Criterion-related validity and reliability of the standing long jump test in adults: The Adult-Fit project

The purpose of this study was to analyze the criterion-related validity and the reliability of the standing long jump test (SLJ) for evaluating the lower-body explosive muscular strength in adults. A total of 410 adults participated in this study. Sociodemographic, anthropometric measurements, laboratory lower-body muscular strength tests, and the field-based SLJ were performed. In validity analysis, stepwise regression analysis showed that maximal horizontal power, sex, percentage of body fat, maximal horizontal force, and lean mass were significantly associated with the SLJ distance (R2 = 0.78; p < 0.001). Reliability analysis showed significant differences between test-retest in the SLJ test, with an overestimation of the second measurement compared to the first [12.14 ± 14.46 cm, intraclass correlation coefficient (ICC) = 0.94 (0.75-0.97), p < 0.001; Cohen's d = 0.31]. The coefficient of variation (CV) was 7.06% and the minimal detectable change (MDC90) was 29 cm. After a learning period, higher reliability values were found [0.45 ± 1.04 cm, ICC = 1.00 (0.99-1.00); p = 0.001; CV = 0.53 %; MDC90 = 1 cm]. The SLJ test may be a valid tool to assess lower-body explosive muscular strength in the adult population. A learning period may be necessary to provide reliability on the SLJ test.

Lifestyle as a Modulator of the Effects on Fitness of an Integrated Neuromuscular Training in Primary Education

The objective was to evaluate changes in fitness after an integrated neuromuscular training (INT) intervention in primary school children and to evaluate how lifestyle behaviors and parental education modulate these changes. One hundred and seventy children (7.45 ± 0.34 years; 52% girls) were included. Cardiorespiratory fitness (half-mile run test), a 10 × 5 m shuttle run test, standing broad jump (SBJ), handgrip dynamometer, body mass index (BMI) and fat mass percentage (FM%) were assessed before and after the 3-month intervention (20 min of INT in the physical education class, twice per week). The Mediterranean diet (MD), sleep time and parental education level (PEL) were evaluated by questionnaires, and adherence to physical activity (PA) recommendations was measured with a triaxial accelerometer before the intervention. After the intervention, there were improvements in the 10 × 5 test and the SBJ. Only girls had improvements in the handgrip test, BMI SDS and FM%. After correcting for confounding variables, only BMI was significantly improved whereas strength improved in the participants non-compliant with the PA recommendations or pertaining to families of high PEL. The INT produced improvements in fitness in a brief period and in different subgroups of pupils (inactive and with diverse sociocultural environments).

How to design and establish a national school-based physical fitness monitoring and surveillance system for children and adolescents: A 10-step approach recommended by the FitBack network

BACKGROUND

Providing individual- and population-level data on children's physical fitness (PF) is a crucial public health and education priority. However, few national fitness monitoring or surveillance systems are currently in practice internationally. We aim to summarize the current European PF monitoring and surveillance systems for school-aged children and to provide experience-based guidelines on how to design such systems.

METHODS

The FitBack network consists of experts from diverse backgrounds with the common interest to improve the accessibility of PF monitoring for young people globally. Through FitBack network, we identified and compared the national or regional PF monitoring and surveillance systems currently in operation across Europe. We formulated a 10-step approach for designing and establishing one's own system, based on analysis of experienced strengths, weaknesses, opportunities, and threats to monitoring childhood fitness.

RESULTS

We identified a total of eight PF monitoring systems in Finland, France, Galicia of Spain, Hungary, Lithuania, Portugal, Serbia, and Slovenia. The FitBack network recommends the following steps for designing and establishing one's own system: (1) set up mission statements and aims, (2) involve stakeholders, (3) utilize scientific background, (4) governance structure, (5) ensure sufficient funding, (6) data management planning, (7) provide meaningful feedback, (8) conduct pilot testing, (9) plan implementation process, and (10) invest in communication with stakeholders.

CONCLUSIONS

This study provides an updated overview of the best practices for school-aged children's fitness monitoring and surveillance in Europe. Additionally, it offers a 10-step approach to assist in the creation of similar systems in Europe or globally.

Musculoskeletal fitness: relative handgrip strength and vertical jump power from 10 to 18 years old

Background

There is an increasing consensus on the relevance of musculoskeletal fitness for health throughout the life cycle, requiring evaluation approaches and description of results capable of characterizing different age groups and body sizes. This study aimed to describe the musculoskeletal fitness of young Portuguese people aged 10-18 through handgrip strength (HGS) and vertical jump power (VJP) and investigate differences between the sexes.

Methods

The sample included 736 participants (359 girls recruited from schools. HGS (kg) was assessed using a handheld dynamometer, and VJP (W) was assessed using a force platform; both measurements were standardized for body mass.

Results

Higher HGS and VJP were observed in boys than in girls from 13 years old (13 years: p ≤ 0.05; 14-18 years: p ≤ 0.001), with no significant differences before this age. The percentile distributions of HGS and VJP are described for each sex using the lambda, mu, sigma (LMS) method. The pattern of development of these variables as a function of age is presented.

Conclusions

Handgrip strength and vertical jump power show differences between the sexes from 13 years of age and similar trajectories to populations in other countries in the same age group.

Physical fitness of Tibetan adolescents at different high altitudes in Tibet, China: A comparative study

OBJECTIVE

High altitude hypoxic environment has a certain negative impact on physical fitness of adolescents. We aimed to understand the physical fitness status of Tibetan adolescents in different high-altitude areas in Tibet, China.

METHODS

Physical fitness items, such as grip strength, standing long jump, sit and reach, 50 m dash, 1000 m run for boys, and 800 m run for girls were tested on 3806 Tibetan adolescents by using stratified whole group sampling method in class units. The mean age of the participants was (15.51 ± 1.69) years for Tibetan males and (15.54 ± 1.69) years for females. One-way analysis of variance (ANOVA) and other methods were used to make cross-sectional comparisons of physical fitness performance of Chinese Tibetan adolescents in different high-altitude regions.

RESULTS

The standing long jump scores of boys (203.37 ± 28.36) were higher than that of girls (152.97 ± 19.46) and the lowest standing long jump scores of adolescents in Shigatse region (166.39 ± 35.04). The highest level of sit and reach was found among boys (10.69 ± 5.34) in Nyingchi and the lowest level of sit and reach was found among girls (8.42 ± 5.84) in Shigatse. Shigatse region adolescents had the lowest performance in 50 m dash (9.09 ± 1.72) while the best performance in 1000 m run (266.23 ± 35.82) and 800 m run (245.40 ± 27.92).

CONCLUSION

There is variability in the physical fitness of Tibetan adolescents in different high-altitude regions of Tibet, China. Targeted physical fitness interventions should be carried out for Tibetan adolescents in different high-altitude regions. The focus should be on improving the endurance quality of Tibetan adolescents in Lhasa and the lower limb muscle strength, flexibility, and speed quality of adolescents in Shigatse.

The Long-Term Adaptations of a Combined Swimming and Aquatic Therapy Intervention in an Adult Person with High-Functioning Autism (Asperger's Syndrome): A Case Study

Individuals with High-Functioning Autism present impairments in communication, social interaction, and motor development. A low level of motor skills, namely difficulties in gross and fine mobility, and in motor control, discourage individuals with High-Functioning Autism from being involved in physical activities, resulting in fewer opportunities for social interaction. There is not much evidence available about the effects of regular swimming exercise and/or aquatic therapy on health promotion in adults with High-Functioning Autism. An adult male (22 yrs) diagnosed with High-Functioning Autism participated in a combined 6-month swimming and aquatic therapy program (two sessions/week, 60 min each). The pre- and post-intervention assessments consisted of physical fitness, balance, functional ability, and psychomotor tests. The post-intervention assessments showed improvements in the standing long jump (+100%), hand grip force (+71.7%), bend arm hang test (+123.1%), and the physiological parameters in the 6 min walk test (+10.2%). On the opposite, decrements in the sit-up (-12%) and sit-and-reach test (-6.3%) were observed. It was noted that the participant frequently lost interest and focus quickly, resulting in the abandonment of the exercise. Conclusively, there is a great need for further research on this topic examining a larger adult population.

Reliability of Fitness Assessments in Children With Emotional and Behavioral Difficulties

PURPOSE

Examine the reliability of field-based fitness assessments in school-aged children with emotional or behavioral difficulties (EBD). Understanding the impact of fitness on physical activity participation for children with EBD is limited by our ability to reliably measure it.

METHODS

Fifteen children aged 7-12 years with EBD completed 7 assessments-standing broad jump, overhead throw, grip strength, isometric plank hold, isometric wall squat, unilateral heel raise, and modified 6-minute walk test-in a random order on 2 separate occasions. Intraclass correlation coefficients (ICCs) were computed to evaluate reliability.

RESULTS

ICCs ranged from .65 to .99 representing moderate to excellent reliability for all assessments. Shorter assessments requiring less attention and behavior regulation tended to demonstrate higher ICC values while assessments with greater attention or behavioral regulation demands tended to have lower ICC values.

CONCLUSION

Results demonstrate varied reliability for fitness tests in children with EBD. Practitioners can use grip strength and standing broad jump assessments with confidence. Other assessments have good reliability but greater variability indicating they may be a challenge for some children with EBD.

Differences in the absolute muscle strength and power of children and adolescents with overweight or obesity: a systematic review

This study aimed to describe absolute muscle strength and power in children and adolescents with obesity, overweight and normal weight, and the assessment tests and tools used. We retrieved observational studies from MEDLINE (PubMed), TripDataBase, Epistemonikos, EBSCO essentials, NICE, SCOPUS, and LILACs up to February 2023. In addition, we recovered data from studies with at least three comparison groups (obesity, overweight, normal weight) and with a description of the absolute muscle strength and power and the assessment tests and instruments used. The methodologic quality of the studies was assessed with the Joanna Briggs checklist, and the review was carried out using the PRISMA 2020 methodology. Eleven studies with 13,451 participants from 6 to 18 years of age were once included, finding that the absolute muscle strength of their upper extremities was greater when they were overweight or obese; however, in the same groups, absolute muscle strength was lower when they carried their body weight. In addition, lower limb absolute muscle strength was significantly lower in obese participants than in normal weight, regardless of age and gender. The most used tools to measure the absolute muscle strength of the upper limbs were the grip dynamometers and push-up exercises. In contrast, different jump tests were used to measure the power of the lower limbs. There are great differences in muscle strength and power between overweight or obese children and adolescents and those with normal weight. Therefore, it is recommended to use validated tests, preferably that assess strength through the load of the patient's body weight, either of the upper or lower limbs, for greater evaluation objectivity that facilitates the management of these children and adolescents.

COVID-19 lockdown effects on the anthropometrics, aerobic capacity, muscle function and metabolic control in children and adolescents with overweight and obesity

OBJECTIVE

The lockdown due to a novel coronavirus (COVID-19) pandemic negatively impacted the daily physical activity levels and sedentary behavior of children and adolescents. The purpose of this study was to determine the effects of lockdown on the anthropometric measurements, aerobic capacity, muscle function, lipid profile and glycemic control in overweight and obese children and adolescents.

METHODS

104 children and adolescents with overweight and obesity were divided in a non-lockdown group (NL) (n = 48) and a lockdown group (L) (n = 56). Both NL and L groups were evaluated on three consecutive days, day one: anthropometric measurements; day two: aerobic capacity and muscle function and day three: lipid profile and glycemic control. Data are presented as mean ± standard deviation (SD) and median plus interquartile range (IQR) according to their assumption of normality.

RESULTS

The L group increased the body weight (81.62 ± 22.04 kg vs 74.04 ± 24.46 kg; p = 0.05), body mass index (32.54 ± 5,49 kg/m2 vs 30.48 ± 6.88 kg/m2; p = 0.04), body mass index by z-score (3.10 ± 0.60 SD vs 2.67 ± 0.85 SD; p = 0.0015), triglycerides [141.00 mg/dl IQR (106.00- 190.00 mg/dl) vs 103.00 mg/dl IQR (78.50- 141.50 mg/dl); p = 0.001], fasting insulin [31.00 mU/L IQR (25.01- 47-17 mU/L vs 21.82 mU/L IQR (16.88 - 33.10 mU/L; p = 0.001)] and HOMA index [6.96 IQR (6.90 - 11.17) vs 4.61 IQR (3.96 - 7.50; p = 0.001)] compared with NL group.

CONCLUSIONS

The lockdown due COVID-19 pandemic had a negative impact on the anthropometric measurements, lipid profile, and glycemic control of overweight and obese children and adolescents.

Relationships of BMI, muscle-to-fat ratio, and handgrip strength-to-BMI ratio to physical fitness in Spanish children and adolescents

This study aimed to determine the relationship of body mass index (BMI), muscle-to-fat ratio (MFR), and handgrip strength-to-BMI ratio to physical fitness parameters in an active young population according to sex across four different time points. A total of 2256 Spanish children and adolescents (aged 5-18) from rural areas participating in an extracurricular sport in different municipal sports schools participated in this study. Participants were divided into children (5-10 years) and adolescents (11-18 years), boys and girls, and across four different time points (2018, 2019, 2020, 2021). Data on anthropometric measures (BMI, MFR, appendicular skeletal muscle mass) and physical fitness (handgrip strength, cardiorespiratory fitness, and vertical jump) were collected. Boys who were overweight, but especially boys with obesity, had higher absolute handgrip strength in children and adolescents than their normal weight counterparts in 2020 and 2021. Boys and girls with normal weight presented higher cardiorespiratory fitness and vertical jump than their overweight and obese peers over the years. The MFR was directly correlated with the cardiorespiratory fitness and vertical jump variables, but not with handgrip strength, in boys and girls. The handgrip strength-to-BMI ratio in both sexes was positively correlated to the different physical fitness parameters.  Conclusion: BMI, MFR, and handgrip strength-to-BMI can be used as health and physical fitness indicators in this population. What is Known: • BMI is the main indicator commonly used as a proxy for obesity for many years. Nevertheless, it cannot differentiate between fat mass and fat-free mass. • There are other indicators such as MFR and handgrip strength-to-BMI that might be more accurate and can serve to monitor the health and fitness of children and adolescents. What is New: • MFR showed a positive and significant correlation with cardiorespiratory fitness and vertical jump in both sexes. On the other hand, the handgrip strength-to-BMI presented a positive correlation with cardiorespiratory fitness, vertical jump, and handgrip strength. • The use of these indicators obtained through different parameters of body composition and physical fitness can serve as a tool to identify the relationships of the paediatric population with physical fitness.

Centile Reference Curves of the SLOfit Physical Fitness Tests for School-Aged Children and Adolescents

ABSTRACT

Blagus, R, Jurak, G, Starc, G, and Leskošek, B. Centile reference curves of the SLOfit physical fitness tests for school-aged children and adolescents. J Strength Cond Res 37(2): 328-336, 2023-The study provides sex- and age-specific centile norms of Slovenian children and youth. Physical fitness was assessed using the SLOfit test battery on population data, including 185,222 children, aged 6-19 years, measured in April and May 2018. Centile curves for both sexes and 12 test items were constructed using the generalized additive models for location, scale, and shape (GAMLSS). Boys generally achieved higher scores in most of the physical fitness tests, except in stand and reach, but this was not consistent throughout childhood and adolescence, nor did it pertain to the entire range of performance. Girls outperformed boys in the arm-plate tapping test throughout childhood; the poorest performing girls outperformed the poorest performing boys in the 600-m run, 60-m dash, backward obstacle course, and standing broad jump. The shapes and trends of physical fitness curves adequately reflect the effects of growth and development on boys' and girls' physical performance. Comparing the existing reference fitness curves showed that Slovenian children and adolescents display higher fitness levels than their peers from other countries. This study provides the most up-to-date sex- and age-specific reference fitness centile curves of Slovenian children, which can be used as benchmark values for health and fitness monitoring and surveillance systems.

Relationship between self-reported and objectively measured physical fitness in young men and women

Self-reported physical fitness has advantages in cost and time over objective methods, but previous studies demonstrate equivocal conclusions regarding validity. Methods for self-reporting are usually based on subjective judgements, while another approach includes performing field tests at home. The Norwegian military relies on the latter method for conscript selection, but its validity is unknown and should be investigated. In total 14,166 young men and women were included in the study. During conscript selection step one, the subjects were requested to perform 3,000 m run, push-up, pull-up and standing long jump tests at home, and report the results online ("self-reported measurements"). Step two took place at a conscript selection centre 1-18 months later. Here, the subjects completed a maximal treadmill test, seated medicine ball throw, pull-up and standing long jump tests ("objective measurements"). The results demonstrated correlation coefficients from 0.29 to 0.82 (P < 0.05) for self-reported vs. objective measurements, with the highest association found for self-reported and objectively measured pull-ups. Kappa values ranged from 0.05 to 0.34 (P < 0.05), with pull-ups demonstrating the highest agreement. More women than men over-reported their physical fitness. Among men and women indicating similar self-reported fitness, men's objective fitness was higher for all objective tests (effect sizes from 0.5 to 3.0). In conclusion, large variations in correlation coefficients were observed between self-reported and objectively measured physical fitness, while the kappa values indicated poor to fair agreement. The finding that more women than men over-reported their fitness level contradicts most previous studies.Highlights Low, moderate, and high correlations, and poor to fair agreements (kappa values), were observed between self-reported and objectively measured endurance and muscle strength variables.More women than men overreported their actual fitness level.Self-reported fitness based on performing field tests at home may be a feasible alternative to traditional methods which rely on self-perceived fitness.

Normative Data for Musculoskeletal Fitness in 13,217 Children and Adolescents: The Croatian Fitness (CROFIT) Study

Purpose: The main purpose of the study was to establish normative data for health-related musculoskeletal fitness. Method: We recruited 13,217 children and adolescents aged 11-18 years (6,181 boys and 7,036 girls; 57% of girls). To evaluate musculoskeletal fitness, the following field tests were applied: standing broad jump (cm), sprint 20 m (sec), medicine-ball throw (dm), sit-ups in one minute (#), sit-ups in one minute (short, #), and squats in one minute (#). Curves for the 10th, 20th, 30th, 40th, 50th (median), 60th, 70th, 80th, and 90th percentiles were calculated using the Lambda (L), Mu (M), and Sigma (S) method. The LMS method assumes that the data can be normalized by using a power transformation and removing the skewness. Results: Median scores for standing broad jump, sprint 20 m, medicine-ball throw, sit-ups in one minute, sit-ups in one minute (short) and squats in one minute were 185.00 cm, 3.66 sec, 80.00 dm, 46.00 x, 56.00 x and 49 x in boys and 160.00 cm, 4.01 sec, 60.00 dm, 40.00 x, 49.00 and 43 x in girls. Effect sizes (ES) showed that boys performed better in all physical fitness tests (ES = 0.50-1.05), compared to girls. In general, age-related physical fitness changes showed the plateau between ages 15 and 16 in boys, while in girls, the plateau was reached at the age of 14. Conclusions: This study shows standards for musculoskeletal tests in youth.

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.

Can high-intensity interval training and small-sided games be effective for improving physical fitness after detraining? A parallel study design in youth male soccer players

Background

The aim of this study was two-fold: (i) analyze the within-group physical fitness adaptations promoted by a detraining period (4 weeks) followed by an intervention period (4 weeks) using small-sided games (SSGs) or running-based high intensity interval training (HIIT); and (ii) analyze the between-group differences aiming to identify the effectiveness of each training intervention on the physical fitness of youth male soccer players.

Methods

This study followed a randomized parallel study design. Forty male soccer players (age: 16.4 ± 0.5 years old) were assessed three times: (i) baseline; (ii) after 4 weeks of detraining; and (iii) after a retraining period of 4 weeks. After returning from detraining, players were randomized to an SSG-based training intervention (n = 20) or running-based HIIT (n = 20). Interventions lasted 4 weeks, with a training frequency of three sessions per week. At all timepoints, players were assessed by: (i) anthropometry (height, body mass, fat mass (FM)), countermovement jump (CMJ), standing broad jump (SBJ), triple hop jump (THJ), linear sprint test (5-, 10-, and 20-m), zig-zag test with (ZZwB) and without (ZZwoB) ball, three corner run test (3CRT), Y-balance test and the Yo-Yo intermittent recovery test level 1 (YYIRT). Mixed ANOVA (time * group) was conducted for testing interactions between the three timepoints of repeated measures and the two groups. Effect size (ES) for pairwise comparisons was calculated using Cohen's.

Results

Between-group analysis revealed significantly smaller SBJ (t = -2.424, p = 0.020, d = -0.767 small ES) and THT (t = -4.353, p < 0.001, d = -1.376 large ES) in the SSG group after the retraining period. At the same time, SSG presented significantly greater FM after retraining compared to HIIT (t = 3.736, p < 0.001, d = 1.181 large ES). Additionally, SSG had significantly smaller values than HIIT in the ZZwB (t = -3.645, p < 0.001, d = -1.153 large ES), but greater times in the ZZwoB (t = 2.679, p = 0.011, d = 0.847 large ES) and 3CRT (t = 3.126, p = 0.003, d = 0.989 large ES).

Conclusions

Although SSG and HIIT interventions improved physical fitness outcomes after a period of detraining, they were not able to effectively restore body composition, CMJ, 20-m sprint, ZZwB, and YYIRT compared with the baseline assessments (before detraining). Only HIIT was significantly effective for restoring SBJ, short linear sprin speed, and change-of-direction compared with baseline. HIIT was also significantly better than SSG in improving SBJ and ZZwoB. Although the small sample, the non determination of maturation status and the need to be cautious regarding generalization, HIIT appears to be more beneficial than SSG after a detraining period for recovery of body composition and physical fitness qualities in this specific context of youth soccer players.

Longitudinal Association between Weight Status, Aerobic Capacity, Muscular Strength, and Endurance among New York City Youth, 2010-2017

Background: Child weight status is inversely associated with fitness, but less is known about this relationship across fitness domains. This study examined the longitudinal association between weight status and fitness domains in a large, diverse sample of children. Methods: Data were drawn from the New York City Fitnessgram (2010-2011 to 2017-2018). Height and weight were collected annually and converted to weight status using Centers for Disease Control and Prevention growth charts. Aerobic capacity, muscular strength, and endurance were measured as age and sex standardized z-scores based on the fitness performance tests. Repeated-measures multilevel models were run testing the association between weight status and 1-year lagged fitness domains. Results: The sample included 917,554 children (51.8% male, 39.3% Hispanic, 29.9% non-Hispanic Black, 13.9%, 4.7%, and 1.7% class I, II, and III obesity, respectively). For each fitness domain, fitness scores decreased with increasing weight status across all demographic categories, with the lowest fitness scores observed in children with the most severe obesity, and highest magnitude of effects for aerobic capacity, and particularly among boys, non-Hispanic Whites, and older youth. For example, compared with youth with healthy weight, youth with overweight had 0.28 standard deviation lower aerobic capacity performance [confidence interval (95% CI): -0.29 to -0.28], followed by class 1 obesity (β = -0.57, 95% CI: -0.58 to -0.57), class 2 obesity (β = -0.88, 95% CI: -0.88 to -0.88), and class 3 obesity (β = -1.19, 95% CI: -1.20 to -1.18). Conclusions: Compared with youth with healthy weight, youth at every other weight status had lower subsequent fitness, with the magnitude of the relationship increasing as weight status increased. Future research should examine interventions targeting aerobic capacity to reduce fitness disparities.

The Effects of a Physical Education Intervention Program on the Bone Properties of Second- and Third-Grade Pupils: A Cluster Randomized Controlled Trial

BACKGROUND

Many young children do not participate in sufficient physical activity for promoting optimal bone growth. The objective of this study was to investigate the effect of young children who participated in a school-based intervention program on bone properties. The program included structured physical activity, with a focus on the application of mechanical loads on the upper and lower limbs.

METHODS

A cluster randomized controlled trial was conducted, in which classes were randomly assigned to the intervention or control groups. A total of 295 (50.17% girls) children from the second and third grades from 12 classes in Israel were randomly allocated to an intervention consisting of three 10-minute weekly medium- to high-intensity activities throughout one academic year or to a treatment as usual control group. Bone properties were measured at the distal radius and tibia shaft using speed of sound, before and after the intervention.

RESULTS

Distal radius properties improved significantly for both boys and girls in the intervention group (boys: meanpre = 3769.95, meanpost = 3875.08, Δ = 2.80%; girls: meanpre = 3766.27, meanpost = 3890.83, Δ = 3.30%; d = 1.03); whereas, tibia shaft properties only significantly improved for boys (meanpre = 3663.98, meanpost = 3732.75, Δ = 1.90%; d = 1).

CONCLUSIONS

These findings indicate that distal radius properties of children can be positively affected by a short, easy to implement intervention program that does not require special resources.

Potential Energy as an Alternative for Assessing Lower Limb Peak Power in Children: A Bayesian Hierarchical Analysis

The aim of this study was to analyze the use of potential energy (PE) as an alternative method to assess peak power of the lower limbs (PP) in children. 815 Spanish children (416 girls; 6–11 years old; Body Mass Index groups (n): underweight = 40, normal weight = 431, overweight = 216, obese = 128) were involved in this study. All participants performed a Countermovement Jump (CMJ) test. PP was calculated using Duncan (PP_DUNCAN), Gomez-Bruton (PP_GOMEZ) and PE_CMJ formulas. A model with PE_CMJ as the predictor variable showed a higher predictive accuracy with PP_DUNCAN and PP_GOMEZ than CMJ height (R² = 0.99 and 0.97, respectively; ELPD_diff = 1037.0 and 646.7, respectively). Moreover, PE_CMJ showed a higher linear association with PP_DUNCAN and PP_GOMEZ across BMI groups than CMJ height (β_PECMJ range from 0.67 to 0.77 predicting PP_DUNCAN; and from 0.90 to 1.13 predicting PP_GOMEZ). Our results provide further support for proposing PE_CMJ as an index to measure PP of the lower limbs, taking into account the children’s weight and not only the height of the jump. Therefore, we suggest the use of PE_CMJ in physical education classes as a valid method for estimating PP among children when laboratory methods are not feasible.

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

Functional relationship between the anatomical structures of the calf and athletic ability

Calf muscle plays an important function in driving the movement of stepping on the ground and moving forward when walking or running. The Achilles tendon has been reported to be closely related to the elasticity of tendons to absorb shock and rebound and convert energy into propulsion. We wanted to determine the effect and correlation of the anatomical structure of the calf region on function. Measurements of anatomical structures were conducted with 51 volunteers using ultrasonography, and exercise capacity tests were conducted to measure anaerobic power, elasticity, and flexibility. The mean power and length of the calf (LoC), muscle thickness (MT), and fascicle angle (FA) of the medial head of gastrocnemius (p < 0.001) showed the strongest positive correlation among the variables of anatomical structures. MT of the Gastrocnemius and LoC Gastrocnemius were also correlated with peak power. In the anatomical structure variables, the FA of the lateral head of gastrocnemius, length and width of the Achilles tendon, and part of the athletic ability, the standing long jump test and sitting trunk flexion test, were not significantly correlated. Based on these results, it can be concluded that the height and degree of development of the calf muscles are structures that affect the exercise of anaerobic power. Hence, it can be used as a predictor of athletic ability. Furthermore, the trainer can predict athletic ability according to the characteristics of the event by first understanding the athlete's physical condition.

The Value of a Motor Intervention for 3 to 6-Year-Old Children Infected with and Affected by HIV

Human immunodeficiency virus (HIV)/Aquired Immune Deficiency Syndrome (AIDS) is a large threat to human health and is challenging to address. This study aims to determine if motor intervention is a possibility for promoting the life expectancy and quality of life of children with HIV. The group consisted of 22 participants: 11 HIV-infected (51.73 months, SD 10.15) and 11 HIV-affected children (44.45 months, SD 10.76). A two-group (intervention and control group) pre-test−post-test research design was followed. The HIV-infected and affected children were randomly matched and grouped into an intervention and control group. The intervention group participated in a 12-week motor intervention of 60 min per session, twice per week. The effect of the program was analyzed with regard to motor skills, as established by the PDMS-2 and two strength capabilities. An ANCOVA adjusted for pre-test differences (p < 0.05) indicated statistically significant improvement (p < 0.05) with large practical significance (d > 0.8) in locomotor, fine motor and overall motor skills. The infected children also showed better improvement compared to the affected children. Motor intervention is recommended in the health care path of children affected and infected with HIV, although modifications for improvement of the program are suggested, based on the results attained.

Early-life activities mediate the association between family socioeconomic status in early childhood and physical fitness in early adolescence

The graded association between family socioeconomic status (SES) and physical fitness is evident, but little is known about the mechanism underlying this association. This study investigated the role of early-life activities as mediators of the longitudinal relationship between early-life SES and health-related physical fitness in 168 adolescents (51.2% boys; final mean age: 12.4 years old). In Wave 1 (2011–12), their parents completed questionnaires about family socioeconomic status (SES), parent–child activities, and child screen time. In Wave 2 (2014–15), participants’ physical activity levels were assessed through parent proxy-reports. In Wave 3 (2018–19), a direct assessment of handgrip strength, standing long-jump, and 6-min walk test (6MWT) performance was conducted. After controlling for demographic factors, results of mediation analyses revealed that (a) Wave 1 SES predicted Wave 3 long-jump and 6MWT performance; (b) child physical activity level in Wave 2 mediated the relation between Wave 1 SES and standing long-jump performance in Wave 3; and (c) recreational parent–child activities and child screen time in wave 1 mediated the relation between Wave 1 SES and 6MWT performance in Wave 3. Our findings suggest that the type and frequency of early-life activities play a role in the graded association between childhood SES and physical fitness in adolescence.

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.

Physical fitness percentiles of Polish children aged 4-7 years

The purpose of this study was to report sex- and age-specific physical fitness level in Polish children aged 4 to 7. 11.709 children participated in the study, including 5.684 girls and 6.025 boys aged 4 to 7 who attended kindergarten institutions throughout Poland. Physical fitness was assessed using four tests developed by Sekita including shuttle run 4 × 5 m with moving the block, standing long jump, throwing 1 kg medicine ball with two hands above the head and 20 m run. Percentile charts were developed separately for males and females using the LMS method. Boys showed higher physical fitness values than girls. In addition, an increase in the level of physical fitness was observed along with the age of the subjects. The developed reference values by age and sex in the field of physical fitness can be used for diagnostic purposes and assessing the level of physical fitness of preschool children. In addition, they can be helpful for healthcare professionals, parents and teachers to develop children's motor activation programs and monitor their physical fitness.

Physical fitness and cognitive function among school-aged children in selected basic schools in the Ho Municipality of Ghana

Physical fitness is thought to promote cognitive function. Evidence about this is however lacking in the Ghanaian context. This study aimed to investigate the association between physical fitness and cognitive function among basic school children aged 8–13 years. A cross-sectional study involving 591 school children, recruited from 12 randomly selected public and private basic schools was conducted. Physical fitness tests were done using a five-test battery (Fifty metre run, handgrip strength, sit-up, flexibility and standing board jump) following standardized procedures. Cognitive function test using the Raven's Coloured Progressive Matrices (RCPM) were carried out. More girls (55%), children from 8-13 years old (49.1%) and public school children (66.1%) participated in the study. For fitness, boys performed better than girls in sit ups 3.4 ± 2.2 (mean ± SD), p = 0.012, handgrip 4.3 ± 2.0, p = 0.001 and overall fitness 4.3 ± 2.0, p = 0.007. Children in public schools performed significantly better in forward jump (p < 0.001) while those in private schools did better in 50m run (p < 0.001). For cognition, 46.1% of participants had less than 50% of the total score. Cognitive test score varied for forward jump and handgrip alone and not for sit ups, 50m run and overall score. Mean forward jump score was lowest in poor cognition group (4.9 ± 2.3), followed by good (5.3 ± 2.2) and highest among excellent (5.5 ± 2.3, p = 0.044) cognition group. Similar observation was made for handgrip. Cognition score and hand grip strength were positively but weakly correlated. (r = 0.132, p = 0.026). Although handgrip strength (measuring muscular strength) was significantly associated with cognitive function, this study found no significant association between overall physical fitness and cognitive function. These results indicate that only some components of physical fitness may be associated with cognitive function. This study is however correlational and one cannot infer causality.

Percentiles and Principal Component Analysis of Physical Fitness From a Big Sample of Children and Adolescents Aged 6-18 Years: The DAFIS Project

Assessing physical fitness has emerged as a proxy of the health status of children and adolescents and therefore as relevant from a public health point of view. DAFIS is a project included in Plan Galicia Saudable (Healthy Galicia Plan) of the regional government of Galicia (Spain). DAFIS consists of an on-line software devoted to record the results of a standard physical fitness protocol carried out as a part of the physical education curriculum. The aims of this study were: to obtain normative values of physical fitness of the Galician school population evaluated in the DAFIS project, and to identify a reduced number of components and tests able to capture a significant amount of the variability in the physical fitness of children and adolescents. From an initial sample of 27784 records, 15287 cases (7543 males, 7744 females) were considered after filtering. Generalized Additive Models for Location, Scale and Shape were used for obtaining percentile curves and tables for each sex. Furthermore, a principal components analysis was performed, selecting the number of components by applying the Kaiser's rule and selecting a subset of variables considering the correlation between each variable and the components. Percentile curves and normative values are reported for each test and sex. Physical fitness was better in boys than in girls throughout age groups, except for flexibility that was consistently higher in girls. Two main components were detected throughout age groups: the first one representing body composition and partially cardiorespiratory fitness and the second one muscular fitness. For boys and girls, waist to height ratio had the highest correlations with the first component in four out of six age groups. The highest correlation with the second component, was most frequently observed for the handgrip test both in boys and girls (four out of six age groups). This study provides evidence about the utility of school community actions like DAFIS aimed to track the health-related fitness of children and adolescents. The results suggest that fat mass distribution (i.e., waist to height ratio and waist circumference) and muscular performance (mainly handgrip) concentrate a high proportion physical fitness variance.

Cognitive and Physical Activity-Related Aspects of Children Associated to the Performance of the Crunning Movement

The aim of this investigation was to identify possible related factors associated to the performance of the crunning test in European children and adolescents. A total number of 559 children and adolescents (age range 6-14 years) of which 308 boys (55.1%) and 251 girls (44.9%), from seven European countries, were screened. A questionnaire concerning demographic and personal life-related factors and a cognitive assessment were performed. A regression analysis was conducted with the performance measures of the crunning movement. T-tests and ANCOVA were used to analyze sub-group differences. Boys have greater crunning performance values compared to girls (5.55 s vs. 7.06 s, p < 0.001) and older children perform better than younger ones (R2 -0.23; p < 0.001). Children with healthy and active habits (exercising or spending time with family members vs. reading or surfing the internet) performed better in the test. Children engaged in team sports had better crunning performances compared to those engaged in individual sports (6.01 s vs. 6.66 s, p = 0.0166). No significant association was found regarding cognitive-related aspects in either children engaged in team or individual sports and the crunning performance. Older and male children performed better in the crunning test than younger and female children. Physical activity-related aspects of children's life are associated with crunning movement performance. No association was found between higher cognitive performance and the crunning test results.

Report Card Brazil: systematic review of muscle strength assessment in children and adolescents in Brazil

ABSTRACT The present study aimed to identify and summarize evidence regarding muscle strength (MS) levels in school children and adolescents (≤ 19 years) in Brazil in order to update previously published evidence from the Report Card Brazil project. The systematic search for information was conducted in seven databases, restricted to studies published during the period from January 2018 to December 2019. Thirteen studies were included, which gathered information from 10,135 children and adolescents from seven Brazilian states. Different tests/protocols for assessing MS were identified, however, handgrip strength was the test most adopted in studies (53.8%). The prevalence of children and adolescents with MS levels considered healthy was 29.8%, considering the totality of information, and 27.6% for males and 31.8% for females. Considering full data reviewed by the Report Card Brazil project (data analyzed in this study in addition to those previously published), information regarding the assessment of MS levels in children and adolescents in Brazil came from studies conducted during the period from 2010 to 2019, which included a sample of 15,208 children and adolescents (aged 7-19 years). According to this information, the prevalence of children and adolescents with MS levels considered healthy in this period was 57.8%, 61.1% for males and 58.8% for females.

Association between Obesity and Overweight and Cardiorespiratory and Muscle Performance in Adolescents

The high prevalence of obesity in childhood and adolescence has major public health consequences, since it is associated with various chronic diseases in the short- and long-term. The goal of our study was to examine the possible association between obesity and overweight and cardiorespiratory and muscle performance during a 4-year follow up period in adolescents. The body mass index (BMI) and physical performance of adolescents (360 girls and 348 boys) between 14-18 years of age was measured twice a year, and the possible correlation between overweight and obesity and cardiorespiratory and muscle performances were investigated. Our results revealed that cardiorespiratory performance increased significantly in boys during the 4 years (p < 0.001), but the aerobic performance of girls only showed seasonal fluctuation. Muscle performance significantly increased both in boys and girls (p < 0.001). Inverse association between obesity and cardiorespiratory and muscle performance was proved. Overweight was also inversely correlated with cardiorespiratory performance, but it demonstrated no correlation with muscle strength. Avoiding increased BMI and decreased physical fitness is essential for adolescents' health to prevent short- and long-term adverse effects.

Fitness, physical activity, or sedentary patterns? Integrated analysis with obesity surrogates in a large youth sample

OBJECTIVE

Physical fitness (PF) and physical activity (PA) are inversely associated with body mass index and waist circumference (WC), whereas sedentary time (ST) seems to boost obesity in youth. The aim was to examine the associations of each selected PF test, PA-related exposures, and specific ST patterns with obesity and determine the most relevant ones, in a large sample of a school-aged adolescent.

METHODS

The sample consisted of 2696 Portuguese youth aged 10 to 18 years. Height, weight, and WC were measured. PA and ST components were measured using accelerometry. PF was evaluated using a battery of tests.

RESULTS

The Progressive Aerobic Cardiovascular Endurance Run (PACER) and push-up tests seemed to be the exposures that presented the strongest and more consistent associations with obesity, independent of PA/ST profiles (P < .05). The second exposure of relevance for adolescent obesity level was the breaks in ST with a negative relationship regardless of PA/PF profiles (P < .05). Finally, ST accumulated in periods of <30 minutes, and moderate-to-vigorous PA were favorably associated with obesity, independent of ST/PF.

CONCLUSIONS

Independent of PA and ST, cardiorespiratory fitness (CRF), measured by PACER, was associated with obesity markers. This may be in part due to the dependence of PACER performance on adiposity. Also, limiting prolonged ST and promoting interruptions in this behavior were associated with obesity. These associations suggest that future research should examine other strategies beyond PA promotion for tackling obesity that consider CRF and breaking ST.

Influence of Body Composition on Physical Fitness in Adolescents

Background and objectives: Childhood obesity is one of the main public health issues facing advanced societies. The Spanish population presents 28.6% overweight or obese adolescents, and Extremadura, 22.3%. Physical fitness is considered one of the most important health markers and a common predictor of morbidity and mortality caused by cardiovascular diseases. Thus, fitness tests are needed for health monitoring, especially in overweight and obese adolescents. Therefore, this study aimed to explore the relationship between body composition and physical fitness in adolescents and to analyse if there are differences in physical condition and body composition between the sexes, as well as to compare the different body mass index (BMI) categories to each other. This project also tried to find regression equations to predict the physical fitness test results. Materials and Methods: A total of 225 adolescents were recruited. Weight status was classified according to WHO 2007 standards. Body composition variables (i.e., BMI, fat mass (FM), FM percentage (FM%), and fat-free mass (FFM)) and physical fitness (standing long jump (SLJ), speed–agility (SA), cardiorespiratory fitness (CF), and handgrip strength (HS)) were assessed. Results: Significant differences were found between the sexes in body composition (FM%, FM, and FFM) and physical fitness (SLJ, SA, CF, and HS) (p < 0.001) in favour of males. Significant differences were also found in speed (p = 0.002), CF (p < 0.001), and SLJ (p = 0.004) in favour of normal-weight adolescents compared to overweight and obese adolescents. Contrarily, the outcomes revealed a significantly greater HS (p = 0.014) in favour of overweight and obese participants compared to normal-weight adolescents. Moreover, the results showed that CF and SLJ correlated inversely with BMI, FM%, and total FM. There was also a direct relationship between SA and FM percentage, as well as between HS and FFM. Finally, four fitness test predictive models are proposed based on body composition, age, sex, and BMI. Conclusions: Overweight and obese adolescents have lower levels of physical fitness than their normal-weight peers, regardless of their sex. Normal-ranged body composition values are related to a greater physical fitness in adolescents. Furthermore, this study presents several equations that can help to predict the performance of different fitness tests in adolescents.

Weight Status Is Related to Health-Related Physical Fitness and Physical Activity but Not to Sedentary Behaviour in Children

Purpose: The aim of this research was to describe, examine, and compare the level of physical fitness, physical activity, and sedentary behaviour in pupils aged 6-13 in the Region of Murcia, Spain, in accordance with weight status. Methods: A total of 370 children (166 girls and 204 boys) aged 6-13 (M = 8.7; DT = 1.8) from the Region of Murcia participated in this descriptive and cross-sectional study. Some anthropometric parameters such as body mass index, waist circumference, as well as skinfold measurements were determined. ALPHA-FIT Test Battery was used to evaluate physical fitness. Krece Plus Short Test was used to measure physical activity level and sedentary behaviour. Results: 52.4% of the children presented excess weight (according to the World Health Organization growth references). Regarding boys, statistically significant differences were found for cardiorespiratory fitness (p < 0.001), relative handgrip strength (p < 0.001), lower muscular strength (p < 0.001), speed-agility (p < 0.001), as well as sport activities hours (p = 0.001) among the three weight status groups (normal weight, overweight, and obesity). As for girls, statistically significant differences were found for cardiorespiratory fitness (p = 0.004), relative handgrip strength (p < 0.001), lower muscular strength (p < 0.001), sport activities hours (p = 0.005), as well as physical activity level (assessed by Krece Plus Test) (p = 0.017). A negative statistically significant correlation was found between body mass index and cardiorespiratory fitness (rho = -0.389), lower muscular strength, (rho = -0.340), and relative handgrip strength (rho = -0.547). At the same time, a positive statistically significant relationship between body mass index and the time spent in speed-agility (rho = 0.263) was shown. Regarding waist circumference and body fat percentage, similar relationships were identified. Moreover, a greater probability of having higher cardiorespiratory fitness (OR = 1.58; CI_95% = 1.38-1.82), relative handgrip strength (OR = 1.25; CI_95% = 1.19-1.31), more hours of sport activities (OR = 1.40; CI_95% = 1.19-1.66), and physical activity level (assessed by Krece Plus Test) (OR = 1.23; CI_95% = 1.07-1.42) was noted in the normal weight group. Conclusions: Children that presented normal weight achieved higher results for health-related physical fitness and physical activity than those with excess weight; this was, however, not found to be the case for sedentary behaviour. The authors emphasise the need for changes in public policies and school-based intervention programmes to develop higher levels of both PF and PA in overweight and obese children.

Weight Status, Adherence to the Mediterranean Diet, and Physical Fitness in Spanish Children and Adolescents: The Active Health Study

The aim of this study was to analyze the differences in body composition and physical fitness according to the weight status (normoweight, overweight and obese) and the level of adherence to the Mediterranean diet (MD; low, medium or high), in physically active children and adolescents. Furthermore, this study also analyzed the relationship between body composition and physical fitness with Body Mass Index (BMI), fat mass and the level of adherence to the MD. In total, 1676 participants aged 6–17 from different municipal sports schools participated in this cross-sectional study. Data on adherence to the MD (a KIDMED questionnaire), anthropometric measurements, body composition and physical fitness parameters (the 20-m shuttle run test and muscular strength) were collected. A total of 43.5% of the sample were presented as overweight and obese, and only 35.7% had high or optimal adherence to the MD. The results revealed that a normoweight status was associated with greater cardiorespiratory fitness (p < 0.05; ES: 0.50 to 0.67) and lower-body muscular strength (p < 0.05; ES: 0.58 to 1.10). The overweight group showed more significant results than the other groups in handgrip strength (p < 0.01). Greater adherence to the MD in this population indicated better physical fitness, but only in boys. It is concluded that normoweight status and optimal adherence to the MD in children and adolescents are associated with health benefits, which are significant in the body composition and the effect on physical fitness.

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.

Relationship between Adherence to the Mediterranean Diet and Body Composition with Physical Fitness Parameters in a Young Active Population

The current study aimed at analyzing the relationship between body composition, adherence to the Mediterranean diet (MD), and physical fitness (PF) in a young active population. A total of 1198 athletes (boys = 875; girls = 323) enrolled in different municipal sports schools participated in this study. Data on adherence to the MD (KIDMED questionnaire), anthropometric measurements, and PF (20 m shuttle run test, handgrip strength, vertical jump and forced spirometry) were collected. Results show that the pubertal boys had a higher score in the KIDMED test than the prepubertal ones (+0.38, p = 0.28). Moreover, boys with better adherence to the MD had significantly higher results in handgrip strength (+12.20 regarding low MD group and +9.13 regarding medium MD group, p < 0.05), as well as in forced vital capacity (FVC) (+0.66 regarding low MD group and 0.29 regarding medium MD group, p < 0.05). No differences were found in the girls. Finally, the result of the KIDMED test is a variable with a positive and significant relationship with cardiorespiratory fitness, along with the FVC, percentage of fat mass, and performance in the vertical jump (p < 0.05). It is concluded that adherence to the MD could show a relationship with various PF variables in boys and could be a predictor of cardiorespiratory fitness in both cases.

Prevalence and Factors Associated with Thinness in Rural Polish Children

A lot of attention has been focused on obesity, however, the other extreme—thinness—may lead to inhibition of physical and intellectual development. The aim was to assess the prevalence of thinness and determine the associated factors in children from rural populations. We used data from the cross-sectional sample of 3048 children, examined in schools from a district in southern Poland. The sample included 89% of the district departments, and included a proportion of rural and small town populations—a representative one for the region. Thinness was determined based on the criteria proposed by Cole and Lobstein. Biological, sociodemographic and lifestyle factors were analysed. The odds ratio (OR) and 95% confidence interval (CI) were calculated using logistic regression analysis. The prevalence of thinness was 11.5% in boys and 13.5% in girls. In the younger group, it was similar in boys and girls at 11.8%; whereas in the older group, it was 11.1% and 14.5%, respectively. The prevalence of thinness Grade 3 in girls was two times higher than in boys. The increased index of leisure time physical activity was connected with thinness in prepubertal boys. The mechanism determining the development of thinness is very complex and further exploration of this trend is recommended.

Comparison of gait patterns and functional measures between Charcot-Marie-Tooth disease type I and II in children to young adults

INTRODUCTION

Charcot-Marie-Tooth (CMT) disease is an inherited peripheral neuropathy that causes progressive distal extremity nerve degeneration and muscle atrophy which can negatively impact function, gait and quality of life. The purpose of this study was to determine if differences exist in gait patterns, clinical examination and functional measures between CMT type I (CMT1) and type II (CMT2) in childhood to young adults. It was hypothesized that individuals with CMT2 would present with greater ankle weakness, increased and/or prolonged ankle dorsiflexion in stance during gait and demonstrate greater disease severity on the CMT Pediatric Scale (CMTPedS) compared to CMT1.

METHODS

Twenty-seven individuals diagnosed with CMT1 or CMT2 underwent three-dimensional gait analysis, clinical examination and evaluation of disease severity using the CMTPedS. Subjects groups were divided based on CMT type: CMT1 (n = 20) and CMT2 (n = 7).

RESULTS

CMT2 group presented with a trend towards increased plantar flexion weakness compared to CMT1 of 61.1 ± 58.1 N to 137.9 ± 51.4 N (p < 0.012), respectively. CMT2 presented with significantly decreased dorsiflexion strength, 31.9 ± 30.9 N, compared to CMT1, 80.4 ± 37.4 N, (p < 0.0052) which negatively influenced gait patterns in CMT2. Associated gait findings demonstrated CMT2 group with significantly decreased peak ankle power generation in stance compared to CMT1 (1.46 ± 0.39 W/kg to 3.13 ± 0.98 W/kg respectively) (p < 0.0001). CMT1 was more likely to demonstrate a dorsiflexion moment in loading response than CMT2. There was a consistent trend of a higher score and therefore greater disease severity for CMT2 based on CMTPedS.

CONCLUSION

Study results suggest that at a given age, individuals with CMT2 have greater limitations in terms of gait function and disease severity than individuals with CMT1. Overall the CMT2 was shown to have greater gait limitations at the ankle during stance and swing with associated compensatory mechanisms at the knee and hip in swing.

Análisis de la condición física según sexo, edad, índice de masa corporal y nivel de actividad física en estudiantes de primaria en España

Introducción. La evidencia científica sugiere que la calidad de vida de los escolares se relaciona de forma directa con el estado de su condición física (CF).Objetivo. Analizar la CF según edad, sexo, índice de masa corporal (IMC) y nivel de actividad física en estudiantes de primaria.Materiales y métodos. Se realizó un estudio descriptivo transversal con 103 escolares entre 8 y 12 años de España. La CF se midió mediante la batería ALPHA-Fitness y la actividad física, con el cuestionario Physician-based Assessment and Counseling for Exercise. Los participantes se categorizaron según su nivel de actividad física (no activos versus activos) y su IMC (normo-peso versus sobrepeso-obesidad). Para el análisis se aplicó estadística paramétrica.Resultados. Los varones tuvieron un mejor nivel de CF, pero en ambos sexos se observó un leve incremento de esta a medida que aumentaba la edad. Los escolares con normopeso o activos físicamente tuvieron una mejor capacidad aeróbica y una composición corporal más saludable.Conclusión. Mantener niveles óptimos de CF a lo largo de la vida requiere de la adopción de un estilo de vida saludable desde la infancia, por tanto, es necesario promover la práctica autónoma de actividad física en los escolares.

Normative health-related fitness values for French children: The Diagnoform Programme

The primary objective of this study was to establish sex- and age-specific physical fitness percentiles for French children. The secondary aim was to assess sex, weight status, and age differences for physical fitness levels in French children. A sample of 31 484 children (16 023 boys, 15 461 girls) aged 6-11 years participated in the Diagnoform programme. Cardiorespiratory fitness, muscular endurance, speed, flexibility, and agility were assessed in this national programme. Percentile values were estimated as a function of age stratified by sex using a parametric method providing smooth centile curves and explicit formulae for the centile estimates. Values from the 10th to the 90th percentile are reported. The influence of body weight according to sex on the physical fitness level was also examined using an analysis of covariance adjusted for age. Physical fitness levels were slightly better in boys, except for agility and flexibility, in which girls performed better (Cohen's coefficient, 0.20-0.45; P < .001). All physical fitness tests were significantly associated with age (P < .0001). In general, overweight and obese children had a significantly poorer physical fitness level compared with their normal-weight counterparts (P < .05). No difference was found between thin and normal-weight boys and girls, except for agility (P < .05). Reference values provide normative data for French children, and these data should be useful for identifying special needs for appropriate intervention programmes.

Physical Fitness and Anthropometric Values Among Lithuanian Primary School Children: Population-Based Cross-Sectional Study

Emeljanovas, A, Mieziene, B, Cesnaitiene, VJ, Fjortoft, I, and Kjønniksen, L. Physical fitness and anthropometric values among Lithuanian primary school children: population-based cross-sectional study. J Strength Cond Res 34(2): 414-421, 2020-The purpose of the current study was to derive representative reference scores on anthropometric measures and test scores for the musculoskeletal, motor, and cardiorespiratory fitness of Lithuanian primary school children according to age and sex. This cross-sectional design study included 3,456 Lithuanian first- to fourth-grade children from age 6 to 10 years. Physical fitness was measured using a nine-item test battery developed by Fjørtoft et al. The test battery included the following tests: standing broad jump (explosive strength), jumping a distance of 7 m on 2 feet, jumping a distance of 7 m on 1 foot (both tests indicate leg muscle strength), throwing a tennis ball with one hand, and pushing a medicine ball with 2 hands (both tests indicate arm muscle strength). These tests measured musculoskeletal fitness. In addition, there were measures of a 10 × 5-m shuttle run (agility), running 20 m as fast as possible (speed), and climbing wall bars (coordination)-general tests of motor fitness. Reduced 6-minute Cooper test (endurance) measured cardiorespiratory fitness. A Student's t test and analysis of variance were performed to indicate differences between sexes and across age, respectively. The significant differences in mean scores in anthropometric and fitness means indicated that boys had higher scores than girls, and older children scored higher than younger children (p < 0.05). Data on normative sex- and age-specific percentile values (3rd, 10th, 25th, 50th, 75th, 90th, and 97th) for physical fitness tests in Lithuanian primary school children are provided. These data are useful for educational settings, parents, clinicians, sports organizations, and sports clubs in identifying problems or outstanding performance and providing sports programs that develop children's athletic performance.

A Review of Countermovement and Squat Jump Testing Methods in the Context of Public Health Examination in Adolescence: Reliability and Feasibility of Current Testing Procedures

BACKGROUND

In the context of a public health physical fitness (PF) examination in adolescence, a countermovement jump (CMJ) and a squat jump (SJ) are two vertical jump (VJ) tests widely used to evaluate lower limb muscle strength and power, respectively. The main criticism of both the CMJ and SJ test is the lack of test standardization. Therefore, the objectives of this review are: (a) to gather information about both jumps; (b) to investigate whether it is possible to identify common procedures referred to in the CMJ and SJ technical execution, and (c) to design standard operating procedures (SOPs) to promote CMJ and SJ standardization in an adolescent population aged 12-18 years.

METHODS

The review partially adopted the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Statement (PRISMA). Due to growing attention in monitoring physical health through field tests in recent years, articles were collected using the PubMed, Web of Science, and Scopus databases from January 2009 to July 2019. Original articles in which CMJ or SJ were used to assess the muscular strength in adolescents were eligible for further analysis. Articles written in English was imposed as a limit.

RESULTS

A total of 117 studies met the inclusion criteria. The description of the CMJ and SJ test procedures was different within the literature, with discrepancies in the jump technique, number of jumps, and measurement devices used.

CONCLUSIONS

A lack of method standardization for both the CMJ and the SJ test was identified. Based on the literature, SOPs for both VJs were proposed. These are useful in the context of public health PF examination in adolescents, as they facilitate an unbiased comparison of jump performance data between published studies.

Balance impairment in pediatric charcot-marie-tooth disease

INTRODUCTION

Balance impairment contributes to gait dysfunction, falls, and reduced quality of life in adults with Charcot-Marie-Tooth disease (CMT) but has been minimally examined in pediatric CMT.

METHODS

The CMT Pediatric Scale (CMTPedS) was administered to 520 children with CMT. Associations between balance function (Bruininks-Oseretsky Test of Motor Proficiency [BOT-2]) and sensorimotor and gait impairments were investigated.

RESULTS

Daily trips/falls were reported by 42.3% of participants. Balance (BOT-2) varied by CMT subtype, was impaired in 42% of 4-year-olds, and declined with age (P < 0.001). Vibration (P < 0.001), pinprick (P < 0.004), ankle dorsiflexion strength (P < 0.001), and foot alignment (P < 0.004) were associated with BOT-2 balance (adjusted R2 = 0.28). The visual dependence of balance increased with age.

DISCUSSION

Balance impairment occurs from a young age in children with CMT. Balance intervention studies are required in pediatric CMT and should consider the degree of sensorimotor impairment, foot malalignment, and visual dependence. Muscle Nerve, 2019.

Feasibility and Reliability of Physical Fitness Tests among Colombian Preschool Children

The aim of the study was to assess the feasibility and reliability of physical fitness field tests used in the "Fuprecol kids" study among Colombian preschool children aged 3-5 years. A total of 90 preschoolers aged 3-5 years participated in the study. Weight, height, waist circumference, cardiorespiratory fitness (CRF), musculoskeletal fitness (handgrip strength and standing broad jump), speed-agility (4 × 10 m shuttle run), and flexibility (sit and reach test) components were tested twice (two weeks apart). The feasibility of the tests (preschoolers able to complete the test) ranged from 96% in the CRF test to 100% in the musculoskeletal fitness, speed-agility, and flexibility tests. Overall, the %TEMs were 0.625% for the weight, 0.378% for the height, 1.035% for the body mass index, and 0.547 % for the waist circumference. In addition, all tests were substantial reliable, for CRF (in stages and laps, concordance correlation coefficient = 0.944 and 0.941, respectively) in both sexes and flexibility (concordance correlation coefficient = 0.949) in girls. There were no significant differences in fitness test-retest mean differences in the boys (P > 0.05), except in CRF (laps P = 0.017). In girls, there were differences in CRF (stages (P = 0.017) and laps (P= 0.013)), and flexibility (P = 0.002) variables. The results from this study indicate that the "Fuprecol kids" battery of tests, administered by physical education teachers, was reliable and feasible for measuring components of physical fitness in preschoolers in a school setting in Colombia.

The Relationship of Age and BMI with Physical Fitness in Futsal Players

The aim of this study was to examine the relationship of age and body mass status with field and laboratory measures of physical fitness in futsal players. Futsal players (n = 65, age 12.9 ± 2.8 years), who were classified into U11 (n = 28, 9-11 years), U13 (n = 21, 11-13 years), and adults (n = 16, >18 years), performed a physical fitness battery consisting of both laboratory and field tests. A similar prevalence of overweight (25%) was observed in all age groups (χ² = 1.94, p = 0.380, φ = 0.17). Age groups differed for all parameters, except body fat percentage, with adult players showing higher values than the younger groups (p < 0.05). U13 was heavier, taller, and had larger fat-free mass than U11 (p < 0.05). Adult players had superior values than their younger counterparts for all physical fitness parameters (p < 0.05). Body mass index (BMI) correlated inversely with aerobic capacity (U13), jumping ability, relative isometric muscle strength, and relative mean power in the Wingate anaerobic test (WAnT) (U11) (p < 0.05). Also, it correlated directly with absolute isometric muscle strength (U11) and peak power, mean power (all groups), and fatigue index (U11, U13) in WAnT (p < 0.05). Considering the results of this study, it was concluded that the prevalence of overweight in futsal players should be an important concern for practitioners working in this team sport. Optimizing BMI should be considered as a training and nutrition goal in order to improve sport performance.

Injury Prevention Strategies for Adolescent Cricket Pace Bowlers

Adolescent cricket pace bowlers are prone to non-contact shoulder, low back and lower-limb injuries. Exercise-based injury prevention programmes (IPPs) are effective for reducing non-contact injuries in athletes; however, a specific programme for adolescent pace bowlers has not been published. This paper therefore seeks to provide a rationale for the development of an exercise-based IPP specific for adolescent pace bowlers. It also outlines design principles and provides an example exercise programme that can be implemented at the community level. In addition, the paper addresses other injury prevention techniques concerned with the prescription of appropriate bowling loads and the modification of poor bowling biomechanics. Performing an exercise-based IPP before cricket training could reduce injury rates in adolescent pace bowlers. Eccentric strengthening exercises can be employed to target injuries to the posterior shoulder muscles, hip adductors and hamstring muscles. The risk of low back, knee and ankle injury could also be reduced with the inclusion of dynamic neuromuscular control exercises and trunk extensor endurance exercises. Other prevention strategies that need to be considered include the modification of poor bowling biomechanics, such as shoulder counter-rotation and lateral trunk flexion. Coaches and players should also aim to quantify bowling load accurately and coaches should use this information to prescribe appropriate individualised bowling loads. Specifically, players would benefit from avoiding both long periods of low load and acute periods when load is excessively high. Future evidence is needed to determine the effectiveness of the example programme outlined in this paper. It would also be beneficial to investigate whether the modification of bowling biomechanics is achievable at the non-elite level and if bowling load can be accurately measured and manipulated within a community-level population.

Muscular Fitness and Cardiovascular Risk Factors in Children and Adolescents: A Systematic Review

Rodrigues de Lima, T, Custódio Martins, P, Henrique Guerra, P, and Augusto Santos Silva, D. Muscular fitness and cardiovascular risk factors in children and adolescents: A systematic review. J Strength Cond Res 34(8): 2394-2406, 2020-The purpose of this study was to identify and summarize the relationships between muscular fitness (MF) and individual components of metabolic syndrome (high waist circumference [WC], high blood pressure [BP], high systolic BP [SBP], high diastolic BP [DBP], high triglycerides [TG], fasting blood glucose [FG], and low HDL cholesterol levels [HDL-C]) in children and adolescents. A systematic review was conducted in 5 electronic databases, with complementary searches in reference lists, and the inclusion criteria were children and adolescents (age group up to 19 years of age) with no special clinical conditions. In all articles, risk of bias was analyzed by a standardized instrument. Of the 5,973 articles initially identified, 21 were included, with data on 22,261 children and adolescents. Higher MF values were associated with lower TG (n = 07) and WC values (n = 15). Different results in relation to the relationship between MF and SBP (n = 10) and MF and DBP (n = 07) were verified. In addition, there was no relationship between MF and FG (n = 06). In addition, inconclusive results were verified in the relationship between MF and HDL-C (n = 07). Concluded higher MF values were related to lower WC values and lower TG concentrations.

Physical fitness reference standards for preschool children: The PREFIT project

OBJECTIVES

Reference values are necessary for classifying children, for health screening, and for early prevention as many non-communicable diseases aggravate during growth and development. While physical fitness reference standards are available in children aged 6 and older, such information is lacking in preschool children. Therefore, the purposes of this study were (1) to provide sex-and age-specific physical fitness reference standards for Spanish preschool children; and (2) to study sex differences across this age period and to characterise fitness performance throughout the preschool period.

DESIGN

Cross-sectional.

METHODS

A total of 3179 preschool children (1678 boys) aged 2.8-6.4 years old from Spain were included in the present study. Physical fitness was measured using the PREFIT battery.

RESULTS

Age- and sex-specific percentiles for the physical fitness components are provided. Boys performed better than girls in the cardiorespiratory fitness, muscular strength, and speed-agility tests over the whole preschool period studied and for the different percentiles. In contrast, girls performed slightly better than boys in the balance test. Older children had better performance in all fitness tests than their younger counterparts.

CONCLUSIONS

Our study provides age- and sex-specific physical fitness reference standards in preschool children allowing interpretation of fitness assessment. Sexual dimorphism in fitness tests exists already at preschool age, and these differences become larger with age. These findings will help health, sport, and school professionals to identify preschool children with a high/very low fitness level, to examine changes in fitness over time, and to analyse those changes obtained due to intervention effects.