Daily physical activity related to aerobic fitness and body fat in an urban sample of children

This study evaluates associations between objectively measured daily physical activity vs aerobic fitness and body fat in children aged 8-11 years. A cross-sectional study of 225 children aged 7.9-11.1 years was performed. Abdominal fat mass (AFM) and total body fat (TBF) were quantified by dual-energy x-ray absorptiometry. TBF was calculated as percentage of total body mass (BF%). Body fat distribution was calculated as AFM/TBF. Aerobic fitness was measured by indirect calorimetry during a maximal cycle ergometer exercise test. Daily physical activity was assessed by accelerometers for 4 days and daily accumulation of moderate-to-vigorous and vigorous activity was calculated. Significant relationships (P<0.05) existed for vigorous activity vs ln BF% (r=-0.40), ln AFM (r=-0.35), TBF/AFM (r=-0.22) and aerobic fitness (r=0.38), whereas moderate-to-vigorous activity displayed weaker relationships (-0.22, -0.18, -0.12 NS, and 0.25). Multiple regression analyses with inclusion of possible confounders concluded that vigorous activity was independently related to aerobic fitness and ln BF% or ln AFM. Moderate-to-vigorous activity was only independently related to aerobic fitness. In this population, low daily accumulation of vigorous activity was, already in children aged 8-11 years, associated with more body fat and lower aerobic fitness. A similar relation was not found for daily accumulation of moderate-to-vigorous activity.     

Gender differences in physical activity and physical fitness in young children in Crete

BACKGROUND: To assess physical activity and physiological fitness parameters among six year old children and to determine whether there were any significant gender differences. METHODS: Design & Setting: comparative study of a representative sample of boys and girls in school and at home. Participants: 569 children (305 boys and 264 girls) selected randomly from a total of 6153 registered in the 1st grade in 1992 on the island of Crete. Measures: assessment of physical activity was based on observational methods involving teachers and parents. Cardiorespiratory fitness was estimated by performance on the 20 meter Shuttle Run Test (20mSRT). BMI, skinfold thickness, Midarm Muscle Circumference (MMC) and hemoglobin were also measured. RESULTS: Both sexes were found to spend a very small proportion of their leisure time in Moderate to Vigorous Physical Activities (MVPA). More boys engaged in MVPA than girls at school and at home, but more girls were involved in physical activity-related lessons and classes out of school. Among the physiological fitness parameters, significant gender differences were found only for MMC. No significant gender difference was found in performance on the 20mSRT. CONCLUSIONS: The results indicate that in this culture stereotypic sex preferences in physical activity begin at a very young age, and that this differentiation cannot be attributed to gender differences in cardiorespiratory fitness. The social, environmental and possibly psychological parameters involved have implications for Health Educators and Physical Education Instructors in the appropriate targeting of physical activity promotion programs among young children.     

Relationship of obesity with physical activity, aerobic fitness and muscle strength in Flemish adults

AIM: The aim of this study was to analyse differences in physical activity, cardiorespiratory fitness (CRF) and muscle strength between normal weight, overweight and obese adults and to investigate the role of physical activity variables in the analyses of differences in CRF and muscle strength between these groups. METHODS: A total of 807 men and 633 women (age: 18-75 years) were included in this cross-sectional study. Weight, height, waist circumference (WC) and bioelectrical impedance were measured. Different dimensions of physical activity were assessed using a validated questionnaire. CRF (VO(2peak)) was evaluated by a maximal test on a cycle ergometer. Knee strength was measured with a calibrated Biodex System Pro 3 dynamometer. Three methods were used for classification in obesity groups: body mass index (BMI), WC and combined BMI-WC classification. RESULTS: Health-related sports and physical activity level are negatively associated with obesity in men, but not in women. Television viewing is positively associated with obesity, while VO(2peak)/fat free mass (FFM) and knee strength/FFM show a negative association with obesity in both genders. Overall, subjects with normal WC seem to be more physically active and to have somewhat better values for CRF compared to those with high WC within the same BMI category. Lower values for relative CRF and knee strength in obese subjects compared to their lean counterparts remain after adjustment for physical activity. CONCLUSION: This study confirms the lower level of physical activity and the impaired CRF and knee strength in obese adults compared to their lean counterparts. This study also sustains the importance of measuring WC and CRF during clinical examinations.     

Motor abilities and aerobic fitness of obese children

Obesity is considered to be epidemic worldwide. Stopping further progression interdisciplinary, outpatient intervention therapy programs for obese children have become increasingly important. FITOC (Freiburg Intervention Trial for Obese Children) consists of a combination of organized sports, behavioral therapy and nutritional advice. The effectiveness of the therapy is determined on the basis of anthropometrical and physical performance data. The purpose of this report is to give a differentiated view of the motor abilities of obese children and to describe changes in the course of the therapy program FITOC. Data were collected on n = 49 obese children (BMI > 97th percentile) aged 8 - 12 in a pretest at the beginning and posttest at the end of the intensive phase of the therapy. These data were compared with an age-matched German reference group. Besides the General Sports-Motor Test (Allgemeiner Sportmotorischer Test [AST]), the BMI-SDS values, the body fat mass (FM %) and the aerobic capacity (Watt/kg body weight) were recorded. In the pretest, the running exercise results and the aerobic capacity checked ranged significantly below the values of the reference group. The performance in the coordinative tests of the AST was differentiated. The medicine-ball toss was significantly above average of the reference group. In the posttest, the BMI-SDS values and the body fat mass (% FM) decreased (p < 0.001) and the aerobic capacity improved (p < 0.001). Performance in all motor abilities tests improved and the difference between the strength of the obese children and the strength of the reference group decreased. This study demonstrates that in obese children weight-bearing activities are below average but not all motor abilities.     

Motor competence,perceived physical competence,physical fitness,and physical activity within Finnish children

The purpose of this study was to investigate reciprocal relationships among students’ motor competence (MC) (leaping, throwing, catching, jumping skills), perceived physical competence, health‐related fitness (HRF) (20 m shuttle run, push‐up, abdominal muscles endurance tests) and objectively measured moderate‐to‐vigorous physical activity (MVPA). Participants included 422 Grade 5 Finnish children (246 girls). Two separate structural equation models investigated paths (a) from MC through both perceived physical competence and HRF to MVPA, and (b) from MVPA through both perceived physical competence and HRF to MC. Model 1 demonstrated an indirect path from MC through HRF to MVPA and a direct path from MC to perceived physical competence for both boys and girls. Additionally, model 1 revealed a direct path from perceived physical competence to MVPA for the girls and from MC to MVPA for the boys. MC, perceived physical competence, and HRF explained 13% of variance in MVPA for the girls and 25% for the boys. Model 2 indicated indirect paths from MVPA through perceived physical competence to MC and from MVPA through HRF to MC for both boys and girls. Additionally, a direct path from MVPA to MC was found in the boys’ group. MVPA, perceived physical competence, and HRF explained 48% of variance in MC for the girls and 53% for the boys. Results of this study provide preliminary support for the reciprocal nature of relationships among MC development, perceived physical competence, HRF and MVPA.     

Daily physical activity in Swedish children aged 8-11 years

Introduction: Physical inactivity is hypothesized to be a contributing factor in the development of a variety of diseases. Recommendations for an adequate level of physical activity have been proposed. There are few studies in which the physical activity in children has been objectively assessed. The purpose of this study was to estimate objectively the level of physical activity in Swedish children. Materials and methods: We studied 248 children (140 boys and 108 girls) aged 7.9–11.1 years from Malmö, Sweden. Physical activity was measured with accelerometers. Children were instructed to wear the accelerometers for 4 days. The mean daily activity was expressed as the mean counts per minute of recording. The time that the child spent performing moderate or vigorous activity was calculated by using previously established cutoff points. Results: The mean daily activity was higher in boys than in girls, 751±243 vs 618±154 counts/min (P<0.001). All children fulfilled the recommendation for moderate physical activity for 60 min or more per day. Ninety‐two percent of the boys and 86% of the girls performed vigorous activity, for 20 min or more per day. Conclusion: All children, aged 8–11 years, who participated in this study reached the recommended level of physical activity, with boys being more active than girls.     

Endurance fitness and blood lactate concentration during stepping exercise in untrained subjects.

The purpose of the present study was to explore the possibility that reference blood lactate concentrations, determined during stepping exercise, could be used to derive an index of endurance fitness. The traditional measure of endurance fitness, maximal oxygen uptake (VO2max) and the individual relationships between blood lactate concentration and submaximal VO2 were determined during stepping for 10 untrained males. VO2 max values were 48.7 +/- 5.1 ml.kg-1.min-1 (mean +/- sd). The time to exhaustion during stepping at 80 per cent VO2 max (38.82 +/- 17.83 min) provided an additional measure of endurance fitness. The per cent VO2 max at a blood lactate concentration of 4 mM was correlated significantly with endurance time (rho = 0.75, P less than 0.05). These results show that a submaximal step test can be used to determine oxygen uptake and per cent VO2 max at a reference blood lactate concentration. However, for this group of subjects, per cent VO2 max at a blood lactate concentration of 4 mM showed only a modest correlation with endurance.     

Rowing ergometry for assessment of aerobic fitness in children

Rowing ergometry has not been utilized as a modality for investigating aerobic fitness in children. This study evaluated the feasibility and reproducibility of measuring peak VO2 during progressive rowing on a Concept II ergometer in 16 healthy boys aged 9-12 years. All subjects were able to row effectively after minimal modeling and verbal instruction. Mean peak VO2 values on two trials were 42.9 (+/-7.9) and 41.6 (+/-8.7) ml x kg(-1) x min(-1) (p>0.05). No significant differences were observed in mean peak heart rate (190+/-11 vs. 191+/-12 bpm), peak ventilation (58.6+/-11.0 vs. 59.1+/-13.9 L x min(-1)), and RER (1.02+/-.07 vs. 1.02+/-.05) on the two trials. The coefficient of variation of peak VO2 was 5.4%. These data suggest that rowing ergometry is an effective method of measuring aerobic fitness in preadolescent boys.     

Occupational physical activity is related to physical fitness in young workers.

PURPOSE: We evaluated the association between occupational physical activity and fitness in young workers, taking into account leisure-time physical activity, body size, and smoking. METHODS: The study population comprised 2188 men and 1987 women, members of the Northern Finland birth cohort 1966, who participated in the 1997-1998 follow-up survey and were employed at the time of the survey. Cardiorespiratory fitness was measured by a 4-min step test and muscular fitness by tests of maximal isometric handgrip and isometric trunk extension. Information on occupational and leisure-time physical activity and smoking was obtained by questionnaire, and body height and weight were measured during medical examination. The data were analyzed by analysis of variance and Cox regression. RESULTS: Men doing heavy physical work scored better in cardiorespiratory fitness, handgrip strength, and trunk muscle endurance than men doing lighter work; the finding for cardiorespiratory fitness was similar in women. The associations were independent of leisure-time physical activity, body weight and height, and smoking. CONCLUSION: A positive association was found between heavy physical work and a high level of fitness in young workers. Due to limitations of the study setting, causality cannot be asserted, but a training effect of heavy work would not seem unreasonable. Previous studies have suggested a reversal of the positive effect of heavy work on fitness with advancing age. Therefore, regular monitoring of workers' fitness at an early phase is justified to enable assessment of workers' capacity for heavy jobs and any possible need for fitness-improving activities.     

Associations of cardiorespiratory fitness,physical activity,and adiposity with arterial stiffness in children

Associations of cardiorespiratory fitness (CRF), physical activity (PA), sedentary behavior, and body fat percentage (BF%) with arterial stiffness and dilation capacity were investigated in 160 prepubertal children (83 girls) 6–8 years of age. We assessed CRF (watts/lean mass) by maximal cycle ergometer exercise test, total PA, structured exercise, unstructured PA, commuting to and from school, recess PA and total and screen‐based sedentary behavior by questionnaire, BF% using dual‐energy X‐ray absorptiometry, and arterial stiffness and dilation capacity using pulse contour analysis. Data were adjusted for sex and age. Poorer CRF (standardized regression coefficient β = ?0.297, P < 0.001), lower unstructured PA (β = ?0.162, P = 0.042), and higher BF% (β = 0.176, P = 0.044) were related to higher arterial stiffness. When CRF, unstructured PA, and BF% were in the same model, only CRF was associated with arterial stiffness (β = ?0.246, P = 0.006). Poorer CRF was also related to lower arterial dilation capacity (β = 0.316, P < 0.001). Children with low CRF (< median) and high BF% (≥ median; P = 0.002), low CRF and low unstructured PA (< median; P = 0.006) or children with low unstructured PA and high BF% (P = 0.005) had higher arterial stiffness than children in the opposite halves of these variables. Poor CRF was independently associated with increased arterial stiffness and impaired arterial dilation capacity among children.     

Circumference-estimated percent body fat vs. weight-height indices: relationships to physical fitness

This study examined whether percent body fat estimated from a simple circumference technique was more strongly associated with physical fitness than commonly used weight-height indices. Participants included 5,710 Navy men and 477 Navy women. Physical fitness measures included a 1.5-mile run, sit-ups test, sit-reach flexibility test, and an average fitness score. Circumference-estimated percent body fat was more strongly correlated with physical fitness than were any of the weight-height indices. Although the overall pattern of associations was similar for men and women, correlations were stronger for men. Circumference-estimated percent body fat may be more strongly associated with physical fitness because it assesses actual body fat more reliably than weight-height indices.     

Trends in physical activity,health-related fitness,and gross motor skills in children during a two-year comprehensive school physical activity program

Objectives

The purpose of this study was to examine the trends in school-day step counts, health-related fitness, and gross motor skills during a two-year Comprehensive School Physical Activity Program (CSPAP) in children.

Inflammatory factors, physical activity, and physical fitness in young people

Cardiovascular disease (CVD) remains one of the leading causes of morbidity and mortality in developed countries. Over the past decade there has been much focus on the role of inflammation in the pathogenesis of atherosclerosis; to this end, there is increasing research on inflammatory factors such as C-reactive protein (CRP), interleukin-6 (IL-6), and fibrinogen (Fg). There is compelling evidence that physical activity (PA) and physical fitness (PF) protect against chronic disease. More recently, research has shown that exercise reduces CRP, IL-6, and Fg concentration in adults, and that this is often independent of adiposity. Although there are some data to suggest that this is similarly true for young people, there is inconsistency in the literature. The following review aims to illustrate what is known about the effects of PA and PF on inflammatory factors in young people aged 5-18 years.     

Habitual physical activity, physical fitness and heart rate variability in preadolescents

The amount and type of physical activity (PA) appropriate in youth for optimal health is still being discussed. The purpose of this study on 12-year-old preadolescents is to evaluate the association of two PA patterns, corresponding to different exercise intensities, with some health-related indexes. PA was evaluated by triaxial accelerometry in 67 student subjects, who were successively classified according to 1) their usual participation or not in moderately intense (> 4 metabolic equivalents, METs) activities (either in daily life or in leisure activities) for at least 210 min a week (4 M (210)); and 2) the habitual practice or not of more intense activities (> 6 METs) for at least 60 min a week (6 M (60)). Health-related indexes consisted of cardiopulmonary (maximum oxygen uptake, V.O 2max), muscular (lower limb strength) fitness parameters and vagal-related indexes of heart rate (HR) variability (HRV), such as the HF/(LF+HF) ratio (where HF and LF stand for high and low frequency power). HR was recorded in the supine position after 15 min of quiet rest, and HRV indexes were calculated in 5-min segments. Energy expenditure due to PA was not significantly associated with any health-related index. Reaching 4 M (210) was associated with both higher estimated V.O 2max (p < 0.05) and higher muscular strength indexes (p < 0.05) but not with enhanced HRV indexes. Subjects who reached 6 M (60) had higher estimated V.O2max (p < 0.05) and higher HF/(LF+HF) (p < 0.05). Our results show that regular moderately intense activities are sufficient to influence physical fitness but suggest that more intense activities are necessary to observe more favorable HRV vagal-related indexes.     

Seven-year stability of physical activity and musculoskeletal fitness in the Canadian population.

BACKGROUND: Knowledge of population patterns of physical activity levels and musculoskeletal fitness are important in the selection of appropriate target groups for public health interventions. PURPOSE: To examine the stability of physical activity levels and musculoskeletal fitness in the Canadian population. METHODS: The sample included 951 male and 958 female subjects, aged 11-69 yr, for whom the appropriate measurements were available in the 1981 Canada Fitness Survey and its 7-yr follow-up, the Campbell's Survey. Participants were divided into 2-yr age groups in childhood (11-18 yr) and 10-yr age groups in adulthood (19-69 yr). Measures of physical activity were estimated activity energy expenditure (AEE) and time spent on activity, whereas indicators of musculoskeletal fitness consisted of sit-ups, push-ups, grip strength, and sit-and-reach (trunk flexibility). RESULTS: 7-yr inter-age correlations ranged from -0.08 to 0.39 for AEE, -0.10 to 0.33 for time on activity, 0.42 to 0.80 for sit-ups, -0.07 to 0.73 for push-ups, 0.44 to 0.82 for grip strength, and 0.47 to 0.85 for sit-and-reach. In general, significant tracking correlations for physical activity levels were limited to adulthood, whereas significant tracking of musculoskeletal fitness was observed at all ages for all indicators except push-ups. Male subjects exhibited greater stability in push-ups than female subjects. The average percentage of participants remaining in the lower and upper quintiles of the distribution over 7 yr was greater for musculoskeletal fitness (36-68%) than for physical activity level (30-34%). CONCLUSION: Physical activity level is not a very stable characteristic in the Canadian population; however, indicators of musculoskeletal fitness are moderately stable over 7 yr.     

Effects of a physical education program on physical activity,fitness, and health in children: The JuvenTUM project

The purpose of the study was to investigate the effects of a school‐based prevention program on physical activity, fitness, and obesity. We performed a prospective study in eight Bavarian primary schools (n = 724 children, 8.4 ± 0.7 years) randomized one to one to either an intervention school (IS, n = 427) or a control school (CS, n = 297). Children in IS attended 10 health‐related lessons at school over a period of 1 year. Parents and teachers attended two and three educational health‐related lessons, respectively, and also received 10 newsletters on health issues. Daily physical activity (≥ 60 min/day), physical fitness (six‐item test battery), and anthropometric data were obtained at baseline and after 1 year. Physical activity and physical fitness increased in IS, but it failed to reach significant intervention effects. Nevertheless, a reduction in waist circumference was observed for all children [mean change 1.7 cm; 95% confidence interval (CI) 1.2–2.3; P < 0.001). This effect was more pronounced in overweight children (> 90th percentile, n = 99, mean change 3.2 cm; 95% CI 1.5–4.8; P < 0.001). This easily administered preventative program involving children, parents, and teachers revealed that a generalized approach increasing physical activity will even be favorable in a subgroup of obese children.     

Self-reported physical activity and preaccession fitness testing in U.S. Army applicants

The Assessment of Recruit Motivation and Strength (ARMS) study evaluated a physical fitness screening test for Army applicants before basic training. This report examines applicants' self-reported physical activity as a predictor of objective fitness measured by ARMS. In 2006, the ARMS study administered a fitness test and physical activity survey to Army applicants during their medical evaluation, using multiple logistic regression for comparison. Among both men and women, "qualified" and "exceeds-body-fat" subjects who met American College of Sports Medicine adult physical activity guidelines were more likely to pass the fitness test. Overall, subjects who met physical activity recommendations, watched less television, and played on sports teams had a higher odds of passing the ARMS test after adjustment for age, race, and smoking status. This study demonstrates that self-reported physical activity was associated with physical fitness and may be used to identify those at risk of failing a preaccession fitness test.