Cardiovascular fitness in obese versus nonobese 8-11-year-old boys and girls

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.     

Lifestyle, body composition, and physical fitness changes in Hungarian school boys (1975-2005)

General socioeconomic conditions as well as the physical environment have undergone remarkable changes in Hungary during the past 30 years. Unfortunately, these positive processes have resulted in a reduction of habitual physical activity along with unfavorable changes in dietary habits. Therefore, the purpose of the present study was to compare some selected morphological and functional parameters of 7-14-year-old Hungarian schoolboys living in the middle of the 1970s and at the beginning of the new millennium. It was hypothesized that there would be significant differences in morphological and functional characteristics of the Hungarian schoolboy populations, because they were assessed 30 years apart. Means of height, body mass, body mass index (BMI), the sum of five skinfold tests, percentage of body fat, and two running performance times (400 m and 1,200 m) of the boys (N = 3,672) studied in 1975 were compared to those of the boys (N = 3,758) in 2005. Data were analyzed using two-tailed independent samples t tests (p < .05). We observed significant secular changes in body mass and height. In addition, boys in 2005 had significantly more subcutaneous fat compared to 1975. The running times for the two distances were significantly poorer at the time of the second investigation. The remarkable and unfavorable changes in body composition and cardiorespiratory performance were attributed to the continuously decreasing intensity of habitual physical exercise and a lifestyle that had become more sedentary (watching TV playing computer games, etc.). Radical interventions are necessary to reduce these risks associated with the high prevalence of cardiovascular disease in Hungary, and the challenge to resolve the problem requires combined efforts at the educational, societal, corporate, and governmental levels.     

Effects of a 12-week physical activity protocol delivered by YMCA after-school counselors (Youth Fit for Life) on fitness and self-efficacy changes in 5-12-year-old boys and girls

To address reduced physical education (PE) in elementary schools, a 12-week physical activity protocol was tested on 5-12-year-old, primarily African American, girls (n = 226) and boys (n = 344) at 14 YMCA after-school care sites. The 3 times/week, 45-min session curriculum included cardiovascular, resistance, and flexibility training, in which all children could participate simultaneously, and a behavioral skills education component. After-school counselors, formerly untrained in PE methods, administered the sessions, with periodic supervision by YMCA wellness staff members. Analyses of the eight Age x Sex subsamples indicated significant improvements on body composition, strength, and endurance, both within-groups and when predicted changes due to maturation were accounted for. Exercise barriers self-efficacy significantly increased in subsamples of 9-10- and 11-12-year-old girls only. The need for replication across ethnic groups was suggested. Limitations and the need for extension of research on supplementation of elementary school PE were discussed.     

Comparison of accelerometer and pedometer measures of physical activity in boys and girls, ages 8-10 years

Accelerometers record total physical activity and time spent at different intensities. Pedometers indicate total activity only. The aim of this study was to assess the relationship between pedometer counts and attainment of > or = 60 min of moderate activity. Thirty-four children, ages 8-10 years, wore a Tritrac accelerometer and Yamax pedometer. Published recommendations of steps per day were compared to attainment of > or = 60 min moderate activity. Boys who accumulated 13,000 steps.d(-1) and girls who accumulated 12,000 steps.d(-1) engaged in > or = 60 min moderate activity. However, 23% of boys and 15% of girls did not reach the pedometer thresholds but did engage in > or = 60 min moderate activity. In conclusion, these pedometer thresholds provide a reasonable estimation when assessment of physical activity intensity is not possible.     

Blood lactate response and critical speed in swimmers aged 10-12 years of different standards

It has previously been shown that measurement of the critical speed is a non-invasive method of estimating the blood lactate response during exercise. However, its validity in children has yet to be demonstrated. The aims of this study were: (1) to verify if the critical speed determined in accordance with the protocol of Wakayoshi et al. is a non-invasive means of estimating the swimming speed equivalent to a blood lactate concentration of 4 mmol x l(-1) in children aged 10-12 years; and (2) to establish whether standard of performance has an effect on its determination. Sixteen swimmers were divided into two groups: beginners and trained. They initially completed a protocol for determination of speed equivalent to a blood lactate concentration of 4 mmol x l(-1). Later, during training sessions, maximum efforts were swum over distances of 50, 100 and 200 m for the calculation of the critical speed. The speeds equivalent to a blood lactate concentration of 4 mmol x l(-1) (beginners = 0.82 +/- 0.09 m x s(-1), trained = 1.19 +/- 0.11 m x s(-1); mean +/- s) were significantly faster than the critical speeds (beginners = 0.78 +/- 0.25 m x s(-1), trained = 1.08 +/- 0.04 m x s(-1)) in both groups. There was a high correlation between speed at a blood lactate concentration of 4 mmol x l(-1) and the critical speed for the beginners (r= 0.96, P < 0.001), but not for the trained group (r= 0.60, P> 0.05). The blood lactate concentration corresponding to the critical speed was 2.7 +/- 1.1 and 3.1 +/- 0.4 mmol x l(-1) for the beginners and trained group respectively. The percent difference between speed at a blood lactate concentration of 4 mmol x l(-1) and the critical speed was not significantly different between the two groups. At all distances studied, swimming performance was significantly faster in the trained group. Our results suggest that the critical speed underestimates swimming intensity corresponding to a blood lactate concentration of 4 mmol x l(-1) in children aged 10-12 years and that standard of performance does not affect the determination of the critical speed.     

对山东省3～6岁幼儿体能指标的现状、特点及变化规律的研究

通过对山东省3～6岁幼儿10米往返跑、立定跳远、网球掷远、双腿连续跳、坐位体前屈、走平衡木6项体能指标的测试，分析了山东省3～6岁男女、城乡幼儿体能变化的年龄、性别与城乡特点，揭示了其自然变化的趋势与规律。     

Effects of 6-month soccer and traditional physical activity programmes on body composition,cardiometabolic risk factors,inflammatory, oxidative stress markers and cardiorespiratory fitness in obese boys

Physical activity is important in obesity prevention, but the effectiveness of different physical activity modalities remains to be determined among children. The main purpose of this study was to compare the effects of a 6-month soccer programme and a traditional physical activity programme on changes in body composition, cardiometabolic risk factors, inflammatory and oxidative markers, cardiorespiratory fitness and perceived psychological status in obese boys. Eighty-eight boys (8–12 years; BMI > +2 standard deviations of WHO reference values) participated in one of three groups: soccer, traditional activity and control. Soccer and traditional activity programmes involved 3 sessions per week for 60–90 min at an average intensity of 70–80% of maximal heart rate. Control group participated in activities of normal daily living. All boys participated in school physical education, two sessions per week of 45–90-min. Measurements were taken at baseline and after 6 months, and included body size and composition, cardiometabolic risk factors, inflammatory and oxidative markers, cardiorespiratory fitness and perceived psychological status. Physical activity and dietary intake were assessed before and immediately following the intervention. The three groups had similar characteristics at baseline. After 6 months, both intervention groups had significantly lower relative fatness (% fat), waist circumference and total cholesterol, and higher cardiorespiratory fitness, self-esteem, perceived physical competence and attraction to physical activity compared with control group. In conclusion, physical activity interventions over 6 months positively influenced several indicators of health status among obese boys. The results also suggested that soccer has the potential as an effective tool for the prevention and reduction of childhood obesity and associated consequences.