Differences in Physical Fitness and Body Composition Between Active and Sedentary Adolescents: A Systematic Review and Meta-Analysis

Adolescents' Assessment of Several Step Tracker Mobile Applications Based on Their Previous Level of Physical Activity

Background: Adolescents' use of step tracker mobile applications (apps) could be influenced by their assessment of the mobile app used. Objectives: To analyze differences in the dropout rate, app assessment, and problematic mobile phone use based on prior physical activity levels and the app used. Methods: A study with a quasi-experimental design was carried out with the participation of 240 adolescents, who were further categorized as either active or inactive. The adolescents carried out a 10-week intervention promoted as a part of the physical education curriculum, three days a week, in which they randomly used the Pokémon Go, MapMyWalk, Pacer, or Strava mobile apps after school for cardiorespiratory training. Results: The results showed a higher dropout rate from Pokémon Go in the group of inactive adolescents (p = 0.012). No differences were found in the assessment of apps based on the level of activity of the adolescents, neither overall nor when analyzing this question based on the app used (p > 0.05). As for problematic mobile phone use, only previously inactive adolescents assigned to the Pacer group significantly increased their final score after the intervention (p = 0.044), with no changes being identified in the other groups or apps (p > 0.05). Furthermore, the active adolescents showed a positive relationship between the volume of training and problematic mobile phone use (p = 0.023), specifically with the conflicting use of this device (p = 0.017). Conclusions: The inactive adolescents had a higher dropout rate when using Pokémon Go. There were no differences in app assessment between the active and the inactive participants. However, the active adolescents showed a link between their training volume and problematic mobile phone use.

Differences in Contractile Characteristics Among Various Muscle Groups in Youth Elite Female Team Handball Players Compared to a Control Group

Muscular strength and explosiveness are generally known as factors that affect physical performance. Physical ability modeling has a profound connection with long-term athlete development and talent identification. The purpose of the current study was to investigate differences in contractile characteristics (maximal isometric force and maximal rate of force development) among various muscle groups in youth elite female team handball players (n = 35, 16.6 ± 1.1 years) compared to a control group (n = 28, 16.7 ± 1.1 years). The following tests were performed: isometric non-dominant hand grip, isometric dominant hand grip, isometric deadlift, isometric standing leg extension, and isometric bilateral ankle extension. For each subject, the maximal isometric force and maximal rate of force development were derived from the isometric strength tests. The research analyzed a total of twenty-four variables, presented in both absolute and relative values. Statistical analysis revealed significant differences among all pairs of variables in the absolute values of maximal isometric force (Λ = 0.531, F = 10.07, p = 0.000) and maximal rate of force development (Λ = 0.692, F = 5.08, p = 0.001) between the two groups. The most significant difference was found in the grip of the dominant hand, where the impact of the difference was 43.6% and 37.0% for the absolute values of force and explosiveness. Conversely, no differences were observed between the pairs of variables representing the relative values across the two subject groups, except for the dominant hand grip relative force (p = 0.006). The results provide information about the contractile potentials of important muscle groups in the game of handball, which could help in adapting strength training according to the specifics of the strength and explosivity development of young female handball players.

Comparative effectiveness of school-based obesity prevention programs for children and adolescents: a systematic review and network meta-analysis

Introduction

While many randomized controlled trials (RCTs) have demonstrated the positive effects of school-based programs in reducing body fat among children and teenagers, there is no conclusive evidence to indicate that one approach is superior to another, largely due to the lack of direct and indirect comparisons. This study evaluated the relative effectiveness of various school-based obesity prevention initiatives in improving body mass index (BMI) among children and adolescents using network meta-analysis.

Methods

Searches included four databases focusing on articles published in English between the years 2002 and 2024. The primary outcomes were the BMI and BMI z-scores (BMIz) (kg/m2). The mean differences (MDs) for each outcome were calculated before and after treatment. The current systematic review synthesized 53 RCTs with a sample of 68,489 children and adolescents.

Results

The results illustrated that the physical activity (PA) only arm was the most effective intervention in improving BMI (MD: -0.42, 95% credible interval (Crl) -0.79, -0.07; p = 0.02), while the multiple-component intervention was the most effective in improving BMIz (MD: -0.08, 95% Crl: -0.16, -0.01; p = 0.03). Inversely, PA and another component arm were the least effective interventions in improving BMI (MD: 0.64, 95% Crl: -0.23, 1.53; p = 0.15). In addition, diet and nutrition only arm was the least effective intervention in improving BMIz (MD: 0.09, 95% Crl: -0.11, 0.28; p = 0.36).

Discussion

In conclusion, both PA-only and multiple-component arms are effective intervention tools/strategies for reducing BMI-related outcomes. However, further large-scale, well-designed studies are needed to investigate the elements of multiple-component arms.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/ identifier CRD42021234742.

Differences in physical activity, sedentary time, and anthropometric variables among children and adolescents: The TUBON project

BACKGROUND

Although physical inactivity may lead to increasing obesity prevalence, research on anthropometric variables changes based on physical activity (PA) in children and adolescents is limited. PA decreases with age, while sedentary behavior increases. The study aimed to examine differences in objectively measured sedentary time, light-intensity physical activity (LPA), and moderate-to-vigorous intensity physical activity (MVPA) between children and adolescents, and the differences in the percentiles of anthropometric variables between physically active and inactive groups according to World Health Organization PA recommendations.

METHODS

A total of 759 participants aged 6-17 years (boys, n=358; girls, n=401) were included in the study. The ActiGraph wGT3x-BT accelerometer was used to measure sedentary time, LPA, and MVPA. Height, weight, waist circumference (WC), triceps skinfold thickness (T-SFT), and medial-calf skinfold thickness (M-SFT) were measured. Body fat percentage (BF%) and body mass index (BMI) were calculated, and the percentiles of anthropometric variables were categorized.

RESULTS

The findings showed that children had less sedentary time and a higher LPA than adolescents for both genders (p<0.05). Children had a higher MVPA than adolescents in girls (p<0.05), but the difference was insignificant in boys (p>0.05). In boys, physically active children were in lower percentiles for T-SFT and BF% than those who did not (p<0.05). In boys, adolescents who were physically inactive were in higher percentiles for BMI, T-SFT, M-SFT, and BF% (p<0.05). In addition, in girls, adolescents who were physically active were in lower percentiles of BMI, M-SFT, and BF%, whereas children who were physically active were in lower percentiles of M-SFT and BF% (p<0.05).

CONCLUSION

Sedentary time increases while PA decreases with age. Children and adolescents who met the WHO PA recommendation had lower percentiles of anthropometric variables, indicating the importance of PA in preventing obesity in these age groups.

Genetic Regulation of Physical Fitness in Children: A Twin Study of 15 Tests from Eurofit and Fitnessgram Test Batteries

PURPOSE

This study aimed to analyze the shared genetic background of physical fitness tests in children.

METHODS

Physical fitness was assessed in 198 Portuguese twin pairs (6-18 yr old, 40% monozygotic) through 15 tests from the Eurofit and Fitnessgram test batteries. Genetic twin modeling was used to estimate the heritability of each test and the genetic correlations between them.

RESULTS

Girls performed better than boys in flexibility, whereas boys performed better than girls in cardiorespiratory endurance and muscular strength. No sex differences were found in the influence of genetic factors on the physical fitness tests or their mutual correlations. Genetic factors explained 52% (standing long jump) to 79% (sit and reach) of the individual variation in motor performance, whereas individual-specific environmental factors explained the remaining variation. Most of the tests showed modest to moderate genetic correlations. Out of all 105 genetic correlations, 65% ranged from 0.2 to 0.6 indicating that they shared from 4% to 36% of genetic variation. The correlations between individual-specific environmental factors were mostly negligible.

CONCLUSIONS

Tests measuring the strength of different muscle groups showed only modest correlations, but moderate correlations were found between tests measuring explosive strength, running speed/agility, and cardiorespiratory endurance. Genetic factors explained a major portion of the variation in tests included in the Eurofit and Fitnessgram test batteries and explained the correlations between them. The modest to moderate genetic correlations indicated that there is little redundancy of tests in either Eurofit or Fitnessgram test batteries.

The influence of physical activity, adherence to Mediterranean diet, and weight status on the psychological well-being of adolescents

The mental health of adolescents is a determining factor for their adequate development, but is influenced by factors such as physical activity, nutrition, gender, and weight status. However, previous research has not analysed differences in psychological status, mainly in basic psychological needs and life satisfaction, among male and female adolescents with different levels of physical activity, weight status and adherence to the Mediterranean diet (AMD). For this reason, the objectives of the present investigation were to establish whether the differences between active and inactive adolescents in basic psychological needs and life satisfaction depend on gender; and to determine the differences in basic psychological needs and life satisfaction of active and inactive adolescents with different weight status and AMD. A total of 791 adolescents aged between twelve and sixteen years old participated in the study. All the participants were measured for basic psychological needs, life satisfaction, and level of physical activity, AMD, and height and body mass. The results showed a higher score in basic psychological needs and life satisfaction for active adolescents in both the males' and females' groups. No differences were found in the psychological variables when comparing adolescents with different weight status. Adolescents with a higher AMD showed higher scores in satisfaction of basic psychological needs and satisfaction with life than adolescents with a worse AMD. Therefore, it can be concluded that the level of physical activity and AMD are factors to be considered for the mental health of adolescents, but the relevance of weight status will have to be confirmed in future research.

Are physical activity and/or adherence to the Mediterranean diet determinants of the changes found in kinanthropometric variables, body composition and physical fitness in adolescents?

The practice of physical activity and adherence to the Mediterranean diet (AMD) have been extensively studied for their relationship with kinanthropometric, body composition and physical fitness variables. However, no previous study has analyzed whether these healthy habits are equally determinant for the differences found in kinanthropometric, body composition and physical fitness variables or, on the contrary, if one of them is more relevant. For this reason, the objectives of the present study were: (1) to analyze the differences in kinanthropometric, body composition, and physical fitness variables between adolescents with different levels of physical activity and AMD, and (2) to determine whether physical activity and/or AMD are predictors of differences in kinanthropometric variables, body composition or physical fitness in adolescents. The sample consisted of 791 adolescents (404 males and 387 females; mean age: 14.39±1.26 year-old) whose physical activity level, AMD, kinanthropometric variables, body composition and physical fitness, were measured. The results showed differences when considering the level of physical activity in kinanthropometric variables, body composition and physical fitness, but not the level of AMD, which was relevant only when it was poor, and the adolescents were inactive. Nevertheless, the AMD did not seem to exert such a determining effect as to produce significant differences on its own. On the other hand, the practice of physical activity did act as a predictor mainly of changes in the fitness variables. Therefore, the main novelty of the present study is the establishment of an order of importance of the healthy habits acquired by adolescents, concluding that the practice of physical activity is more determinant for the differences found in the study variables.

Body mass composition analysis as a predictor of overweight and obesity in children and adolescents

INTRODUCTION

Body mass composition is directly related to health and its disorders are correlated with diseases such as obesity, diabetes, osteoporosis and sarcopenia. The purpose of this study was to analyze body mass composition among traditional elementary school students and ballet school students.

METHODS

A total of 340 students participated in the study, 95 of whom attended ballet school and 245 elementary school students. A Tanita BC-418 MA analyzer was used to analyze body mass composition. Such body composition indices as BMI (Body Mass Index), muscle mass, fat mass, lean body mass and water content were evaluated.

RESULTS

The results show statistical significance for BMI between high school ballet students and elementary school ballet students, as well between high school ballet students and elementary school students. Comparisons in relation to gender and schools BMI, statistical significance was obtained for: BHSw (ballet high school women) and EBSw (elementary ballet school women), BHSw and ESw (elementary school women), BHSm (ballet high school men) and EBSm (elementary ballet school men), and between BHSm and ESw. Comparing muscle mass index (kg) between ballet high school and elementary school, between ballet high school and elementary school, and between ballet high school and elementary school - statistical significance was obtained for all comparisons. Analyzing in pairwise comparisons by gender and school achieved a statistically significant difference for: BHSw and EBSw, BHSm and EBSw, EBSw and ESm. Comparing the fat mass index (kg), no significant differences were observed between the analyzed schools and the school and gender of the children studied. The value of the lean body mass index differed significantly between groups by school and gender. Comparing the water content index, statistically significant differences were obtained for school and gender.

DISCUSSION

The body mass composition of ballet school students differs from that of standard school students.

Mediation effects of lean mass and fat mass on the relationship between body mass index and handgrip strength

OBJECTIVE

This study aimed to assess the mediation effects of lean mass and fat mass on the relationship between body mass index (BMI) and handgrip strength (HGS) in adolescents.

METHOD

The sample included 118 adolescents (60 girls) aged 10-14 years. Body composition, determined from lean mass (LM) and fat mass (FM), was measured by dual-energy x-ray absorptiometry. HGS was measured using a digital dynamometer. Moderate-to-vigorous physical activity and sexual maturation, treated as covariates, were evaluated by accelerometry and pubic hair development, respectively. Spearman correlation and simple mediation analysis were used for statistical analysis.

RESULTS

A positive relationship was observed between BMI and HGS (rho = .364, p < .001), BMI and LM (rho = .466, p < .001), LM and HGS (rho = .784, p < .001), BMI and FM (rho = .907, p < .001), and FM and HGS (rho = .291, p = .001). LM was the only significant mediator of the relationship between BMI and HGS.

CONCLUSION

Only LM mediated the association between BMI and HGS, almost entirely explaining the relationship. The findings reinforce the need to include LM measurements in routine strength testing. Furthermore, strategies focused on LM development may be promising in preventing low muscle strength in adolescents.

Importance of training volume through the use of step trackers apps promoted from the subject of physical education to change body composition, physical fitness and physical activity in adolescents and the influence of gender✰,✰✰

The aim of the present study was to determine the changes in physical activity level (PA), kinanthropometric and derived variables, and physical fitness in adolescents, as a result of an out-of-school intervention with mobile step tracker apps promoted from the field of physical education, according to the volume of training completed and gender. A randomized controlled trial was carried out with 400 adolescents (210 males and 190 females) aged 12 to 16 years old (mean age: 13.96 ± 1.21 years-old). Adolescents were divided into experimental group (EG) (n = 240) and control group (CG) (n = 160). Two measurements were carried out, separated by a 10-week intervention, and PA, kinanthropometric variables and physical condition were measured. During the intervention, EG must use Strava (n = 74); Pokémon Go (n = 59); Pacer (n = 60); and MapMyWalk (n = 47) a minimum of 3 times per week, covering an incremental distance from 7,000 steps per day (week 1) to 12,500 steps per day (week 10). After that, EG were divided in quartile according to the volume of training completed. The results obtained showed a significant increase between pre-and post in PA (p = 0.009-0.044) and curl-up (p < 0.001-0.040) in EG regardless the quartile of compliance, and a reduction in fat variables (p < 0.001) and an increase in CMJ in 75-100 % compliance group (p = 0.005). The introduction of the covariate gender did not introduce changes in the intra-group evolution. On inter-group differences, differences were only found for the post-test values between 0-25 % Vs 25-50 % and between 50-75 % Vs 75-100 % with the group that completed a longer distance being the one that showed the lowest values in the post-test in both cases. When including the covariate gender, no significant differences were found for either the pre-test or the post-test on either variable. To conclude, a higher training volume with mobile apps seems to be relevant in the increase PA and strength and decrease of fat mass. The gender factor is not influential in the intra-group changes, but it is influential in the inter-group differences.

Mobile application interventions to increase physical activity and their effect on kinanthropometrics, body composition and fitness variables in adolescent aged 12-16 years old: An umbrella review

BACKGROUND

The aims of the present umbrella review were (a) to summarize the available evidence on the effectiveness of mobile applications aimed at increasing physical activity; (b) to analyse the effect of an increase in physical activity on kinanthropometric variables, body composition and physical fitness of adolescents aged 12-16 years old; and (c) to determine the strengths and limitations of the interventions carried out with adolescents aged 12-16 years old through the use of mobile applications, to provide recommendations for future research.

METHODS

The most relevant inclusion criteria were (a) adolescents aged 12-16 years old; (b) interventions carried out only with mobile apps; (c) pre-post measurements; (d) participants without illnesses or injuries; and (e) interventions lasting more than 8 weeks. The databases used to identify the systematic reviews were the Web of Science, Google Scholar, PubMed and Scopus. Two reviewers independently used the AMSTAR-2 scale to measure the methodological quality of the included reviews and also carried out an analysis of external validity, with a third reviewer participating in the cases in which consensus was not reached.

RESULTS

A total of 12 systematic reviews were included (these included a total of 273 articles that used electronic devices, of which 22 studies exclusively used mobile applications with adolescents aged 12-16). Regarding physical activity and its effect on body composition, kinanthropometric variables and physical fitness, no significant differences were found for any of the variables analysed, and the results were not sufficiently consistent to determine the influence of these interventions.

CONCLUSIONS

It is important to highlight that the scientific research conducted so far showed that mobile applications were not effective in increasing physical activity and changing the kinanthropometric variables, body composition or physical fitness of adolescents. Thus, future research with stronger methodological rigour and larger samples is needed to provide stronger evidence.

Moving beyond moderate-to-vigorous physical activity: the role of light physical activity during adolescence

Regular physical activity is an important component of a healthy lifestyle for young people. However, an estimated 80% of adolescents globally are insufficiently active. Traditionally, health benefits were attributed only to physical activity of at least moderate intensity, and recommendations focused on achieving a threshold of moderate-to-vigorous physical activity, without consideration of other aspects of movement within the 24 h cycle. Recently, the overall daily balance of active and sedentary behaviours has gained recognition as an important determinant of health. However, the relationship between light intensity physical activity and health has not been fully explored. In this perspective paper, we discuss key challenges in defining, measuring and analysing light physical activity which have hindered the advancement of knowledge in this area. Next, we suggest three ways in which light physical activity may enhance adolescent wellbeing: firstly, by replacing sedentary behaviours to increase daily movement; secondly, by supporting the accumulation of higher intensities of physical activity; and thirdly, by providing positive experiences to facilitate lifelong engagement with physical activity. In highlighting the importance of light physical activity during adolescence, we aim to encourage critical reflection and the exploration of new approaches towards physical activity within public health and beyond.

Influence of Pokémon Go Playing Style on Physical Activity and Its Effect on Kinanthropometry Variables and Body Composition in Adolescents

BACKGROUND

Pokémon Go is a mobile app that offers both continuous and intermittent (gamified) gameplay, but no previous research in adolescents is known to have addressed changes in physical activity and body composition according to playing style. For this reason, the aims of the present investigation were (1) to establish the differences in the level of physical activity, and its influence on the kinanthropometric and body composition, of the adolescent population, considering their Pokémon Go playing style; and (2) to analyze whether the practice of previous physical activity has an influence on the effects of the use of Pokémon Go on the level of physical activity and changes in kinanthropometric and body composition variables.

METHODS

A total of 94 adolescents (50 males and 44 females; mean age: 13.66 [1.17] years-old; mean body mass index: 20.82 [4.03] kg/m2) whose physical activity level and body composition were measured, participated in the investigation. Two groups of adolescents completed a 10-week intervention using Pokémon Go continuously (n = 30) or intermittently (n = 31), while the control group (n = 33) did not use any after-school app. A one-way analysis of variance (ANOVA), a multivariate analysis of variance, and 2 repeated-measures ANOVA were performed to analyze the data.

RESULTS

Inactive adolescents in the continuous use group increased their physical activity between the pretest and posttest (P = .038), but this did not occur in the active group. Regarding body composition variables, the increase in body mass (P < .001) and body mass index (P = .006) in the control group was significantly higher than in the continuous use group of adolescents who were inactive, but not in the active group, while the decrease in fat mass (P < .001-.036) and sum of 3 skinfolds (P < .001-.003) was significantly higher in both Pokémon Go use groups as compared to the control group, regardless of the previous physical activity level.

CONCLUSIONS

The continuous style of play seems to be more effective in increasing physical activity in adolescents, but the changes in body composition and kinanthropometric variables occur similarly with continuous and intermittent gameplay. Therefore, the playful use of Pokémon Go can be used in educational and health fields to produce changes in body composition in this population.

The Role of Basic Psychological Needs in the Adoption of Healthy Habits by Adolescents

Previous research in this field has not examined the significance of each of the basic psychological needs (BPNs) on changes in the physical activity level, adherence to the Mediterranean diet (AMD), kinanthropometric and derived variables, and the physical fitness of adolescents. Therefore, the purpose of this study was (a) to examine the variances in physical activity, AMD, and kinanthropometric and derived variables, as well as fitness levels, among adolescents with varying degrees of satisfaction regarding each of the BPNs and (b) to assess the differences in the study variables among adolescents based on whether the BPNs are satisfied individually or jointly. The sample consisted of 791 adolescents (404 males and 387 females; average age: 14.39 ± 1.26 years old). The findings indicated that adolescents in the highest percentiles (75-100) of competence, autonomy, or relatedness showed higher scores in physical activity and AMD and better kinanthropometric and physical fitness variables than adolescents in the lowest percentiles (0-25). Adolescents who showed joint satisfaction of all BPNs showed the best results on all variables analyzed. In addition, it should be noted that competence played the most relevant role.

Influence of High-Intensity Interval Training on IGF-1 Response, Brain Executive Function, Physical Fitness and Quality of Life in Sedentary Young University Women-Protocol for a Randomized Controlled Trial

Sedentary lifestyles have become a social problem, mainly among women. A sedentary lifestyle has been associated with poorer health in this population, negatively affecting physical and mental health. Physical exercise, in particular high-intensity interval training (HIIT), has been shown to be a neuroprotective tool. The present study provides a protocol design for a parallel-group Randomized Controlled Trial (RCT), whose aim will be to compare the effect of two physical interventions, HIIT and physical activity (increasing daily steps), on Insulin Growth Factor-1 (saliva IGF-1 concentrations), executive functions, quality of life, body composition, physical fitness, and physical activity in young sedentary women. At least 77 women will be recruited and randomly assigned to either a HIIT group (12-week exercise HIIT intervention, 3 sessions/week), the HIIT + PA group (12-week exercise HIIT intervention, 3 sessions/week, plus 10,000 steps/day), or a control group (usual care). The primary outcome measure will the chronic change in IGF-1 concentration levels measured in saliva. Secondary outcome measures will be: (i) executive functions; (ii) body composition; (iii) physical fitness; (iv) physical activity; and (v) quality of life. All outcomes will be assessed at the beginning of the study, after the intervention, and after three months of follow-up. After this intervention, we will be able to determine whether HIIT together with increased physical activity could be more effective than HIIT alone in IGF-1 stimulation. Furthermore, by comparing both intervention groups, we will be able to determine the differential effects on numerous health-related variables. Consequently, the conclusions of this study could help better understand the effects of a training program on IGF-1 concentration levels and executive functions. In addition, various strategies could be proposed through physical exercise to improve cognition in this age group, as well as to improve the health status of this sedentary population.

The Importance of Healthy Habits to Compensate for Differences between Adolescent Males and Females in Anthropometric, Psychological and Physical Fitness Variables

Adolescence is a crucial stage in human development, and differences in psychological, physical and body composition variables between males and females have been amply demonstrated. However, the role played by certain healthy habits, such as the practice of physical activity, adherence to the Mediterranean diet (AMD) or the maintenance of an adequate weight status, in compensating for the differences found between males and females in these variables, is not well known. For this reason, the study aimed to analyze whether the practice of physical activity, optimal AMD, and adequate weight status can compensate for the differences between adolescent males and females in anthropometric variables, psychological state, and physical fitness. The sample was composed of 791 adolescents (404 males and 387 females) aged twelve to sixteen years old, whose anthropometric, psychological (autonomy, competence, relatedness, and life satisfaction), and physical fitness variables (cardiorespiratory fitness, upper strength and explosive lower limb power, hamstring and lower back flexibility, and speed) were measured. All measurements were carried out in a single day using the sports pavilion of the four participating schools. The most novel results of this research show that the practice of physical activity was determinant mainly in females, as it reduced the differences found in comparison with males in psychological (p < 0.001−0.045) and anthropometric variables (p < 0.001). Regarding weight status and AMD, these were still relevant for the adolescent population, mainly the achievement of optimal AMD, but males continued to present higher values in physical fitness tests (p < 0.001) and lower values in fat accumulation (p < 0.001), regardless of weight status or AMD. Thus, physical activity seems to be the most determining factor that compensates for the differences between adolescent boys and girls.

Assessment of Motor Abilities and Physical Fitness in Youth in the Context of Talent Identification-OSF Test

(1) Background: Physical fitness during childhood is an important indicator of current and future health status. Defining physical fitness levels is a key element of talent identification in the training of children and adolescents. It is also crucial in developing a sports career path. This study sought to validate a physical fitness test (OSF test) and to determine fitness norms for children and adolescents with a special focus on talent identification within its particular sub-tests of endurance, speed, strength and power. (2) Methods: A total of 27,187 athletes who participated in the 'Athletics for all' (AFA) programme were included in the analysis. Physical fitness was assessed using a validated OSF test (3 × 10 shuttle run, standing broad jump, 1 kg medicine ball overhead throw, 4-min run). (3) Results: Four key motor abilities (speed, power, strength and endurance) were assessed in children and adolescents. The OSF test was normalised, i.e., a reference frame in the form of centile charts was developed. (4) Conclusions: The centile charts developed for particular parts of the OSF test make it possible to interpret scores in particular motor sub-tests and, first and foremost, enable users to compare a given score with results obtained by their peers.

Physical, Psychological, and Body Composition Differences between Active and Sedentary Adolescents According to the "Fat but Fit" Paradigm

The practice of physical activity during adolescence is essential for the proper development of the population. In recent decades, the relevance of physical activity has been increasing, due to the development of the "fat but fit" paradigm. This paradigm shows that adolescents with a high level of physical fitness are healthier than adolescents with poorer physical fitness, regardless of their weight, giving importance to sports practice over other aspects. However, few previous studies have analyzed the differences in physical and body composition between active and sedentary adolescents in this paradigm. For this reason, the objectives of the present study were to establish the differences in body composition, physical performance, and adherence to the Mediterranean diet between active and sedentary adolescents; and to analyze the differences between active and sedentary adolescents according to the "fat but fit" paradigm. The sample consisted of 791 adolescent whose body composition, level of physical activity, adherence to the Mediterranean diet, and physical fitness were measured. It was found significant between active and sedentary adolescents in most of the anthropometric, AMD, and physical fitness variables, with a significant effect of the covariates gender, age, BMI, and biological maturation on the model. The binary logistic regression analysis performed shows that anthropometric variables, AMD, and VO2 max can be considered as primary outcomes to distinguish between active and sedentary groups of adolescents. Furthermore, the results showed that the active adolescents, regardless of their weight status, had lower fat mass and greater muscle mass, as well as a higher performance in the physical fitness tests, and greater adherence to the Mediterranean diet than the sedentary adolescents. To conclude, the practice of physical activity is a determinant for the improvement of body composition, physical performance, and adherence to the Mediterranean diet of the adolescent population, regardless of their gender, age, weight, or maturity status.

Differences in body composition and physical fitness parameters among prepubertal and pubertal children engaged in extracurricular sports: the active health study

Background

This study aimed to analyze the associations of maturity status, chronological age and sex with physical fitness and body composition among active children.

Methods

A total of 1682 children (72% boys; age = 11.22 ± 2.64 years; height = 147.57 ± 15.87 cm; weight = 44.55 ± 15.29 kg) from rural areas participating in extracurricular sports were divided into four groups according to their sex and maturity status (prepubertal and pubertal according to stages described by Tanner). Body composition (body mass index, muscle mass and fat mass) and physical fitness (20-m shuttle-run test, handgrip strength and vertical jump) were assessed using standardized procedures. A two-way ANOVA and product–moment correlations were performed.

Results

Prepubertal boys had more fat mass (%) than pubertal boys [P<0.001; effect size (ES): 0.45], while prepubertal girls had more muscle mass (%) than pubertal girls (P<0.001; ES: 0.47). The pubertal group displayed higher fitness outcomes (absolute values) regardless of sex (P<0.05). However, the prepubertal group had higher percentile values in the 20-m shuttle-run test and vertical jumps than the pubertal group regardless of sex (P < 0.001; ES: 0.29–0.48). All the measures of physical fitness were positively associated with chronological age and muscle mass (%).

Conclusions

Although absolute values of body composition and physical fitness appear to increase among pubertal children participating in extracurricular sports, the percentiles indicate that puberty is accompanied with a loss of a physical fitness levels. Thus, extracurricular sports might not be enough to enhance fitness among adolescents.

Association of Body Weight and Physical Fitness during the Elementary School Years

Physical fitness and body weight are key correlates of health. Nevertheless, an increasing number of children display poor physical fitness and high body weight. The aim of this study was to examine the prospective association of physical fitness with body weight throughout the elementary school years with a special emphasis on children with high body weight or poor physical fitness at baseline. A total of 303 Austrian children (55.1% male) completed the German motor test up to eight times over a 4-year time span (between the ages 6 and 10 years). Physical fitness did not differ across quartiles of body weight at baseline. A more pronounced weight gain, however, was associated with an impaired development of physical fitness and this association was more pronounced in children with higher baseline body weight. In addition, the detrimental effects of an impaired development of physical fitness on subsequent body weight were more pronounced in children with higher baseline body weight. No differences in the longitudinal association between body weight and physical fitness, on the other hand, were observed across quartiles of baseline fitness. These results emphasize the importance of the promotion of physical fitness, particularly in children with increased body weight, to ensure future health.

Change in physical fitness due to the COVID-19 pandemic lockdown in French adolescents: a comparison between two independent large samples from Diagnoform battery

Numerous studies reported a significant decline in physical activity level in adolescents as a result of the COVID-19 lockdown. Physical fitness is recognized as a powerful marker of health in youth. The aim of this study was to evaluate the impact of the COVID-19 pandemic lockdown on health-related physical fitness in French adolescents. Two cross-sectional studies were performed comparing two different groups of French adolescents, before (sample 1) and after the first lockdown (sample 2). A total of 1231 adolescents (aged to 16.5 ± 1.5 years) participated in the two cross-sectional studies. Complete data for physical fitness and anthropometrics data were obtained. Adolescents from sample 2 showed lower physical fitness levels compared to adolescents from sample 1. Regarding physical fitness for boys and girls, physical fitness levels were significantly lower in both sex between adolescents from the sample 1 and adolescents from the sample 2, except for cardiorespiratory fitness and flexibility for boys and girls, respectively. The physical fitness global score was also significantly lower between adolescents from the sample 1 and 2 for boys (-9.8%, p < 0.01) and girls (-16.2%; p < 0.01), respectively. Overall, the higher difference was found for performance in the speed body displacement test (-30%). A difference of 12.8% and 25% was observed for boys and girls, respectively.   Conclusion: COVID-19 pandemic lockdown had a negative impact on physical fitness in French youth. This study highlights the need to develop, in a near future, prevention programmes in order to improve the physical fitness in youth. What is Known: • COVID-19 pandemic deeply impacted lifestyle habits. A worrying decrease of physical activity, associated to a dramatic increase of time spent in sedentary behaviors was found in many coutries. What is New: • Our study bring first data on the health-related physical fitness consequences due to lockdown in French adolescents. Our study demonstrate the negative impact of COVID-19 pandemic lockdown on health-related physical fitness in French adolescents.