Tracking of muscular strength and power from youth to young adulthood: Longitudinal findings from the Childhood Determinants of Adult Health Study. Relationships between physical activity, physical fitness, muscle strength and nutritional state in 5- to 11-year-old children Correlates of cardiorespiratory and muscular fitness among Brazilian adolescents. Childhood cardiorespiratory fitness, muscular fitness and adult measures of glucose homeostasis. Muscle strength and physical performance as predictors of mortality, hospitalization, and disability in the oldest old. Relations of moderate and vigorous physical activity to fitness and fatness in adolescents. Normative values for musculoskeletal- and neuromotor fitness in apparently healthy Norwegian adults and the association with obesity: a cross-sectional study Effect of fitness and physical activity on bone mass in adolescents: the HELENA Study Is Objectively Assessed Sedentary Behavior, Physical Activity and Cardiorespiratory Fitness Linked to Brain Plasticity Outcomes in Old Age? Muscular fatigue in response to different modalities of CrossFit sessions Physical fitness as a protective factor for cognitive impairment in a prospective population-based study in Germany. The association of physical activity and physical fitness with pre-adolescent obesity: an observational study in Metromanila, Philippines. Muscular and performance fitness and the incidence of type 2 diabetes: prospective study of Japanese men. The effect of exercise hypertrophy and disuse atrophy on muscle contractile properties: a mechanomyographic analysis Cross sectional analysis of the association between mode of school transportation and physical fitness in children and adolescents Association of muscle power with functional status in community-dwelling elderly women. A policy-driven multifaceted approach for early childhood physical fitness promotion: impacts on body composition and physical fitness in young Chinese children
OBJECTIVES Low muscular fitness levels have previously been reported as an independent risk factor for chronic disease outcomes . Muscular fitness tracking , the ability to maintain levels measured at one point in time to another point in time , was assessed from youth to adulthood to provide insight into whether early identification of low muscular fitness in youth is possible . DESIGN Prospect i ve longitudinal study . METHODS Study including 623 participants who had muscular fitness measures in 1985 ( aged 9 , 12 or 15 years ) and again 20 years later in young adulthood . Measures of muscular fitness were strength ( right and left grip , leg , shoulder extension and flexion measured by dynamometer , and a combined strength score ) and power ( st and ing long jump distance ) . RESULTS Strength and power were relatively stable between youth and adulthood ; the strongest tracking correlations were observed for the combined strength score ( r=0.47 , p≤0.001 ) , right grip strength ( r=0.43 , p≤0.001 ) and st and ing long jump ( r=0.43 , p≤0.001 ) . Youth in the lowest third of muscular fitness had an increased risk of remaining in the lowest third of muscular fitness in adulthood ( strength : relative risk (RR)=4.70 , 95 % confidence interval ( CI ) ( 3.19 , 6.92 ) ; power : RR=4.06 ( 2.79 , 5.90 ) ) . CONCLUSIONS Youth with low muscular fitness are at increased risk of maintaining a low muscular fitness level into adulthood . These findings warrant investigation into the long term effects of early interventions that focus on improving low muscular fitness levels in youth which could potentially improve adult muscular fitness and reduce future chronic disease outcomes 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 OBJECTIVE To analyze socioeconomic indicators , physical activity ( PA ) opportunities , and behavioral correlates of cardiorespiratory and muscular fitness among Brazilian boys and girls . METHODS A sample of 1555 adolescents was r and omly selected . Age- and sex-specific st and ard scores were calculated for each fitness component . RESULTS Among boys , head of household 's schooling , involvement in organized PA , meeting the PA recommendations , and computer/games use were associated with cardiorespiratory fitness . Involvement in organized PA and active time in Physical Education ( PE ) classes were predictors of muscular fitness . Among girls , active time in PE classes and TV watching were predictors of cardiorespiratory fitness . Meeting the PA recommendations was associated with muscular fitness . CONCLUSION PA variables and sedentary behaviors should be independently considered for physical fitness promotion in youth OBJECTIVES To assess whether childhood cardiorespiratory fitness ( CRF ) and muscular fitness phenotypes ( strength , power , endurance ) predict adult glucose homeostasis measures . DESIGN Prospect i ve longitudinal study . METHODS Study examining participants who had physical fitness measured in childhood ( aged 7 - 15 years ) and who attended follow-up clinics approximately 20 years later  and provided  a fasting blood sample which was tested for glucose and insulin . Physical fitness measurements included muscular strength ( right and left grip , shoulder flexion , shoulder and leg extension ) , power ( st and ing long jump distance ) and endurance ( number of push-ups in 30s ) , and CRF ( 1.6 km run duration ) . In adulthood , fasting glucose and insulin levels were used to derive glucose homeostasis measures of insulin resistance ( HOMA2-IR ) and beta cell function ( HOMA2-β ) . RESULTS A st and ard deviation increase in childhood CRF or muscular strength ( males ) was associated with fasting glucose ( CRF : β=-0.06mmol/L ) , fasting insulin ( CRF : β=-0.73mU/L ; strength : β=-0.40mU/L ) , HOMA2-IR ( CRF : β=-0.06 ; strength : β=-0.05 ) and HOMA2-β ( CRF : β=-3.06 % ; strength : β=-2.62 % ) in adulthood , independent of the alternative fitness phenotype ( all p<0.01 ) . Adjustment for childhood waist circumference reduced the effect by 17 - 35 % for CRF and 0 - 15 % for muscular strength ( males ) and statistical significance remained for all associations expect between CRF , fasting glucose and HOMA2-β ( p>0.06 ) . CONCLUSIONS CRF and muscular fitness in childhood were inversely associated with measures of fasting insulin , insulin resistance and beta cell function in adulthood . Childhood CRF and muscular fitness could both be potential independent targets for strategies to help reduce the development of adverse glucose homeostasis OBJECTIVES To evaluate the predictive value of muscle strength and physical performance in the oldest old for all-cause mortality ; hospitalization ; and the onset of disability , defined as a decline in activities of daily living ( ADLs ) , independent of muscle mass , inflammatory markers , and comorbidities . DESIGN A prospect i ve , observational , population -based follow-up study . SETTING Three well-circumscribed areas of Belgium . PARTICIPANTS Five hundred sixty participants aged 80 and older were followed for 33.5 months ( interquartile range 31.1 - 35.6 months ) . MEASUREMENTS  Grip strength , Short Physical Performance Battery ( SPPB ) score , and muscle mass  were measured at baseline ; ADLs at baseline and after 20 months ; and all-cause mortality and time to first hospitalization from inclusion onward . Kaplan-Meier curves and Cox proportional hazards models were calculated for all-cause mortality and hospitalization . Logistic regression analysis was used to determine predictors of decline in ADLs . RESULTS Kaplan-Meier curves showed significantly higher all-cause mortality and hospitalization in subjects in the lowest tertile of grip strength and SPPB score . The adjusted Cox proportional hazards model showed that participants with high grip strength or a high SPPB score had a lower risk of mortality and hospitalization , independent of muscle mass , inflammatory markers , and comorbidity . A relationship was found between SPPB score and decline in ADLs , independent of muscle mass , inflammation , and comorbidity . CONCLUSION In people aged 80 and older , physical performance is a strong predictor of mortality , hospitalization , and disability , and muscle strength is a strong predictor of mortality and hospitalization . All of these relationships were independent of muscle mass , inflammatory markers , and comorbidity BACKGROUND It is unclear how moderate and vigorous intensities of physical activity ( PA ) are associated with cardiovascular fitness ( CVF ) and percentage of body fat ( % BF ) in adolescents . OBJECTIVE We tested the hypothesis that vigorous PA , to a greater degree than moderate PA , would be associated with better CVF and lower % BF . DESIGN This was a cross-sectional study of 421 black and white high school students ( x age : 16 y ) .  PA was measured with 5 d of accelerometry and expressed in min/d of moderate or vigorous PA .  CVF was measured with a multistage treadmill test and was expressed as the oxygen consumption at a heart rate of 170 bpm . % BF was measured with dual-energy X-ray absorptiometry . Multiple regressions were used to determine the degree to which variance in CVF and % BF was explained by PA , after control for age , sex , race , and the sex x race interaction . RESULTS A higher index for CVF was associated with higher amounts of moderate and vigorous PA ;  more variance was explained by vigorous than by moderate PA .  Lower % BF was associated with higher amounts of vigorous PA but not with the amount of moderate PA . CONCLUSION Black and white adolescents who engaged in relatively large amounts of free-living vigorous exercise were likely to be relatively fit and lean Background Up-to- date research on musculoskeletal- and neuromotor fitness ( MSMF ) is lacking . The aims of the present paper were to a ) establish normative values of MSMF by gender and age , and b ) to assess how much of the variance in MSMF can be explained by obesity in adults . Methods A r and om selection of 726 Norwegians ( 20–65 years ) participated in a national cross-sectional study . Muscular endurance , muscular strength , explosive power , flexibility and balance were assessed in addition to  waist circumference ( WC ) . Results Females displayed significantly higher scores compared to males on muscular endurance of the back extensors and on the flexibility tests ( p < 0.001 ) . Males displayed significantly higher scores than females ( p < 0.001 ) on h and grip strength , modified push-ups , and explosive power . An inverse association was found between age and all MSMF scores for females ( Beta:−0.06–(−0.92 ) , p ≤ 0.044 ) and males ( Beta:−0.15–(0.91 ) , p ≤ 0.006 ) , where younger participants displayed higher test scores on all MSMF tests , compared to older participants . Furthermore , participants showing higher scores on WC displayed lower scores on the following MSMF tests for both females and males : muscular endurance of the back extensors , balance , flexibility of the shoulder , and explosive power ( p < 0.001 ) . Additionally , male participants with higher WC scores showed lower scores on muscular endurance of the upper body and flexibility of the hamstrings compared to males with lower WC scores ( p < 0.001 ) . Conclusions The data provide normative values of MSMF for adults based on age and gender , and support an inverse relationship of MSMF to age and WC 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 The aim of this cross-sectional study was to determine the associations of objective ly assessed habitual physical activity and physical performance with brain plasticity outcomes and brain-derived neurotrophic factor ( BDNF ) levels in cognitively healthy older adults . Physical performance was analyzed based on cardiopulmonary exercise-testing data and accelerometer-based physical activity was analyzed as total activity counts , sedentary time , light physical activity and moderate to vigorous physical activity . Brain plasticity outcomes included magnetic resonance spectroscopy (MRS)-based markers , quantitative imaging-based hippocampal volume and BDNF serum levels . The association between physical performance and hippocampal volume was strongly influenced by participants ' education , sex , age and BMI . Confounder-controlled correlation revealed significant associations of brain plasticity outcomes with physical activity but not with performance . MRS-based adenosine triphosphate to phosphocreatine and glycerophosphocholine to phosphocreatine ratios were significantly associated with accelerometer total activity counts . BDNF was detrimentally associated with sedentary time but beneficially related to  accelerometer total activity  counts and moderate to vigorous physical activity . Exceeding the current moderate to vigorous physical activity recommendations led to significantly higher BDNF levels . Our results indicate that regular physical activity might be beneficial for preserving brain plasticity in higher age . In this study these associations were not mediated significantly by physical performance . Overall physical activity and exceeding current moderate to vigorous physical activity recommendations were positively associated with BDNF . Sedentary behavior , however , seems to be negatively related to neurotrophic factor bioavailability in the elderly Background CrossFit is a new strength and conditioning regimen involving short intense daily workouts called workouts of the day ( WOD ) . This study assesses muscular fatigue levels induced by the three modalities of CrossFit WOD ; gymnastics ( G ) , metabolic conditioning ( M ) and weightlifting ( W ) . Material and methods 34 healthy subjects undertook three WOD ( one per week ) : a G WOD consisting of completing the highest number of sets of 5 pull-ups , 10 push-ups and 15 air squats in 20 min ; an M WOD , in which the maximum number of double skipping rope jumps was executed in 8 sets ( 20 s ) , resting ( 10 s ) between sets ; and finally , a W WOD in which the maximum number of power cleans was executed in 5 min , lifting a load equivalent to 40 % of the individual 's 1RM . Before and after each WOD , blood lactate concentrations were measured . Also , before , during , and after each WOD , muscular fatigue was assessed in a countermovement jump test ( CMJ ) . Results Significant reductions were produced in the mechanical variables jump height , average power and maximum velocity in response to G ; and in jump height , mean and peak power , maximum velocity and maximum force in response to W ( P<0.01 ) . However , in M , significant reductions in mechanical variables were observed between pre- and mid session ( after sets 2 , 4 , 6 and 8) , but not between pre- and post session . Conclusions Muscular fatigue , reflected by reduced CMJ variables , was produced following the G and W sessions , while recovery of this fatigue was observed at the end of M , likely attributable to rest intervals allowing for the recovery of phosphocreatine stores . Our findings also suggest that the high intensity and volume of exercise in G and W WODs could lead to reduced muscular-tendon stiffness causing a loss of jump ability , related here to a longer isometric phase during the CMJ To evaluate the predictive effects of subjective measures of physical activity ( PA ) and objective measures of physical fitness ( PF ) on dementia risk , Participants of the prospect i ve population -based ILSE- study ( * 1930 - 1932 ; 12-year follow-up ) were examined at three examination waves ( t1 : 1993/94 ; t2 : 1997/98 ; t3 : 2005/07 ) . 381 subjects of the original cohort ( n = 500 ) were re-examined at t3 . 29 % of the subjects who were cognitively healthy at baseline received the diagnosis of mild cognitive impairment ( MCI ) and 7 % of Alzheimer 's disease ( AD ) . Subjects were screened for physical and mental health using medical interviews , physical , and neuropsychological examinations . Participants completed a question naire on their current and past PA at t1 . Subjects were classified as physically active if they reported a regular sport activity for at least 2 hours per week in the past year . Muscular strength ( h and grip ) and motor coordination ( balance ) served as objective indicators of PF . Subjects who passed the balance-test at t1 had a reduced risk of developing MCI/AD at t3 ( OR = 0.35 , 95%CI 0.19 - 0.66 , p < 0.01 ) and performed significantly better on various neuropsychological measures . Muscular strength or subjective reports of PA did not predict MCI/AD development . Our results confirm the hypothesis that PF acts as a protective factor for the development of cognitive disorders . In our study , context , motor coordination served as a better predictor than muscular strength or self-rated PA . Since subjects with cognitive disorders due to cerebral and /or systemic disorders were excluded from the analyses , our findings suggest that the effect of skill-related PF extends beyond the reduction of cardiovascular risk factors 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 BACKGROUND Limited data are available on the relationship between muscular and performance fitness ( MPF ) and the incidence of  type 2 diabetes . METHODS A cohort of 3792 Japanese men completed a medical examination that included MPF and cardiorespiratory fitness tests .  MPF index composite score was calculated using Z-scores from vertical jump , sit-ups , side step , and functional reach tests . RESULTS The mean follow-up period was 187 months ( 15.6 years ) . There were 240 patients who developed  type 2 diabetes  during follow-up . Relative risks and 95 % confidence intervals ( CI ) for incidence of diabetes across baseline quartiles of MPF index composite score were obtained using the Cox proportional hazards model while adjusting for age , BMI , diastolic blood pressure , cigarette smoking , alcohol intake , and family history of diabetes . The relative risks for developing diabetes across quartiles of MPF index composite scores ( lowest to highest ) were 1.0 ( referent ) , 1.15 ( 95 % CI 0.83 - 1.60 ) , 1.10 ( 0.78 - 1.55 ) , and 0.57 ( 0.37 - 0.90 ) ( P for trend = .061 ) . These results were attenuated after adjustment for cardiorespiratory fitness ( P for trend = .125 ) . CONCLUSIONS This prospect i ve study suggests that MPF is a predictor of type 2 diabetes , although its predictive ability was attenuated after adjusting for cardiorespiratory fitness Purpose To determine whether mechanomyographic ( MMG ) determined contractile properties of the biceps brachii change during exercise-induced hypertrophy and subsequent disuse atrophy . Methods Healthy subjects ( mean ± SD , 23.7 ± 2.6 years , BMI 21.8 ± 2.4 , n = 19 ) performed unilateral biceps curls ( 9 sets × 12 repetitions , 5 sessions per week ) for 8 weeks ( hypertrophic phase ) before ceasing exercise ( atrophic phase ) for the following 8 weeks ( non-dominant limb ; treatment , dominant limb ; control ) . MMG measures of muscle contractile properties ( contraction time ; Tc , maximum displacement ; Dmax , contraction velocity ; Vc ) , electromyographic ( EMG ) measures of muscle fatigue ( median power frequency ; MPF ) , strength measures ( maximum voluntary contraction ; MVC ) and measures of muscle thickness ( ultrasound ) were obtained . Results Two-way repeated measures ANOVA showed significant differences ( P < 0.05 ) between treatment and control limbs . During the hypertrophic phase treatment MVC initially declined ( weeks 1–3 ) , due to fatigue ( decline in MPF ) , followed by improvement against control during weeks 6–8 . Between weeks 5 and 8 treatment , muscle thickness was greater than control , reflecting gross hypertrophy . MMG variables Dmax ( weeks 2 , 7 ) and Vc ( weeks 7 , 8) declined . During the atrophic phase , MVC ( weeks 9–12 ) and muscle thickness ( weeks 9 , 10 ) initially remained high before declining to control levels , reflecting gross atrophy . MMG variables Dmax ( weeks 9 , 14 ) and Vc ( weeks 9 , 14 , 15 ) also declined during the atrophic phase . No change in Tc was found throughout the hypertrophic or atrophic phases . Conclusions MMG detects changes in contractile properties during stages of exercise-induced hypertrophy and disuse atrophy suggesting its applicability as a clinical tool in musculoskeletal rehabilitation Objective To investigate the associations between body composition , cardiorespiratory and muscular fitness in relation to travel mode to school in children and adolescents . Method Children and adolescents from 40 elementary schools and 23 high schools representing all regions in Norway were invited to participate in the study . Anthropometry , cardiorespiratory and muscular fitness  were tested at the school location . Question naires were used in order to register mode of transport to school , age , gender and levels of leisure time physical activity . Results A total of 1694 ( i.e. 60 % of all invited participants ) children and adolescents at a mean age of 9.6 and 15.6 respectively ( SD = 0.4 for both groups ) were analyzed for associations with physical fitness variables . Males cycling to school had lower sum of skin folds than adolescents walking to school . Higher cardiorespiratory fitness in adolescents and male cyclists compared to walkers and passive commuters were observed . Among children , cycling and walking to school , higher isometric muscle endurance in the back extensors compared to passive commuters was observed . Conclusion Based on this national representative cross-sectional examination of r and omly selected children and adolescents there is evidence that active commuting , especially cycling , is associated with a favourable body composition and better cardiorespiratory and muscular fitness as compared to passive commuting BACKGROUND Identification of the physiologic factors most relevant to functional independence in the elderly population is critical for the design of effective interventions . It has been suggested that muscle power may be more directly related to impaired physical performance than muscle strength in elderly persons . We tested the hypothesis that peak muscle power is closely associated with self-reported functional status in sedentary elderly community-dwelling women . METHODS We used baseline data that were collected as part of a 1-year r and omized controlled clinical trial of a combined program of strength , power , and endurance training in 80 elderly women ( mean age 74.8 + /- 5.0 years ) with 3.2 + /- 1.9 chronic diseases , selected for baseline functional impairment and /or falls . RESULTS Functional status at baseline was related in univariate analyses to physiologic capacity , habitual physical activity level , neuropsychological status , and medical diagnoses . Leg power had the strongest univariate correlation to self-reported functional status ( r = -.47 , p < .0001 ) of any of the physiologic factors we tested . In a forward stepwise regression model , leg press power and habitual physical activity level were the only two factors that contributed independently to functional status ( r = .64 , p < .0001 ) , accounting for 40 % of the variance in functional status . CONCLUSIONS Leg power is a strong predictor of self-reported functional status in elderly women Background The prevalence of obesity increased while certain measures of physical fitness deteriorated in preschool children in China over the past decade . This study tested the effectiveness of a multifaceted intervention that integrated childcare center , families , and community to promote healthy growth and physical fitness in preschool Chinese children . Methods This 12-month study was conducted using a quasi-experimental pretest/posttest design with comparison group . The participants were 357 children ( mean age = 4.5 year ) enrolled in three grade levels in two childcare centers in Beijing , China . The intervention included : 1 ) childcare center intervention ( physical activity policy changes , teacher training , physical education curriculum and food services training ) , 2 ) family intervention ( parent education , internet website for support , and family events ) , and 3 ) community intervention ( playground renovation and community health promotion events ) . The study outcome measures included body composition ( percent body fat , fat mass , and muscle mass ) , Body Mass Index ( BMI ) and BMI z-score and physical fitness scores in 20-meter agility run ( 20M-AR ) , broad jump for distance ( BJ ) , timed 10-jumps , tennis ball throwing ( TBT ) , sit and reach ( SR ) , balance beam walk ( BBW ) , 20-meter crawl ( 20M-C ) ) , 30-meter sprint ( 30M-S ) ) from a norm referenced test . Measures of process evaluation included monitoring of children ’s physical activity ( activity time and intensity ) and food preparation records , and fidelity of intervention protocol implementation . Results Children in the intervention center significantly lowered their body fat percent ( −1.2 % , p < 0.0001 ) , fat mass ( −0.55 kg , p < 0.0001 ) , and body weight ( 0.36 kg , p < 0.02 ) and increased muscle mass ( 0.48 kg , p < 0.0001 ) , compared to children in the control center . They also improved all measures of physical fitness except timed 10-jumps ( 20M-AR : −0.74 seconds , p < 0.0001 ; BJ : 8.09 cm , p < 0.0001 ; TBT : 0.52 meters , p < 0.006 ; SR : 0.88 cm , p < 0.03 ; BBW : −2.02 seconds , p < 0.0001 ; 30M-S : −0.45 seconds , p < 0.02 ; 20M-C : −3.36 seconds , p < 0.0001 ) . Process evaluation data showed that the intervention protocol was implemented with high fidelity . Conclusions The study demonstrated that a policy-driven multi-faceted intervention can improve preschool children ’s body composition and physical fitness . Program efficacy should be tested in a r and omized trial . Trial registration ChiCTR-ONRC-14004143
Results There was consistent evidence for a positive association between MF and physical activity .
For both MF components , there was support for objective ly measured physical activity , particularly for activity of vigorous intensity .
Sports participation was also consistently linked with both MF components , whereas the association with active transport was inconsistent .
For both MF components , associations with sedentary behaviors were inconsistent irrespective of measurement method , and the association between MF and sleep was considered uncertain .
Conclusions The available evidence supports a link between MF and physical activity , particularly for vigorous intensity activity and organized sports participation .
Background Muscular fitness ( MF ) is considered a powerful marker of health , but the extent to which common health behaviors are associated with MF during childhood and adolescence is currently unclear .
Objective We conducted a systematic review of studies investigating associations between MF ( i.e. , strength/power , local muscular endurance ) and physical activity , sedentary behaviors , and sleep in children and adolescents .