title: Adiposity, aerobic fitness, muscle fitness, and markers of inflammation in children. Effect of fitness and physical activity on bone mass in adolescents: the HELENA Study Combined influence of cardiorespiratory fitness and body mass index on cardiovascular disease risk factors among 8-18 year old youth: The Aerobics Center Longitudinal Study. Adolescent determinants of cardiovascular risk factors in adult men and women Tracking of health and risk indicators of cardiovascular diseases from teenager to adult: Amsterdam Growth and Health Study. The association of physical activity and physical fitness with pre-adolescent obesity: an observational study in Metromanila, Philippines. Exercise training normalizes vascular dysfunction and improves central adiposity in obese adolescents. Effects of Home- and University-Based Programs on Physical Self-Perception in Mothers and Daughters Effect of physical education and activity levels on academic achievement in children. Eight months of regular in-school jumping improves indices of bone strength in adolescent boys and Girls: the POWER PE study. Muscle strength in youth and cardiovascular risk in young adulthood (the European Youth Heart Study) Regular participation in sports is associated with enhanced physical fitness and lower fat mass in prepubertal boys Physical inactivity is a risk factor for physical activity-related injuries in children Enhanced bone mass and physical fitness in young female handball players. The Impact of a 12-Week Resistance Training Program on Strength, Body Composition, and Self-Concept of Hispanic Adolescents Physical fitness and physical activity in obese and nonobese Flemish youth. Isometric endurance of the back extensors in school-aged adolescents with and without low back pain. The effect of high-intensity progressive resistance training on adiposity in children: a randomized controlled trial Health-related fitness in school children: compliance with physical activity recommendations and its relationship with body mass index and diet quality. Association between bone mass and fractures in children: a prospective cohort study. Relationships between physical activity, physical fitness, muscle strength and nutritional state in 5- to 11-year-old children The Significance of High Lumbar Mobility and Low Lumbar Strength for Current and Future Low Back Pain In Adolescents Changes in physical activity are reflected in changes in fitness during late adolescence. A 2-year follow-up study. Relationship of physical fitness to prevalence and incidence of overweight among schoolchildren. Muscular strength in male adolescents and premature death: cohort study of one million participants Effect of an individualised training programme during weight reduction on body composition: a randomised trial Relationships between physical activity and physical capacity in adolescent females and bone mass in adulthood. Low Back Pain in the Young A Prospective Three‐Year Follow‐up Study of Subjects With and Without Low Back Pain Determinants of Self‐Reported Neck‐Shoulder and Low Back Symptoms in a General Population Effects of resistance training on insulin sensitivity in overweight Latino adolescent males. Physical fitness of obese school children in Hat Yai, southern Thailand. Weight-bearing, muscle loading and bone mineral accrual in pubertal girls--a 2-year longitudinal study. Positive, site-specific associations between bone mineral status, fitness, and time spent at high-impact activities in 16- to 18-year-old boys. Association between muscular strength and mortality in men: prospective cohort study
abstract: PURPOSE The purpose of this study was to describe levels of inflammation markers in Norwegian children and to examine the associations of adiposity , aerobic fitness , and muscle fitness with markers of inflammation . METHODS In 2005 - 2006 , 1467 nine-year-olds were r and omly selected from all regions in Norway . The participation rate was 89 % . The inflammatory markers evaluated included C-reactive protein ( CRP ) , leptin , adiponectin , plasminogen activator inhibitor-1 , tumor necrosis factor-α , hepatocyte growth factor , resistin , and interleukin-6 . We assessed muscular strength by measuring  explosive , isometric , and endurance strength . Aerobic fitness was measured directly during a maximal cycle ergometer test .  Adiposity was expressed as waist circumference ( WC ) . RESULTS The girls had significantly higher levels of CRP , leptin , adiponectin , and resistin and lower levels of tumor necrosis factor-α compared with the boys . We observed a grade d association of CRP and leptin levels across quintiles of WC , aerobic fitness , and muscle fitness ( P ≤ 0.001 for all participants ) . The regression analyses revealed that WC , aerobic fitness , and muscle fitness were independently associated with the CRP ( WC β = 0.158 , P < 0.001 ; aerobic fitness β = -0.190 , P < 0.001 ; muscle fitness β = -0.122 , P < 0.002 ) after adjustments for sex , age , Tanner pubertal stage , and the other independent variables . The same pattern was observed for leptin levels ( WC β = 0.406 , P < 0.001 ; aerobic fitness β = -0.298 , P < 0.001 ; muscle fitness β = -0.064 , P < 0.036 ) . CONCLUSIONS These data represent a reference material with respect to inflammatory markers . Our results show that adiposity , aerobic fitness , and muscle fitness were independently associated with the CRP and leptin levels Our aim is to analyse the effect on bone mass of : ( 1 ) physical fitness performance on a specific group of physical activity ( PA ) and , ( 2 ) PA on a specific physical fitness performance group . Bone mineral content ( BMC ) by dual energy X-ray absorptiometry ( DXA ) and PA by accelerometers was assessed in 373 Spanish adolescents ( 182 males ) . Adolescents were classified as : active and non-active ( ≥60 or < 60 min day−1 of moderate-vigorous PA ) . Fitness was assessed through speed/agility , strength and cardiorespiratory tests . Adolescents were classified by tertiles ( T1 , T2 and T3 ) . ANCOVA was used for the analysis with sex , height , lean mass , calcium intake and pubertal status as covariates . Adolescents with lower strength , speed/agility and cardiorespiratory fitness ( CRF ) showed lower BMC in the whole body and extremities compared with adolescents with better results in these tests , mainly those non-active adolescents . Non-active adolescents with high fitness levels showed higher BMC ( whole body and upper limbs ) than active ones . The conclusions included : ( 1 ) within the non-active group , lower levels of fitness were associated with lower BMC ; this might be through PA or trough an effect of PA on muscle mass . ( 2 ) Non-active adolescents with high level of fitness in most fitness tests showed higher BMC than their active peers , in spite of their lower PA levels . These unexpected results could be influenced by several factors such as genetics , nutrition , type of exercise or sport , hormones and skeletal age OBJECTIVE The purpose of this study was to examine differences in cardiovascular disease ( CVD ) risk factors across four cross-tabulated groups of cardiorespiratory fitness and body mass index in 8- to 18-year-old children and adolescents . METHODS The sample included 296 boys and 188 girls ( mean age=15.7 years ) participating in the Aerobics Center Longitudinal Study . Participants were cross tabulated into four groups using a median split of age-adjusted treadmill time to exhaustion ( TM ) and body mass index ( BMI ) . Group differences in CVD risk factors ( blood pressure [ BP ] , fasting total cholesterol [ TC ] , low density lipoprotein-cholesterol [ LDL-C ] , high density lipoprotein-cholesterol [ HDL-C ] , TC : HDL-C , triglycerides [ TG ] , glucose , and a metabolic syndrome score ) were examined by ANCOVA , controlling for age . RESULTS In males , significant differences across groups were observed for systolic BP , mean arterial pressure ( MAP ) , TC , LDL-C , TC : HDL-C and the metabolic syndrome score ( p<0.05 ) . In females , only TG was significantly different across groups ( p<0.05 ) . A trend for significance was also observed for DBP and TG in males ( p=0.09 to 0.11 ) and diastolic BP , MAP , HDL-C , and the metabolic syndrome score in females ( p=0.14 to 0.16 ) . In general , males and females in the low BMI group , either fit or unfit , had lower BP and blood lipid values than those in the high BMI group . In both sexes , the high BMI /low fit group had the highest ( most adverse ) metabolic syndrome score . CONCLUSION This study utilized a unique approach to examine the possible interaction of fitness and fatness on CVD risk factors in children and adolescents . The results provide some evidence for the consideration of both variables when interpreting CVD risk factors in young people Aims : To investigate how physical activity , physical performance and sociodemographic characteristics at the age of 16 are related to adult health habits ( physical activity , dietary intake , smoking ) and biological risk factors for cardiovascular diseases ( being overweight , low aerobic fitness , unfavorable levels of serum lipids , high blood pressure ) . Methods : A r and omly selected group of 220 male and 205 female students at 16 years of age was tested in 1974 , and reinvestigated 18 years later . Results : The predictive health profiles for adult lifestyle and biological risk factors were different in men and women . Leisure sports activity along with high performance in the nine-minute run among the boys and in the two-h and lift test among the girls were significant predictors of adult physical activity . A positive attitude to aerobic exercise  and high performance in the nine-minute run test among the boys and high marks in physical education among the girls decreased the risk of smoking .  Leisure sports activities together with body mass index at young ages were the most powerful predictors of adult biological risk factors , but attitudes to sports and educational level were also significant determinants . Conclusion : These results contribute to the knowledge of which factors at young ages may promote adult healthy habits in particular physical activities Cardiovascular disease is recognized as a serious public health problem . Because the underlying pathological processes start shortly after birth , tracking of recognized cardiovascular disease indicators during childhood and adolescence can help in developing preventive pediatric strategies . A prospect i ve follow-up of both genetic and behavioral lifestyle parameters ( serum cholesterol , blood pressure , percentage body fat , maximal oxygen uptake ( VO2max ) , smoking , physical inactivity , and type A behavior ) was design ed . In the Amsterdam Growth and Health Study a population of 93 males and 107 females was measured annually from 1977 to 1980 and a fifth measurement was made in 1985 . In that way longitudinal data covering a period of 8 years was collected for a group of adolescents/adults between 13 and 21 years of age . Analyses of these parameters provided the following results : The stability over the 9 years of tracking cardiovascular disease indicators , measured as the interperiod correlations , is fairly high . It varies from 0.4 to 0.8 in percentage body fat , cholesterol , and VO2max . Blood pressure values are low ( between 0.3 and 0.4 ) . The probability of 13-year-olds having relatively high values of cardiovascular disease indicators on the basis of a quartile distribution with that at age 21 indicated a moderate to high predictive value . According to the literature , the levels of subjects that are continuously relatively high over the years are more in the direction of optimal health than risk values . The exception is for percentage body fat . Interrelation of the seven cardiovascular disease indicators in constantly relatively high-risk and relatively low-risk groups during the teenage period , measured during young adulthood ( 21.5 years ) , appeared to be weak : only males and females with a high percentage body fat and a low VO2max showed significantly high total cholesterol , low high-density lipoprotein cholesterol , and high total cholesterol/high-density lipoprotein cholesterol levels . From the three environmental cardiovascular disease indicators ( smoking , physical activity , and type A/B behavior ) measured in 1985 , only physical activity was significantly correlated among males and females with high-density lipoprotein cholesterol , percentage body fat , and VO2max . It can be concluded that measurement of percentage body fat in the early teenage period seems to be the most important cardiovascular disease indicator in predicting risk levels in the young adult . The amount of physical activity measured at young adult age is the only behavioral parameter to show a significant interrelation with other cardiovascular disease risk indicators . ( ABSTRACT TRUNCATED AT 400 WORDS BACKGROUND Childhood obesity has been inconsistently associated with decreased levels of physical activity and fitness . Moreover , little is known about this relationship among Filipino preteens . METHODS This cross sectional study reports the association between childhood obesity , measures of physical activity , and fitness .  Children aged 11 to 12 from r and omly selected schools from San Juan , Metromanila were included . Outcome measures were body mass index , Filipino modified Physical Activity Question naire for Older children ( F_PAQ-C ) ,  st and ing broad jump , 50 m sprint  and  20 m multistage shuttle run .  RESULTS 380 children participated in the study . Obese children had significantly lower median scores in the F_PAQ-C compared with overweight children . Overweight children had lower scores in the st and ing broad jump , 50 m sprints and predicted VO2max as compared with children with normal BMI . There were modest associations between the 50 m sprint , predicted VO2max , and F_PAQ-C. CONCLUSION Our study has showed that physical activity and fitness scores were strongly correlated with childhood obesity . If childhood physical fitness is a predictor of physical fitness in adulthood which is a risk factor in cardiovascular diseases , there is a strong possibility that the prevalence of cardiovascular disease in the Philippines will increase dramatically in the future OBJECTIVES We sought to characterize the impact of obesity on vascular function in adolescents and to determine whether an exercise program reverses abnormalities in endothelial function . BACKGROUND Obesity , a major modifiable risk factor for cardiovascular disease , is epidemic in Western societies , with rapid rates of increase in the young . Atherosclerosis begins in childhood , and endothelial dysfunction is its earliest detectable manifestation . METHODS The influence of eight weeks of circuit training ( CT ) was examined in 19 obese subjects ( 14.3 + /- 1.5 years ) , using a r and omized , crossover protocol . Functional capacity and muscular strength were assessed by st and ard techniques .  Body composition was examined using anthropometric measures and dual-energy X-ray absorptiometry .  Conduit vessel endothelial function was assessed using high-resolution ultrasound and flow-mediated dilation ( FMD ) of the brachial artery . RESULTS Circuit training decreased abdominal and trunk fat and significantly improved fitness and muscular strength ( p < 0.05 ) . In the obese group , FMD was significantly impaired relative to control subjects ( n = 20 ) at entry ( 5.3 + /- 0.9 % vs. 8.9 + /- 1.5 % , p < 0.05 ) and was normalized after CT ( 8.8 + /- 0.8 % , p < 0.05 ) . CONCLUSIONS Circuit training improved functional capacity , muscular strength , and body composition in obese adolescents . Furthermore , conduit vessel function was normalized after exercise training . If vascular dysfunction is an integral component of the pathogenesis of vascular disease , this study supports the value of an exercise program in the management of obese adolescents ABSTRACT The primary purpose of this study was to compare two  mother-daughter interventions design ed to increase fitness and activity and improve physical self-perception ( PSP ) . A secondary purpose was to test two of the proposed mechanisms for using physical activity to enhance PSP .  Twenty mother-daughter pairs ( n = 40 ) were r and omly assigned to a  university-based ( UB ) or home-based ( HB ) group . Initially , both groups received classroom training design ed to improve PSP . Then , the UB group met three times per week , whereas the HB group received information concerning home-based activities . The Fitnessgram ® activity question naire and fitness test battery were used to measure physical activity and fitness level . The Physical Self-Perception Profile ( PSPP ) was used to detect changes in PSP . Separate 2 ( group ) × 2 ( age ) × 2 ( time ) ANOVAs with repeated measures on the last factor were conducted to examine changes in PSP , physical activity , and fitness . Correlations between physical activity , fitness , and PSP were examined to test the two mechanisms . Perceived sports competence and body attractiveness improved in UB and HB mothers and daughters ( p = .002 and .005 , respectively ) . UB and HB mothers and daughters increased their participation in aerobic ( p = .000 and .015 ) , muscular strength ( p = .001 and .001 ) , and flexibility ( p = .000 and .000 ) activities . Support was not provided for the proposed mechanisms for the relationship between physical activity and PSP . These interventions demonstrate the potential to foster positive short-term changes in PSP and physical activity in mothers and daughters . More research is needed to test mechanisms explaining the relationship between activity and PSP PURPOSE This study was conducted to determine the effect of physical education class enrollment and physical activity on academic achievement in middle school children . METHODS Participants were 214 sixth- grade students r and omly assigned to physical education during either first or second semesters .  Moderate and vigorous physical activity ( MVPA ) ( number of 30-min time blocks ) outside of school was assessed using the 3-d physical activity recall ( 3DPAR ) . The 3DPAR time blocks were converted to ordinal data with scores of 1 ( no activity ) , 2 ( some activity ) , or 3 ( activity meeting Healthy People 2010 guidelines ) . Academic achievement was assessed using grade s from four core academic classes and st and ardized test scores ( Terra Nova percentiles ) . RESULTS Grade s were similar regardless of whether students were enrolled in physical education during first or second semesters . Physical education classes averaged only 19 min of MVPA . Students who either performed some or met Healthy People 2010 guidelines for vigorous activity had significantly higher grade s ( P < 0.05 ) than students who performed no vigorous activity in both semesters . Moderate physical activity did not affect grade s. St and ardized test scores were not significantly related to physical education class enrollment or physical activity levels . CONCLUSION Although academic achievement was not significantly related to physical education enrollment , higher grade s were associated with vigorous physical activity , particularly activity meeting recommended Healthy People 2010 levels The POWER PE study was an 8-mo , r and omized , controlled , school-based exercise intervention design ed to apply known principles of effective bone loading to practical opportunities to improve life-long musculoskeletal outcomes . A total of 99 adolescents ( 46 boys and 53 girls ) with a mean age of 13.8 + /- 0.4 yr ( peri- to postpubertal ) volunteered to participate . Intervention subjects performed 10 min of jumping activity in place of regular physical education ( PE ) warm up . Control subjects performed usual PE warm-up activities .  Bone mass ( DXA and QUS ) was assessed at baseline and follow-up along with anthropometry , maturity , muscle power , and estimates of physical activity and dietary calcium . Geometric properties ( such as femoral neck [ FN ] moment of inertia ) were calculated from DXA measures . Boys in the intervention group experienced improvements in calcaneal broadb and ultrasound attenuation ( BUA ) ( + 5.0 % ) and fat mass ( -10.5 % ) , whereas controls did not ( + 1.4 % and -0.8 % , respectively ) . Girls in the intervention group improved FN BMC ( + 13.9 % ) and lumbar spine ( LS ) BMAD ( + 5.2 % ) more than controls ( + 4.9 % and + 1.5 % , respectively ) . Between-group comparisons of change showed intervention effects only for whole body ( WB ) BMC ( + 10.6 % versus + 6.3 % ) for boys . Boys in the intervention group gained more lean tissue mass , trochanter ( TR ) BMC , LS BMC , and WB BMC and lost more fat mass than girls in the intervention group ( p < 0.05 ) . Ten minutes of jumping activity twice a week for 8 mo during adolescence seems to improve bone accrual in a sex-specific manner . Boys increased WB bone mass and BUA , and reduced fat mass , whereas girls improved bone mass at the hip and spine Background Whether muscle strength in youth is related to cardiovascular risk later in life independent of cardiorespiratory fitness is unclear . Methods We examined the independent association of isometric muscle strength in youth with cardiovascular risk factors in young adulthood using data from the Danish European Youth Heart Study ; a population -based prospect i ve cohort study among boys and girls ( n=332 ) followed for up to 12 years . In youth maximal voluntary contractions during isometric back extension and abdominal flexion were determined using a strain-gauge dynamometer and cardiorespiratory fitness was obtained from a maximal cycle ergometer test . Cardiovascular risk factors were obtained in youth and in young adulthood . Associations were examined using multivariable-adjusted regression models including major confounding factors . Results Each 1 SD difference in isometric muscle strength in youth ( 0.17 N/kg ) was inversely associated with body mass index ( BMI ; −0.60 kg/m2 , 95 % CI −0.97 to −0.22 ) , triglyceride ( −0.09 mmol/l , 95 % CI −0.16 to −0.02 ) , diastolic blood pressure ( BP ) ( −1.22 mm Hg , 95 % CI −2.15 to −0.29 ) and a composite cardiovascular risk factor score ( −0.61 SD , 95 % CI −1.03 to −0.20 ) in young adulthood in multivariable-adjusted analyses including fitness . Associations to triglyceride , diastolic BP and the cardiovascular risk factor score remained with additional adjustment for waist circumference or BMI . Each 1 SD difference in isometric muscle strength in youth was significantly associated with 0.59 ( 95 % CI 0.40 to 0.87 ) lower odds of general overweight/obesity in young adulthood ( p=0.007 ) and was marginally associated with incident raised BP , raised triglyceride and low high-density lipoprotein cholesterol . Conclusions This study suggests that greater isometric muscle strength in youth is associated with lower levels of cardiovascular risk factors in young adulthood independent of fitness , adiposity and other confounding factors OBJECTIVE : To study the effect of physical activity on whole body fat ( BF ) , its regional deposition and the influence of body fatness on physical performance in prepubertal children . DESSIGN : Cross-sectional study .SUBJECTS : A total of 114 boys ( 9.4±1.5 y , Tanner I – II ) , r and omly sample d from the population of Gran Canaria ( Spain ) , 63 of them physically active ( PA , at least 3 h per week during the previous year ) and 51 nonphysically active ( non-PA ) .  MEASUREMENTS : Body composition ( DXA ) , anthropometric variables ( body circumferences and skinfolds ) and physical fitness were determined in all subjects . RESULTS : The PA obtained better results in maximal oxygen uptake , isometric leg extension force , vertical jump ( muscular power ) , and 300 m ( anaerobic capacity ) and 30 m running tests ( speed ) than the non-PA . A lower percentage of body fat ( % BF ) ( 4 U less , P<0.05 ) , whole BF mass ( 36 % less , P<0.05 ) and regional fat mass ( 28 , 25 , and 30 % less in the trunk , legs and arms , respectively , all P<0.05 ) was observed in the PA compared to the non-PA . The waist and hip circumferences correlated more closely with both the fat mass accumulated in the trunk region and the % BF ( r=0.81–0.95 , P<0.001 ) than the waist-to-hip ratio ( WHR ) . The WHR correlated with the percentage of the whole fat mass accumulated in the trunk ( PFT ) ( r=0.52–0.53 , P<0.001 ) . In both groups , the PFT increased curvilinearly with the % BF , regardless of the level of physical activity . ANCOVA analysis revealed that total and regional fat masses explained less than 40 % of the difference in performance between the PA and non-PA group . The mean speed in the 30 m running test ( V30 ) , combined with the height and whole body mass , has predictive value for the BF mass ( R=0.98 , P<0.001 ) . The % BF may be estimated from the body mass index ( BMI ) and V30 ( % BF=8.09 + 2.44 · BMI ( kg m−2)–5.8·V30 ( m s−1 ) , R=0.94 , P<0.001 ) in prepubertal boys . CONCLUSIONS : Regular participation in at least 3 h per week of sports activities and competitions on top of the compulsory physical education program is associated with increased physical fitness , lower whole body and trunkal fat mass in prepubertal boys Objectives To describe the risk factors associated with injuries result ing from physical education ( PE ) , leisure time physical activity ( leisure time PA ) and sports in 9–12-year-old children . Design Prospect i ve cohort study . Setting Primary schools . Participants Nine hundred and ninety-five children aged 9–12 years . Main outcome measures Injuries occurring during either PE class  , leisure time PA or sports , and caused the child to at least stop the current activity were recorded prospect ively . Individual weekly exposure was estimated from baseline and follow-up question naires . Potential risk factors were gender , age , socioeconomic status , ethnicity , habitual level of PA , body mass index and a motor fitness . A multivariate Cox proportional hazard regression model was developed , accounting for clustering within schools . Results Gender , age and level of PA were independent significant risk factors for injury . Different modalities of PA had different injury risk factors . Most importantly , the low levels of habitual PA  significantly increased injury risk . Conclusions The children at highest injury risk are the target audience of the contemporary PA promotion efforts . PA promotion should also focus on injury prevention This study evaluates the effect of physical activity on the bone content ( BMC ) and density ( BMD ) in 51 girls ( 14.2+/-0.4 yr ) . Twenty-four were placed in the h and ball group as they have been playing h and ball for at least 1 year ( 3.9+/-0.4 ) . The other 27 who did not perform in any kind of regular physical activity other than that programmed during the compulsory physical education courses comprised the control group .  Bone mass and areal density were measured by dual-energy X-ray absorptiometry ( DXA ) . The maximal leg extension isometric force in the squat position with knees bent at 90 degrees and the peak force , mean power , and height jumped during vertical squat jump were assessed with a force plate . Additionally , 30-m run ( running speed ) and 300-m run ( as an estimate of anaerobic capacity ) tests were also performed . Maximal aerobic capacity was estimated using the 20-m shuttle-run tests . Compared to the controls , h and ballers attained better results in the physical fitness tests and had a 6 % and 11 % higher total body and right upper extremity lean mass ( all P<0.05 ) . The h and ballers showed enhanced BMC and BMD in the lumbar spine , pelvic region , and lower extremity ( all P<0.05 ) . They also showed greater BMC in the whole body and enhanced BMD in the right upper extremity and femoral neck than the control subjects ( all P<0.05 ) . As expected , total lean mass strongly correlated with total and regional BMC and BMD ( r=0.79 - 0.91 P<0.001 ) . Interestingly , 300-m running speed correlated with BMC and BMD variables ( r=0.59 - 0.67 and r=0.60 - 0.70 , respectively ; all P<0.001 ) . Multiple regression analysis showed that the 30-m running speed test , combined with the height and body mass , has also predictive value for whole-body BMC and BMD ( R=0.93 and R=0.90 , P<0.001 ) . In conclusion , h and ball participation is associated with improved physical fitness , increased lean and bone masses , and enhanced axial and appendicular BMD in young girls . The combination of anthropometric and fitness-related variables may be used to detect girls with potentially reduced bone mass Velez , A , Golem , DL , and Are nt , SM . The impact of a 12-week resistance training program on strength , body composition , and self-concept of Hispanic adolescents . J Strength Cond Res 24(4 ) : 1065 - 1073 , 2010-Current evidence suggests that a resistance training program may be physically and psychologically beneficial for adolescents . The purpose of this study was to examine the effects of a structured resistance training program on strength , body composition , and self-concept in normal and overweight Hispanic adolescents . Male and female participants ( n = 28 ; 16.1 ± 0.2 y ; 164.5 ± 1.4 cm ; 63.3 ± 2.5 kg ; 20.0 ± 1.7 % body fat [ BF ] ) were recruited from a predominantly Hispanic high school . Prior to the 12-week program , strength , body composition , and self-concept were assessed . Subjects were r and omly assigned to a control group ( CON ; n = 15 ) or to a resistance training group ( RT ; n = 13 ) that participated in supervised strength training 3 days/week . All measures were repeated at the end of the 12-week program . RT had significantly greater strength increases for bench press ( p < 0.001 ) , seated row ( p = 0.002 ) , shoulder press ( p < 0.001 ) , and squats ( p = 0.002 ) . RT had significant reductions in % BF ( p = 0.001 ) , whereas CON had slightly increased % BF . RT had an increase in condition/stamina competence ( p = 0.008 ) , attractive body adequacy ( p = 0.017 ) , and global self-worth ( p = 0.013 ) from pretest to posttest , whereas no change was observed for CON . In conclusion , resistance training result ed in significant physiological and psychological improvements in Hispanic adolescents compared to typical school-based activities . These findings indicate that resistance training can be incorporated into the activities of Hispanic adolescents to promote improved health and fitness OBJECTIVE To assess different aspects of physical fitness and physical activity in obese and nonobese Flemish youth . RESEARCH METHODS AND PROCEDURES A r and om sample of 3214 Flemish schoolchildren was selected and divided into an " obese " and " nonobese " group based on body mass index and sum of skinfolds . Physical fitness was assessed by the European physical fitness test battery . Physical activity  was estimated by a modified version of the Baecke Question naire . RESULTS Obese subjects had inferior performances on all tests requiring propulsion or lifting of the body mass ( st and ing-broad jump , sit-ups , bent-arm hang , speed shuttle run , and endurance shuttle run ) compared with their nonobese counterparts ( p < 0.001 ) . In contrast , the obese subjects showed greater strength on h and grip ( p < 0.001 ) . Both groups had similar levels of leisure-time physical activity ; however , nonobese boys had a higher sport index than their obese counterparts ( p < 0.05 ) . DISCUSSION Results of this study show that obese subjects had poorer performances on weight-bearing tasks , but did not have lower scores on all fitness components . To encourage adherence to physical activity in obese youth , it is important that activities are tailored to their capabilities . Results suggest that weight-bearing activities should be limited at the start of an intervention with obese participants and alternative activities that rely more on static strength used BACKGROUND AND OBJECTIVE Studies on back extensor endurance in adolescents are scarce . This study sought to establish reference data and pattern of back extensor endurance in school-aged adolescents with and without low-back pain ( LBP ) from Nigeria . SUBJECTS AND METHODS This study recruited 625 adolescents aged 11 to 19 years from eight r and omly selected secondary schools . The modified Biering-Sørensen test of Static Muscular Endurance ( BSME ) was used to assess isometric endurance of the back extensors . Demographic and anthropometric data were collected . A modified LBP question naire was used to assess the presence of LBP . Descriptive and inferential analyses were used to analyze data . Significance was set at 0.05 alpha-level . RESULTS The mean isometric holding time ( IHT ) of all the participants was 132.9 $ \pm$ 65.6 . Males had significantly higher significant ( p=0.026 ) IHT than females . Adolescents without LBP had a higher significant IHT ( p=0.042 ) than those with reported history of previous LBP and those with present LBP ( p=0.000 ) respectively . Using percentile values , poor endurance was defined as IHT that is < 90.0 s and < 67 s for males and females respectively ; medium endurance was defined as IHT that ranged between 90 and 193 s and 67 and 170 s for males and females respectively while good endurance was defined as IHT that is > 193 s and > 170 s for males and females respectively . IHT was significantly related to each of body mass index , hip circumference and waist-to-hip ratio ( p < 0.05 ) . CONCLUSION Isometric back extensors endurance in Nigerian adolescents was comparable to the original Biering-Sørensen mean value . Majority of the participants had medium endurance performance with the back endurance pattern in the ratio 1:2:1 . Male had higher isometric back extensors endurance than females . Decreased isometric back extensors endurance was associated with the presence of LBP in adolescents Background : High-intensity progressive resistance training ( PRT ) improves adiposity and metabolic risk in adults , but has not been investigated in children within a r and omized controlled trial ( RCT ) . Objective : We hypothesized that high-intensity PRT ( 8 weeks , twice a week ) would decrease central adiposity in children , as assessed via waist circumference . Methods Design / Setting / Participants : Concealed r and omization stratified by age and gender was used to allocate rural New Zeal and school students to the wait-list control or PRT group . Intervention : Participants were prescribed two sets ( eight repetitions per set ) of 11 exercises targeting all the major muscle groups at high intensity . Primary Outcome : Waist circumference ; secondary outcomes included whole body fat , muscular fitness ( one repetition maximum ) , cardiorespiratory fitness ( peak oxygen consumption during a treadmill test ) , lipids , insulin sensitivity and fasting glucose . Results : Of the 78 children ( 32 girls and 46 boys ; mean age 12.2(1.3 ) years ) , 51 % were either overweight ( 33 % ) or obese ( 18 % ) . High-intensity PRT significantly improved waist circumference ( mean change PRT −0.8 ( 2.2 ) cm vs + 0.5 ( 1.7 ) cm control ; F=7.59 , P=0.008 ) , fat mass ( mean change PRT + 0.2 ( 1.4 ) kg vs + 1.0 ( 1.2 ) kg control ; F=6.00 , P=0.017 ) , percent body fat ( mean change PRT –0.3 (1.8)% vs + 1.2 (2.1)% control ; F=9.04 , P=0.004 ) , body mass index ( mean change PRT −0.01 ( 0.8 ) kg m−2 vs + 0.4 ( 0.7 ) kg m−2 control ; F=6.02 , P=0.017 ) , upper body strength ( mean change PRT+11.6(6.1 ) kg vs + 2.9(3.7 ) kg control ; F=48.6 , P<0.001 ) and lower body strength ( mean change PRT + 42.9(26.6 ) kg vs + 28.5(26.6 ) kg control ; F=4.72 , P=0.034 ) compared to the control group . Waist circumference decreased the most in those with the greatest baseline relative strength ( r=−0.257 , P=0.036 ) , and greatest relative ( r=−0.400 , P=0.001 ) and absolute ( r=0.340 , P=0.006 ) strength gains during the intervention . Conclusion : Isolated high-intensity PRT significantly improves central and whole body adiposity in association with muscle strength in normal-weight and overweight children . The clinical relevance and sustainability of these changes in adiposity should be addressed in future long-term studies This study establishes the relationship between the compliance with the governmental physical activity guidelines ( at least a minimum of one hour of moderate to vigorous physical activity , MVPA , five times a week ) , health-related physical fitness and different health related lifestyle variables in a representative sample of Spanish children . Subjects were a representative group of scholars from five schools r and omly selected in Extremadura , a mainly rural region with a very low population density . Statistical analysis comprises a t-test to calculate physical fitness differences between groups , according to the compliance with the mentioned physical activity guidelines . A multinomial logistic regression coefficient is established to determine the differences between the better physical fitness status group (= percentile 75 ) and the poorer physical fitness status group (= percentile 25 ) for each fitness test and gender , body mass index , physical activity , Mediterranean diet index and population size . Main findings show that the compliance with physical activity guidelines result in a better h and grip strength in left h and ( p < 0.05 ) , leg strength ( p < 0.000 ) , speed-agility run ( p < 0.000 ) and 20 m endurance shuttle run ( p < 0.000 ) . Being a girl , being overweighed and living in an urban setting are associated with a lower physical fitness (= percentile 25 ) , whereas there is no relationship between diet quality and subjects ' performance in all physical fitness test evaluated . As a conclusion , this study emphasizes the need to promote an active lifestyle in which physical activity suppose a minimum of one hour of regular MVPA , at least five times a week , to achieve a healthy fitness status UNLABELLED This is the first prospect i ve cohort study of the association between bone mass and fracture risk in childhood . A total of 6213 children 9.9 years of age were followed for 24 months . Results showed an 89 % increased risk of fracture per SD decrease in size-adjusted BMC . INTRODUCTION Although previous case-control studies have reported that fracture risk in childhood is inversely related to bone mass , this has not been confirmed in prospect i ve studies . Additionally , it remains unclear which constituent(s ) of bone mass underlie this association . We carried out a prospect i ve cohort study to examine the relationship between DXA measures in children 9.9 years of age and risk of fracture over the following 2 years . MATERIAL S AND METHODS Total body DXA scan results obtained at 9.9 years of age were linked to reported fractures over the following 2 years in children from a large birth cohort in southwest Engl and .  DXA measures consisted of total body less head ( TBLH ) BMD , bone area , and BMC , and results of subregional analysis of the humerus .  Analyses were adjusted for age , sex , ethnicity , and social position . RESULTS Complete data were available on 6213 children . There was a weak inverse relationship between BMD at 9.9 years and subsequent fracture risk ( OR per SD decrease = 1.12 ; 95 % CI , 1.02 - 1.25 ) . In analyses examining the relationship between fracture risk and volumetric BMD , fracture risk was inversely related to BMC adjusted for bone area , height , and weight ( OR = 1.89 ; 95 % CI , 1.18 - 3.04 ) and to estimated volumetric BMD of the humerus ( OR = 1.29 ; 95 % CI , 1.14 - 1.45 ) . Fracture risk was unrelated to both TBLH and humeral bone area . However , in analyses of the relationship between fracture risk and bone size relative to body size , an inverse association was observed between fracture risk and TBLH area adjusted for height and weight ( OR = 1.51 ; 95 % CI , 1.17 - 1.95 ) . CONCLUSIONS Fracture risk in childhood is related to volumetric BMD , reflecting an influence of determinants of volumetric BMD such as cortical thickness on skeletal fragility . Although bone size per se was not related to fracture risk , we found that children who fracture tend to have a smaller skeleton relative to their overall body size Abstract The purpose of the present study was to assess different aspects of physical activity and fitness in order to develop a basis for sport programmes for overweight and obese children . Eighty-eight prepubertal children ( 49 boys , 39 girls , 4.8–11.4 years old , 61 % obese , 14 % overweight and 25 % normal weight ) were examined . Body composition was assessed by combined use of anthropometrics and bioelectrical impedance analysis . Resting energy expenditure ( REE ) and total energy expenditure ( TEE ) were measured by indirect calorimetry ( IC ) and individually calibrated 24-h heart rate ( HR ) monitoring , respectively . Activity-related energy expenditure ( AEE ) and physical activity level ( PAL )  were calculated from TEE and REE .  Fitness [ assessed by O2-pulse , respiratory exchange ratio ( RER ) at submaximal work intensities ] was determined by ergometry . The maximal isometric muscle strength of the legs ( m. quadriceps , Fa max , m. ischiocruralis , Fb max ) was measured by computer tensiometry .  Children were grouped according to their nutritional state , AEE , O2-pulse and muscle strength . When compared with normal weight children , obese and overweight children had increased fat mass ( FM ) , fat-free mass ( FFM ) , waist-to-hip ratio and REE , but no group differences were observed for TEE , AEE , and PAL . Obese and overweight children spent more hours per day watching TV  . After correction for body weight and FFM , no group differences in REE were observed , but normal weight children had a higher O2-pulse than overweight and obese children . By contrast , RER was increased in the latter group . The fittest group had the lowest body weight , BMI , FM and FFM . Children with a low O2-pulse spent more hours per day watching TV . Grouping children according to their degree of muscle strength , younger children ( 4–7.5 years ) did not show group differences in nutritional state , energy expenditure , physical activity and fitness . However , in the group of 7.6- to 11-year-old children , those with the greatest muscle strength and FFM had reduced BMI , skin folds , FM and FFM . FM correlated inversely with O2-pulse , but was not associated with TEE , AEE , PAL or muscle strength . By contrast TV consumption was positively associated with FM . To summarize , overweight and obese children were less fit and watched more TV than their normal weight counterparts . FM did not correspond to TEE , AEE or PAL . Muscle strength was not associated with FM in young children , but was inversely associated with FM in older children . Our cross-sectional data are consistent with the idea that increased fitness and reduced physical inactivity may prevent children from being overweight Study Design . This study comprised a cross-sectional part and a prospect i ve part . Objective . To study whether low lumbar extension strength , high lumbar mobility , and high mobility – extension strength ratios are related to current and future low back pain in adolescents . Summary of Background Data . Knowledge is sparse about the significance of lumbar mobility and strength for low back pain in adolescents . Methods . The study population included all the adolescents in the eighth and ninth grade s of a rural municipality ( n = 44 ) and in an urban area ( n = 61 ) during the 1996–1997 school year . At baseline , 88 adolescents ( mean age , 14.7 years ) participated in the study , giving a response rate of 84 % .  Low back pain was assessed by question naire as pain or discomfort in the low back during the preceding year . Sagittal lumbar mobility  was tested by Schober ’s modified technique , and lumbar strength as  static endurance extension strength  . The follow-up part was conducted 3 years later , which included 98 % of the adolescents . Results . By bivariate and multivariate analyses in the cross-sectional part of the study , low back pain was found to be highly associated with low lumbar extension strength ( P = 0.004–0.02 ) , and high lumbar mobility – extension strength ratios ( P = 0.005–0.04 ) . Baseline low lumbar extension strength and high lumbar sagittal mobility – extension strength ratios ( P = 0.03 and P = 0.02 , respectively ) predicted low back pain at follow-up assessment in multivariate analyses when control was used for gender , previous low back pain , physical activity , and well-being . No associations were found between plain sagittal mobility and low back pain . Conclusion . The study findings support theories suggesting insufficient strength and stability in the low back as important factors for both concurrent and future low back pain in adolescents The study describe changes over 2 years in different physical fitness measures and the relationship between these changes and changes in physical activity . Maximal aerobic work capacity ( Wattmax ) , functional strength , muscle endurance , agility and flexibility were measured in 259 r and omly selected high school boys and girls 16.5 years of age and followed-up 2 years later , while they still attended school . Most physical fitness measures increased over time in boys , and in girls an increase was found in arm extensor strength and trunk extensor endurance , but Wattmax per kg body mass decreased . Changes in physical performance between 16 and 18 years of age seem to be very similar in different countries , despite differences in physical activity patterns and absolute level of performance . No change was found in time of participation in physical activity or sports activity  in either gender , but fewer girls participated in  leisure-time sports  at the 2nd test ( p < 0.001 ) . Change in physical activity or sports activity  did not relate to change in physical fitness level . The relationships between level of sports participation ( competition , for health or none ) and physical fitness measures at baseline and at the 2nd test were weak or non-significant . Three explanations for the weak relationship between physical activity and fitness are suggested : ( A ) part of the variability in fitness is explained by genetics , ( B ) growth and hormonal changes , especially in boys , override the stimulus of training , and ( C ) the physical fitness level in adolescents is so high that only physical activity at high relative intensity is supposed to have an effect on the fitness level OBJECTIVES We examined the relationship between comprehensive fitness tests and overweight using a school surveillance system in a racially diverse city in the United States . RESEARCH METHODS AND PROCEDURES Trained physical education teachers  measured weight , height , and fitness annually from 2001 to 2003 . We compiled data for a cross-sectional analysis ( 11,845 measurements on 6297 students , 5 to 14 years of age ) and a 1-year prospect i ve analysis ( 4215 measurements on 2927 students not overweight at baseline , 5 to 13 years of age ) . Overweight was defined as a BMI > or = 95th percentile ( Centers for Disease Control and Prevention 2000 growth charts ) , and underfit was defined as failing at least one of five fitness tests : endurance run , abdominal strength , flexibility , upper body strength , and agility ( Amateur Athletic Union and Fitnessgram ) . Associations between fitness and overweight were examined using multivariate logistic regression models , adjusting for sociodemographic status and repeated measurements over time . RESULTS The mean number of fitness tests passed was lower among students with a BMI above the 80th percentile . Overweight incidence over 1 year was 7 % and 2 % for underfit and fit girls , respectively ( odds ratio , 3.3 ; 95 % confidence interval , 2.0 to 5.6 ) . Not passing either the endurance run or upper body strength test was associated with overweight incidence in both boys and girls . After adjusting for baseline BMI , the endurance run remained a significant predictor of incident overweight among girls ( odds ratio , 2.0 ; 95 % confidence interval , 1.1 to 3.5 ) . DISCUSSION Findings support a cross-sectional inverse relationship between physical fitness and  overweight among school-aged children . The direction of causation between fitness and overweight is not clearly established and merits further study Objectives To explore the extent to which muscular strength in adolescence is associated with all cause and cause specific premature mortality ( < 55 years ) . Design Prospect i ve cohort study . Setting Sweden . Participants 1 142 599 Swedish male adolescents aged 16 - 19 years were followed over a period of 24 years . Main outcome measures Baseline examinations included  knee extension , h and grip , and elbow flexion strength tests  , as well as measures of  diastolic and systolic blood pressure and body mass index . Cox regression was used to estimate hazard ratios for mortality according to muscular strength categories ( tenths ) . Results During a median follow-up period of 24 years , 26 145 participants died . Suicide was a more frequent cause of death in young adulthood ( 22.3 % ) than was cardiovascular diseases ( 7.8 % ) or cancer ( 14.9 % ) . High muscular strength in adolescence , as assessed by knee extension and h and grip tests , was associated with a 20 - 35 % lower risk of premature mortality due to any cause or cardiovascular disease , independently of body mass index or blood pressure ; no association was observed with mortality due to cancer . Stronger adolescents had a 20 - 30 % lower risk of death from suicide and were 15 - 65 % less likely to have any psychiatric diagnosis ( such as schizophrenia and mood disorders ) . Adolescents in the lowest tenth of muscular strength showed by far the highest risk of mortality for different causes . All cause mortality rates ( per 100 000 person years ) ranged between 122.3 and 86.9 for the weakest and strongest adolescents ; corresponding figures were 9.5 and 5.6 for mortality due to cardiovascular diseases and 24.6 and 16.9 for mortality due to suicide . Conclusions Low muscular strength in adolescents is an emerging risk factor for major causes of death in young adulthood , such as suicide and cardiovascular diseases . The effect size observed for all cause mortality was equivalent to that for well established risk factors such as elevated body mass index or blood pressure OBJECTIVE To study the effect of a st and ardised training programme focusing on maintenance of fat free mass during weight reduction by energy reduction in obese children . DESIGN R and omised trial of physical training programme and dietary advice ( group A ) versus dietary advice alone ( group B ) . SUBJECTS Thirty obese children and adolescents ( 14 group A , 16 group B ) participated in the 12 week long programme ; 20 children ( 10 group A , 10 group B ) were also reassessed after one year . MEASUREMENTS Fat free mass was estimated from the resistance index , obtained by bioelectrical impedance analysis at baseline , after four , eight , and 12 weeks in all subjects , and after one year in 20 subjects . RESULTS The mean ( SD ) change in fat free mass was significantly different between the two groups after 12 weeks ( group A , 2.68 ( 3.74 ) kg ; group B , 0.43 ( 1.65 ) kg ) . The change in body weight after one year was inversely correlated with the change in fat free mass after 12 weeks ( r = −0.44 ) , as assessed in the 20 subjects . CONCLUSIONS A st and ardised training programme as used in this study can prevent reduction in fat free mass during weight loss in obese children . Reduction in fat free mass during weight reduction might be a risk factor for regain of weight This study investigates whether physical activity and physical performance in adolescence are positively related to  adult bone mineral density ( BMD ) . In 1974 , physical activity , endurance , and muscular strength were measured in 204 r and omly selected female students , age 16.1 + /- 0.3 year ( range 15 - 17 years ) . Twenty years later , 36 of the women volunteered to undergo a measurement of their BMD . Women who were members in a sports club in adolescence had significantly higher adult BMD ( mean differences of 5 % to 17 % depending on site ) compared with subjects who were not engaged in a sports club . Furthermore , women with persistent weight-bearing activity in adulthood had significantly higher BMD compared with women who had stopped being active or had never been active . The differences ranged between 5 % and 19 % with the highest difference found in trochanter BMD . Stepwise regression analyses showed that membership in a sports club at baseline was a significant independent predictor of BMD in the total body , lumbar spine , legs , trochanter , and femoral neck , explaining 17 - 26 % of the variation in BMD . Change in body weight was a strong independent predictor of BMD of the total body and arms , explaining 8 % of the variation in both sites . In addition , running performance at baseline was an independent predictor of total body BMD , whereas the two-h and lift performance significantly predicted BMD of the total body , legs and trochanter . The hanging leg-lift and h and grip were both significant predictors of arm BMD . In conclusion , membership in a sports club and site-specific physical performance in adolescence together with the change in body weight were significantly associated with adult BMD in premenopausal women Study Design . This was a prospect i ve 3-year follow-up study of r and omized matched subgroups of 15-year-old school children with or without low back pain initially . Objective . In addition to low back pain and leisure time physical activity , spinal mobility , trunk muscle strength , and early degenerative findings of the lumbar spine were evaluated . Summary of Background Data . Reliable epidemiologic studies on the prevalence of low back pain and development of early degenerative changes of the lumbar spine in young persons have been sparse . Along with several other characteristics , the relationship of these changes to frequent low back pain in young persons is not known . Methods . After a question naire-based survey was administered , subjects with or without low back pain were examined initially and at follow-up with special reference to leisure time physical activity , anthropometry , spinal mobility , trunk muscle strength , and magnetic resonance imaging findings of the lumbar spine . Results . At baseline and at follow-up , those subjects with initial low back pain were characterized by a low frequency of physical activity and decreased spinal function . During follow-up , the occurrence of disc degeneration increased significantly more in the original group with low back pain than among asymptomatic subjects . Furthermore , disc degeneration at baseline significantly predicted future frequent low back pain . Initial disc protrusion also predicted future frequent low back pain . Conclusion . After the rapid physical growth period , there seemed to be a causal relationship between the early evolution of the degenerative processes of the lower lumbar discs and frequent low back pain in several subjects Study Design . A combined cross‐sectional and longitudinal design . Objectives . To investigate relation between , on one h and , self‐reported neck‐shoulder symptoms and , on the other h and , low back symptoms and self‐reported work‐related physical load , psychosocial factors , and individual characteristics and to study the influence of physical capacity in adolescence on neck‐shoulder and low back symptoms in adulthood . Summary of Background Data . Heavy physical work and exposure to vibration constitute risk factors for low back problems , and repetitive and static work are risk factors for neck‐shoulder symptoms in many jobs . The interplay between individual factors and work‐related psychosocial and physical exposure , however , is not well documented . This study addresses effects of adolescent capacity on this interplay in a general population . Methods . A r and om sample of 425 Swedish students was investigated when the students were 16 years and 34 years of age . Sixty‐five percent participated in both examinations ; only those who worked ≥ 6 hours/week at the follow‐up period , 148 men and 90 women , were included in these analyses .  Data about musculoskeletal symptoms , work , and sociodemographic and individual characteristics were collected at the age of 34 years ; physical performance data were collected at the ages of 16 years and 34 years . Results . Among the men , self‐employment and worry were associated with neck‐shoulder symptoms ; among the women , monotonous work and high decision latitude were associated with neck‐shoulder symptoms . Low back problems were related to monotonous work among men and women and to exposure to vibration among men . Performance in certain fitness tests at the ages of 16 years and 34 years was negatively associated with musculoskeletal symptoms . Conclusions . The inverse relationships between performance at the age of 16 years and adult musculoskeletal symptoms may imply benefits of early fitness training PURPOSE Insulin resistance is thought to be a core defect in the pathophysiology of obesity-related comorbidities in children , such as type 2 diabetes . Exercise training is known to improve insulin resistance and reduce the risk of type 2 diabetes in adults . However , very little is known regarding the effects of exercise on insulin resistance in youth . Therefore , we examined the effects of a 16-wk resistance training exercise intervention on insulin sensitivity in youth at high risk for developing type 2 diabetes . METHODS Twenty-two overweight Latino adolescent males were r and omly assigned to either a twice-per-week resistance training group ( RT=11 ) or a nonexercising control group ( C=11 ) for 16 wk . Strength was assessed by one-repetition maximum , body composition was quantified by dual-energy x-ray absorptiometry , and insulin sensitivity was determined by the frequently sample d intravenous glucose tolerance test with minimal modeling . RESULTS Significant increases in upper- and lower-body strength were observed in the RT compared with the C group . The RT group significantly increased insulin sensitivity compared with the C group ( P<0.05 ) , and this increase remained significant after adjustment for changes in total fat mass and total lean tissue mass ( P<0.05 ) . Compared with baseline values , insulin sensitivity increased 45.1+/-7.3 % in the RT group versus -0.9+/-12.9 % in controls ( P<0.01 ) . CONCLUSION A twice-per-week 16-wk resistance training program can significantly increase insulin sensitivity in overweight Latino adolescent males independent of changes in body composition 259 primary school children ( average age 9.2 years ) were r and omly selected from three groups of children whose weights-for-height were 90 - 110 % ( normal 111 ) , > 110 - 120 % ( over weight 25 ) , and > 120 % ( obesity 123 ) of reference values for Bangkok children . They underwent physical fitness tests which included measurement of speed ( 50 meters run ) , flexibility ( sit-reach ) , abdominal strength and endurance ( 30 seconds sit-up ) , vital capacity ( spirometer ) , and indirect maximum oxygen uptake ( VO2 max-submaximal bicycle ergometer ) .  The results showed that all physical fitness tests were statistically significantly different ( p < 0.05 ) between groups , except for flexibility in boys . But for the girls , only 50 meters run , sit-up and VO2 max showed statistically significant differences ( p < 0.05 ) . In the comparison of physical fitness tests between sexes , normal weight boys did better than girls ( p < 0.05 ) for all tests except flexibility . There were no statistically significant differences between sexes in overweight and obese children . This study demonstrated that physical fitness of obese children was worse than that of normal children in both sexes , especially as measured by 50 meters run , sit-up and VO2 max tests . Thus , promotion of exercise  in obese children should be stimulated to develop better physical fitness and weight reduction . In comparison of physical fitness between the sexes , boys had better physical fitness than girls , significant in the normal weight group only . There is no definite explanation as to why increase in weight results in no difference of physical fitness between sexes . Lifestyle , physical skills , and genetic determinants should be considered for interpretation of physical fitness OBJECTIVES The mechanical environment is considered to be the most important determinant of bone strength . Local muscle force , in turn , is regarded as the largest source of loading applied to bones . However , the effect of weight-bearing on bone mineral accrual is unclear . Comparing the relationship between muscle force and bone mineral content ( BMC ) in the upper and lower limbs provides a means of investigating this issue . SUBJECTS AND METHODS The study group comprised 258 healthy girls aged 10 - 13 years old at baseline .  BMC , lean body mass ( LM ) and fat body mass ( FM ) of total body were assessed by dual-energy X-ray absorptiometry at baseline and 2 years after . The maximal isometric voluntary contraction ( MVC ) of left elbow flexors and knee extensors was evaluated by a dynamometer . A hierarchical linear statistical model with r and om effects was used to analyze the relationship between BMC and limb-matched MVC . Fisher 's z-transformation was used to compare the correlation coefficients between arms and legs . The ratio of BMC to MVC ( BMC /MVC ) in upper and lower limbs was compared using Student 's t-test . RESULTS BMC was highly correlated with MVC in arms and legs ( r(2)=0.54 and 0.50 , respectively ) , and the correlation coefficients did not differ between upper and lower limbs . On the other h and , BMC /MVC was significantly ( 30 % ) higher in leg than in arm . CONCLUSIONS The results indicate that local muscle contraction and weight-bearing exert an additive effect on bone mass accretion in the lower limbs . Exercise regimes combining resistance and impact training should provide larger bone response than either one of them alone in growing children The incidence of hip and forearm fracture in elderly men in the United Kingdom is a public health issue , but there is limited knowledge on lifestyle factors affecting male bone health . The aim of this cross-sectional study was to evaluate the relationships between whole body and regional bone mineral status and self-reported participation time in no- , low- , moderate- , and high-impact activities and fitness measurements in 16- to 18-year-old boys . One hundred twenty-eight boys underwent absorptiometry ( DXA ) measurements ( Hologic QDR 1000W ) of  bone mineral content ( BMC ) , bone area ( BA ) , and bone mineral density ( BMD ) at the whole body , hip , spine , and forearm . They also completed the EPIC ( European Prospect i ve Investigation of Cancer ) physical activity question naire , which allowed categorization of activities according to impact and aerobic intensity . Fitness and strength were assessed in each subject using estimated VO2 max , grip strength , and back strength . Significant positive relationships were found between BMC , BA , and BMD and the fitness and strength measurements and participation time in high-impact sports at most skeletal sites . The relationships were further examined after adjustment of BMC for height , weight , and bone area , thereby minimizing the influence of body and bone size on these relationships . VO2 max was a significant positive determinant of size-adjusted BMC at the whole body , the ultradistal and one-third radius , and all the hip sites , except the trochanter . Size-adjusted BMC at the forearm sites and trochanter was significantly positively associated with grip strength . Size-adjusted BMC at the whole body and all the hip sites was significantly positively associated with time spent at high-impact activities . Differences in size-adjusted BMC across thirds of time spent at high-impact activities were also examined . Boys in the highest third of high-impact activity had significantly greater size-adjusted whole body BMC and total hip BMC compared to subjects in the lowest third [ + 3.4 (1.2)% for whole body and + 8.5 (2.2)% for hip , both P = 0.001 ] . Boys in the highest third of high-impact activity spent most activity time jogging , playing tennis , football and rugby , basketball , and exercising with weights . Back strength and lean mass were significantly greater in subjects in the highest third compared to those in the middle ( P = 0.02 ) and lowest third ( P = 0.03 ) . No significant differences were found between subjects in each third of high-impact activity for potential confounders including TV viewing , calcium intake , body fat , and height . These findings indicate that participation of male adolescents in a range of high-impact activities for 1 h or more a day is associated with greater bone size and mineral content , especially at the hip Objective To examine prospect ively the association between muscular strength and mortality from all causes , cardiovascular disease , and cancer in men . Design Prospect i ve cohort study . Setting Aerobics centre longitudinal study . Participants 8762 men aged 20 - 80 . Main outcome measures All cause mortality up to 31 December 2003 ; muscular strength , quantified by combining one repetition maximal measures for leg and bench presses and further categorised as age specific thirds of the combined strength variable ; and cardiorespiratory fitness assessed by a maximal exercise test on a treadmill . Results During an average follow-up of 18.9 years , 503 deaths occurred ( 145 cardiovascular disease , 199 cancer ) . Age adjusted death rates per 10 000 person years across incremental thirds of muscular strength were 38.9 , 25.9 , and 26.6 for all causes ; 12.1 , 7.6 , and 6.6 for cardiovascular disease ; and 6.1 , 4.9 , and 4.2 for cancer ( all P<0.01 for linear trend ) . After adjusting for age , physical activity , smoking , alcohol intake , body mass index , baseline medical conditions , and family history of cardiovascular disease , hazard ratios across incremental thirds of muscular strength for all cause mortality were 1.0 ( referent ) , 0.72 ( 95 % confidence interval 0.58 to 0.90 ) , and 0.77 ( 0.62 to 0.96 ) ; for death from cardiovascular disease were 1.0 ( referent ) , 0.74 ( 0.50 to 1.10 ) , and 0.71 ( 0.47 to 1.07 ) ; and for death from cancer were 1.0 ( referent ) , 0.72 ( 0.51 to 1.00 ) , and 0.68 ( 0.48 to 0.97 ) . The pattern of the association between muscular strength and death from all causes and cancer persisted after further adjustment for cardiorespiratory fitness ; however , the association between muscular strength and death from cardiovascular disease was attenuated after further adjustment for cardiorespiratory fitness . Conclusion Muscular strength is inversely and independently associated with death from all causes and cancer in men , even after adjusting for cardiorespiratory fitness and other potential confounders
target: Results Strong evidence was found for an inverse association between MF and total and central adiposity , and CVD and metabolic risk factors .
  Strong evidence was also found for a positive association between MF and bone health and self-esteem .
  Conclusion The findings of this review highlight the importance of developing MF in youth for a number of health-related benefits
background: Background Physical fitness during childhood and adolescence has been identified as an important determinant of current and future health status .
  While research has traditionally focused on the association between cardio-respiratory fitness and health outcomes , the association between muscular fitness ( MF ) and health status has recently received increased attention .
  Objective The aim of this systematic review and meta- analysis was to evaluate the potential physiological and psychological benefits associated with MF among children and adolescents .