Strong inverse association between physical fitness and overweight in adolescents: a large school-based survey

Association of body mass index with muscle strength and cardiorespiratory fitness: A cross-sectional study based on Chinese adolescents

BACKGROUND

Muscle strength and cardiorespiratory fitness are important components of physical fitness and are important for the physical and mental health development of university students. However, obesity is also an important factor affecting physical fitness, and there are few studies on how body mass index (BMI), which reflects obesity, is associated with muscle strength and cardiorespiratory fitness among Chinese university students. Therefore, this study analyzed the association between BMI and muscle strength and cardiorespiratory fitness among Chinese university students in order to provide a reference and basis for promoting the development of physical fitness among Chinese university students.

METHODS

A stratified whole-group sampling method was used to test physical fitness items in 27 973 (15 527 boys, 55.51%) university students in 800 first- to fourth-year university classes in Anhui, Fujian, Xinjiang, Shanghai, and Jiangxi, China. The physical fitness items included height, weight, standing long jump, 1000 m running (boys), and 800 m running (girls) items. Curvilinear regression analysis was used to analyze the correlations that existed between BMI and standing long jump and VO2max.

RESULTS

The BMI of Chinese 19-22 years old university students was (21.14 ± 2.92) kg/m2. The mean standing long jump score was (197.31 ± 34.07) cm. In general, the BMI reached the highest point of 207.92 cm when the BMI was 26.25 kg/m2, and then showed a decreasing trend with the increase of BMI. The overall relationship between BMI and vertical jump showed an inverted "U"-shaped curve. In terms of VO2max, the overall trend of VO2max increased gradually with the increase of BMI, and when BMI reached 40 kg/m2, VO2max was 4.34 L-kg-1-min-1.

CONCLUSION

Chinese university students showed an inverted "U" curve relationship between BMI and standing long jump in general, while VO2max showed a gradual increase with increasing BMI. Compared with the cardiorespiratory fitness of Chinese university students, the effect of BMI changes on muscle strength was greater.

Assessment of nutritional status, physical fitness and physical activity of school going adolescents (12-15 years) in Delhi

BACKGROUND

Adolescence is a distinct period that is crucial for setting the foundation for long-term health.

OBJECTIVE

To assess the nutritional status, physical fitness, and physical activity of adolescents.

METHODS

The present cross-sectional study recruited 100 adolescents purposively. Information regarding general profile and lifestyle-related factors was collected using a questionnaire. Anthropometric data such as height, weight, BMI, and body fat% were collected using appropriate equipment. Physical fitness was assessed using a battery adapted from FITNESSGRAM® and PAQ-A assessed the physical activity. Dietary intake was analysed using a 2-day 24-hour dietary recall.

RESULT

The study revealed, 19% of the participants were overweight and 6% were obese. The majority (74%) were physically inactive and 15% had high body fat %. There was lower consumption of energy, carbohydrates, iron, and calcium, than the recommendations. Also, physical activity scores were negatively associated with macronutrient intake and trunk lift (strength and flexibility) [p < 0.05]. Data showed lower physical fitness scores. BMI and hand-grip strength was positively correlated [p < 0.05]. Push Ups (endurance) and Standing Broad Jump (power) showed a negative correlation with body fat%. Tennis ball throw and PACER (cardiorespiratory fitness) were positively associated with protein intake. A multiple regression analysis significantly showed that a unit increase in cell phone usage increases body fat% by 11.64 units. Standing broad jump increases by 38.6 cm and decreases with 28.76 cm with a unit increase in playing outside and tuitions timings respectively.

CONCLUSION

Poor nutritional status, physical fitness, and physical activity were reported among adolescents. It is imperative to plan intervention strategies to improve the overall health of adolescents.

Body Mass Index and Physical Fitness among Chinese Adolescents Aged 15-18: A Cross-Sectional Study of Gender Differences

OBJECTIVE

The aim of this study is to examine the relationship between varying levels of obesity and physical fitness test scores among Chinese adolescents, while also investigating gender differences in physical fitness and overall health. Data on height, weight, 50 m sprints, 1000/800 m runs, standing long jumps, sit and reach exercises, pull-ups/bent-leg sit-ups, and additional variables were collected from the DYH health database. Physical fitness indicators were evaluated based on the revised 2014 National Physical Fitness Standards for Students, and scores were assigned accordingly. An ordinal logistic regression (ologit) model was employed to analyze the relationship between body mass index (BMI) and physical fitness.

RESULTS

(1) Normal-weight boys achieved significantly higher physical fitness test scores than boys in other weight categories. (2) Underweight and normal-weight girls obtained significantly higher physical fitness test scores compared to overweight and obese girls, with underweight girls scoring slightly higher than those with a normal weight.

CONCLUSIONS

(1) There is a significant non-linear relationship between BMI levels and physical fitness test scores. (2) Gender differences were observed in physical fitness and overall health outcome. (3) The findings indicate an inverted U-shaped association between BMI and physical fitness among boys, while girls displayed an inverse relationship. This could be attributed to the cultural association between thinness and beauty among girls in China.

Knowledge, attitude, and practice of body shape and fitness among university students in China

BACKGROUND

Body shape and fitness (BSF) is critical for overall well-being, while university students in China are subjected to stress, peer pressure, performance anxiety, busy schedules, and lack of sleep, which can easily lead to poor BSF. This study aimed to explore the knowledge, attitude, and practice of BSF and related factors among university students in China.

METHODS

This web-based cross-sectional study was conducted on students of 15 universities in China between September 1st and November 30th, 2022. The KAP scores were evaluated using a 38-item questionnaire, including social demography, knowledge, attitude, and practice. Univariable and multivariable regression analyses were performed to identify the factors associated with KAP.

RESULTS

A total of 995 valid questionnaires were collected. There were 431 (43.3%) males and 564 (56.7%) females. Most participants were sophomores (51.2%) and freshmen (36.3%). Most participants had a BMI of 18-24 kg/m2 (66.1%). The students scored highly on BSF-related knowledge (8.30 ± 1.49), moderately on attitude (37.20 ± 4.46), and low on practice (19.64 ± 4.62). Multivariate logistic regression analysis showed that attitude score (P = 0.001), sex (P = 0.001), grade (P = 0.011), body mass index (BMI) (P < 0.050), parent's education level (P = 0.005), monthly allowance (P < 0.050), and sleep quality and habits (P = 0.016) were independently associated with practice scores.

CONCLUSIONS

University students in China were found to have good knowledge, moderate attitude, and poor practice toward BSF. Attitude, sex, grade, BMI, parents' education, monthly living expenses, and sleep quality and habits affected their practice. More BSF-related courses or activities are required to motivate students, especially females.

Secular trends in 20 m shuttle run test performance of 14- to 15-year-old adolescents from 1995 to 2020

PURPOSE

To investigate whether Finnish adolescents' cardiorespiratory fitness measured using the 20 m shuttle run test (20mSRT) changed between 1995 and 2020 and to examine between-group variation in the five datasets during the past 25 years.

METHODS

Data on five cohorts were collected in 1995 (n = 498), 1998 (n = 796), 2003 (n = 2383), 2010 (n = 1383), and 2020 (n = 719). The 20mSRT was administered, following the exact same protocol, to all cohorts. A general linear contrast model was used to examine cohort differences in the 20mSRT scores. Variation across cohorts was tested using chi-square-based between-group tests.

RESULTS

Girls' 20mSRT scores decreased from 1995 to 2010 and remained stable from 2010 to 2020. Boys' 20mSRT scores decreased continuously from 1995 to 2020. In addition, the variation in girls' 20mSRT scores was larger in the 2020 than 2003 cohort, indicating the growth of SRT differences between individuals in 2020 cohort compared to 2003 cohort. Similarly, boys' scores showed greater variation, especially in the 2010 and 2020 cohorts than in the 1998 cohort.

CONCLUSION

The results of this study showed an overall decline in the cardiorespiratory fitness performance measured by 20mSRT of Finnish adolescents. Boys' scores decreased continuously from 1995 to 2020, whereas girls' scores remained stable after 2010. Examination of the variation in scores further revealed that the gap in scores between the adolescents with the highest and lowest scores increased over time.

Analysis of Self-Perceived Physical Fitness of Physical Education Students in Public Schools in Extremadura (Spain)

Adolescence is a stage of crucial physiological and psychological changes within the individual's life cycle, where fitness work is important. With self-perception being crucial in relation to adolescent health and well-being, a positive perception of fitness is directly related to increased practice or higher level of physical activity (PA). Thus, the aims were: (1) to analyze, with the Visual Analogue Fitness Perception Scale for Adolescents (FP VAS A), the self-perceived physical fitness (PF) of high school students, (2) to investigate if there are differences according to sex and school location, and (3) to study the correlations between the items of the FP VAS A with age and body mass index (BMI). For this purpose, a cross-sectional study was designed with a total of 961 participants, 48.8% boys and 51.2% girls in secondary education, where 31.9% studied in rural schools and 68.1% in urban schools. The FP VAS A scale was used to assess self-reported PF. Regarding the results, there were statistically significant differences between sexes (p < 0.001), with boys showing higher scores than girls in all the items of the FP VAS A scale, with the exception of global flexibility. Inverse, mean and significant correlations were established between BMI and self-perceived overall PF (r = -0.202; p < 0.001), cardiorespiratory endurance (r = -0.226; p < 0.001) and movement speed (r = -0.268; p < 0.001). Between age and self-perceived cardiorespiratory endurance (r = -0.138; p < 0.001) an inverse, mean and significant correlation was also observed. In conclusion, boys showed a better self-perception of PF than girls for all physical abilities, with the exception of flexibility. School location was not shown to influence students' self-perceived PF. In addition, most of the self-perceived PF abilities for overall fitness correlated inversely with BMI.

Influence of muscle volume on jumping performance in healthy male and female youth and young adults

BACKGROUND

Sex differences that appear throughout puberty have a substantial impact on the training process. It remains unclear what effect these sex differences should have on how training programs are planned and performed and what objectives should be established for boys and girls of different ages. This study aimed to investigate the relationship between vertical jump performance and muscle volume based on age and sex.

METHODS

One hundred eighty healthy males (n = 90) and females (n = 90) performed three different types of vertical jumps (VJ): squat jump (SJ), counter movement jump (CMJ), and counter movement jump with arms (CMJ with arms). We used the anthropometric method to measure muscle volume.

RESULTS

Muscle volume differed across age groups. There were significant effects of age, sex, and their interaction on the SJ, CMJ, and CMJ with arms heights. From the age of 14-15, males exhibited better performances than females, and large effect sizes became apparent in the SJ (d = 1.09, P = 0.04), CMJ (d = 2.18; P = 0.001) and CMJ with arms (d = 1.94; P = 0.004). For the 20-22-year-old age group, there was a significant difference in VJ performance between males and females. Extremely large effect sizes became apparent in the SJ (d = 4.44; P = 0.001), CMJ (d = 4.12; P = 0.001) and CMJ with arms (d = 5.16; P = 0.001). When performances were normalized to the lower limb length, these differences persisted. After normalization to muscle volume, males exhibited better performance when compared to females. This difference persisted only for the 20-22-year-old group on the SJ (p = 0.005), CMJ (p = 0.022) and CMJ with arms (p = 0.016). Among male participants, muscle volume was significantly correlated with SJ (r = 0.70; p < 0.01), CMJ (r = 0.70; p < 0.01) and CMJ with arms (r = 0.55; p < 0.01).

CONCLUSIONS

The results indicate that muscle volume may be one of the major determining factors in sex differences in vertical jumping performance.

Relationship between body mass index and physical fitness index in Chinese college students: Results from a cross-sectional survey

BACKGROUND

To explore the cross-sectional relationship between the body mass index (BMI) and physical fitness index (PFI) of Chinese college students.

METHODS

In total, 30 497 (male 16 197, 55.5%) Chinese college students aged 19-22 were tested for height, weight and five physical fitness indicators (50-m sprint, sit and reach, standing long jump, 1000/800-m run, pull-up/bent-leg sit-up). Stratified according to age and gender, according to BMI percentile, divided into BMI < 10th Percentile (A), 10th ≤ BMI < 25th Percentile (B), 25th ≤ BMI < 75th Percentile (C), 75th ≤ BMI < 90th Percentile (D), BMI ≥ 90th Percentile (E), a total of 5 groups, and the PFI composed of 5 indicators of physical fitness was calculated according to age and gender. The comparison of PFI between different BMI groups was carried out using the effect size, and the non-linear relationship between BMI-Z and PFI was analyzed.

RESULTS

The relationship between BMI-Z and PFI of male and female college students in China showed an inverted "U"-shaped curve. With comparable BMI, PFI change was greater in males than in females.

CONCLUSION

The relationship between BMI and PFI of Chinese college students is nonlinear. The physical fitness level of college students who are underweight or overweight and those with obesity is lower than that of normal-weight students.

The Association of Body Mass Index and Fat Mass with Health-Related Physical Fitness among Chinese Schoolchildren: A Study Using a Predictive Model

Body fat mass (FM) has advantages over body mass index (BMI) in terms of accuracy of fitness assessment and health monitoring. However, the relationship between FM and fitness in Chinese children has not yet been well studied. This study aimed to investigate the relationship between health-related physical fitness, BMI, and FM, which was estimated using a predictive model among elementary schoolchildren in China. This cross-sectional study included 2677 participants (boys, 53.6%; girls, 46.4%) who underwent anthropometric measurements (height, weight, BMI, and FM) and five health-related fitness tests: 50-m sprint (speed), sit and reach (flexibility), timed rope-skipping (coordination), timed sit-ups (muscular endurance), and 50-m × 8 shuttle run (endurance). In boys, BMI showed a positive correlation with speed (p < 0.001) and endurance (p < 0.006) tests and a negative correlation with flexibility (p < 0.004) and coordination (p < 0.001) tests. In girls, a positive correlation between speed (p < 0.001) and endurance (p < 0.036) tests was observed. Both BMI and FM (estimated using the predictive model) were strongly associated with the health-related physical fitness of elementary schoolchildren. Our findings indicate that health-related physical fitness was similarly affected by FM and BMI. As FM can be quantified, it could therefore be used to develop strategies and intervention programs for the prevention and management of obesity in children.

Changes in Anthropometric Measurements and Physical Fitness of Polish Students in 20-Year Period

BACKGROUND

Intergenerational changes are still being recorded worldwide, although their magnitude and direction may vary in different countries. The aim of this study was to determine changes in the magnitude and direction of changes in the body morphology and motor abilities of physically active adults over 20 years.

METHODS

Two hundred and fifty-two individuals aged 18-28 years volunteered to participate in the study. The changes were analyzed over a 20-year period (March 2001; P₁ vs. March 2022; P₂). The measured parameters were body height, weight, and body fat. Further, hand grip strength with dynamometer measurement, a sit-up test, a sit and reach test, and a standing long jump were performed to examine motor abilities. The results of the conducted tests were compared between subjects from both periods.

RESULTS

Our study confirms changes in trends concerning body morphology and motor ability performance. Higher values of body mass index and body fat were observed in P₂ women, whereas these differences were not significant in men. Additionally, in terms of physical performance, the P2 group noted worse results than their peers from the past.

CONCLUSION

Despite young adults claiming to have similar physical activity levels to those observed in the past, they demonstrate poorer physical performance and higher body fat levels. The observed changes can be considered negative.

The relationship between lower limb muscle volume and peak vertical jump power in children

BACKGROUND: Vertical jump is an index representing leg power. It is important to determine factors that influence the vertical jump to help athletes improve their leg power. OBJECTIVE: This study aimed to determine the relationship between lower limbs muscle volume and peak vertical jump (VJ) power in children for both sexes. METHODS: Fourty children healthy boys (n= 20) and girls (n= 20) aged 10 to 12 years old, randomly performed three VJ modalities: squat jump (SJ), counter movement jump without (CMJ) and with arm swings (CMJarms). Lower limbs muscle volume (MV) estimated using a standard anthropometric method. Peak power (PP) calculated by Sayers equation. RESULTS: significant correlations between MV and Peak vertical jump power showed for both sexes. Likewise, significant correlations were found between MV and body mass for boys (r= 0.66; p= 0.001) and for girls (r= 0.59; p= 0.006). CONCLUSIONS: The correlation observed between peak vertical jump power and MV in both sexes can be considered as estimation tool of the lower limbs muscle power. Lower limb’s muscle volume are determining factor in muscle power for both sexes.

Physical Fitness and Dietary Intake Improve Mental Health in Chinese Adolescence Aged 12-13

Background

Mental health has become a major public health issue worldwide. Biological and epidemiological studies have suggested that diet and physical fitness play a role in the prevention or cure of mental disorders. However, further research is required to elucidate the relationship between diet, physical fitness, and mental health. The study aims to provide a theoretical basis for promoting an adolescent healthy lifestyle and preventing mental problems by exploring the relationship between physical fitness, calcium intake, calorie intake, and adolescent mental health.

Methods

A cross-sectional study of a sample of adolescents (N = 253, 12-13 years) was conducted. The study involved adolescents from three middle schools in Central Jiangsu Province, including 136 boys and 117 girls. Weight, height, and body mass index were measured. Physical fitness was scored using the Chinese National Student Physical Fitness Standard. Diet data were collected using a weighed 7-day food diary to estimate energy intake and dietary calcium intake. The mental health status of the participants was assessed using the Chinese Middle School Student Mental Health Scale. A T-test and analysis of variance were used to analyze the differences of variables between different genders and body mass index, and Pearson correlation and stepwise multiple regression were used to explore the relationship between physical fitness, dietary intake, and mental health.

Results

The height (165.13 ± 8.07), weight (55.24 ± 13.00), and strength quality (64.93 ± 21.66) of boys are higher than those of girls (161.67 ± 6.44,48.99 ± 8.97, 58.40 ± 23.75, P < 0.05), and the flexibility quality (74.59 ± 14.75) of girls is higher than that of boys (68.30 ± 20.84) (P < 0.05). There were significant differences in the total scores of speed and physical fitness (F values were 4.02187.73, 3.07, 5.95, 10.33, and 9.52, respectively, P < 0.05). There was a significant positive correlation between calcium intake, cardiopulmonary fitness, and mental health (r = 0.276, P < 0.01; r = 0.159, P < 0.05). Calcium intake and cardiopulmonary fitness could explain 8.4% of the changes in the mental health of adolescents aged 12-13(ΔR2 = 0.084, P < 0.05).

Conclusion

Adequate calcium intake and the improvement of cardiopulmonary fitness in adolescents aged 12-13 are essential for the good development of their mental health. Future research in this field should examine the prospective associations between multiple measures of physical fitness composition and other nutrients ingested and mental health outcomes, as well as intervention studies that seek to provide evidence of causality.

ACTIVITIES OF DAILY LIVING AND PARTICIPATION LIMITATION IN ADOLESCENTS WITH OBESITY

Purpose: Childhood obesity is one of the most severe public health problems in recent years. We aimed to compare physical fitness and activities of daily living (ADL)-participation limitations in adolescents with obesity and peers without obesity and investigate whether the differences in these parameters are affected by gender in this study. Methods: Fifteen adolescents with obesity and 16 adolescents without obesity included in this cross-sectional study. Physical fitness was determined using the Munich Physical Fitness Test (MFT) and Modified Shuttle Walk test (MSWT). ADL were determined using the TGlittre-P test, quality of life and participation was assessed using the Pediatric Outcomes Data Collection Instrument (PODCI). Results: The MSWT distance, peak oxygen consumption, and MFT total score were decreased in adolescents with obesity regardless of gender (p

Are adolescents' physical activity and body-related factors associated with medically attended injuries?

BACKGROUND

Injuries are the major cause of disability and death during adolescence, representing a significant public health burden among youth. Body-related factors such as body composition and cardiovascular fitness (CVF) may affect adolescents' vulnerability to injuries. As evidence is lacking, we aimed to explore the associations of medically attended injuries with adolescents' physical activity (PA) and body-related factors, and whether these associations are modified by age, gender and family affluence.

METHODS

We used data on 888 11- to 15-year-old adolescents (mean age = 13.5, 56% boys) from the Health Behaviour in School-aged Children study conducted in 2018 in Slovakia. We used binary logistic regression analysis to assess the association of medically attended injuries with adolescents' PA and body-related factors (body composition, CVF), considering age, gender and family affluence.

RESULTS

Adolescents were more likely to report medically attended injuries if they were physically very active (odds ratio/confidence interval OR/CI:2.76/1.83-4.15) or active (OR/CI:1.91/1.27-2.87) rather than inactive. Body-related factors were not associated with medically attended injuries among adolescents. Moreover, age, gender and family affluence did not modify the association of medically attended injuries with adolescents' PA and body-related factors. The only exception was the modifying effect of gender: the association of medically attended injuries with being very active was stronger in boys (OR/CI: 3.04/1.32-6.99).

CONCLUSION

Very physically active adolescent boys are the most vulnerable group of adolescents in terms of injuries. PA promotion programmes should further consider gender-specific strategies aimed at preventing injuries.

Roles of age, sex, and weight status in the muscular fitness of Chinese Tibetan children and adolescents living at altitudes over 3600 m: A cross-sectional study

OBJECTIVE

This study aimed to assess the role of age, sex, and weight status in the development of muscular fitness in a large sample of Chinese Tibetan children and adolescents aged 7-18 years living in areas over 3600 m.

METHOD

A sample of 4673 Chinese Tibetan children and adolescents aged 7-18 years were recruited from 21 schools in three cities (Lhasa, Naqu, and Anduo) of Tibet, China. Grip strength, standing long jump, 30-s sit-ups, and 50-m dash were conducted to determine muscular fitness. Independent sample t tests were conducted to compare muscular fitness between boys and girls for each age group. The changes in mean scores on each muscular fitness test were estimated. The influence of weight status on muscular strength level was also estimated using one-way ANOVA and LSD tests. We also compared the average muscular fitness between Chinese Tibetan and Chinese average level.

RESULTS

The muscular fitness of Chinese Tibetan boys aged 7-18 years was higher than that of girls, with older children outperforming younger children. Among the Chinese Tibetan boys, those in the normal-weight group showed the best performance, whereas overweight group showed the best performance among the girls. The performance of Chinese Tibetan children and adolescents in standing long jump and 50-m dash was lower while that in sit-ups was higher than the performance of their Chinese counterparts.

CONCLUSION

Chinese Tibetan children and adolescents have relatively strong abdominal strength, but lower limb strength, which needs to be improved. Age, sex, and weight status should be considered when designing interventions to improve muscular fitness.

The Associations Between Physical Performance and Anthropometric Characteristics in Obese and Non-obese Schoolchild Handball Players

This study investigated the relationship of body fat and fitness measures in schoolchild handball players. Twenty-eight young male handball players from handball first youth league volunteered for the present investigation (age: 10.9 ± 0.72 years; body mass: 54.8 ± 22.9 kg; height: 1.48 ± 0.10 m; body fat: 27.6 ± 9.23%). Measures included the Yo-Yo Intermittent Recovery Test level 1 (Yo-Yo IR1), jumping ability [squat and counter-movement jumps (SJ, CMJ)], and sprint tests (10 m, 15 m). Anthropometry was assessed by body mass, body mass index (BMI), and fat percentage (%BF). The power of the upper limb was measured as the total distance thrown overhead using a 2 kg medicine ball. Intrarater reliability for all parameters showed a coefficient of variation (CV) below 10% and an intraclass correlation coefficient (ICC) above 0.75. All ICC were excellent (ICC ≥ 0.96). Reliability as shown by the CV differed between 1.0 (sprint 15 m) and 5.6 (sprint 10 m). With the exception of medicine ball throw, we found significant differences between non-obese and obese in all performance parameters. The differences ranged from η _p ² = 0.47 (sprint 10 m) to η _p ² = 0.09 (medicine ball throw). The two-step-linear regression analysis using the predictors body height and body weight (step 1) and body fat (step 2) showed a marked increase of explained variance by adding body fat. The largest r² changes were calculated for sprint 10 m (0.54), CMJ (0.49), and sprint 15 m (0.42). The lowest influence of the predictors was observed for medicine ball throw (step 1: r ² = 0.03, step 2: r ² = 0.07). With the exception of sprint parameters (β-coefficient sprint 10 m: -0.74; β-coefficient sprint 20: -0.66), a decrease of %BF leads to a higher performance in all parameters. %BF in youth handball players should be an important concern for practitioners working in this team sport in contrast to the frequently used BMI. It seems sensible and appropriate to engage very young children in physical activities such as team handball in order to improve their physical fitness. Decrease in% body fat could be considered both as a training and nutritional target to enhance and optimize sport performance-related outcomes.

The association of physical fitness with mental health in children: A serial multiple mediation model

There is growing interest in the association between physical fitness and mental health. This study aimed to extend current knowledge by investigating the potential mediating roles of resilience and anxiety in the association between physical fitness and mental health in children. A total of 269 children were selected by stratified random sampling from three primary schools in China. Physical fitness was scored using the Chinese National Student Physical Fitness Standard. Resilience, anxiety, and mental health data were collected using the following questionnaires: Resilience Scale for Chinese Adolescents, Multidimensional Anxiety Scale for Children, and the Mental Health Test. The PROCESS macro developed by Hayes was used to conduct serial multiple mediation analysis. We found that physical fitness, resilience, anxiety, and mental health were significantly correlated. Children with higher physical fitness had lower mental health problems; however, this statistical significance was not detectable after controlling for resilience and anxiety. Serial multiple mediation analysis revealed that the association of physical fitness with mental health was partially mediated by resilience and anxiety. These results indicate that the positive association of physical fitness with mental health in children may be changed through resilience and anxiety, which appear to play serial multiple mediating roles in this association. These findings contribute to deeper understanding of the associations between these factors and suggest that promoting physical fitness independent of considering resilience and anxiety may be insufficient to achieve good mental health in children.

The Relationship between Body Mass Index and Physical Fitness among Chinese University Students: Results of a Longitudinal Study

Over the past few decades, a gradual increase in sedentary lifestyles along with the increased consumption of a modern, hypercaloric diet has resulted in a substantial increase in the number of those classified as overweight or obese in China. The prevalence of overweight and obesity has become a key public health issue. However, it is important to be cautious when interpreting the literature as the majority of studies apply cross-sectional data to assess and subjectively compare the relationship between physical fitness and being overweight and obese. In the present study, longitudinal data were collected from 3066 students (enrolled in 2014) at a university in China at the beginning of each academic year throughout their four-year university program. The aim of this study was to analyze the various associations between BMI, explosive power, flexibility, and cardiorespiratory endurance, and a random-intercept panel model (RIPM) was separately employed on male and female participants to identify between- and within-person variations. In this way, the associations for between-person physical fitness and normal/overweight/obese weight ranges, and for within-person physical fitness and normal/overweight/obese weight ranges could be observed. The results of this study revealed that every physical fitness test chosen for evaluation (such as the standing long jump for explosive power or the distance run for cardiorespiratory endurance) was negatively related to the BMI results, irrespective of sex, with the notable exception of the flexibility results. In addition, this study showed that both males and females exhibited positively correlated results in both between-person BMI and flexibility as well as within-person BMI and flexibility. Furthermore, the relationships between and within persons of cardiorespiratory endurance, explosive power, and flexibility all showed positive correlations across both sexes. The dynamics between physical fitness and BMI identified in this study could prove useful to practitioners and researchers investigating such relationships in the future.

Association Between Physical Fitness and Anxiety in Children: A Moderated Mediation Model of Agility and Resilience

Background: Anxiety is one of the most prevalent mental health problems in children. Although physical fitness as a predictor of mental health, the mechanisms underlying any association between physical fitness and anxiety in children have been understudied. Thus, the aim of the present study was to determine whether an association exists between physical fitness and anxiety and to explore the roles of agility and resilience in such an association.

Methods: This cross-sectional study investigated 269 children aged 7 to 12 years from three public primary schools in Shanghai (China). Physical fitness and agility were objectively measured, and resilience and anxiety were assessed using self-reported questionnaires. The moderated mediation model was examined using the SPSS PROCESS macro, in which the moderator variable was agility, and the mediator variable was resilience.

Results: Physical fitness was inversely associated with anxiety. Resilience partially and indirectly mediated this association, and agility moderated the association between physical fitness and resilience. Physical fitness had a greater impact on resilience in children with higher agility levels.

Conclusions: Agility moderated the mediation of resilience on the indirect, inverse association between physical fitness and anxiety; thus, incorporating methods to develop agility and resilience may lead to better outcomes for physical fitness programs designed to prevent or alleviate anxiety in children.

The Association between Body Mass Index and Physical Fitness of Normal Weight/Overweight/Obese University Students

This study aimed to apply longitudinal data (in four waves) to examine relationships between body mass index (BMI), flexibility, muscular endurance, and explosive power, and employed a random-intercept panel model (RIPM) to divide the variations of different waves into between- and within-person variations. Furthermore, a multi-group model test was conducted to explore whether an interaction effect existed between sex and these relationships. The data were collected from a university in Taiwan between August 2009 and July 2010, and 3863 freshman and junior students were recruited. Results showed that the between- and within-person relationships between BMI and explosive power, and between BMI and muscular endurance, were negative (independent of sex). The negative between- and within-person associations between BMI and muscular endurance were both invariant with respect to sex. The negative between-person associations between BMI and explosive power were not equivalent for both sexes, yet the within-person associations between BMI and explosive power were equivalent for both sexes. The between-person associations between BMI and flexibility were positive for both sexes, but the within-person associations of these two variables were negative for both sexes. The invariance test confirmed that the positive associations of between-person BMI and between-person flexibility were invariant for both sexes, yet the negative associations of within-person BMI and within-person flexibility were not equivalent for both sexes. Between-and within-person correlations among explosive power, muscular endurance, and flexibility were significantly positive. Only the auto-regressions of BMI and muscular endurance were significant and equivalent for both sexes.

Relationship between body mass index and physical fitness in Italian prepubertal schoolchildren

The objective of this study was to investigate the association between physical fitness and body mass index categories (obesity, OB; overweight, OW; normal-weight, NW; and underweight, UW) in prepubertal children. Anthropometric and physical fitness characteristics were collected from a convenience sample of 30472 Italian schoolchildren (6–11 years old). Six field-based tests were used: Léger, agility shuttle, long jump, frontal throw of the basketball, Sit & Reach and standing balance. Significant differences were found in the anthropometric characteristics, physical fitness and weight status prevalence between girls and boys (p<0.05) and, except for flexibility, by age class (p<0.05). Obese children performed worse than their NW counterparts in aerobic capacity (p<0.001), agility (p<0.001), muscular power of the lower limb (p<0.001) and balance (p<0.001). Conversely, children with obesity showed greater upper limb power than NW children (p<0.001). The discrepancy in physical fitness between OB and NW children increased in older girls (flexibility, p = 0.002; muscular power of the lower and upper limb, p = 0.002 and p = 0.005) and boys (aerobic capacity, p = 0.009; agility, p = 0.006; standing balance, p = 0.019; muscular power of the lower and upper limb, p<0.001 and p = 0.011) compared to their younger counterparts. On the other hand, UW children performed worse than NW children mainly in terms of muscular power of the arms (p<0.001). Additionally, there was an increasing disparity in the frontal throw test scores of UW and NW girls (p = 0.003) and boys (p = 0.011) in older children compared to younger children. In conclusion, the effect of body mass index on children’s physical fitness intensifies with age. OB and OW negatively affect aerobic capacity, agility, lower limb power and balance but positively affect upper limb power. UW negatively affects upper limb power. This study underscores the importance of preventing childhood OW, OB, and UW in early life to promote children’s health and proper fitness development.

The association between BMI and health-related physical fitness among Chinese college students: a cross-sectional study

Background

Existing studies reporting on the levels of physical fitness among college students used relatively few fitness tests as a reflection of physical fitness, which could not comprehensively evaluate the levels of physical fitness. Thus, the current study aimed to investigate the cross-sectional relationship between body mass index (BMI) and a physical fitness index (PFI) based on six indicators of fitness in Chinese college students.

Method

Anthropometric measurements and six measures of physical fitness (Vital capacity, 50-m sprint, sit and reach, standing long jump, 800/1000-m run, pull-up/bent-leg sit-up) were measured. BMI was calculated to classify individuals into underweight, normal weight, overweight, and obesity groups. Z-scores based on sex-specific mean and standard deviation were calculated, and the sum of z-scores for the six fitness tests was used as a PFI. Three models (a linear regression model, polynomial regression model with a second-order BMI term and a restricted cubic spline regression model) were fitted to discuss the potential relation between BMI and PFI. We compared the models using Akaike Information Criterion (AIC) and R square.

Results

Totally, 8548 freshmen from the years 2014 to 2016 in a medical college completed the physical fitness tests. There was a decreasing trend of physical fitness index from the years 2014 to 2016 (P for trend < 0.01). More male than female students were overweight or obese (23.5% vs. 11.9%), but more female than male students were normal weight (74.7% vs. 64.8%). A restricted cubic spline regression model was superior to linear and polynomial regression model with lower AIC and higher R square.

Conclusions

The relationships between BMI and PFI in college students were non-linear. Underweight, overweight and obese students had poorer performance in physical fitness index than normal weight students. Future prospective, longitudinal cohort studies to identify the causal relations and potential mechanism in a good manner are required.

Cardiorespiratory Fitness Normative Values in Latin-American Adolescents: Role of Fatness Parameters

The aim of this study was to provide percentile values for a cardiorespiratory fitness (CRF) field test for Latin-American adolescents (34,461 girls and 38,044 boys) aged 13 to 15 years. The role of fatness parameters on the CRF level across age groups was also examined, with a focus on non-obese (healthy) and obese groups. CRF was assessed using the 20-meter shuttle run test protocol. Anthropometric parameters were measured using body mass index z-score (body mass index (BMI) z-score), BMI, waist circumference (WC), and waist-to-height ratio (WHtR). Participants were categorized according to the BMI z-score, WC, and WHtR international cut-off points as healthy and obese. Age- and sex-specific reference tables for the 3rd, 10th, 25th, 50th, 75th, 90th, and 97th centile scores were calculated using Cole’s lambda, mu, and sigma method. The prevalence of obesity according to the BMI z-score, WC, and WHtR was 9.6%, 11.2%, and 15.0%, respectively. Across all age and sex groups, a negative association was found between relative peak oxygen uptake (V˙O₂peak) and BMI, WC, and WHtR. In boys and girls there were higher levels of performance across all age groups, with most apparent gains between the ages of 13 and 14 years old. Overall, participants categorized in the healthy group had shown to have significantly higher V˙O₂peak than their obese counterparts (p < 0.001; Cohen’s d > 1.0). In conclusion, our study provides age- and sex-specific reference values for CRF (V˙O₂peak, mL·kg⁻¹·min⁻¹). The anthropometric parameters were inversely associated with CRF in all ages in both sexes. The obese group had worse CRF than their healthy counterparts independent of anthropometric parameters used to determine obesity.

Modified Shuttle Test Distance Correlates With Peak Oxygen Uptake in Children and Adolescents With Severe Therapy-Resistant Asthma

Introduction

Several tests may be used to assess exercise intolerance in severe therapy-resistant asthma (STRA), including the gold standard cardiopulmonary exercise test (CPET) and the modified shuttle test (MST).

Objective

To correlate the distance achieved in the MST with peak oxygen uptake (VO₂peak) and to compare the maximal heart rate (HRmax) obtained in both tests in children and adolescents with STRA.

Methods

This is a cross-sectional study, with 19 children and adolescents with STRA. Demographic, anthropometric, clinical data, and spirometric values were collected. CPET and the MST were performed in two consecutive visits. HRmax, pulse oxygen saturation, and dyspnea were compared between tests. The distance achieved in the MST was correlated with VO₂peak.

Results

Nineteen patients with a mean age of 11.5 ± 2.5 years were included. The mean HRmax (bpm) achieved was 180.8 ± 12.10 for the MST and 187.6 ± 9.35 for CPET, whereas the mean HRmax as a percentage of predicted (HRmax%) was 90.7 ± 6.5 for the MST and 93.8 ± 4.5 for CPET. A difference of only 6 bpm was found for HRmax (p = 0.10) and of 3% for HRmax% (p = 0.06) between tests. A strong correlation was found between the MST (r = 0.79; p = 0.001) and VO₂peak measured through CPET. However, there were no correlations between the MST and both body mass index (r = -0.14; p = 0.564) and forced expiratory volume in the first second - FEV₁ (r = -0.02; p = 0.917).

Conclusion

The results demonstrate that the MST distance strongly correlates with VO₂peak, measured through CPET, and the main physiological variable responses were similar between both tests. Our results provide additional data for the use of the MST to assess exercise capacity in children and adolescents with STRA.

Health-related physical fitness and weight status in 13- to 15-year-old Latino adolescents. A pooled analysis

OBJECTIVE

The aim of this study was to investigate the relation between health-related physical fitness and weight status in 13- to 15-year-old Latino adolescents.

METHOD

The final sample consisted of 73,561 adolescents aged 13-15 years (35,175 girls) from Chile (n=48,771) and Colombia (n=24,790). Cardiorespiratory and musculoskeletal fitness were measured using 20-m shuttle run (relative peak oxygen uptake - VO_2peak) and standing broad jump test (lower body explosive strength), respectively. The International Obesity Task Force definition was used to define weight status (i.e., underweight, normal weight, overweight, and obese).

RESULTS

The present study found an inverted J-shape relationship between body mass index, cardiorespiratory fitness, and musculoskeletal fitness in both genders and all age groups (p<0.01). Results also suggest that underweight adolescents, and not just overweight and obese adolescents, have lower odds of having a healthy cardiorespiratory fitness (based on new international criterion-referenced standards) profile when compared with their normal weight peers, except in girls aged 14 (p=0.268) and 15 years (p=0.280).

CONCLUSIONS

The present results indicate low cardiorespiratory fitness and musculoskeletal fitness levels in underweight, overweight, and obese adolescents when compared with their normal weight peers. The findings appear to suggest that exercise programs should to decrease fat mass in overweight/obese adolescents and increase muscle mass in underweight adolescents.

The Relationships Between Weight Status and Physical Fitness Among Chinese Children and Youth

PURPOSE

This study examined the prevalence of different weight status and the relationships between weight status and physical fitness among Chinese children and youth.

METHODS

Participants were 107,206 Grade 4 children and 70,213 Grade 8 youth from the China National Assessment of Educational Quality - Physical Education & Health in 2015 (CNAEQ-PEH 2015). Using World Health Organization (WHO) and US Centers for Disease Control and Prevention (CDC) criteria, weight status was divided into four groups (underweight, normal weight, overweight, and obese) according to Body Mass Index (BMI). The differences of physical fitness performances (15-m progressive aerobic cardiovascular endurance run [PACER], standing long jump, and 50-m sprint) among four weight status groups were compared. Data were analyzed using descriptive statistics, MANCOVA, and Cohen's d.

RESULTS

The prevalence of weight status varied by criteria (e.g., for Grade 4 boys, the prevalence of underweight by WHO and CDC were 5.9% and 10.5%; overweight were 14.5% and 11.4%, respectively). Compared with the normal weight group, the selected physical fitness performances in the overweight and obese groups were worse (p < .001) with small to large effect sizes.

CONCLUSION

The prevalence of underweight and overweight/obese was relatively high among Chinese children and youth. The prevalence of underweight, overweight, and obesity varied slightly depending on the criteria used for evaluating BMI. The overweight/obese participants tended to perform poorer in selected physical fitness tests. The performance disparities between the normal weight group and overweight/obese groups were larger in Grade 4 than in Grade 8 and among boys than among girls.

A Comparative Study of Fitness Levels among Norwegian Youth in 1988 and 2001

We compared the fitness levels of cohorts of 15-year-old youth in 1988 and 2001 to ascertain whether there was a negative trend in fitness. The subjects were 15-year-old boys and girls from the same geographical area, n = 192 in 1988 and n = 191 in 2001. They participated voluntarily and could leave the project whenever they wished. The following variables were used to assess fitness: Maximal oxygen uptake, jump height, shoulder flexibility, and hamstring flexibility. Maximal oxygen uptake was estimated with submaximal ergometer cycling, jump height by the Sargent jump-and-reach test, shoulder flexibility as the distance between thumbs when doing straight-arm backwards circling while holding a broomstick, and hamstring flexibility by an active straight-leg-raise test. Differences between groups and quartiles were analyzed by Gosset’s (Student’s) t-test, using a significance level of 0.05. The two cohorts did show different levels of physical fitness. The 1988 group was 3.9 cm better on jump height and 4.2 cm better on shoulder flexibility, while the 2001 group had 3.3° better hamstring flexibility. The lowest performing quartile did less well in 2001 on oxygen uptake and jump height. We recommend an increased focus on improving fitness in low-performing adolescents.

Exercise Capacity Assessment by the Modified Shuttle Walk Test and its Correlation with Biochemical Parameters in Obese Children and Adolescents

OBJECTIVES

To evaluate exercise capacity of obese children and adolescents compared with normal-weight individuals and to investigate possible correlations with blood biochemical parameters.

METHODS

In this study, children and adolescents between 6 and 18 y were included and divided into control (eutrophic) and obese groups according to body mass index (BMI). Data were collected regarding demographic, anthropometric, waist circumference and exercise capacity through the Modified Shuttle Walk Test (MSWT). In the obese group, biochemical parameters in the blood (total cholesterol, HDL, LDL, triglycerides and glucose) were evaluated, and a physical activity questionnaire was applied.

RESULTS

Seventy seven participants were included; 27 in the control group and 50 obese. There was no significant difference between the two groups regarding sample characteristics, except for body weight, BMI and waist circumference. Most obese children presented results of biochemical tests within the desirable limit, though none were considered active. There was a significant exercise capacity reduction (p < 0.001) in the obese group compared to control subjects. Positive correlations were identified for the MSWT with age and height, and a negative correlation with BMI. However, there were no correlations with the biochemical parameters analyzed.

CONCLUSIONS

Obese children and adolescents have reduced exercise capacity when compared to normal individuals. The MSWT performance seems to have a negative association with BMI, but is not correlated with blood biochemical parameters.

The Effect of Body Mass Index on Acute Cardiometabolic Responses to Graded Exercise Testing in Children: A Narrative Review

Although the beneficial role of exercise for health is widely recognized, it is not clear to what extent the acute physiological responses (e.g., heart rate (HR) and oxygen uptake (VO₂)) to a graded exercise test are influenced by nutritional status (i.e., overweight vs. normal-weight). Therefore, the main objectives of the present narrative review were to examine the effect of nutritional status on acute HR, and VO₂ responses of children to exercise testing. For this purpose, we examined existing literature using PubMed, ISI, Scopus, and Google Scholar search engines. Compared with their normal-body mass index (BMI) peers, a trend of higher HRrest, higher HR during submaximal exercise testing, and lower HRmax was observed among overweight and obese children (according to BMI). Independent from exercise mode (walking, running, cycling, or stepping), exercise testing was metabolically more demanding (i.e., higher VO₂) for obese and overweight children than for their normal-weight peers. Considering these cardiometabolic differences according to BMI in children might help exercise specialists to evaluate the outcome of a graded exercise test (GXT) (e.g., VO2max, HRmax) and to prescribe optimal exercise intensity in the context of development of exercise programs for the management of body mass.

Body mass index and motor coordination: Non-linear relationships in children 6-10 years

BACKGROUND

Given the concern for health-related consequences of an elevated body mass index (BMI; obesity), the potential consequences of a low BMI in children are often overlooked. The purpose was to evaluate the relationship between the BMI across its entire spectrum and motor coordination (MC) in children 6-10 years.

METHODS

Height, weight, and MC (Körperkoordinationstest für Kinder, KTK test battery) were measured in 1,912 boys and 1,826 girls of 6-10 years of age. BMI (kg/m² ) was calculated. KTK scores for each of the four tests were also converted to a motor quotient (MQ). One-way ANOVA was used to test differences in the BMI, individual test items, and MQ among boys and girls within age groups. Sex-specific quadratic regressions of individual KTK items and the MQ on the BMI were calculated. Girls and boys were also classified into four weight status groups using International Obesity Task Force criteria: thin, normal, overweight, and obese. Differences in specific test items and MQ between weight status groups were evaluated by age group in each sex.

RESULTS

Thirty-one percent of the sample was overweight or obese, whereas 5% was thin. On average, normal weight children had the highest MQ in both sexes across the age range with few exceptions. Overweight/obese children had a lower MQ than normal weight and thin children. The quadratic regression lines generally presented an inverted parabolic relationship between the BMI and MC and suggested a decrease in MC with an increase in the BMI.

CONCLUSION

In general, BMI shows a curvilinear, inverted parabolic relationship with MC in children 6-10 years.

FTO POLYMORPHISM AND PHYSICAL FITNESS IN OBESE SCHOOLCHILDREN AFTER AN INTERVENTION PROGRAM

ABSTRACT Introduction: Recent studies have shown that the association of FTO rs9939609 gene polymorphism with obesity depends on the level of the individual’s physical activity. However, there are some studies that evaluated physical fitness, health, and motor performance in relation to the rs9939609 FTO gene polymorphism. Objective: To evaluate how the rs9939609 FTO gene polymorphism affects the results of physical fitness tests related to health and athletic performance in schoolchildren after 4 months of intervention of physical exercise. Method: The rs9939609 FTO gene polymorphism was genotyped in a total of 36 schoolchildren from southern Brazil, aged 8 to 16 years. Body mass index (BMI), health-related physical fitness (cardiorespiratory fitness, abdominal strength/endurance, and flexibility) and motor performance (upper and lower limb strength, agility, and speed) were evaluated. The intervention included exercise strategies based on Physical Education, healthy eating, and oral and postural care. Results: In the experimental group, after the intervention, significant differences were noted in individuals with the TT genotype. These individuals showed improvements in abdominal strength (p=0.025), lower limb strength (p=0.037) and agility (p=0.021). For individuals with the AA/AT genotype, improvements in flexibility (p=0.026), abdominal strength (p=0.002), upper limb strength (p=0.008) and lower limb strength (p=0.001) were observed. However, these differences were not statistically significant when comparing the TT and AT/AA genotypes. Conclusions: The experimental group showed improvements in abdominal strength, lower limb strength, and speed. Yet, individuals with different genotypes (AA/AT and TT) for polymorphism rs9939609 exhibited similar values for indicators of physical fitness, health, and motor performance. Level of Evidence II; Lesser quality RCT.

Longitudinal Changes in AbsoluteVO2peak, Physical Activity Level, Body Mass Index, and Overweightedness among Adolescents in Vocational and Non-Vocational Studies

The purpose of the study was to examine differences in physical activity level, physical fitness, body mass index, and overweight among adolescents in vocational and non-vocational studies, at the age of 14, 16, and 19, using a 5-year longitudinal design. Students in sport studies had the highest absoluteVO2peak and higher physical activity levels, than students in vocational subjects and students with a specialization in general studies. However, there were no significant differences between students in vocational subjects and students with a specialization in general studies according to absoluteVO2peak and physical activity levels. Students in vocational subjects were significantly more overweight/obese at 19 years of age, compared with the other students. Our findings support previous research pointing to overweightedness as being more widespread among adolescents in vocational programs than in non-vocational programs. However, differences in the physical activity level and physical fitness do not seem to explain these differences.

Changes in physical fitness of a home-based physical exercise program in childhood obesity: A quasi-experimental uncontrolled study

Few studies have evaluated the changes in physical fitness (PF) of obese children and adolescents of a physical activity program for the treatment of obesity, and even fewer have explored the modality of home-based physical exercise. The objective of this study is to evaluate the changes in PF and body composition (BC) of a home-based physical exercise for treating childhood obesity. Thirty-three overweight/obese children and adolescents participated for six months in a home-based intervention that combined aerobics and muscular strength exercises. The results were compared, before and after the intervention, for the different PF components (VO2_max, abdominal muscle resistance strength, and lower body explosive strength) and BC (body mass index Z-score (BMI-Z), percentage of body fat, and fat-free mass) variables. A significant reduction was observed in the percentage of body fat (4.7%) and the BMI- Z score (.23), and there was an increase in the fat-free mass of 2.9 kg ( p < .001). In addition, the VO2_max showed a significant increase ( p < .05). The results of the different strength tests also showed significant improvements ( p < .05). Our findings support the effectiveness of this program improving not only BC but also PF. However, our results should be interpreted with caution due to lack of control group.

Vertical Jump and Leg Power Normative Data for Colombian Schoolchildren Aged 9-17.9 Years: The FUPRECOL Study

Ramírez-Vélez, R, Correa-Bautista, JE, Lobelo, F, Cadore, EL, Alonso-Martinez, AM, and Izquierdo, M. Vertical jump and leg power normative data for Colombian schoolchildren aged 9-17.9 years: the FUPRECOL study. J Strength Cond Res 31(4): 990-998, 2017-The aims of the present study were to generate normative vertical jump height and predicted peak power (Ppeak) data for 9- to 17.9-year-olds and to investigate between-sex and age group differences in these measures. This was a cross-sectional study of 7,614 healthy schoolchildren (boys n = 3,258 and girls n = 4,356, mean [SD] age 12.8 [2.3] years). Each participant performed 2 countermovement jumps; jump height was calculated using a Takei 5414 Jump-DF Digital Vertical (Takei Scientific Instruments Co., Ltd.). The highest jump was used for analysis and in the calculation of predicted Ppeak. Centile smoothed curves, percentiles, and tables for the 3rd, 10th, 25th, 50th, 75th, 90th, and 97th percentiles were calculated using Cole's LMS (L [curve Box-Cox], M [curve median], and S [curve coefficient of variation]) method. The 2-way analysis of variance tests showed that maximum jump height (in centimeters) and predicted Ppeak (in watts) were higher in boys than in girls (p < 0.01). Post hoc analyses within sexes showed yearly increases in jump height and Ppeak in all ages. In boys, the maximum jump height and predicted Ppeak 50th percentile ranged from 24.0 to 38.0 cm and from 845.5 to 3061.6 W, respectively. In girls, the 50th percentile for jump height ranged from 22.3 to 27.0 cm, and the predicted Ppeak was 710.1-2036.4 W. For girls, jump height increased yearly from 9 to 17.9 years old. Our results provide, for the first time, sex- and age-specific vertical jump height and predicted Ppeak reference standards for Colombian schoolchildren aged 9-17.9 years.

Reference values for running sprint field tests in preschool children: A population-based study

The purpose of this study was to determine reference values in the 20m sprint test for Spanish preschool children and to examine the influence of age, sex and anthropometrics characteristics in sprint performance. A cross-sectional study was used. A total of 3076 children, aged 3 to 6 years, participated in this study (1539 girls and 1537 boys). To measure running speed, the 20m sprint test was used. In the analysis of reliability, using test-retest with 89 children (48% boys), the following descriptive results were obtained (mean, SD): at pretest=5.72±0.98s, at retest=5.71±0.87s (p=0.819), and an intraclass correlation coefficient=0.929 (95% confidence interval 0.891-0.954). Boys are faster than girls at 3 to 5 years old, but no significant differences were found at 6 years old. In relation to age, the sprint time was shorter as kids got older. This study provides reference values for running speed assessment through a 20m sprint test carried out on a large sample of Spanish preschoolers.

Performance and reproducibility on shuttle run test between obese and non-obese children: a cross-sectional study

BACKGROUND

Due to the increasing prevalence of obesity among children, Shuttle Run Test (SRT) has been used as primary outcome for assessment of both physical performance and responses to different physical training programs. Thus, this study aimed to compare the performance on SRT between obese and non-obese children and the reproducibility of two SRTs carried out on different days.

METHODS

A cross-sectional study in which 40 children, aged from 8 to 10, were recruited from a public school. This study consisted of three visits in each school. On the first visit, we carried out a medical screening for recruited children. On the second visit, we applied the first SRT (SRT1), which was repeated on the third visit (SRT2, 24 hours apart).

RESULTS

There was a significant difference in the distance traveled by non-obese in comparison with obese children (mean difference: 88 meters and 95% of confidence interval: 21 meters to 156 meters). Time and distance traveled of 27 children were higher in the SRT1, whereas nine children traveled a greater distance and presented higher testing time on the SRT2, with only four children showing the same distance traveled in both tests. Although both groups presented with reduction from the SRT1 to SRT2, this reduction was not significant (non-obese: 342 ± 97 meters to 319 ± 106 meters, respectively; obese: 269 ± 91 meters to 246 ± 90 meters, respectively). In obese children, the distance traveled in the best SRT had correlation with weight (r = -0.495, p = 0.043) and BMI (r = - 0.602, p = 0.011). No correlation was observed in the non-obese children.

CONCLUSIONS

Overweight children had lower performance in SRT. Although reproducible, the best performance was in the first test, which leads us to suggest applying only one test.

Association between Body Composition and Sport Injury in Canadian Adolescents

Purpose: To examine the association between overweight or obesity and sport injury in a population-based sample of Canadian adolescents. Methods: Cross-sectional analyses were performed using the Canadian Community Health Survey (2009-2010), a nationally representative sample (n=12,407) of adolescents aged 12-19 years. Body composition was quantified using BMI, grouping participants into healthy weight, overweight, or obese. The outcome of interest was acute or repetitive strain injury sustained during sport in the previous year. We examined the relationship between sport injury and overweight or obesity compared with healthy weight using multivariate logistic regression, controlling for sex, ethnicity, physical activity, and socio-economic status. We also examined the interaction between physical activity and body composition in a secondary analysis with a subset of active adolescents. Results: No significant relationship was found between being overweight and sport injury (odds ratio [OR]=1.04, 95% CI: 0.92, 1.17); however, a protective effect was seen between obesity and sport injury (OR=0.67, 95% CI: 0.53, 0.84). Secondary analysis revealed that overweight youths with the highest activity level (quartile 4) did have increased odds of sport injury (OR=1.38, 95% CI: 1.04, 1.83), yet obese youths with a moderate activity level (quartile 2) were protected compared with healthy-weight youths (OR=0.46, 95% CI: 0.24, 0.91). Conclusions: Further examination of active adolescents is warranted. Studies should consider sport-specific differences and comprehensive measurement of exposure to sport.

Reliability of Sargent Jump Test in 4- to 5-Year-Old Children

We assessed the test-retest reliability of the Sargent jump (VJ) for vertical jumping performed by 4 and 5 years old pre-schoolers. The VJ was administered three times (familiarization, test, and retest) to 163 children (mean age: 4.48 ± 0.5 years; 55.8% girls). The results were compared with those obtained in the standing long jump (SLJ) and in the 25 -m dash test to identify how its performance correlated with other measures of leg power. Systematic change in the mean and retest correlations with these other measures were used to help analyze VJ test-retest reliability. Additionally, Pearson correlation coefficients were used to examine the degree of association between the test and retest trials of the VJ. The VJ showed a higher correlation and agreement in the 4-year-old, compared with the 5-year old, group (r_c = 0.956 vs. 0.796; α = 0.95 vs. 0.84; ICC: 0.828; 95% CI: 0.730-0.891 vs 0.739; 95% CI: 0.589-0.834). Effect sizes were small ( d ≤ 0.285) for all the VJ tests performed. Fair to poor significant relationships were established between the VJ (test), VJ (retest), and the SLJ. No significant association was observed between the VJ and the 25 -m dash tests. Our findings suggest that the Sargent jump test is reliable when executed by 4- and 5-year-olds. The lack of a strong association with other measures of leg power should be taken into account at the time of selecting the most appropriate test to assess this strength dimension.

International variability in 20 m shuttle run performance in children and youth: who are the fittest from a 50-country comparison? A systematic literature review with pooling of aggregate results

OBJECTIVES

To describe and compare 20 m shuttle run test (20mSRT) performance among children and youth across 50 countries; to explore broad socioeconomic indicators that correlate with 20mSRT performance in children and youth across countries and to evaluate the utility of the 20mSRT as an international population health indicator for children and youth.

METHODS

A systematic review was undertaken to identify papers that explicitly reported descriptive 20mSRT (with 1-min stages) data on apparently healthy 9-17 year-olds. Descriptive data were standardised to running speed (km/h) at the last completed stage. Country-specific 20mSRT performance indices were calculated as population-weighted mean z-scores relative to all children of the same age and sex from all countries. Countries were categorised into developed and developing groups based on the Human Development Index, and a correlational analysis was performed to describe the association between country-specific performance indices and broad socioeconomic indicators using Spearman's rank correlation coefficient.

RESULTS

Performance indices were calculated for 50 countries using collated data on 1 142 026 children and youth aged 9-17 years. The best performing countries were from Africa and Central-Northern Europe. Countries from South America were consistently among the worst performing countries. Country-specific income inequality (Gini index) was a strong negative correlate of the performance index across all 50 countries.

CONCLUSIONS

The pattern of variability in the performance index broadly supports the theory of a physical activity transition and income inequality as the strongest structural determinant of health in children and youth. This simple and cost-effective assessment would be a powerful tool for international population health surveillance.

[Physical fitness levels in French adolescents: The BOUGE program]

BACKGROUND

A high level of physical fitness is associated with cardiovascular health in adolescents. The aims of this study were to assess the levels of physical fitness of French adolescents and to determine the prevalence of these adolescents below the minimum level of cardiorespiratory fitness needed to guarantee future favorable cardiovascular profile.

METHODS

Participants were 12,082 French children and adolescents (5975 boys, 6107 girls) aged to 9 from 16 years. Cardiorespiratory fitness, muscular endurance, speed, flexibility and speed agility were tested. The associations of physical fitness measures with adolescent's characteristics were analyzed using Student t test, one-way ANOVA, or Pearson correlations as appropriate.

RESULTS

Boys were physically fitter than girls, expected for flexibility (P<0.0001). Subjects of normal weight adolescents had significantly better results than overweight or obese adolescents (P<0.05 for all comparisons), but also in comparison with underweight adolescents for muscular endurance, flexibility, cardiorespiratory fitness test (P<0.05). Our findings indicate that, on the basis of cardiorespiratory fitness, 16% of French boys and 7.7% of French girls have a risk of future cardiovascular disease (P<0.0001). This subgroup also performed poorly in all other tests of physical fitness used (P<0.0001). Aerobic fitness decreased significantly with the age (r=-0.168 for boys; r=-0.261 for girls).

CONCLUSIONS

Our results indicate that the physical fitness of French adolescents must be improved to help protect against cardiovascular disease in adulthood, especially in boys. The study showed also a dramatically decrease of the cardiorespiratory fitness during the adolescence period. Developing and introducing a health promotion curriculum in the French schools is suggested to improve health and physical fitness.