Neighborhood-level socioeconomic factors moderate the association between physical activity and relative age effect: a cross-sectional survey study with Japanese adolescents.

BACKGROUND: Relative age effect is defined as a phenomenon where children born early generally perform better than children born later in the same cohort. Physical activity is an important factor that might be influenced by the relative age effect. Socioeconomic factors (e.g., parent's income, education level) are also associated with the adolescent's physical activity. However, no existing study has examined whether socioeconomic factors moderate the relative age effect on the adolescent's physical activity. This study aims to clarify whether and how birth month and socioeconomic factors relate to organized sports and physical activity among adolescents in Japan. METHODS: We conducted a questionnaire survey targeting 21,491 adolescents who live in a widespread neighborhood. We included 8102 adolescents (4087 males and 4015 females: mean age 13.1 ± 1.4) in the analysis. Based on the participants' birth months, we divided them into four groups (April to June, July to September, October to December, January to March). We asked participants to report their organized sports participation. Using the International Physical Activity Questionnaire for Japanese Early Adolescents, we identified their moderate to vigorous physical activity (MVPA). Neighborhood-level socioeconomic factors (areal deprivation, average annual income, education level) were analyzed based on national surveys, such as the population census. We performed multilevel logistic and linear regression analysis for organized sports participation and MVPA, respectively. Moreover, a simple slope analysis was implemented if the interaction between birth month and socioeconomic factor was significant in the multilevel linear regression analysis. RESULTS: Among males, relatively younger adolescents (adolescents who were born later in the same grade) were less likely to participate in organized sports activites (OR=0.90, 95% CI 0.82-0.97, p<0.05), while both males and females engaged in less MVPA (b=-0.54, b=-0.25, p< 0.01, respectively). We observed an interaction between birth month and socioeconomic factors. Among males in low-income neighborhoods, and females in more deprived neighborhoods, relatively younger adolescents engaged in less MVPA. CONCLUSIONS: Socioeconomic factors moderate the relative age effect on adolescents' physical activity. The relative age effect on adolescents' physical activity might be more likely to appear among adolescents from socioeconomically disadvantaged neighborhoods.

Content validity and reliability of an enjoyable multicomponent agility test for boys: The N-challenge test.

Agility is a crucial fitness component for success in sports and daily playful activities for children. The purpose of this study was to develop a multicomponent agility test, N-challenge, to determine the content validity and reliability of N-challenge, and to investigate the enjoyment level of N-challenge among elementary school boys. N-challenge consisted of six sections and total running time. The running time of N-challenge was measured in a single trial concomitantly with timing/speed gates. Content validity was assessed by eight experts in sports science. To measure reliability, intraclass correlation coefficient (ICC) and standard error of measurement (SEM) were calculated using a test-retest procedure. The enjoyment levels of the boys who performed N-challenge were assessed using a questionnaire. The item-content validity index of the total running time of N-challenge was 1.00. The ICC of the total running time of N-challenge was 0.97 (95% confidence interval: 0.96-0.98), which was categorized as an almost perfect level of reliability. The SEM of N-challenge was 0.18 s (1.9%), indicating good absolute reliability. Approximately 95% of the boys showed enjoyment after performing the test. These results suggest that N-challenge has adequate content validity and excellent reliability as an agility test for boys.

Relationship of participation in specific sports to academic performance in adolescents: A 2-year longitudinal study.

Physical activity is considered a promising behavior to improve cognitive function and academic performance in adolescents. As evidence on the relationship of specific sports activity is not conclusive, this study aimed to determine the longitudinal relationships of different sports to academic performance in adolescents and evaluate the cardiorespiratory fitness mediation effect of these sports. We focused on the demands of complex motor skills and the differences between individual sports vs team sports. Four hundred and sixty-three 7th-grade students (227 girls and 236 boys) were followed up over 2 years. Data regarding participation in sports activities, types of sports activities, academic performance, and cardiorespiratory fitness were obtained at baseline and after a 2-year follow-up. Structural equation modeling revealed that participation in all sports activity was positively associated with improvement of academic performance from baseline to follow-up, and that these associations were mediated by cardiorespiratory fitness gains. Participation in sports activities that require more complex motor skills and individual sports activity was directly associated with an improvement of academic performance from baseline to follow-up. Furthermore, quitting sports activities was negatively associated with academic performance via a reversal in cardiorespiratory fitness gains. These findings indicate that participation in specific sports may have significant benefits for academic performance in adolescents. Although these relationships are presumably mediated by cardiorespiratory fitness, sports activities that require more complex motor skills and individual sports participation may be directly related to academic performance. Considering that quitting sports activities reversed these benefits, sustained participation in sports is important for academic success.

Non-linear growth trends of toe flexor muscle strength among children, adolescents, and young adults: a cross-sectional study.

PURPOSE: There are only a few studies on the muscular strength of the foot in children and adolescents; thus, the developmental pattern and normative data of these populations during growth are unclear. We sought to elucidate the developmental pattern of the foot muscle strength among children, adolescents, and young adults compared with that of the hand. METHODS: A total of 747 children, adolescents, and young adults participated in this study, and their maximum isometric toe flexor strength (TFS), hand grip strength (HGS), and foot length were measured. RESULTS: TFS was correlated with HGS (r = 0.785), age (r = 0.659), height (r = 0.757), body mass (r = 0.737), and foot length (r = 0.594). Multiple regression analyses revealed that TFS was correlated with age (ß = 0.243 in boys; ß = 0.461 in girls), squared value of age (age2; ß = - 0.296 in boys; ß = - 0.260 in girls), and body mass (ß = 0.256 in boys; ß = 0.311 in girls) in both sexes, indicating a non-linear relationship between age and TFS development. In a regression model for HGS, age was a significant variable, but not age2. HGS increased linearly from childhood until young adulthood, whereas TFS increased from childhood until adolescence and then levelled off. CONCLUSION: Our results demonstrate that TFS has a different developmental pattern compared with HGS.

Reliability and validity of a reactive agility test with soccer goalkeeper-specific movements for adolescents.

BACKGROUND: There is a lack of objective measures and assessments of goalkeeping proficiency and performance in the literature. Furthermore, no reports have focused on adolescent goalkeepers (under the age of 15). The aim of this study was to determine the reliability and validity of the Goalkeeper Reactive Agility Test for Adolescents (GRATA). METHODS: Content validity was assessed by seven experts and the Item-Content Validity Index (I-CVI) was calculated. We used similar settings to an agility test for college-aged goalkeepers, although the number of repetitions and running direction of the latter parts of the test were modified (number of repetitions: from 3 to 2; running direction: from forward to backward). Eighty-five adolescent male goalkeepers (age: 13.4 years) performed the test three times. The intraclass correlation coefficient (ICC) was used for relative reliability and the standard error of measurement (SEM) and the smallest worthwhile change (SWC) for absolute reliability. RESULTS: The I-CVI was 0.86, above the acceptable level of 0.78. The mean running time of the GRATA was 11.98 s. The ICC value was 0.91 (P<0.01; 95% confidence interval [95% CI]: 0.87-0.94), the SEM 0.26 s and the SWC 0.17 s. CONCLUSIONS: Our results demonstrate that the GRATA has sufficient reliability and content validity in adolescent GKs.

Muscular stress is equal when resistance exercise with blood flow restriction is matched in total work volume: A cross-sectional, cross-over study.

AIM: We compared muscular metabolic stress during exercise performed at multiple intensities, from very low to moderate, with blood flow restriction (BFR) adjusted by the same work volume. METHODS: Twenty-five healthy young adults performed unilateral plantar flexion at 1 repetition/2 s in a magnetic resonance system. The BFR exercise protocols were as follows: (A) exercise with 10% of one repetition maximum (1-RM) for 360 s, (B) 15% 1-RM for 240 s, (C) 20% 1-RM for 180 s, (D) 30% 1-RM for 120 s, and (E) 40% 1-RM for 90 s. All protocols had the same total work volume (load × repetitions = 1800). A high-intensity protocol at 65% 1-RM without BFR (60 s) was also performed for comparison. We used 31 P-magnetic resonance spectroscopy to evaluate the muscular metabolic stress in the subjects' calf muscle, defined as decreases in phosphocreatine and intramuscular pH. RESULTS: The phosphocreatine depletion (A: 15.6 ± 0.7, B: 14.8 ± 0.8, C: 15.2 ± 0.6, D: 14.3 ± 0.6, E: 10.9 ± 0.5 mM; no significant difference [ns]) and the intramuscular pH decrease (A: 6.82 ± 0.02, B: 6.84 ± 0.01, C: 6.83 ± 0.02, D: 6.83 ± 0.02, E: 6.77 ± 0.02; ns) at the end of each exercise were similar and greater than those produced by the 65% 1-RM without BFR. CONCLUSION: If the total work volumes are equal, the metabolic stress in exercising muscle may reach similar levels at the end of exercise with BFR and could provide similar successful training effects.

Is gender a factor in the reduction of cardiovascular risks with exercise training?

BACKGROUND: This study compared older men and women with cardiovascular (CV) risk factors in terms of the effects of a 6-month exercise intervention on high-sensitivity C-reactive protein (hsCRP) levels, blood pressure (BP) and other risk factors. METHODS AND RESULTS: Sixty older (age 61-79) overweight men and 71 such women with 2 or more risk factors (ie, systolic BP 130-179 mmHg, non-fasting blood glucose 110-139 mg/dl, and low-density lipoprotein cholesterol 120-219 mg/dl) participated in a 6-month exercise intervention. The exercise program consisted of moderate-intensity bicycle exercise for ∼40 min, performed on average 2.5 times per week. Systolic and diastolic BP reductions were found to be greater in women than in men (SBP, -10.6 vs. -5.5 mmHg; DBP, -6.2 vs. -3.3 mmHg; both P<0.05). Decreases in body mass index were larger in women than in men (P<0.05). There was no significant gender difference in the changes in blood glucose and lipid profiles and hsCRP levels. After adjustment for confounders (exercise frequency, weight loss, age, and baseline values), there were still significant gender differences in the SBP and DBP reductions. hsCRP reduction were similar in both genders even after adjusting for weight loss. CONCLUSIONS: There could be gender differences in the beneficial effects of exercise training on the potent CV risk factors of BP and body weight, but not on hsCRP.

Extracurricular music and visual arts activities are related to academic performance improvement in school-aged children.

The present longitudinal study examined whether extracurricular activities in the arts and corresponding scores in art classes have a positive association with general academic performance. Data were collected from 488 seventh-grade children (259 boys and 229 girls) for over two years. Information regarding their participation in extracurricular activities in music and visual arts, grade points in general academic performance (i.e., Japanese, Social Studies, Mathematics, Science, and English), music, and arts were obtained at the end of the seventh and ninth grades. Structural equation modeling revealed that participation in extracurricular activities in both music and visual arts was positively associated with improvements in general academic performance from the seventh and ninth grades, and these associations were related to changes in music and visual arts scores. This finding suggests that arts education can contribute to improving general academic performance; however, the current study shows correlational relationships. Future research should examine the causal relationship between art involvement and academic performance by controlling for other factors (e.g., IQ, motivation, etc.).

Effect of multiple set on intramuscular metabolic stress during low-intensity resistance exercise with blood flow restriction.

Our previous study reported that intramuscular metabolic stress during low-intensity resistance exercise was significantly enhanced by combining blood flow restriction (BFR); however, they did not reach the levels achieved during high-intensity resistance exercise. That study was performed using a single set of exercise; however, usual resistance exercise consists of multiple sets with rest intervals. Therefore, we investigated the intramuscular metabolic stress during multiple-set BFR exercises, and compared the results with those during multiple-set high-intensity resistance exercise. Twelve healthy young subjects performed 3 sets of 1-min unilateral plantar flexion (30 repetitions) with 1-min intervals under 4 different conditions: low intensity (L, 20% 1 RM) and high intensity (H, 65% 1 RM) without BFR, and L with intermittent BFR (IBFR, only during exercise) and with continuous BFR (CBFR, during rest intervals as well as exercise). Intramuscular metabolic stress, defined as intramuscular metabolites and pH, and muscle fiber recruitment were evaluated by 31P-magnetic resonance spectroscopy. The changes of intramuscular metabolites and pH during IBFR were significantly greater than those in L but significantly lower than those in H. By contrast, those changes in CBFR were similar to those in H. Moreover, the fast-twitch fiber recruitment, evaluating by a splitting Pi peak, showed a similar level to H. In conclusion, the multiple sets of low-intensity resistance exercise with continuous BFR could achieve with the same metabolic stress as multiple sets of high-intensity resistance exercise.

Reliability and Validity of a Novel Reactive Agility Test with Soccer Goalkeeper-Specific Movements.

The purpose of this study was to develop a reactive agility test with soccer goalkeeper (GK)-specific movements (G-RAT) and to examine the reliability and validity of college-aged GKs. We designed a five-branch star-shaped course with diving and ball-catching movements under reactive conditions. In the setup, a start−goal line was set on the top of a branch and 3.5 m away from the center of the star-shaped setting. Content validity was assessed by six experts, and the item-content validity index (I-CVI) was calculated. Thirty-three male GKs performed the test trial twice. One test trial of G-RAT consists of three shuttles from the start−goal line to diving and ball-catching. For the reactive condition, GKs were instructed on which ball directions should dive when their body trunk reached 1.5 m away from the start−goal line. GKs were classified into regular (R) or non-regular (NR) groups. The intraclass correlation coefficient (ICC) and the receiver operating characteristic (ROC) curve analyses were used to assess the reliability and predictive power as convergent validity. The I-CVI was 0.83, which was greater than the acceptable level of 0.78. The ICC value was 0.94 (p < 0.01; 95% confidence interval (95%CI), 0.88−0.97). The GKs completed the test 14.3 ± 0.7 and 15.3 ± 1.0 s in the R and NR group (p < 0.01; Cohen's d = 0.89), respectively. The area under the curves of G-RAT was 0.80 (95%CI, 0.64−0.96). These results show that a GK-specific agility test under reactive conditions would have sufficient reliability and both content and convergent validity in college-aged GKs.

Differential effects of changes in cardiorespiratory fitness on worst- and best- school subjects.

Accumulating evidence shows a beneficial association between physical fitness and school children's academic performance. However, several other studies have failed to demonstrate such an association. We reanalyzed data of a two-year longitudinal study of the association between changes in cardiorespiratory fitness and academic performance of school children by focusing on intra-individual variability in grade points as a possible source of this discrepancy. We analyzed data from 469 junior high school students to examine if improvements in cardiorespiratory fitness had a differential effect on an individual student's worst and best grade points. Results indicated that improvements in physical fitness were associated with an improvement in the worst grade points. On the contrary, we did not observe a similar longitudinal association with the best grade points. These findings suggest that improving cardiorespiratory fitness improves the worst grade points of an individual, selectively. We suggest that intra-individual variability in grade points might moderate the association between physical fitness and academic performance changes.

Association of Neighborhood Food Environment and Physical Activity Environment With Obesity: A Large-Scale Cross-Sectional Study of Fifth- to Ninth-Grade Children in Japan.

Objective: This study examined the relationship between neighborhood food and physical activity environment, and obesity among elementary and junior high school students in Japan. Methods: The participants were fifth- to ninth-grade children (n=7277), who were attending municipal schools in Japan. Percent overweight (POW) was calculated using their age, gender, height, and weight, which were collected through a questionnaire. A POW of < 20% was considered non-obese, while ≥ 20% was considered obese. Furthermore, using a geographic information system, we investigated the density of convenience stores, fast-food stores, casual restaurants, supermarkets and department stores, parks, sports facilities, stations, and intersections in the school district. Additionally, from the census, we obtained information regarding the population density of the municipality where the participants' schools were located. Multiple logistic regression analysis was used to examine the relationship between obesity and food environment (the food environment model), between obesity and physical activity environment (the physical activity environment model), and among obesity, food, and physical activity environment (the food and physical activity environment model). Results: In the food environment model and the food and physical activity environment model, the density of convenience stores showed a significant positive association. In the physical activity environment model, the density of stations showed a significant negative association. Conclusion: This study's findings can contribute to the development of appropriate community interventions for improving children's health in Japan and similar areas.

Effects of oral single-dose administration of sarpogrelate hydrochloride on saturation O(2) of calf muscle during plantar flexion exercise.

To investigate the effects of a 100-mg oral single-dose administration of sarpogrelate hydrochloride (SH) on saturation O(2) (StO(2)) of calf muscle in healthy subjects experiencing simulated peripheral arterial disease (0.6 ankle brachial pressure index). Ten subjects performed three kinds of plantar flexion exercises at a work rate of 50% of maximal volunteer contraction for 4 min by using cuff occlusion ischemia,. Subjects performed a control test (C) without ischemia and SH, an ischemia test (I) without SH, and an I + SH test with ischemia. StO(2), blood pressures (BP), and heart rate (HR) were measured through all experiments. At the end of the exercise, the decrease in StO(2) from baseline in the C and I + SH tests was significantly less than that in the I test (p < 0.05, respectively). However, there were no significant differences in mean BP or HR in any of the exercise conditions. These results indicated that an oral single-dose administration of SH might improve peripheral circulation independent of any changes in BP and HR.

Longitudinal relationship of favorable weight change to academic performance in children.

Although there is a growing consensus about the positive relationship between prevention of overweight/obesity and academic performance in children, relevant studies targeting the relationship between underweight and academic performance are scarce. This study aimed to examine the longitudinal relationship of favorable weight change to academic performance in schoolchildren. We analyzed 2-year longitudinal data derived from 197 seventh-grade children aged 12-13 years. Academic performance was assessed using the total grade points of five academic subjects. Body mass index (BMI) was calculated as body weight (kg)/height (m2). A significant interaction effect of baseline BMI and BMI changes over 2 years (B = -0.10, SE B = 0.03, ß = -0.40, t = -3.37, p < 0.001) was noted after controlling for confounders such as socioeconomic status, afterschool learning duration, screen time, exercise habits, and cardiorespiratory fitness. When the centered baseline BMI was outside the interval [-2.49, 3.21], the slope of the change in BMI was significant (p < 0.05). Simple slope analyses revealed a positive relationship of weight gain when baseline BMI = mean - 1 SD (B = 0.40, SE B = 0.18, ß = 0.31, t = 2.20, p = 0.03) and weight loss when baseline BMI = mean + 1 SD (B = -0.26, SE B = 0.13, ß = -0.20, t = -1.97, p = 0.05) to total grade points of five school subjects. A split-group validation was performed and robust results of original analyses were detected (i.e., significant interaction effect of baseline BMI and BMI changes over 2 years (group A: B = -0.11, SE B = 0.05, ß = -0.47, t = -2.39, p = 0.02; group B: B = -0.14, SE B = 0.05, ß = -0.47, t = -2.78, p = 0.007). Favorable changes in weight status, i.e., weight loss in children with overweight/obesity and weight gain in children with mild underweight/underweight, have a positive influence on academic performance in children independent of socioeconomic factors, learning habits, screen time, exercise habits, and cardiorespiratory fitness.

Intramuscular metabolism during low-intensity resistance exercise with blood flow restriction.

Although recent studies have reported that low-intensity resistance training with blood flow restriction could stress the muscle effectively and provide rapid muscle hypertrophy and strength gain equivalent to those of high-intensity resistance training, the exact mechanism and its generality have not yet been clarified. We investigated the intramuscular metabolism during low-intensity resistance exercise with blood flow restriction and compared it with that of high-intensity and low-intensity resistance exercises without blood flow restriction using (31)P-magnetic resonance spectroscopy. Twenty-six healthy subjects (22 +/- 4 yr) participated and performed unilateral plantar flexion (30 repetitions/min) for 2 min. Protocols were as follows: low-intensity exercise (L) using a load of 20% of one-repetition maximum (1 RM), L with blood flow restriction (LR), and high-intensity exercise using 65% 1 RM (H). Intramuscular phosphocreatine (PCr) and diprotonated phosphate (H(2)PO(4)(-)) levels and intramuscular pH at rest and during exercise were obtained. We found that the PCr depletion, the H(2)PO(4)(-) increase, and the intramuscular pH decrease during LR were significantly greater than those in L (P < 0.001); however, those in LR were significantly lower than those in H (P < 0.001). The recruitment of fast-twitch fiber evaluated by inorganic phosphate splitting occurred in only 31% of the subjects in LR, compared with 70% in H. In conclusion, the metabolic stress in skeletal muscle during low-intensity resistance exercise was significantly increased by applying blood flow restriction, but did not generally reach that during high-intensity resistance exercise. This new method of resistance training needs to be examined for optimization of the protocol to reach equivalence with high-intensity resistance training.

Effects of High Intensity Interval Training on Executive Function in Children Aged 8-12 Years.

This study investigated the effects of a high intensity interval training (HIIT) program on both physical fitness and executive functions in children. Fifty-six children aged 8-12 years participated in this study, and were divided into a HIIT group and a control group. The HIIT group performed three sessions of the 8- to 10-min HIIT program per week for 4 weeks. Before and after the intervention, 20-m shuttle runs, sit-ups, and standing long jumps were assessed as test of physical fitness. In addition, the executive function was assessed using the digit span forward (DSF) test, digit span backward (DSB) test, and Tower of Hanoi test. Only the HIIT group experienced significant improvement when completing the 20-m shuttle run (p = 0.042) and sit-ups (p < 0.001). Regarding executive function, the number of correct answers in DSB test significantly increased only in the HIIT group (p = 0.003). However, the standing long jump, DSF, and the Tower of Hanoi test performance did not change after intervention. The findings of the present study suggest that HIIT has positive effects on a core executive function such as working memory in addition to components of the physical fitness such as cardiorespiratory endurance and muscular endurance.

Resistance training with interval blood flow restriction effectively enhances intramuscular metabolic stress with less ischemic duration and discomfort.

Increases in muscle size and strength similar to those obtained with high resistance load can be achieved by combining lower loads with continuous blood flow restriction (BFR). However, high ratings for distress have been reported for continuous BFR. Therefore, we investigated the efficacy (metabolic stress) of BFR applied only during intervals in resistance exercise. Seven healthy men performed three 1-min sets of plantar flexion (30 reps/min) with 1-min rest intervals under 4 conditions: low-load resistance exercise (L, 20% 1-repetition maximum (1RM)) without BFR (L-noBFR), L with BFR during exercise sets (L-exBFR), L with BFR during rest intervals (L-intBFR), and L with continuous BFR during both exercise and rest intervals (L-conBFR). Based on the results of the first experiment, we performed additional protocols using a moderate load (M, 40% 1RM) with intermittent (exercise or rest intervals) BFR (M-exBFR and M-intBFR). Intramuscular metabolic stress, defined as decreases in phosphocreatine and intramuscular pH, was evaluated by 31P magnetic resonance spectroscopy. Rated perceived exertion (RPE) was also assessed. At the end of exercise, total decreases in phosphocreatine and intramuscular pH were similar among L-noBFR, L-intBFR, and L-exBFR and significantly less than those in L-conBFR (p < 0.05). In contrast, changes in these variables in M-intBFR but not in M-exBFR were similar to those in L-conBFR. Nevertheless, RPE was lower in M-intBFR than in both M-exBFR and L-conBFR (p < 0.05). The effect of intermittent BFR during exercise might be insufficient to induce metabolic stress when using a low load. However, effective metabolic stress for muscle adaptation could be obtained by moderate-load resistance exercise with BFR during intervals with less ischemic duration and discomfort.

Modeling relationships of achievement motivation and physical fitness with academic performance in Japanese schoolchildren: Moderation by gender.

The aim of this study was to determine, using structural equation modeling, the comprehensive relationships of achievement motivation (self-fulfillment achievement motivation [SFAM] and competitive achievement motivation [CAM]), daily behaviors (exercise habits, screen time, and learning duration), body mass index [BMI], and cardiorespiratory fitness [CRF]) with academic performance among schoolchildren. Three hundred twenty-five schoolchildren (172 males and 153 females; 12-13 years old) were recruited. Academic performance was assessed using the total grade points in 8 academic subjects (GP8); CRF using the 20-m shuttle run; and achievement motivation, daily behaviors, and socioeconomic status using questionnaires. Socioeconomic status was included as a control variable. In males, two cascade associations of achievement motivation to GP8 were detected: (1) SFAM → screen time/learning duration → GP8, and (2) CAM → exercise habit → CRF → GP8 (χ2 = 8.72, p = .19, AGFI = .92). In females, two cascade associations were also detected: (1) SFAM → screen time/learning habit → GP8, and (2) exercise habit → BMI2 → GP8 (χ2 = 6.17, p = .41, AGFI = .93). Our results suggest that greater achievement motivation is associated with academic success via various physiological/behavioral factors, and that these associations differ by gender.

Direct and indirect relationships of physical fitness, weight status, and learning duration to academic performance in Japanese schoolchildren.

The purpose of this study was to determine, using structural equation modelling (SEM), the direct and indirect influence of daily behaviours (i.e. exercise/learning durations), weight status, and physical fitness on academic performance among seventh-grade schoolchildren, after controlling for socioeconomic status. We analysed cross-sectional data from 274 schoolchildren (159 males and 115 females; 12-13 years old). Academic performance was assessed using the total grade points in eight academic subjects. Physical fitness was evaluated using the total score of eight physical fitness tests and weight status using body mass index. The daily behaviours and socioeconomic status were assessed by the questionnaire. The SEM showed an adequate fit to the data (χ2 = 0.684, p = .710, RMSEA = .000). Physical fitness and learning durations had direct effects on academic performance (ß = .301, p < .001; ß = .132, p = .037, respectively) after controlling for confounders. Healthy weight status and exercise habits positively indirectly influenced academic performance via physical fitness. These findings suggest that, independent of socioeconomic status and learning durations, exercise habits and maintaining healthy weight status may indirectly contribute to academic success via better physical fitness in children.

Effects of exercise in overweight Japanese with multiple cardiovascular risk factors.

PURPOSE: The effects of exercise in subjects with multiple cardiovascular risk factors (RF) have never been tested in a large-scale randomized controlled trial. The favorable results from our observational study led to this randomized controlled trial. METHODS: The participants, recruited from a community, were overweight, with two of the following three risk factors: hypertension, hyperlipidemia, or glucose intolerance (N=561; 44% male; mean age (SD) 67 (6); mean BMI 26.4 (2.0)). All participants received a standard health exam with counseling, followed by randomization. The intervention group (INT) was to exercise two to four times per week for 6 months at a fitness club. RESULTS: Dropout rate was 11% for INT and 10% for the controls. INT exercised an average of 2.6 times per week. Among primary outcome measures, there was a marginally significant between-group difference in changes in systolic blood pressure (intervention minus control, -2.46 mm Hg). Reductions in LDL cholesterol (-1.9 mg.dL) and hemoglobin A1c (-0.042%) were not significant. Among secondary outcomes, between-group differences were significantly greater (P<0.05) for INT in mean body weight (-1.60 kg), waist circumference (-1.8 cm), triglyceride (-7 mg.dL), hsCRP (-0.063 mg.L), and estimated VO2peak (2.0 mL.kg.min). All directional mean RF changes consistently favored INT. A cardiovascular risk reduction estimated from the changes in RF was about 24%. A greater improvement was also found in health-related quality-of-life measures (SF-36) in INT. No difference was found in the adverse event rate. CONCLUSIONS: Exercising an average of 2.6 times per week for 6 months produced a significant improvement in cardiovascular risk profile in subjects with multiple cardiovascular risk factors through cumulative results of modest yet pervasive changes in all conventional risk factors, without increased adverse effects.