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1.
The purpose of this study was to compare cardiovascular fitness between obese and nonobese children. Based on body mass index, 118 were classified as obese (boys [OB] = 62, girls [OG] = 56), while 421 were nonobese (boys [NOB] = 196, girls [NOG] = 225). Cardiovascular fitness was determined by a 1-mile [1.6 km] run/walk (MRW) and estimated peak oxygen uptake (VO2peak) and analyzed using two-way analyses of variance (Gender x Obese/Nonobese). MRW times were significantly faster (p < .05) for the NOB (10 min 34 s) compared to the OB (13 min 8 s) and the NOG (13 min 15 s.) compared to the OG (14 min 44 s.). Predicted VO2peak values (mL x kg(-1) x min(-1)) were significantly higher (p < .05) for the NOB (48.29) compared to the OB (41.56) and the NOG (45.99) compared to the OG (42.13). MRW was compared between obese and nonobese participants on the President's Challenge (2005), the National Children and Youth Fitness Study, and FITNESSGRAM HFZ standards. The nonobese boys and girls scored higher on all three, exhibiting better cardiovascular fitness as compared to obese counterparts.  相似文献   

2.
ABSTRACT

Sedentary time (ST) has been inconsistently associated with adiposity and cardiorespiratory fitness in children in previous studies. We studied cross-sectional associations of ST, light physical activity (LPA), and moderate-to-vigorous physical activity (MVPA) with fat mass index (FMI) and cardiorespiratory fitness (estimated VO2max). Associations were evaluated with and without considering pattern of ST by bout length. We measured ST and activity by a wrist-worn accelerometer, FMI by bioelectrical impedance, and VO2max by Pacer test in 443 children (51.2% girls, 10.2 ± 0.6 years). Isotemporal substitution regression models estimated the effects of substituting ST, LPA, and MVPA on FMI and VO2max. Further models repeated analyses separating ST into short (<10 min) and long (≥10 min) bouts. Only replacing ST or LPA with MVPA was consistently associated with lower FMI and greater VO2max. When separated by bout length, only one unique association was found where replacing long ST bouts with short ST bouts was associated with lower FMI in girls only. In conclusion, activity pattern is associated with adiposity in girls and fitness in boys and girls. Separating ST into long and short ST bouts may be of minimal importance when assessing associations with adiposity and fitness using wrist-worn accelerometry in children.  相似文献   

3.
Abstract

We investigated cardiovascular fitness and haemodynamic responses to maximal cycle ergometer exercise test in children. The participants were a population sample of 425 children (204 girls, 221 boys) aged 6–8 years. Heart rate (HR) and systolic blood pressure (SBP) were measured from the beginning of pre-exercise rest to the end of recovery period. We provided reference values for peak workload and changes in HR and SBP during and after maximal exercise test in girls and boys. Girls had a lower cardiovascular fitness, indicated by peak workload per body weight [mean (2 s) 2.7 (0.9) vs. 3.1 (1.0) W · kg–1, P < 0.001] and lean mass [mean (2 s) 3.5 (0.9) vs. 3.8 (1.0) W· kg–1, P < 0.001] than boys. Plateau or decline in SBP close to the end of the test was found in about third of children and was considered a normal SBP response. Girls had a slower HR decrease within 2 min after the test than boys [mean (2 s) 53 (18) vs. 59 (22) beats · min–1, P < 0.001]. The results are useful for physicians and exercise physiologists to evaluate cardiovascular fitness and haemodynamic responses to exercise in children and to detect children with low exercise tolerance or abnormal haemodynamic responses to exercise.  相似文献   

4.
BackgroundThis study sought to explore the dose–response rate/association between aerobic fitness (VO2max) and self-reported physical activity (PA) and to assess whether this association varies by sex, age, and weight status.MethodsVO2max was assessed using the 20-m shuttle-run test. PA was assessed using the Physical Activity Questionnaire (PAQ) for Adolescents (aged >11 years, PAQ-A) or for Children (aged ≤11 years, PAQ-C). The associations between VO2max and PAQ were analyzed using analysis of covariance (ANCOVA), adopting PAQ and PAQ2 as covariates but allowing the intercepts and slope parameters of PAQ and PAQ2 to vary with the categorical variables sex, age group, and weight status.ResultsANCOVA identified a curvilinear association between VO2max and PAQ, with positive linear PAQ terms that varied for both sex and weight status but with a negative PAQ2 term of −0.39 (95% confidence interval (CI): –0.57 to –0.21) that was common for all groups in regard to age, sex, and weight status. These curvilinear (inverted U) associations suggest that the benefits of increasing PA (same dose) on VO2max is greater when children report lower levels of PA compared to children who report higher levels of PA. These dose–response rates were also steeper for boys and were steeper for lean children compared to overweight/obese children.ConclusionHealth practitioners should be aware that encouraging greater PA (same dose) in inactive and underweight children will result in greater gains in VO2max (response) compared with their active and overweight/obese counterparts.  相似文献   

5.
The purpose of this study was to evaluate two practical interval training protocols on cardiorespiratory fitness, lipids and body composition in overweight/obese women. Thirty women (mean ± SD; weight: 88.1 ± 15.9 kg; BMI: 32.0 ± 6.0 kg · m2) were randomly assigned to ten 1-min high-intensity intervals (90%VO2 peak, 1 min recovery) or five 2-min high-intensity intervals (80–100% VO2 peak, 1 min recovery) or control. Peak oxygen uptake (VO2 peak), peak power output (PPO), body composition and fasting blood lipids were evaluated before and after 3 weeks of training, completed 3 days per week. Results from ANCOVA analyses demonstrated no significant training group differences for any primary variables (P > 0.05). When training groups were collapsed, 1MIN and 2MIN resulted in a significant increase in PPO (?18.9 ± 8.5 watts; P = 0.014) and time to exhaustion (?55.1 ± 16.4 s; P = 0.001); non-significant increase in VO2 peak (?2.36 ± 1.34 ml · kg?1 · min?1; P = 0.185); and a significant decrease in fat mass (FM) (??1.96 ± 0.99 kg; P = 0.011). Short-term interval exercise training may be effective for decreasing FM and improving exercise tolerance in overweight and obese women.  相似文献   

6.
High Intensity Interval Training (HIIT) can be performed with different effort to rest time-configurations, and this can largely influence training responses. The purpose of the study was to compare the acute physiological responses of two HIIT and one moderate intensity continuous training (MICT) protocol in young men. A randomised cross-over study with 10 men [age, 28.3?±?5.5years; weight, 77.3?±?9.3?kg; height, 1.8?±?0.1?m; peak oxygen consumption (VO2peak), 44?±?11?mL.kg?1.min?1]. Participants performed a cardiorespiratory test on a treadmill to assess VO2peak, velocity associated with VO2peak (vVO2peak), peak heart rate (HRpeak) and perceived exertion (RPE). Then participants performed three protocols equated by distance: Short HIIT (29 bouts of 30s at vVO2peak, interspersed by 30s of passive recovery, 29?min in total), Long HIIT (3 bouts of 4?min at 90% of vVO2peak, interspersed by 3?min of recovery at 60% of vVO2peak, 21?min in total) and MICT (21?min at 70% of vVO2peak). The protocols were performed in a randomised order with ≥48 h between them. VO2, HRpeak and RPE were compared. VO2peak in Long HIIT was significantly higher than Short HIIT and MICT (43?±?11 vs 32?±?8 and 37?±?8?mL.kg?1.min?1, respectively, P?P?P?2, HR and RPE than Short HIIT and MICT, suggesting a higher demand on the cardiorespiratory system. Short HIIT and MICT presented similar physiologic and perceptual responses, despite Short HIIT being performed at higher velocities.  相似文献   

7.
A popular algorithm to predict VO2Peak from the one-mile run/walk test (1MRW) includes body mass index (BMI), which manifests practical issues in school settings. The purpose of this study was to develop an aerobic capacity model from 1MRW in adolescents independent of BMI. Cardiorespiratory endurance data were collected on 90 adolescents aged 13–16 years. The 1MRW was administered on an outside track and a laboratory VO2Peak test was conducted using a maximal treadmill protocol. Multiple linear regression was employed to develop the prediction model. Results yielded the following algorithm: VO2Peak = 7.34 × (1MRW speed in m s?1) + 0.23 × (age × sex) + 17.75. The New Model displayed a multiple correlation and prediction error of R = 0.81, standard error of the estimate = 4.78 ml kg?1·min?1, with measured VO2Peak and good criterion-referenced (CR) agreement into FITNESSGRAM’s Healthy Fitness Zone (Kappa = 0.62; percentage agreement = 84.4%; Φ = 0.62). The New Model was validated using k-fold cross-validation and showed homoscedastic residuals across the range of predicted scores. The omission of BMI did not compromise accuracy of the model. In conclusion, the New Model displayed good predictive accuracy and good CR agreement with measured VO2Peak in adolescents aged 13–16 years.  相似文献   

8.
Abstract

The purpose of this study was to examine the influence of motor coordination (MC), physical fitness (PF) and physical activity (PA) on the development of subcutaneous adiposity in a sample of children followed longitudinally from 6 to 10 years of age. Participants were 142 girls and 143 boys. Height, weight, and the triceps and subscapular skinfolds were measured annually between the ages of 6 and 10 years. PA was estimated with the Godin–Shephard questionnaire. MC was evaluated with the Körperkoordination Test für Kinder (KTK) test battery, and PF was assessed with four Fitnessgram tests: curl-ups (CU), push-ups (PU), trunk-lifts (TL) and one mile run/walk (MRW). Hierarchical linear modelling with MC, PF items and PA as predictors of the sum of two skinfolds (SKF) was used. The results showed that boys and girls differed significantly in SKF at baseline (girls: 19.7 mm; boys: 16.6 mm). Three PF items (CU, PU and MRW) and MC had a positive influence on SKF. For each unit improvement in CU, PU, MRW and MC, SKF was reduced by 0.06, 0.04, 0.06 and 0.12 mm, respectively. In conclusion, motor coordination, muscular strength and endurance, and aerobic endurance attenuated the accumulation of subcutaneous adipose tissue during childhood.  相似文献   

9.
The aims of this study were: (1) to identify the exercise intensity that corresponds to the maximal lactate steady state in adolescent endurance-trained runners; (2) to identify any differences between the sexes; and (3) to compare the maximal lactate steady state with commonly cited fixed blood lactate reference parameters. Sixteen boys and nine girls volunteered to participate in the study. They were first tested using a stepwise incremental treadmill protocol to establish the blood lactate profile and peak oxygen uptake ([Vdot]O2). Running speeds corresponding to fixed whole blood lactate concentrations of 2.0, 2.5 and 4.0?mmol?·?l?1 were calculated using linear interpolation. The maximal lactate steady state was determined from four separate 20-min constant-speed treadmill runs. The maximal lactate steady state was defined as the fastest running speed, to the nearest 0.5?km?·?h?1, where the change in blood lactate concentration between 10 and 20?min was?<0.5?mmol?·?l?1. Although the boys had to run faster than the girls to elicit the maximal lactate steady state (15.7 vs 14.3?km?·?h?1, P?<0.01), once the data were expressed relative to percent peak [Vdot]O2 (85 and 85%, respectively) and percent peak heart rate (92 and 94%, respectively), there were no differences between the sexes (P?>0.05). The running speed and percent peak [Vdot]O2 at the maximal lactate steady state were not different to those corresponding to the fixed blood lactate concentrations of 2.0 and 2.5?mmol?·?l?1 (P?>0.05), but were both lower than those at the 4.0?mmol?·?l?1 concentration (P?<0.05). In conclusion, the maximal lactate steady state corresponded to a similar relative exercise intensity as that reported in adult athletes. The running speed, percent peak [Vdot]O2 and percent peak heart rate at the maximal lactate steady state are approximated by the fixed blood lactate concentration of 2.5?mmol?·?l?1 measured during an incremental treadmill test in boys and girls.  相似文献   

10.
Purpose: To evaluate whether excess body mass influences the heart rate variability (HRV) indexes at rest, and to correlate adiposity indicators and the aerobic fitness with cardiac autonomic variables in metabolically healthy young adults. Method: In all, 41 untrained males (Mage = 21.80, SD = 2.14 years), 14 normal weight (MBMI = 22.28, SD = 1.86 kg?m?2), 11 overweight (MBMI = 26.95, SD = 1.43 kg?m?2), and 16 obese (MBMI = 33.58, SD = 3.06 kg?m?2) metabolically healthy (normal values of blood pressure, fasting blood glucose, triglycerides, and total cholesterol), underwent evaluations of the HRV at rest and of the peak oxygen consumption (VO2 peak) during maximal exercise on a cycle ergometer. Results: Blood pressure, heart rate, HRV indexes, casual blood glucose, oxidative stress, and antioxidant activity did not differ among the groups. The VO2 peak (mL?kg?1?min?1) was lower in the obese group compared with the normal weight and overweight groups. The body mass (r = ?.40 to ?.45) and abdominal circumference (r = ?.39 to ?.52) were slightly to moderately correlated with SD1, SD2, RMSSD, SDNN, pNN50, LF, and HF indexes and total power. The VO2 peak (mL?kg?1?min?1) was slightly to moderately correlated (r = .48 to .51) with SD2, SDNN, and LF indexes in the individuals with excess body mass. Conclusion: Cardiac autonomic modulation at rest was preserved in metabolically healthy obese young men. However, the indicators of adiposity, as well as the aerobic fitness were correlated with cardiac autonomic modulation in the individuals with excess body mass.  相似文献   

11.
Abstract

Our purpose was to determine the aerobic capacities (VO2max) of a group of black female adolescents (age = 11.4 ? 15.8 years) randomly chosen from a single urban school. Of 91 girls selected, 64 performed an incremental treadmill running test to volitional exhaustion and achieved VO2max as determined from expired gas measures. Other measures included height (m), weight (kg), and calf and triceps skinfolds (for % fat estimates). Girls were also asked whether they had achieved menarche. VO2max averaged 37.3 ± 6.2 ml·kg?1 ·min?1 and was significantly correlated (r[62]) with height (?.32, p < .01), body mass index (?.63, p < .001), and % fat (?.65, p < .001) but not with age (?.16, p > .10). Postmenarchal girls were significantly taller and older than premenarchal girls. Contrary to previous studies, the girls' VO2max values were not related to biological age. Our subjects' aerobic capacity values averaged 14% less than those of nonblack U.S. female adolescents previously reported in the literature. This difference in VO2max was primarily a function of body weight. Study implications support the possibility that overweight in adult black women may originate prior to or during early adolescence. Future longitudinal studies should be designed to investigate the effects of aerobic fitness on cardiovascular risk factor reduction in black adolescent girls.  相似文献   

12.
Abstract

In this study, we examined fat oxidation rates during exercise in obese pubescent boys. Three groups of pubescent boys (16 pre-pubescent, Tanner's stage I; 16 pubescent, Tanner's stage III; and 14 post-pubescent, Tanner's stage V) performed a graded test on a leg cycle ergometer. The first step of the test was fixed at 30 W and power was gradually increased by 20 W every 3.5 min. Oxygen consumption ([Vdot]O2) and carbon dioxide production ([Vdot]CO2) were determined as the means of measurements during the last 30 s of each step, which allowed us to calculate fat oxidation rates versus exercise intensity. Between 20 and 50% of peak oxygen consumption ([Vdot]O2peak), fat oxidation rate in relative values (mg · min?1 · kg FFM?1) decreased continuously with pubertal development. In the same way, the maximum rate of fat oxidation occurred at a lower percentage of [Vdot]O2peak (pre-pubescent: 49.47 ± 1.62%; pubescent: 47.43 ± 1.26%; post-pubescent: 45.00 ± 0.97%). Our results confirm that puberty is responsible for a decrease in fat free mass capacities to use fat during exercise. The results suggest that post-pubescent obese boys need to practise physical activity at a lower intensity than pre-pubescent boys to enhance lipolysis and diminish adipose tissue and the consequences of obesity.  相似文献   

13.
Research from several countries has documented a decline in physical activity (PA) levels and in participation in organized sport with increasing age, indicating that organized sport may be of importance to adolescents’ cardiorespiratory fitness (CRF). Purpose: The purpose of this study was to examine how regular participation in organized and unorganized PA affected the development of adolescents’ CRF (peak oxygen consumption [VO2peak]), when controlled for sex interaction. Method: Data on direct measures of VO2peak and participation in organized PA among adolescents organized into 3 groups (participation in organized sport, participation in unorganized PA, and no weekly PA) were collected from 76 students (39 boys and 37 girls), when they were aged 14 and 19 years old. Results: Statistically significant differences were found between VO2peak values in the 3 groups at both 14 years of age, F(2, 73) = 7.16, p < .05, ?2 = .170, and 19 years of age, F(2, 73) = 14.00, p < .05, ?2 = .300, independent of sex at both 14 and 19 years of age, F(2, 73) = 0.05, p > .05, ?2 = .02, and F(2, 73) = 0.05, p > .05, ?2 = .00. Adolescents participating in organized sport also had statistically significantly higher VO2peak values than adolescents participating in unorganized PA and those with no weekly PA, at both 14 and 19 years of age. Conclusion: From a health perspective, in terms of CRF, the findings highlight the importance of encouraging adolescents to participate in organized sport and to refrain from dropping out of organized sport programs.  相似文献   

14.
To examine the reliability and validity of 1-mile walk tests for estimation of aerobic fitness (VO2max) in 10- to 13-year-old children and to cross-validate previously published equations. Participants (n = 61) walked 1-mile on two different days. Self-reported physical activity, demographic variables, and aerobic fitness were used in multiple regression analyses. Eight models were developed with various combinations of predictors. The recommended model for fitness testing in schools was: VO2max = 120.702 + (4.114 × Sex [F = 0, M = 1]) – (2.918 × 1-mile Walk Time [min]) – (2.841 × Age), R = .73, standard error of estimate = 6.36 mL·kg?1·min?1. Cross-validation of previously published equations demonstrated lower correlations with measured VO2max than the newly developed walk tests. Evidence of reliability and validity for 1-mile walk tests to estimate VO2max in young children was provided. The model that included 1-mile walk time, age, and sex may be appropriate for youth fitness testing in physical education, particularly for unmotivated or overweight young children.  相似文献   

15.
Abstract

A five-level Children's Activity Rating Scale (CARS) was designed to categorize the intensity of physical activities and discriminate between levels of energy expenditure in young children. The CARS was used by trained observers over a 12-month period to assess physical activities of 3-4 year-old children during field observations. Agreement among observers using the CARS was 84.1% for 389 paired observation periods. The energy expenditure for each level was assessed by measuring VO2s and heart rates of 5-6 year-old children (12 boys, 13 girls) while they performed eight activities representing the CARS levels. Mean VO2s for the eight activities in Levels 1-5 ranged from 7.1 to 37.5 ml kg BW?1 min?1 (1 to 5.42 METS; 145% to 80.6% of VO2max). Mean heart rates ranged from 89 to 183 b min?1 for activities in Levels 1-5. VO2s and heart rates at each level were significantly different from all other levels. These data demonstrate that the CARS encompasses a wide range of energy expenditures, discriminates between levels of energy expenditure, and can be used by trained observers to reliably evaluate physical activity and estimate energy expenditure of young children.  相似文献   

16.
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17.
This study aimed to investigate if moderate to vigorous physical activity (MVPA) and aerobic fitness are associated with cardiovascular risk factors in HIV+ children and adolescents. Sixty-five children and adolescents (8 to 15 years) provided minutes of MVPA measured by accelerometers and peak oxygen uptake (peak VO2) by breath-by-breath respiratory exchange. Cardiovascular risk factors were characterized by body fat, blood pressure, total cholesterol, HDL-c, LDL-c, triglycerides, glucose, insulin, C-reactive protein (CRP), interleukin (IL)-6, tumor necrosis factor-alpha (TNF-α) and carotid intima-media thickness. Results indicated that higher MVPA was associated with lower values of total (β = ?3.566) and trunk body fat (β = ?3.495), total cholesterol (β = ?0.112) and LDL-c (β = ?0.830). Likewise, higher peak VO2 was associated with lower total (β = ?0.629) and trunk body fat values (β = ?0.592) and levels of CRP (β = ?0.059). The physically active participants had lower total cholesterol (?24.4 mg.dL?1) and LDL-c (?20.1 mg.dL?1) compared to participants judged to be insufficiently active. Moreover, participants with satisfactory peak VO? showed lower total (?4.1%) and trunk (?4.3%) body fat, CRP (?2.3 mg.L?1), IL-6 (?2.4 pg.mL?1) and TNF-α (?1.0 pg.mL?1) compared to low peak VO2 peers. High levels of MVPA and aerobic fitness may prevent developing of cardiovascular risk factors in children and adolescents HIV+.  相似文献   

18.
Abstract

This study was designed to examine the magnitude and duration of excess postexercise oxygen consumption (EPOC) following upper body exercise, using lower body exercise for comparison. On separate days and in a counterbalanced order, eight subjects (four male and four female) performed a 20-min exercise at 60% of mode-specific peak oxygen uptake (VO2) using an arm crank and cycle ergometer. Prior to each exercise, baseline VO2 and heart rate (HR) were measured during the final 15 min of a 45-min seated rest. VO2 and HR were measured continuously during the postexercise period until baseline VO2 was reestablished. No significant difference between the two experimental conditions was found for magnitude of EPOC (t [7] = 0.69, p > .05). Mean (± SD) values were 9.2 ± 3.3 and 10.4 ± 5.8 kcal for the arm crank and cycle ergometer exercises, respectively. Duration of EPOC was relatively short and not significantly different (t [7] = 0.24, p > .05) between the upper body (22.9 ± 13.7 min) and lower body (24.2 ± 19.4 min) exercises. Within the framework of the chosen exercise conditions, these results suggest EPOC may be related primarily to the relative metabolic rate of the active musculature, as opposed to the absolute exercise VO2 or quantity of active muscle mass associated with these two types of exercise.  相似文献   

19.
The purpose of this study was to identify which averaging methods most accurately measures peak cardiorespiratory fitness (CRF) parameters [peak O2 uptake (VO2), peak O2pulse and peak respiratory exchange ratio (RER)] in a sample of healthy children and adolescents. In this cross-sectional multicenter study, we recruited 278 healthy children aged 12–17 years. We compared the mean peak value of three CRF parameters using the recommended averaging methods (30-second block average) with alternative averaging methods such as moving averages or shorter smoothing periods. We also assessed averaging methods for accuracy by individually reviewing breath-by-breath scatter plots. The 30-second block average method resulted in a lower mean peak VO2 and in an increased proportion of underestimated peak values. Using a 30-second moving average significantly increased mean peak values which increased accuracy. Similar results were found for peak RER and peak O2pulse. In conclusion, the currently recommended averaging method (30-second block average) increased the risk of misinterpretation of peak CRF values in children. Using a moving average approach decreased misinterpretation and increased accuracy.  相似文献   

20.
Body dissatisfaction is a phenomenon that may already occur in childhood and is linked to a variety of psychosocial risks. As the role of physical activity in the context of body dissatisfaction is still ambivalent, a cross-sectional study with 602 normal weight children (50.2% girls; Mage?=?9.23 years; SD?=?0.79) was conducted. The children filled in the MoMo-Questionnaire, including items about their physical activities and motives for being physically active, as well as Bender’s Body Esteem and Muscularity Concern Scale with the three subscales “body satisfaction”, “weight and shape concerns”, and “muscularity concerns”. Independent t-tests revealed that girls were less worried about muscularity than boys (Mgirls?=?1.94, SDgirls?=?1.11 vs. Mboys?=?3.12, SDboys?=?1.43; t(560)?=?11.33, p?d?=?0.92), whereas girls showed greater weight and shape concerns than boys (Mgirls?=?2.24, SDgirls?=?0.97 vs. Mboys?=?2.05, SDboys?=?0.92; t(549)?=?2.32, p?=?.02, d?=?0.20). In boys, physical activity is associated with less muscularity, weight, and shape concerns. Body satisfaction increases with health and fitness motives. In girls, the role of physical activity is ambivalent: girls who engage in sports do not differ in body dissatisfaction from non-active girls. In sportive girls, weight and shape concerns increased with more health and fitness motives. Finally, the study provides first insights into body dissatisfaction and the different role of physical activity in boys and girls in childhood.  相似文献   

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