from other cultural backgrounds. Conclusion: Patterns of energy expenditure among adolescent boys and girls should be considered in developing interventions to ensure needs are adequately met. [ABSTRACT FROM AUTHOR]

Focuses on the concept of fitness activities of students. Recognition of the educational evaluation; Maintenance of the health-enhancing level; Flexibility of the frequency, intensity and time management.

Purpose: To study the pacing behavior and performance of novice youth exercisers in a controlled laboratory setting. Method: Ten healthy participants (seven male, three female, 15.8 ± 1.0 years) completed four, 2-km trials on a Velotron cycling ergometer. Visit 1 was a familiarization trial. Visits 2 to 4 involved the following conditions, in randomized order: no opponent (NO), a virtual opponent (starting slow and finishing fast) (OP-SLOWFAST), and a virtual opponent (starting fast and finishing slow) (OP-FASTSLOW). Repeated measurement ANOVAs (p < .05) were used to examine differences in both pacing behavior and also performance related to power output, finishing- and split times, and RPE between the four successive visits and the three conditions. Expected performance outcome was measured using a questionnaire. Results: Power output increased (F3,27 = 5.651, p = .004, η2p = .386) and finishing time decreased (F3,27 = 9.972, p < .001, η2p = .526) between visit 1 and visits 2, 3 and 4. In comparison of the first and second visit, the difference between expected finish time and actual finishing time decreased by 66.2%, regardless of condition. The only significant difference observed in RPE score was reported at the 500 m point, where RPE was higher during visit 1 compared to visits 3 and 4, and during visit 2 compared to visit 4 (p < .05). No differences in pacing behavior, performance, or RPE were found between conditions (p > .05). Conclusion: Performance was improved by an increase in experience after one visit, parallel with the ability to anticipate future workload. [ABSTRACT FROM AUTHOR]

Background: The purpose of this study was to examine relationships among biomarkers of iron status, athletic performance, growth and development, and dietary intakes in pre-adolescent and adolescent male and female athletes. Methods: Two-hundred and forty-nine male (n = 179) (mean ± standard deviation for age = 12.0 ± 2.1 years, height = 156.3 ± 13.9 cm, and weight = 49.1 ± 16.5 kg) and female (n = 70) (12.0 ± 2.2 years, 152.4 ± 12.3 cm, 45.3 ± 14.5 kg) athletes volunteered for capillary blood sample, anthropometric, athletic performance, and dietary intake assessments. Outcomes included maturity offset from peak height velocity, percent body fat, estimated muscle cross-sectional areas, vertical jump height (VJ), broad jump distance (BJ), pro-agility time (PA), L-cone time, 20-yard dash time (20YD), power push up (PPU) force, dietary intakes, and ferritin, soluble transferrin receptor (sTfR), and hemoglobin (Hb) concentrations. Results: Athletic performance was consistently correlated with Hb in males (r =.237–.375, p < 0.001–0.05) and with sTfR (r =.521–.649, p < 0.001–0.004) and iron intake (r =.397–.568, p = 0.001–0.027) in females. There were no relationships between dietary intakes and ferritin, sTfR, or Hb (p > 0.05). After partialing out age and height, VJ, PA, LC, and 20YD remained correlated with Hb in males (|rHb,y.Age| =.208–.322, p = 0.001–0.041; |rHb,y.Height| =.211–.321, p = 0.001–0.038). After partialing out iron intake, PA and LC remained correlated with sTfR in females (|rsTfR,y.ironintake| =.516–.569, p = 0.014–0.028). Conclusions: Iron status biomarkers demonstrated sex-specific relationships with anaerobic exercise performance in youth athletes, which may be more dependent on maturity status and dietary intake than age. Moderate relationships between sTfR and athletic performance in adolescent female athletes emphasizes the importance of iron intake in this demographic. [ABSTRACT FROM AUTHOR]

Adolescents are an increasingly sedentary population segment, which has negative repercussions on their health. The aim of the study was to analyse the effect of high-intensity interval training based on functional exercises on body fat percentage and cardiorespiratory capacity in a group of adolescents. An experimental pretest–posttest study was carried out, with two intervention groups, in physical education warm-ups over 7 weeks. Twenty-six schoolchildren were randomly assigned to an experimental group and to a control group. During the warm-up, the EG performed functional HIIT training and the control group the planned standardised warm-up. The HIIT workouts were based on functional bodyweight exercises with a work-to-rest ratio of 20/10s. The repeated measures ANOVA was used to analyse whether or not differences exist between the variables before and after the protocol period. The experimental group significantly increased its cardiorespiratory capacity (t = −5.11, d = 2.01, P < 0.001) and significantly reduced its percentage of fat (t = 4.05, d = 1.59, P < 0.001). For its part, the control group only significantly increased its cardiorespiratory capacity (t = −4.79, d = 1.87, P < 0.001). Functional HIIT shows the necessary potential to become a reliable strategy for countering obesity in the young population, given its impact on the reduction of body fat in the individuals involved. The short workouts mean that it can be introduced simply and frequently into physical education sessions. [ABSTRACT FROM AUTHOR]

Objective: To investigate the associations of muscular strength in adolescence with later disability pension (DP), across different body mass index (BMI) categories and in combination with aerobic fitness.Method: This prospective cohort study consisted of males aged 16-19 years, recruited from the Swedish military conscription register between 1969 and 1994. A total of 1 212 503 adolescents met all the inclusion criteria and were therefore included in the analyses. Knee extension, handgrip and elbow flexion strength and aerobic fitness (bicycle ergometer test) were measured during conscription. Causes of DP were retrieved from the Social Insurance Office between years 1971 and 2012 (average follow-up time: 29.6 years).Results: Knee extension strength in adolescence was inversely associated with men's risk of obtaining DP due to all causes (HR 1.40, 95% CI 1.36 to 1.44 for lowest vs highest strength quintile). Thus, muscular weakness was associated with DP. The risk associated with low muscular strength differed between specific causes of DP and the strongest associations were found for psychiatric, nervous system and other causes (HRs between 1.47 and 1.90 for lowest vs highest quintile). Being strong was associated with lower DP risk across BMI categories and being unfit, weak and obese was associated with the highest DP risk (HR 3.70, 95% CI 2.99 to 4.58).Conclusion: There was a strong association between muscular weakness and disability. A combination of muscular weakness and low aerobic fitness was an especially important risk factor for disability. This adds weight to call for muscular strength and fitness enhancing exercise for adolescents in all BMI categories. [ABSTRACT FROM AUTHOR]

Purpose: A systematic review was conducted to identify facilitators and barriers to movement integration (MI) in elementary school classrooms.Method: Online databases (Educational Resources Information Center, Google Scholar, PsycINFO, and PubMed) served as data sources for the study. Following the PRISMA guidelines, relevant published research on MI was identified and screened for inclusion in a qualitative synthesis. Content analysis of the included articles (N = 28) was used to identify themes of MI facilitators and barriers. Facilitators and barriers were then categorized using a social-ecological framework.Results: A total of 12 themes of MI facilitators and barriers were identified and categorized into two social-ecological levels: institutional factors (e.g., administrative support, resources) and intrapersonal factors (e.g., teacher confidence, ease of implementation).Conclusion: This review can inform research and practice aimed at supporting the implementation of MI in elementary classrooms. [ABSTRACT FROM AUTHOR]

International Journal of Exercise Science 12(3): 800-810, 2019. Electroencephalography (EEG) is a noninvasive method of measuring electrical activity of the brain during exercise. There is conflicting evidence as to how neural activity changes in relation to incremental exercise testing (IET), or if age has any effect. The purpose of this study was to determine 1) how brain activity changes throughout an IET, and 2) if age affects this response. 13 younger (age: 24.9 ± 2.6 years, 9 males) and 10 middle-aged (49.1 ± 3.2 years, 3 males) recreationally active individuals volunteered for this study. A self-paced, perceptually regulated IET was performed, while subjects wore an EEG electrode strip. Power spectral density (PSD) was calculated; alpha (8-13 Hz) and beta (13-30 Hz) activity from the prefrontal and motor cortices was compared to baseline measures. A one-way repeated-measures ANOVA with age as a between-subjects factor was used to determine the effect of test stage and age on PSD. Relative PSD in both the alpha and beta frequency bands increased with exercise intensity. In the prefrontal and motor cortices there was a main effect of stage (both p < .05), and PSD increased markedly at the end of the test. There was no difference between age groups (all p > .05). The lack of a downregulation in neural activity in the final stage of the test is in contrast to some studies but corroborates others. A likely cause for the differences between studies is exercise modality preference. There was no age effect, which may be due to the subjects used (middleaged regular exercisers). [ABSTRACT FROM AUTHOR]

International Journal of Exercise Science 12(3): 748-763, 2019. The purpose of this study was to develop regression equations for estimating the intensity of the exercise work rate (relative peak oxygen uptake-heart rate [%VO2-HR]) and the metabolic energy expenditure (MEE) for exercise prescription and rehabilitation medicine that are specific to children. This study took into account that the specific data in terms of obesity, sex, and pubertal status are currently unavailable. Our hypothesis was that obesity would affect the submaximal exercise the oxygen uptake (VO2), heart rate (HR), and metabolic energy expenditure (MEE), and exercise economy (ExEco). In this retrospective study, the regression analysis was performed on 126 children, matching groups for Tanner pubertal status (prepubertal: 1.8±0.7; postpubertal: 4.1±0.7), BMI-for-age percentile (lean: 50±26; obese: 96±4), and sex (girls: 48%; boys: 52%). Percent peakVO2 was regressed against HR, MEE against work rate (watt), and exercise economy (ExEco, mLO2·kg lean body mass-1·min-1) against work rate. Additionally, stepwise linear regression was used to identify predictors for exercise peak work rate. Prepubertal and postpubertal boys exercise at lower work rates than obese (%peakVO2-HR slope; P=0.01). The reverse was true in girls, lean prepubertal work at lower compared lean postpubertal (%peakVO2-HR slope; P=0.03). Boys expend more calories during exercise compared to girls (MEEslope; P=0.01), with no effect of puberty or obesity. Obese prepubertal children have poor ExEco compared to lean prepubertal children (ExEco-work rate slopes; P<0.01) but not in postpubertal children. Strong correlations (r=0.92-0.94) for %peakVO2-HR and MEE regressions for boys and girls accounted for 85-92% variation. Height, lean leg, and leg fat mass accounted for 83% of the variance for predicting peak work rate. Obesity, sex, and puberty affect exercise characteristics in children and should be considered for an individualized approach to exercise prescription in children. [ABSTRACT FROM AUTHOR]

A cross-sectional design was used to study the associations among sex, age, maximal aerobic speed (MAS), and running time to exhaustion at 100% of MAS (Tlim ). The subjects were 1,448 schoolchildren (685 males and 763 females) ages 6 to 17 years. The MAS of males increased significantly (p &It; .001) from 6 (9.0 ± 0.8 km · h-1) to 17 years (14.1 ± 1.6 km · h-1). The MAS of females increased significantly (p &It; .001) from 6 (8.7 ± 0.6 km · h-1) to 12 years (10.7 ± 1.2 km · h-1), then remained relatively constant at approximately 11 km · h-1 between 12 and 17 years. Tlim increased significantly from 6 to 13 years for males and from 6 to 11 years for females, then remained relatively constant around 350 s for both males and females. [ABSTRACT FROM AUTHOR]

To assess the relationship of changes in physical fitness and body composition to heart growth and rising blood pressure (BP) during early puberty, fat-free mass (FFM), body fatness (% fat), physical fitness (peak VO2, peak mechanical power, peak O2 pulse, peak systolic blood pressure [SBP], and grip strength). Tanner stage, resting BP, and echocardiographic left ventricular mass (LVM) were measured in 123 children (age M = 10 years) and remeasured 2 years later. Increased FFM, increased grip strength, and increased peak power explained 28% of the variability in heart growth. Increased FFM, increased % fat, and decreased peak O2 pulse explained 23% of the variability in rising SBP. During puberty, physical fitness is an independent predictor of changing heart size and systolic blood pressure. Results suggest that improvements in physical fitness and decreases in body fatness may have beneficial effects on children's blood pressure. [ABSTRACT FROM AUTHOR]

During the 1993 International Consensus Conference on Physical Activity Guidelines for Adolescents, specific recommendations were made concerning the levels and types of physical activity in which adolescents should be encouraged to engage. This paper addresses the promotion of these guidelines by primary health care providers. Based on social cognitive theory, principles for promoting changes in health behaviors are described. Using the GAPS model (gather information, assess further, problem identification, and self-efficacy and solving barriers), methods of implementing these principles in a physician's office are presented. Promoting physical activity in other health care settings and situations is also discussed. Primary health care providers can be effective promoters of physical activity to their adolescent patients. [ABSTRACT FROM AUTHOR]

This paper reviews the descriptive epidemiology of physical activity in adolescents. Large population-based studies were reviewed, along with smaller studies using objective monitoring of physical activity. Estimates showed that adolescents engage in physical activity of any intensity for a mean of one hour per day. Approximately two thirds of males and one quarter of females participate in moderate to vigorous activity for 20 min 3 or more days per week. Activity levels decline with increasing age across adolescence, and this decrease is more marked in females than in males. Comparison of these data to physical activity guidelines for adolescents suggests the vast majority are meeting the guideline of accumulating physical activity. However, a substantial number of males, and the majority of females, are not meeting the guideline for moderate to vigorous physical activity. [ABSTRACT FROM AUTHOR]

This review summarizes information on the rate of injury among adolescents who participate in specific sports or recreational activities. Injury-related mortality is high among adolescents, accounting for over 75% of the deaths occurring among those between 15 and 19 years of age, with about 5% of these deaths attributed to sports injuries. Several difficulties were encountered in conducting this review. There was no standard definition for injury, resulting in widely diverse operational definitions. The underlying denominator and time period used to obtain rates also varied widely. In spite of these difficulties, several sports were identified as particularly dangerous due to the nature of the injury: football for males and gymnastics for females. Consistent injury definitions and larger prospective studies are needed to confirm these rates and to identify risk factors. [ABSTRACT FROM AUTHOR]

The positive emotion of enjoyment has been shown to be an important ingredient to motivation in youth and elite sport. This article first summarizes the progress made to date in developing and measuring the enjoyment construct, and in understanding its sources and motivational consequences. Then a field study is presented that focuses on sources of enjoyment in a large youth sample (N=1,342) that is diverse in age, ethnicity, and gender. Factor analytic and multiple regression techniques were used to determine categories and predictors of sport enjoyment. The significant sources of enjoyment for these participants were greater effort and mastery, positive team interactions and support, and positive coach support and satisfaction with the players' seasonal performance. These findings accounted for 47% of the variance in sport enjoyment and shed light on the predictors of this important affect for a diverse group of athletes. [ABSTRACT FROM AUTHOR]

The purpose of the present study was to determine the validity of the 20- meter multistage shuttle run (MSR) for predicting peak VO2 in Hong Kong Chinese students, ages 12-17 years. Fifty-five subjects, 27 boys and 28 girls, performed the MSR in the school environment and had peak VO2 determined in the laboratory. A correlation of 0.72 (p<0.001) was found between peak VO2 and predicted peak VO2 using an equation previously developed with Canadian children (6). However, maximal shuttle run speed alone was a better predictor in this group (r=0.74. SEE=4.6 ml·kg-1·min-1, p<0.001). Multiple-regression analysis (best-subsets) was performed and the best predictor variables were maximal speed and sex with either triceps skinfold or weight. For practical application in the school setting, the equation peak VO2 = 24.2 - 5.0(sex) - 0.8(age) + 3.4(maximal speed) (r=0.82, SEE=4.0), where for sex, male = 0 and female = 1, is suggested. [ABSTRACT FROM AUTHOR]

A physiological profile of 40 early adolescent female dancers was completed to investigate the characteristics of dancers this age and the possible physical fitness benefits of high levels of dance training. Of those physical fitness variables studied, the only significant difference between performing (high level) and recreational (low level) dancers was the degree of hip flexibility (p<.01). Both groups exhibited lean body density (combined mean of 1.069 g ml-1) as well as moderate aerobic (combined mean of 45.8 ml kg-1 min-1) and anaerobic power (combined mean of 6.5 Watt kg-1). These data suggest that early adolescent dance training encourages a certain level of physical fitness, but higher levels or duration of dance training do not result in or demand exceptional aerobic or anaerobic power. [ABSTRACT FROM AUTHOR]

The Astrand-Ryhming est was modified to overcome problems of predicting V2max in children. VO2max was measured directly during a maximal treadmill test and estimated by means of a submaximal protocol in a test group of 51 subjects ages 10-18 years. A multiple regression equation was developed with directly measured VO2max as the dependent variable and age, body weight, and VO2max estimated from the Astrand nomogram as independent variables. The validity and reliability of this equation to predict VO2max in children and adolescents was cross-validated. No significant difference was found between the measured VO2max and that estimated from the equation. The correlation coefficient between measured and estimated VO2max for the cross-validation group was 0.89, with a standard error of estimate of 12%. Test-retest reliability was 0.95. It was concluded that this modification of the Astrand nomogram provides a valid and reliable prediction of VO2max in children and adolescents. [ABSTRACT FROM AUTHOR]

The article presents a response to an editorial piece by T. W. Rowland in a 1995 issue regarding the reform of youth physical fitness testing methods. The author supports Rowland's recommendation to emphasize the lifetime physical activity model, especially when working with youth. A unified effort on the part of professional, government and corporate organizations is called for.