title: Effects of exercise intensity on cardiovascular fitness, total body composition, and visceral adiposity of obese adolescents. Bone mass and structure are enhanced following a 2-year randomized controlled trial of exercise in prepubertal boys. Low cardiorespiratory fitness is a strong predictor for clustering of cardiovascular disease risk factors in children independent of country, age and sex Effects of modifying physical activity and sedentary behavior on psychosocial adjustment in overweight/obese children. In the absence of weight loss, exercise training does not improve adipokines or oxidative stress in overweight children. Physical activity and functional limitations in older adults: a systematic review related to Canada's Physical Activity Guidelines A school-based exercise intervention elicits substantial bone health benefits: a 2-year randomized controlled trial in girls. Treatment of childhood syndrome X. Prevalence of risk for type 2 diabetes in school children. Physical activity and clustered cardiovascular risk in children: a cross-sectional study (The European Youth Heart Study) Active transportation to school over 2 years in relation to weight status and physical activity. A school-based exercise intervention augments bone mineral accrual in early pubertal girls. The feasibility of creating a checklist for the assessment of the methodological quality both of randomised and non-randomised studies of health care interventions. Effects of exercise training and its cessation on components of the insulin resistance syndrome in obese children Effect of physical training on total and visceral fat in obese children. The effects of physical activity and exercise training on psychological stress and well-being in an adolescent population. Resistance training and bone mineral density in adolescent females. Exercise training and cardiovascular risk factors in type 1 diabetic adolescent girls. Improvement of fitness, body composition, and insulin sensitivity in overweight children in a school-based exercise program: a randomized, controlled study. “Bounce at the Bell”: a novel program of short bouts of exercise improves proximal femur bone mass in early pubertal children Relationship of physical fitness to prevalence and incidence of overweight among schoolchildren. Correlates of depression in a representative nationwide sample of adolescents (15-19 years) and young adults (20-24 years). Improvement of early vascular changes and cardiovascular risk factors in obese children after a six-month exercise program. A school curriculum-based exercise program increases bone mineral accrual and bone size in prepubertal girls: two-year data from the pediatric osteoporosis prevention (POP) study. Effect of 4 weeks of Pilates on the body composition of young girls. Effects of resistance training on insulin sensitivity in overweight Latino adolescent males. The effects of endurance training on selected coronary risk factors in children Does previous participation in high-impact training result in residual bone gain in growing girls? One year follow-up of a 9-month jumping intervention. Augmented trochanteric bone mineral density after modified physical education classes: a randomized school-based exercise intervention study in prepubescent and early pubescent children. Systematic Reviews: Synthesis of Best Evidence for Clinical Decisions A randomized school-based jumping intervention confers site and maturity-specific benefits on bone structural properties in girls: a hip structural analysis study. Effects of school-based aerobic exercise on blood pressure in adolescent girls at risk for hypertension.
abstract: BACKGROUND Little is known about how the intensity of exercise influences cardiovascular fitness and body composition , especially in obese adolescents . OBJECTIVE Our goal was to determine the effects of physical training intensity on the cardiovascular fitness , percentage of body fat ( % BF ) , and visceral adipose tissue ( VAT ) of obese adolescents . DESIGN Obese 13 - 16-y-olds ( n = 80 ) were assigned to 1 ) biweekly lifestyle education ( LSE ) , 2 ) LSE + moderate-intensity physical training , or 3 ) LSE + high-intensity physical training . The intervention lasted 8 mo . Physical training was offered 5 d/wk , and the target energy expenditure for all subjects in physical training groups was 1047 kJ ( 250 kcal)/session . Cardiovascular fitness was measured with a multistage treadmill test , % BF with dual-energy X-ray absorptiometry , and VAT with magnetic resonance imaging . RESULTS The increase in cardiovascular fitness in the high-intensity physical training group , but not in the moderate-intensity group , was significantly greater than that in the LSE alone group ( P = 0.009 ) ; no other comparisons of the 3 groups were significant . Compared with the LSE alone group , a group composed of subjects in both physical training groups combined who attended training sessions > or=2 d/wk showed favorable changes in cardiovascular fitness ( P < 0.001 ) , % BF ( P = 0.001 ) , and VAT ( P = 0.029 ) . We found no evidence that the high-intensity physical training was more effective than the moderate-intensity physical training in enhancing body composition . CONCLUSIONS The cardiovascular fitness of obese adolescents was significantly improved by physical training , especially high-intensity physical training . The physical training also reduced both visceral and total-body adiposity , but there was no clear effect of the intensity of physical training Exercise during growth has a positive influence on bone mineral accrual , yet little is known about how bone geometry and strength adapt to loading during growth . Our primary objective was to compare changes in proximal femur bone geometry and strength between 31 prepubertal ( Tanner Stage 1 ) boys who participated in a school-based , high-impact circuit intervention ( 12 min , three times a week ) for 20 months and 33 maturity-matched controls . Our secondary objective was to compare changes in total body ( TB ) , proximal femur ( PF ) , and lumbar spine ( LS ) bone mineral content ( BMC ) and bone area ( BA ) in these groups . We assessed geometric variables and bone strength at the narrow neck ( NN ) , intertrochanteric ( TR ) region , and femoral shaft regions by applying the Hip Structure Analysis program to proximal femur dual energy X-ray absorptiometry scans ( DXA , Hologic QDR 4500 ) . Further , we assessed total body , lumbar spine , and proximal femur BMC and BA by DXA and derived total body lean mass and fat mass from total body scans . Intervention ( 10.2 + /- 0.5 years ) and control boys ( 10.1 + /- 0.5 years ) had similar baseline height ( 140.8 vs. 141.3 cm ) and weight ( 36.9 vs. 35.4 kg ) , and average 20-month physical activity scores ( Physical Activity Question naire for Children , PAQ-C ) and calcium intakes ( 861 vs. 852 mg/day , food frequency question naire ) . Twenty-month height and weight changes were not significantly different between groups ; lean mass changed more ( P < 0.05 ) in intervention boys ( 22.8 % ) than control boys ( 18.6 % ) . At the NN region , intervention boys had greater bone expansion on both the periosteal ( + 2.6 % , P = 0.1 ) and endosteal ( + 2.7 % , P = 0.2 ) surfaces , result ing in significantly greater changes in section modulus ( bone bending strength ) ( + 7.5 % , P = 0.02 , ANCOVA , adjusting for height change , final Tanner Stage , and baseline bone values ) . Changes at the intertrochanteric and femoral shaft regions were not significantly different between groups . Femoral neck ( FN ) BMC changes were significantly greater in intervention boys ( + 4.3 % , P < 0.01 ) ; changes in BA and BMC for other regions were not significantly different between groups . In summary , a school-based , high-impact exercise intervention implemented three times a week for 12 min is an effective strategy for site-specific gains in bone strength at the narrow neck region of the proximal femur Background and design Few studies have investigated the association between maximal cardiorespiratory capacity ( fitness ) and the clustered cardiovascular disease ( CVD ) risk in children and youth from culturally diverse countries . This cross-sectional study examined the association between fitness and clustered CVD risk in children and adolescents from three European countries . Methods Participants were 2845 r and omly selected school children aged 9 or 15 years from Portugal ( n = 944 ) , Denmark ( n = 849 ) and Estonia ( n = 1052 ) .  Cardiorespiratory fitness was determined during a maximal test on a cycle ergometer . CVD risk factors selected to assess the degree of clustering were the total cholesterol/high-density lipoprotein cholesterol ratio , plasma triglycerides , insulin resistance ( homeostasis model assessment ) , sum of four skinfolds , and systolic blood pressure . Results There was a strong association between cardiorespiratory fitness and the clustering of CVD risk factors . The odds ratios for clustering in each quartile of fitness , using the quartile with the highest fitness as reference , were 13.0 [ 95 % confidence interval ( CI ) 8.8 - 19.1 ] ; 4.8 ( 95 % CI 3.2 - 7.1 ) and 2.5 ( 95 % CI 1.6 - 3.8 ) , respectively , after adjusting for country , age , sex , socio-economic status , pubertal stage , family history of CVD and diabetes . In stratified analyses by age group , sex and country , similar strong patterns were observed . Conclusion Low cardiorespiratory fitness is strongly associated with the clustering of CVD risk factors in children independent of country , age and sex OBJECTIVES To evaluate the relationship between changes in  physical activity ( PA ) , sedentary behavior , and physical self-perceptions and global self-worth in 30 , 8 - 12 years old , overweight/obese children ( 13 boys , 17 girls ) . METHODS Secondary analyses from a r and omized controlled trial design ed to increase PA and reduce sedentary behavior . PA was measured by accelerometers worn by participants every day for 8 weeks .  Sedentary behavior , defined as minutes per day spent in television viewing , was assessed by self-report . RESULTS Increases in PA were associated with increases in perceived physical conditioning ( r = .54 , p < .01 ) , body satisfaction ( r = .55 , p < .01 ) , and overall physical self-worth ( r = .44 , p < .05 ) independent of changes in body mass index ( BMI ) . Reductions in TV viewing were also related to increased physical and global self-worth . CONCLUSIONS Increases in PA are associated with improvements in physical self-perceptions but not global self-worth , while reductions in TV viewing are associated with increased physical and global self-worth , and these psychosocial benefits appear to be independent of changes in adiposity The aim of the present study was to examine the effect of exercise training on adipokines , inflammatory markers , and oxidative stress in overweight children . Nineteen overweight children were r and omly assigned to an aerobic exercise training or sedentary control group for 8 weeks . Measurements included peak oxygen uptake ( V o(2)max ) , body weight and composition , adipokines ( C-reactive protein , interleukin 6 , tumor necrosis factor alpha , adiponectin , leptin , and resistin ) , and oxidative stress ( 8-isoprostane ) . There were no differences between groups for change in body weight or composition over the 8 weeks . Exercise training improved V o(2)max ( exercise group , 1.64 + /- 0.13 to 1.85 + /- 0.17L/min vs control group , 1.83 + /- 0.12 to 1.60 + /- 0.13 L/min , P < .05 ) but did not change any of the measured adipokines or the marker of systemic oxidative stress , 8-isoprostane . These data suggest that in the absence of weight loss , exercise training alone does not improve the adipokine profile or levels of oxidative stress in overweight children Background The purpose was to conduct systematic review s of the relationship between physical activity of healthy community-dwelling older ( > 65 years ) adults and outcomes of  functional limitations , disability , or loss of independence .  Methods Prospect i ve cohort studies with an outcome related to functional independence or to cognitive function  were search ed , as well as exercise training interventions that reported a functional outcome . Electronic data base search strategies were used to identify citations which were screened ( title and abstract ) for inclusion . Included articles were review ed to complete st and ardized data extraction tables , and assess study quality . An established system of assessing the level and grade of evidence for recommendations was employed . Results Sixty-six studies met inclusion criteria for the relationship between physical activity and functional independence , and 34 were included with a cognitive function outcome . Greater physical activity of an aerobic nature ( categorized by a variety of methods ) was associated with higher functional status ( expressed by a host of outcome measures ) in older age . For functional independence , moderate ( and high ) levels of physical activity appeared effective in conferring a reduced risk ( odds ratio ~0.5 ) of functional limitations or disability . Limitation in higher level performance outcomes was reduced ( odds ratio ~0.5 ) with vigorous ( or high ) activity with an apparent dose-response of moderate through to high activity . Exercise training interventions ( including aerobic and resistance ) of older adults showed improvement in physiological and functional measures , and suggestion of longer-term reduction in incidence of mobility disability . A relatively high level of physical activity was related to better cognitive function and reduced risk of developing dementia ; however , there were mixed results of the effects of exercise interventions on cognitive function indices . Conclusions There is a consistency of findings across studies and a range of outcome measures related to functional independence ; regular aerobic activity and short-term exercise programmes confer a reduced risk of functional limitations and disability in older age . Although a precise characterization of a minimal or effective physical activity dose to maintain functional independence is difficult , it appears moderate to higher levels of activity are effective and there may be a threshold of at least moderate activity for significant outcomes OBJECTIVE Childhood weight-bearing physical activity is recognized as an important determinant of peak bone mass , and physical activity intervention may represent a feasible strategy for primary prevention of osteoporosis . Previous school-based exercise interventions have all been of < 10 months in duration . We implemented a high-impact , circuit-based , jumping intervention ( 10 minutes , 3 times a week ) over 2 school years and compared changes in bone mineral content ( BMC ) over 20 months ( 2 school years ) in 9.9 + /- 0.6-year-old intervention girls ( N = 32 ) and controls ( 10.3 + /- 0.4 years , N = 43 ) . METHODS We measured BMC for the total body , lumbar spine , proximal femur ( and femoral neck and trochanteric subregions ) , and lean and fat mass by dual-energy radiograph absorptiometry ( Hologic QDR 4500 ) , and height , sitting height , leg length , and weight at baseline and 20 months . We assessed Tanner stage , general physical activity , and calcium intake by question naire . RESULTS Girls were Tanner breast stage 1 to 3 at baseline . There were no significant differences in baseline or 20-month change in body size or composition , average physical activity , or calcium intake between groups . There were substantially greater gains in lumbar spine ( 41.7 % vs 38.0 % ) and femoral neck ( 24.8 % vs 20.2 % ) BMC in intervention than in control girls ( P < .05 , analysis of covariance ; covariates were baseline BMC and height , change in height , physical activity , and final Tanner stage ) . CONCLUSION Three brief sessions of high-impact exercise per week implemented over 2 consecutive years within the elementary school curriculum elicited a substantial bone mineral accrual advantage in pubertal girls OBJECTIVE Hyperinsulinemia , hyperlipidemia , hypertension , and coronary artery disease comprise a quartet known as Syndrome X. This syndrome was first described in adults , but has recently been described in children and adolescents . The purpose of our study was to determine if diet or exercise is able to change the clinical profile of Syndrome X in children . STUDY DESIGN We recruited 36 obese ( % ideal body weight = 170.3 + /- 31.1 ) , children ( 9 to 12 yrs old ) known to have high fasting cholesterol levels ( 177.5 + /- 33.5 mg/dL ) . Each participated in a 6-week protocol in one of three groups : control ( C ) , diet ( D ) , or exercise ( E ) . Twenty-five of the patients completed the study with full compliance . At the beginning and end of the study , we measured weight , height , blood pressure , serum insulin , and a lipid profile including : cholesterol , low density lipoprotein , high density lipoprotein ( HDL ) , triglycerides , and apolipoprotein A ( ApoA ) . All subject groups were similar before the study . The D group had the greatest attrition ( 40 % ) and all of the E group completed the study . RESULTS After the 6-week study period , there was no significant weight loss or change in body mass index for any group . There was no significant change in blood pressure and there was no significant decline of fasting cholesterol or low density lipoprotein levels in any of the groups . HDL levels were low in all groups and did not significantly change with treatment . There was a significant decline in the triglyceride levels in both the diet and exercise groups after the study ( preD = 150 + /- 60 ; postD = 122 + /- 50 ; preE = 165 + /- 50 ; postE = 116 + /- 39 ) . Both the D and E groups also demonstrated a significant decrease in ApoA levels ( preD = 174 + /- 33 ; postD = 142 + /- 24 ; preE = 200 + /- 50 ; postE = 161 + /- 23 ) . Most impressively , fasting insulin levels significantly decreased with both diet and exercise , but did not change in controls during the 6 weeks ( preC = 52 + /- 19 ; postC = 53 + /- 21 ; preD = 54 + /- 23 ; postD = 15 + /- 8 ; preE = 48 + /- 21 ; postE = 9 ) . CONCLUSIONS The findings of this study are consistent with previous studies describing the presence of Syndrome X in childhood . Both diet and exercise were effective in lowering triglyceride , ApoA levels , and insulin levels . However , due to the large rate of noncompliance in the diet group , exercise seems to be the best treatment for improvement in Syndrome X in children According to the Centers for Disease Control and Prevention , 1 in 3 children born in 2000 in the United States will become diabetic . The odds are higher for African American and Hispanic children as nearly 50 % of them will develop diabetes . R and om screening is not effective in identifying children at risk for type 2 diabetes mellitus ( T2DM )  ; therefore , there is a need to apply screening strategies that guide the development of appropriate primary prevention efforts . To assess the prevalence of risk factors for T2DM , 1066 fifth- grade children were screened using American Diabetes Association guidelines . Overall , 22.6 % were found at risk ; African American and Hispanic children were almost 8 times more likely to be at risk when compared to Caucasians ( odds ratio = 7.41 and 7.87 ) . Children who reported watching TV/playing video games 2 or more hours/day were 73 % more likely to be at risk . Children identified to be at risk were referred to their primary care provider and were invited to participate in a counseling session . The environmental risk factors for T2DM identified in this study are modifiable and should be targeted in preventive interventions at the school and community level to reduce overweight and consequently prevent T2DM in children , especially among minority children BACKGROUND Atherosclerosis develops from early childhood ; physical activity could positively affect this process . This study 's aim was to assess the associations of objective ly measured physical activity with clustering of cardiovascular disease risk factors in children and derive guidelines on the basis of this analysis . METHODS We did a cross-sectional study of 1732 r and omly selected 9-year-old and 15-year-old school children from Denmark , Estonia , and Portugal . Risk factors included in the composite risk factor score ( mean of Z scores ) were systolic blood pressure , triglyceride , total cholesterol/HDL ratio , insulin resistance , sum of four skinfolds , and aerobic fitness . Individuals with a risk score above 1 SD of the composite variable were defined as being at risk . Physical activity was assessed by accelerometry . FINDINGS Odds ratios for having clustered risk for ascending quintiles of  physical activity  ( counts per min ; cpm ) were 3.29 ( 95 % CI 1.96 - 5.52 ) , 3.13 ( 1.87 - 5.25 ) , 2.51 ( 1.47 - 4.26 ) , and 2.03 ( 1.18 - 3.50 ) , respectively , compared with the most active quintile . The first to the third quintile of physical activity had a raised risk in all analyses . The mean time spent above 2000 cpm in the fourth quintile was 116 min per day in 9-year-old and 88 min per day in 15-year-old children . INTERPRETATION  Physical activity  levels should be higher than the current international guidelines of at least 1 h per day of physical activity of at least moderate intensity to prevent clustering of cardiovascular disease risk factors OBJECTIVE To prospect ively examine potential benefits of active commuting to school on measures of weight status and physical activity in a sample of youth . RESEARCH METHODS AND PROCEDURES A cohort of students from seven elementary schools was measured four times -- in the fall and spring of fourth grade ( N = 1083 ) and fifth grade ( N = 924 ) . Participants were classified as active ( walking , biking , or skateboarding to school almost every day for baseline analyses or at least 2 d/wk for analyses of consistent active commuting ) or non-active commuters to school . Accelerometers were used to measure physical activity . Height , weight , and skinfolds were objective ly assessed . RESULTS Boys who actively commuted to school had lower BMI ( p < 0.01 ) and skinfolds ( p < 0.05 ) than non-active commuters to school in the fourth grade . Active commuting to school over 2 years was not associated with BMI change or overweight status . DISCUSSION Walking and cycling to school may contribute to preventing excessive weight gain , or leaner children may walk or cycle to school OBJECTIVE To evaluate the effects of an elementary school-based physical education exercise intervention program on bone mineral accrual in prepubertal and early pubertal girls . STUDY DESIGN A total of 14 schools were r and omly assigned to control ( C ) and intervention ( I ) groups . Girls in the I group completed a 10-minute , 3 times per week circuit of varied jumping activities over 7 months . We measured total body , lumbar spine , proximal femur , femoral neck , and trochanteric bone mineral content and areal bone mineral density and estimated femoral neck volumetric bone mineral density at baseline and final measurement in 87 girls in the I group and 90 girls in the C group . Girls were between 8.7 and 11.7 years at baseline . Tanner stage 1 girls were considered prepubertal ; Tanner stages 2 and 3 girls were considered early pubertal . We used analysis of covariance ( adjusting for baseline bone values , change in size , age , and maturity ) to compare 7-month change in bone mineral content , areal bone mineral density , and volumetric bone mineral density between C and I groups within prepubertal and early pubertal girls . RESULTS There was no difference in 7-month change in bone parameters between prepubertal I and C groups . Early pubertal girls in the I group gained 1.5 % to 3.1 % more bone at the femoral neck and lumbar spine than early pubertal girls in the C group ( P < .05 ) ; gain at other sites did not differ . CONCLUSIONS In girls , early puberty may be a particularly opportune time during growth for simple exercise interventions to have a positive effect on bone health OBJECTIVE : To test the feasibility of creating a valid and reliable checklist with the following features : appropriate for assessing both r and omised and non-r and omised studies ; provision of both an overall score for study quality and a profile of scores not only for the quality of reporting , internal validity ( bias and confounding ) and power , but also for external validity . DESIGN : A pilot version was first developed , based on epidemiological principles , review s , and existing checklists for r and omised studies . Face and content validity were assessed by three experienced review ers and reliability was determined using two raters assessing 10 r and omised and 10 non-r and omised studies . Using different raters , the checklist was revised and tested for internal consistency ( Kuder-Richardson 20 ) , test-retest and inter-rater reliability ( Spearman correlation coefficient and sign rank test ; kappa statistics ) , criterion validity , and respondent burden . MAIN RESULTS : The performance of the checklist improved considerably after revision of a pilot version . The Quality Index had high internal consistency ( KR-20 : 0.89 ) as did the subscales apart from external validity ( KR-20 : 0.54 ) . Test-retest ( r 0.88 ) and inter-rater ( r 0.75 ) reliability of the Quality Index were good . Reliability of the subscales varied from good ( bias ) to poor ( external validity ) . The Quality Index correlated highly with an existing , established instrument for assessing r and omised studies ( r 0.90 ) . There was little difference between its performance with non-r and omised and with r and omised studies . Raters took about 20 minutes to assess each paper ( range 10 to 45 minutes ) . CONCLUSIONS : This study has shown that it is feasible to develop a checklist that can be used to assess the method ological quality not only of r and omised controlled trials but also non-r and omised studies . It has also shown that it is possible to produce a checklist that provides a profile of the paper , alerting review ers to its particular method ological strengths and weaknesses . Further work is required to improve the checklist and the training of raters in the assessment of external validity OBJECTIVE : To determine the effect of exercise training ( ET ) on components of the insulin resistance syndrome ( IRS ) in obese children . DESIGN : R and omized , modified cross-over study , with subjects assigned to one of two conditions : ( 1 ) 4 months of ET followed by 4 months of no-ET ; or ( 2 ) 4 months of no-ET followed by 4 months of ET . Measurements were made at three time points : 0 , 4 and 8 months . SUBJECTS : 79 obese , but otherwise healthy children ( age : 7–11 y , percent fat ( % fat ) 27–61 % ) . MEASUREMENTS : Plasma lipid and lipoprotein concentrations , plasma insulin and glucose concentrations ; % fat ; submaximal heart rate ( HR ) as an index of fitness . EXERCISE TRAINING : ET was offered 5 d/week 40 min/d . For the 73 children who completed 4 months of ET , the mean attendance was 80 % ( that is , 4 d/week ) and the average HR during ET was 157 bpm . RESULTS : Significant ( P<0.05 ) group x time interactions were found for plasma triglyceride ( TG ) and insulin concentrations and % fat . The average change for both groups , from just before ET to just after the 4 month ET was −0.24 mmolċl−1 for TG , −25.4 pmolċl−1 for insulin and −1.6 units for % fat . When Group 1 ceased ET , over the following 4 month period the average change for insulin was + 26.6 pmolċl−1 and for % fat + 1.3 units . CONCLUSION : Some components ( plasma TG , insulin , % fat ) of the IRS are improved as a result of 4 months of ET in obese children . However , the benefits of ET are lost when obese children become less active PURPOSE Children with high levels of total body fat mass ( TFM ) and visceral adipose tissue ( VAT ) have elevated levels of certain risk factors for coronary artery disease and non-insulin-dependent diabetes mellitus . We tested the hypothesis that controlled physical training , without dietary intervention , would have a favorable impact on VAT and percent body fat ( % BF ) in obese children . METHODS A volunteer sample of 74 obese children , 7 - 11 yr of age , accepted r and om assignment to physical training  or  control groups .  Before and after 4 months of intervention , measurements were obtained for VAT , TFM , % BF , daily physical activity , and cardiovascular fitness . The intervention involved 4 months of controlled physical training 5 d x wk(-1 ) , 40 min per session , at a mean heart rate ( HR ) of 157 beats x min(-1 ) . The estimated energy expenditure ( EE ) per training session was 925+/-201 kJ. RESULTS Compared with the control group , the physical training group declined significantly in % BF ( delta = -2.2 % ) ( P < 0.01 ) , TFM ( delta = -3.1 % ) ( P < 0.01 ) , and subcutaneous abdominal adipose tissue ( delta = - 16.1 % ) ( P < 0.05 ) , and increased significantly in fat-free mass ( delta = + 6.1 % ) ( P < 0.05 ) and moderate-to-very hard physical activity ( delta = + 14.1 % ) ( P < 0.05 ) . The increase in VAT was significantly less in the physical training group ( delta = + 0.5 % ) as compared with that in the control group ( delta = + 8.1 % ) ( P < 0.05 ) . CONCLUSIONS This study showed that during physical training  obese children : 1 ) were capable of participating in a substantial amount of high intensity physical training over a 4-month period : 2 ) accumulated significantly less VAT as compared with nonexercising controls ; and 3 ) experienced other beneficial changes in total and regional body composition To determine whether participating in physical activity affects psychological well-being in an adolescent population , 147 adolescents completed self-reports of exercise and psychological stress and well-being . Analysis revealed that those who reported greater physical activity also reported less stress and lower levels of depression . Adolescents who experienced a higher incidence of life events also demonstrated a strong association between stress and anxiety/depression/hostility . To investigate the effects of exercise training on psychological well-being , adolescents were assigned to either high or moderate intensity aerobic training , flexibility training or a control group . The training groups met twice per week for 25 - 30 min . Aerobic fitness levels , heart rate , blood pressure and self-report of stress and well-being were measured prior to and following 10 weeks of training . Post-training fitness measures confirmed the effectiveness of the high intensity aerobic exercise and between groups differences for physiological and some psychological measures were found . Subjects undergoing high intensity exercise reported significantly less stress than subjects in the remaining three groups . The relationship between stress and anxiety/depression/hostility for the high intensity group was considerably weakened at the end of the training period . For the remaining subjects , however , this relationship was , if anything , strengthened . This experiment provides evidence to suggest that in an adolescent population , high intensity aerobic exercise has positive effects on well-being OBJECTIVE To examine the effects of 15 months of resistance training on bone mineral density ( BMD ) in female adolescents ( aged 14 to 17 years ) . STUDY DESIGN Participants were r and omly assigned to either a training ( n = 46 ) or control group ( n = 21 ) .  BMD and body composition were measured by using dual-energy x-ray absorptiometry . Strength was assessed by means of one-repetition maximums for the leg press and bench press . The exercise group trained 30 to 45 minutes a day , 3 days per week , using 15 different resistance exercises . Control participants remained sedentary ( < 2 hours of exercise per week ) . RESULTS Leg strength increased significantly ( 40 % ) in the exercise group , but there were no changes in the control group . Femoral neck BMD increased significantly in the training group ( 1.035 to 1.073 g/cm(2 ) , P < .01 ) but not in the control group ( 1.034 to 1.048 g/cm(2 ) ) . No significant changes were seen in either group in lumbar spine BMD ( 1.113 to 1.142 g/cm(2 ) and 1.158 to 1.190 g/cm(2 ) , respectively ) or total body BMD ( 1.103 to 1.134 g/cm(2 ) and 1.111 to 1.129 g/cm(2 ) , respectively ) . CONCLUSION Resistance training is a potential method for increasing bone density in adolescents , although such a program would be best done as part of the school curriculum Sixteen postmenarcheal Type 1 diabetic adolescent girls were r and omized into training ( involving aerobic and strength exercises ) and nontraining groups .  Body composition ( skinfold thickness ) , aerobic fitness ( PWC170 ) , plasma lipids , serum apolipoproteins , lipoprotein(a ) , leptin , and adiponectin were assessed before and after the 6-month period . After the 6-month period , fat mass and leptin increased significantly in the nontraining group but not in the training group . Conversely , in the latter group , fat-free mass increased ( P < .01 ) . Moreover , PWC170 improved and apolipoproteinB : apolipoproteinA-1 ratio decreased with physical training ( P < .05 ) . Thus , physical training reduces cardiovascular risks and the increase of insulin resistance risk factors in diabetic adolescent girls BACKGROUND Obesity and poor physical fitness constitute a health problem affecting an increasing number of children . Causes include a pervasive " toxic " environment that facilitates increased caloric intake and reduced physical activity . An effective strategy for prevention and treatment of childhood obesity likely includes a collaborative effort in the school setting . OBJECTIVE To determine whether a school-based fitness program can improve body composition , cardiovascular fitness level , and insulin sensitivity in overweight children . DESIGN Fifty overweight middle school children with a body mass index ( BMI ) above the 95th percentile for age were r and omized to lifestyle-focused , fitness-oriented gym classes ( treatment group ) or st and ard gym classes ( control group ) for 9 months . Children underwent evaluation of  fasting insulin and glucose levels , body composition by means of  dual energy absorptiometry , and maximum oxygen consumption ( V0(2)max ) treadmill testing  at baseline ( before the school year ) and at end of the school year . SETTING S Rural middle school and an academic children 's hospital . MAIN OUTCOME MEASURES Baseline test results for cardiovascular fitness , body composition , and fasting insulin and glucose levels . RESULTS At baseline , there were no differences between groups before intervention ( values for age , 12 + /- 0.5 years [ all results , mean + /- SD ] ; BMI [ calculated as weight in kilograms divided by the square of height in meters ] , 31.0 + /- 3.7 ; percentage of body fat , 36.5 % + /- 4.6 % ; lean body mass , 41.4 + /- 8.6 kg ; and V0(2)max , 31.5 + /- 5.1 mL/kg per minute ) . Compared with the control group , the treatment group demonstrated a significantly greater loss of body fat ( loss , -4.1 % + /- 3.4 % vs -1.9 % + /- 2.3 % ; P = .04 ) , greater increase in cardiovascular fitness ( V0(2)max , 2.7 + /- 2.6 vs 0.4 + /- 3.3 mL/kg per minute ; P<.001 ) , and greater improvement in fasting insulin level ( insulin level , -5.1 + /- 5.2 vs 3.0 + /- 14.3 microIU/mL [ -35.4 + /- 36.1 vs 20.8 + /- 99.3 pmol/L ] ; P = .02 ) . CONCLUSIONS Children enrolled in fitness-oriented gym classes showed greater loss of body fat , increase in cardiovascular fitness , and improvement in fasting insulin levels than control subjects . The modification to the school physical education curriculum demonstrates that small but consistent changes in the amount of physical activity has beneficial effects on body composition , fitness , and insulin levels in children . Partnering with school districts should be a part of a public health approach to improving the health of overweight children Objectives : To examine the effects of a simple and inexpensive physical activity intervention on change in bone mass and structure in school aged children . Methods : Fifty one children ( n = 23 boys and 28 girls ; mean age 10.1 years ) participated in “ Bounce at the Bell ” which consisted of 10 counter-movement jumps 3 × per day ( total ∼3 min/day ) . Controls were 71 matched children who followed usual school practice . We assessed dietary calcium , physical activity , physical performance , and anthropometry in September and after 8 months of intervention ( June ) . We measured bone mineral content ( BMC ) and bone area at the lumbar spine , total body , and proximal femur . Proximal femur scans were also analysed for bone geometry and structural strength using the hip structural analysis program . Lean and fat mass ( g ) were also calculated . Results : Groups were similar at baseline and did not differ in weight , height , total body , lumbar spine , proximal femur , or femoral neck BMC . Control children had a greater increase in adjusted total body BMC ( 1.4 % ) . Intervention children gained significantly more BMC at the total proximal femur ( 2 % ) and the intertrochanteric region ( 27 % ) . Change in bone structural parameters did not differ between groups . Conclusions : This novel , easily implemented exercise program , took only a few minutes each day and enhanced bone mass at the weight bearing proximal femur in early pubertal children . A large , r and omised study of boys and girls should be undertaken powered to test the effectiveness of Bounce at the Bell in children at different stages of maturity , and in boys and girls independently 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 BACKGROUND The authors investigated correlates of depression in a general population sample of adolescents ( 15 - 19 years ) and young adults ( 20 - 24 years ) . METHODS As part of the Finnish Health Care Survey a r and om sample of 509 adolescents ( 281 females , 228 males ) and 433 young adults ( 224 females , 209 males ) was interviewed in 1996 .  DSM-IIR major depressive episode ( MDE ) was assessed by the University of Michigan Composite International Diagnostic Interview Short Form ( UM-CIDI SF ) . RESULTS In multivariable regression analysis , current smoking ( odds ratio ( OR ) 5.54 ; 95 % confidence interval ( CI ) 1.44 , 21.3 ) and chronic illness ( OR 3.77 ; 95 % CI : 1.04 , 13.7 ) associated with MDE among adolescents . Among young adults , drunkenness at least twice a month ( OR 4.48 ; 95 % CI : 1.44 , 14.0 ) or once a month ( OR 2.79 ; 95 % CI : 1.14 , 6.83 ) , not being married nor cohabiting ( OR 3.50 ; 95 % CI : 1.35 , 9.08 ) and infrequent physical exercise ( OR 4.01 ; 95 % CI : 1.18 , 14.0 ) were related to MDE . Female MDE associated with not being married nor cohabiting ( OR 3.56 ; 95 % CI : 1.23 , 10.1 ) and living in southern Finl and ( OR 2.30 ; 95 % CI : 1.06 , 5.02 ) . Drunkenness at least twice a month was related to MDE among males ( OR 4.54 ; 95 % CI : 1.27 , 16.3 ) . CONCLUSIONS Attention should be paid to compromised health and health-related behaviour associating with MDE in youth . Specifically , the association between smoking and major depression in early adolescence should be borne in mind , and drinking habits or frequency of drunkenness should be carefully noted OBJECTIVES The present study aim ed to assess the effect of a 6-month exercise program  in obese children on flow-mediated vasodilation ( FMD ) carotid intima-media thickness ( IMT ) and cardiovascular risk factors ( RF ) . BACKGROUND Childhood obesity contributes to adult obesity and subsequent cardiovascular disease . Physical inactivity is a major RF for obesity , endothelial dysfunction , and elevated carotid IMT , culminating in early atherosclerotic disease . METHODS Sixty-seven obese subjects ( age 14.7 + /- 2.2 years ) were r and omly assigned to 6 months ' exercise or non-exercise protocol . We examined the influence of exercises ( 1 h , 3 times/week ) on FMD , IMT , and cardiovascular risk profile . RESULTS Compared with lean control subjects , obese children demonstrated at baseline significantly impaired FMD ( 4.09 + /- 1.76 % vs. 10.65 + /- 1.95 % , p < 0.001 ) , increased IMT ( 0.48 + /- 0.08 mm vs. 0.37 + /- 0.05 mm , p < 0.001 ) , and a number of obesity-related cardiovascular RF . Significant improvements were observed in the exercise group for IMT ( 0.44 + /- 0.08 mm , p = 0.012 , -6.3 % ) and FMD ( 7.71 + /- 2.53 % , p < 0.001 , + 127 % ) . This improvement correlated with reduced RF , such as body mass index st and ard deviation scores , body fat mass , waist/hip ratio , ambulatory systolic blood pressure , fasting insulin , triglycerides , low-density lipoprotein/high-density lipoprotein ratio , and low-degree inflammation ( C-reactive protein , fibrinogen ) . CONCLUSIONS The present study documented increased IMT , impaired endothelial function , and various elevated cardiovascular RF in young obese subjects . Regular exercise over 6 months restores endothelial function and improves carotid IMT associated with an improved cardiovascular risk profile in obese children UNLABELLED This 2-year prospect i ve controlled exercise intervention trial in 99 girls at Tanner stage 1 , evaluating a school curriculum-based training program on a population -based level , showed that the annual gain in BMC , aBMD , and bone size was greater in the intervention group than in the controls . INTRODUCTION Most exercise intervention studies in children , evaluating the accrual of BMD , include volunteers and use specifically design ed osteogenic exercise programs . The aim of this study was to evaluate a 2-year general school-based exercise intervention program in a population -based cohort of girls at Tanner stage 1 . MATERIAL S AND METHODS Forty-nine girls 7 - 9 years of age in grade s 1 and 2 in one school were included in a school curriculum-based exercise intervention program of general physical activity for 40 minutes per school day ( 200 minutes/week ) . Fifty healthy age-matched girls in three neighboring schools , assigned to the general Swedish school curriculum of physical activity ( 60 minutes/week ) , served as controls . All girls were premenarchal , remaining in Tanner stage 1 during the study . BMC ( g ) and areal BMD ( aBMD ; g/cm2 ) were measured with DXA of the total body ( TB ) , the lumbar spine ( L2-L4 vertebrae ) , the third lumbar vertebra ( L3 ) , the femoral neck ( FN ) , and the leg . Volumetric BMD ( vBMD ; g/cm3 ) and bone size were calculated at L3 and FN . Total lean body mass and total fat mass were estimated from the total body scan . Height and weight were also registered . Baseline measurements were performed before the intervention was initiated . Follow-up was done after 2 years . RESULTS No differences between the groups were found at baseline in age , anthropometrics , or bone parameters . The annual gain in BMC was greater in the intervention group than in the controls : L2-L4 , mean 3.8 percentage points ( p = 0.007 ) ; L3 vertebra , mean 7.2 percentage points ( p < 0.001 ) ; legs , mean 3.0 percentage points ( p = 0.07 ) . The intervention group had a greater annual gain in aBMD : total body , mean 0.6 percentage points ( p = 0.006 ) , L2-L4 , mean 1.2 percentage points ( p = 0.02 ) , L3 vertebra , mean 1.6 percentage points ( p = 0.006 ) ; legs , mean 1.2 percentage points ( p = 0.007 ) . There was also a greater mean annual gain in bone size in the L3 vertebra ( mean 1.8 percentage points ; p < 0.001 ) and in the FN ( mean 0.3 percentage points ; p = 0.02 ) . CONCLUSIONS A general school-based exercise program for 2 years for 7- to 9-year-old girls ( baseline ) enhances the accrual of BMC and BMD and increases bone size BACKGROUND There is a need to find ways to increase the physical activity levels and improve the body composition and blood pressure of girls . METHODS Thirty 11-year-old girls were recruited from two after school programs in Houston Texas in Spring 2005 . Participants from one program ( 16 ) were r and omly assigned to intervention , the other ( 14 ) served as controls .  BMI , BMI percentile , waist circumference and blood pressure were assessed before and after the intervention . Pilates classes were provided free of charge for an hour per day at the intervention site , 5 days a week , for 4 weeks . Four participants wore  heart rate monitors  during every session and completed enjoyment and perceived exertion question naires . Repeated measures analysis of variance with time ( within ) and group ( between ) as factors was performed . RESULTS Mean attendance was 75 % , mean heart rate 104 bpm , mean perceived exertion 5.9 ( 1 - 10 scale ) and enjoyment 4.4 ( 1 - 5 scale ) . There was a significant ( P = 0.039 ) time by group interaction for BMI percentile . Graphs indicated that this difference was influenced by large reductions in the BMI percentile of healthy girls . CONCLUSIONS Girls enjoyed Pilates , and participation for 4 weeks lowered BMI percentile .  Pilates holds promise as a means of reducing obesity 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 The effects of regular aerobic exercise on blood concentrations on high‐density lipoprotein cholesterol and prostacyclin were studied in 18 healthy sedentary boys who exercised on a bicycle ergometer for 1 h , four times per week , for 2 months at 75 % of their physical working capacity . The results were compared with those of 10 control boys who did not participate in any specific program . The exercise group revealed a significantly higher mean high‐density lipoprotein cholesterol and 6‐keto‐PGF1a concentration at the end of the training program ( p < 0:005 and p < 0:001 , respectively ) . These results suggest that regular aerobic exercise has beneficial effects upon the high‐density lipoprotein cholesterol and 6‐keto‐PGF1a in healthy young boys and may be beneficial in the long term , by preventing atherosclerosis of coronary artery disease in adulthood The skeletal response to exercise and training on bone is exceptionally good during the growing years . However , it is not known whether the benefit of training on bone is maintained after the training . This 20-month follow-up study assessed the effect of a 9-month jumping intervention on bone gain and physical performance in 99 girls ( mean age 12.5 + /- 1.5 years at the beginning of the study ) one year after the end of the intervention . Both bone mineral content ( BMC ) , by dual energy X-ray absorptiometry ( DXA ) at the lumbar spine and proximal femur , and physical performance parameters ( st and ing long jump , leg extension strength , and shuttle run tests ) were measured at baseline and at 20 months . A multivariate regression analysis was first used to determine the best predictors of the BMC accrual by time . Analysis showed that age at baseline and square of age , changes in height and weight , and pubertal development into Tanner stages 4 and 5 during the follow-up explained the majority of the BMC gain . Then , the effect of participation in the 9-month exercise intervention on BMC accrual and physical performance was analysed adding this variable ( participation : yes/no ) into the model . The regression analysis showed that the trainees ( N = 50 ) had 4.9 % ( 95 % CI , 0.9 % to 8.8 % , p = 0.017 ) greater BMC increase in the lumbar spine than the controls ( N = 49 ) . The mean 20-month BMC increase in the lumbar spine was 28 % ( SD 19 ) in the trainees compared to 22 % ( 12 ) increase in the controls . In the proximal femur , the trend was similar but the obtained 2 to 3 % higher BMC accrual in the trainees ( compared to that in controls ) were statistically insignificant . Among the performance variables , using the same model that best predicted the BMC accrual , the only statistically significant between-groups difference , in favour of the trainees , was the improvement in the st and ing long jump test ( 6.4 % , 95 % CI , 2.3 % to 10.4 % , p = 0.002 ) . Improvements in the leg extension strength and shuttle run tests showed no between-groups difference . In conclusion , although the greatest proportion of bone mineral accrual in growing girls is attributable to growth , an additional bone gain achieved by jumping training is maintained at the lumbar spine at least a year after the end of the training BACKGROUND Of the few exercise intervention studies focusing on pediatric population s , none have confined the intervention to the scheduled physical education curriculum . OBJECTIVE To examine the effect of an 8-month school-based jumping program on the change in areal bone mineral density ( aBMD ) , in grams per square centimeter , of healthy third- and fourth- grade children . STUDY DESIGN Ten elementary schools were r and omized to exercise ( n = 63 ) and control groups ( n = 81 ) . Exercise groups did 10 tuck jumps 3 times weekly and incorporated jumping , hopping , and skipping into twice weekly physical education classes . Control groups did regular physical education classes . At baseline and after 8 months of intervention , we measured aBMD and lean and fat mass by dual-energy x-ray absorptiometry ( Hologic QDR-4500 ) . Calcium intake , physical activity , and maturity were estimated by question naire . RESULTS The exercise group showed significantly greater change in femoral trochanteric aBMD ( 4.4 % vs 3.2 % ; P < .05 ) . There were no group differences at other sites . Results were similar after controlling for covariates ( baseline aBMD change in height , change in lean , calcium , physical activity , sex , and ethnicity ) in hierarchical regression . CONCLUSIONS An easily implemented school-based jumping intervention augments aBMD at the trochanteric region in the prepubertal and early pubertal skeleton At the end of a long week in the office , you sink back into your chair , reflecting on some of the more memorable patients you cared for and counseled . Through gentle history taking , you discovered that urinary incontinence is the underlying cause of an elderly patient 's increasing social isolation . During a careful physical examination , you detected bruising on the torso of a woman with chronic headaches and began to explore the longst and ing abusive relationship between the woman and her alcoholic partner . You discontinued procainamide therapy in a 72-year-old man who had asymptomatic premature ventricular contractions after myocardial infa rct ion . To prevent bleeding from esophageal varices , you started -blocker therapy in a woman with long-st and ing cryptogenic cirrhosis and portal hypertension . In couples ' therapy , discussing the future quality of life of a middle-aged gay man with human immunodeficiency virus infection , you journeyed through emotionally intense dialogue about advance directives . You presented the risk factors for major and minor bleeding to a 39-year-old woman who was considering warfarin therapy because of recently diagnosed atrial fibrillation and valvular heart disease . You listened to , made diagnoses for , treated , advised , and comforted many patients . Yet there were some hiccoughs in your practice along the way . You stumbled while debating the pros and cons of breast cancer screening with a healthy 48-year-old woman who has been staying current with information on the Internet . You question ed the merits of a personalized walking program suggested to you by a motivated 66-year-old man with severe claudication . Explaining that you wanted to review the best current evidence on these issues , you resolved to address your uncertainties before these patients made their next office visits , in a week 's time . Sighing deeply , you acknowledge that you have little time to read . You subscribe to three journals , which you browse months after they arrive-either when your journal stack becomes precariously high or when your guilt is sufficiently motivational . You sometimes find the conclusions of individual articles conflicting or confusing . You know that some of the decisions and suggestions you made this week , specifically your decisions about stopping procainamide therapy and starting -blocker therapy and your advice about bleeding risks from anticoagulant therapy , were based on the best current research evidence [ 1 - 3 ] . On the other h and , your patients ' inquiries about breast cancer screening and exercise treatment for claudication highlight your need for a concise , current , rigorous synthesis of the best available evidence on each of these topics : in brief , a systematic review [ 4 , 5 ] . Incorporating Research Evidence into Clinical Decision Making The foregoing scenario is familiar to practitioners . In a typical week , we encounter patients with diverse problems ; exercise numerous clinical , interpersonal , and technical skills ; and make many decisions . The factors that affect these decisions and their outcomes are complex . For instance , each patient has unique sociodemographic characteristics , cultural circumstances , and personal preferences . Each physician has unique knowledge , experiences , and values . Moreover , practitioners and their patients make decisions within the context of a rapidly changing health care system that influences the availability , accessibility , and cost of diagnostic tests and therapies [ 6 ] . Timely , useful evidence from the biomedical literature should be an integral component of clinical decision making . If one treatment has been shown to be better than another , we need to know , so that we can recommend the treatment to the appropriate patients . The worldwide effort to develop new tests and treatments , and to determine their usefulness , has never been stronger , and our patients and their families expect us to be fonts of the knowledge that results from this effort [ 7 ] . Unfortunately , it is easy for current best research evidence to pass us by [ 8 ] . We may lack the time , motivation , and basic skills needed to find , critically appraise , and synthesize information , all of which we must do if we are to integrate the results of original studies into our practice . Fortunately , several potent methods are emerging that can greatly enhance our ability to interpret and apply research evidence ; foremost among them is the systematic review . This article begins a series in Annals that will examine systematic review s in detail and explore their many applications . Systematic review s represent the best chance that most practitioners will have to underst and and accurately apply the key signals arising from the robust and increasingly productive search for solutions to medical problems . A properly conducted systematic review faithfully summarizes the evidence from all relevant studies on the topic of interest , and it does so concisely and transparently . What Is a Systematic Review ? Systematic review s are scientific investigations in themselves , with pre-planned methods and an assembly of original studies as their subjects . They synthesize the results of multiple primary investigations by using strategies that limit bias and r and om error [ 9 , 10 ] . These strategies include a comprehensive search of all potentially relevant articles and the use of explicit , reproducible criteria in the selection of articles for review . Primary research design s and study characteristics are appraised , data are synthesized , and results are interpreted . When the results of primary studies are summarized but not statistically combined , the review may be called a qualitative systematic review . A quantitative systematic review , or meta- analysis , is a systematic review that uses statistical methods to combine the results of two or more studies . The term overview is sometimes used to denote a systematic review , whether quantitative or qualitative . Summaries of research that lack explicit descriptions of systematic methods are often called narrative review s. Review articles are one type of integrative publication ; practice guidelines , economic evaluations , and clinical decision analyses are others . These other types of integrative articles often incorporate the results of systematic review s. For example , practice guidelines are systematic ally developed statements intended to assist practitioners and patients with decisions about appropriate health care for specific clinical circumstances [ 11 ] . Evidence -based practice guidelines are based on systematic review s of the literature , appropriately adapted to local circumstances and values . Economic evaluations compare both the costs and the consequences of different courses of action ; the knowledge of consequences that are considered in these evaluations is often generated by systematic review s of primary studies . Decision analyses quantify both the likelihood and the valuation of the expected outcomes associated with competing alternatives . Differences between Systematic and Narrative Review s All review s , narrative and systematic alike , are retrospective , observational research studies and are therefore subject to systematic and r and om error . Accordingly , the quality of a review - and thus its worth-depends on the extent to which scientific review methods have been used to minimize error and bias . This is the key feature that distinguishes traditional narrative review s from systematic review s ( Table 1 ) . If a review is prepared according to the steps outlined in the right column of Table 1 , it is more likely to be systematic and to provide unbiased conclusions . If review methods approximate those found in the middle column of Table 1 , the article is more likely to be a narrative review , and the conclusions are less likely to be based on an unbiased summary of all relevant evidence . Table 1 . Differences between Narrative Review s and Systematic Review s Systematic review s are generated to answer specific , often narrow , clinical questions in depth . These questions can be formulated explicitly according to four variables : a specific population and setting ( such as elderly out patients ) , the condition of interest ( for example , hypertension ) , an exposure to a test or treatment ( such as pharmacologic management ) , and one or more specific outcomes ( such as cardiovascular and cerebrovascular events and mortality ) [ 12 ] . Thus , an example of a well-formulated , clinical ly relevant question is , Does pharmacologic treatment of hypertension in the elderly prevent strokes and myocardial infa rct ions or delay death ? If the question that is driving the review is not clear from the title , abstract , or introduction , or if no methods section is included , the paper is more likely to be a narrative review than a systematic review [ 13 ] . Most narrative review articles deal with a broad range of issues related to a given topic rather than addressing a particular issue in depth [ 9 ] . For example , a narrative review on diabetes ( such as that which might be found in a textbook chapter ) might include sections on the physiology and pathophysiology of carbohydrate , lipid , and protein metabolism ; the epidemiology of and prognosis associated with diabetes ; diagnostic and screening approaches ; and preventive , therapeutic , rehabilitative , and palliative interventions . Thus , narrative review s may be most useful for obtaining a broad perspective on a topic ; they are less often useful in furnishing quantitative answers to specific clinical questions . Narrative review s are appropriate for describing the history or development of a problem and its management . Narrative review s may better describe cutting-edge developments if research is scant or preliminary or if studies are very limited by flawed design or execution [ 13 ] . They may be particularly useful for discussing data in light of underlying theory and context . Narrative review s can draw analogies and can conceptually integrate two independent fields of research , such as We compared 7-month changes in bone structural properties in pre- and early-pubertal girls r and omized to exercise intervention ( 10-minute , 3 times per week , jumping program ) or control groups .  Girls were classified as prepubertal ( PRE ; Tanner breast stage 1 ; n = 43 for intervention [ I ] and n = 25 for control [ C ] ) or early-pubertal ( EARLY ; Tanner stages 2 and 3 ; n = 43 for I and n = 63 for C ) . Mean + /- SD age was 10.0 + /- 0.6 and 10.5 + /- 0.6 for the PRE and EARLY groups , respectively . Proximal femur scans were analyzed using a hip structural analysis ( HSA ) program to assess bone mineral density ( BMD ) , subperiosteal width , and cross-sectional area and to estimate cortical thickness , endosteal diameter , and section modulus at the femoral neck ( FN ) , intertrochanter ( IT ) , and femoral shaft ( FS ) regions . There were no differences between intervention and control groups for baseline height , weight , calcium intake , or physical activity or for change over 7 months ( p > 0.05 ) . We used analysis of covariance ( ANCOVA ) to examine group differences in changes of bone structure , adjusting for baseline weight , height change , Tanner breast stage , and physical activity . There were no differences in change for bone structure in the PRE girls . The more mature girls ( EARLY ) in the intervention group showed significantly greater gains in FN ( + 2.6 % , p = 0.03 ) and IT ( + 1.7 % , p = 0.02 ) BMD . Underpinning these changes were increased bone cross-sectional area and reduced endosteal expansion . Changes in subperiosteal dimensions did not differ . Structural changes improved section modulus ( bending strength ) at the FN ( + 4.0 % , p = 0.04 ) , but not at the IT region . There were no differences at the primarily cortical FS . These data provide insight into geometric changes that underpin exercise-associated gain in bone strength in early-pubertal girls OBJECTIVES This study evaluated the effects of aerobic exercise physical education on blood pressure in high-risk , predominantly African-American , adolescent girls . METHODS Ninth- grade girls ( n = 99 ) with blood pressure above the 67th percentile were r and omized to 1 semester of aerobic exercise classes or st and ard physical education classes . RESULT The study was completed by 88 girls . At posttest , only members of the aerobic exercise group increased their estimated cardiorespiratory fitness . The aerobic exercise group had a greater decrease in systolic blood pressure than the st and ard physical education group ( P < .03 ) . CONCLUSIONS Aerobic exercise physical education is a feasible and effective health promotion strategy for high-risk adolescent girls
target: Results Physical activity was associated with numerous health benefits .
  The dose-response relations observed in observational studies indicate that the more physical activity , the greater the health benefit .
  Results from experimental studies indicate that even modest amounts of physical activity can have health benefits in high-risk youngsters ( e.g. , obese ) .
  Vigorous intensity activities may provide even greater benefit .
  Aerobic-based activities had the greatest health benefit , other than for bone health , in which case high-impact weight bearing activities were required .
  Some of the health benefits can be achieved through an average of 30 minutes per day . [
  Level 2 , Grade A ] .
background: Background The purpose was to : 1 ) perform a systematic review of studies examining the relation between physical activity , fitness , and health in school-aged children and youth , and 2 ) make recommendations based on the findings .