Comparison Between Cardiorespiratory Fitness and Functions of Cognitive Control in Adolescents: A Tracking Study of 3 Years

PURPOSE

Compare tracking groups with cognitive control functions and plasma brain-derived neurotrophic factors concentrations from childhood to adolescence.

METHODS

This is a prospective study with 3 years of follow-up. At baseline, data from 394 individuals were collected (11.7 y), and data were obtained from 134 adolescents (14.9 y) at the 3-year follow-up. At both time points, anthropometric and maximal oxygen uptake data were collected. Cardiorespiratory fitness (CRF) groups were classified into high or low CRF. At follow-up, cognitive outcomes were collected via the Stroop and Corsi block test; plasma brain-derived neurotrophic factors concentrations were also analyzed.

RESULTS

Comparisons demonstrated that maintaining high CRF over 3 years results in shorter reaction time, better inhibitory control, and higher working memory values. Likewise, the group that moved from low to high CRF over 3 years presented better reaction time. Plasma brain-derived neurotrophic factors concentrations were higher for the group that increased its CRF over the 3 years in relation to the low-low group (90.58 pg·mL-1; P = .004). However, after scaling by an allometric approach, differences were only found for reaction time and working memory between high-high and high-low groups.

CONCLUSION

Maintaining high CRF over 3 years was positively related to reaction time and working memory in relation to adolescents that decreased their levels of CRF.

Association between cardiorrespiratory fitness and cognitive control: is somatic maturity an important mediator?

BACKGROUND

Recently some articles presented information related to the possible effect of maturity over the cognitive control and cardiorespiratory fitness, however little is known about the real effects of maturity in the relation of these variables. In this sense, the purpose of this study was to examine the potential mediating role of somatic maturity on the association between cardiorespiratory fitness (CRF) and cognitive control.

METHODS

This three-year longitudinal research comprises two data collection groups: a baseline conducted in 2016 with 394 adolescents (aged 11.7 ± 0.6 years) and a follow-up in 2019 with 134 adolescents (aged 14.9 ± 0.7 years). Anthropometry data, 20-m shuttle run test and peak height velocity (PHV) to determine the maximum oxygen uptake (VO_2max) and somatic maturity, respectively, were collected at both sampling times. In parallel, the Sociodemographic and cognitive control function variables were included in the follow-up to evaluate the inhibitory control (by the Stroop test) and the visuo-spatial working memory (by the Corsi block-tapping test). Associations between CRF and cognitive functions were computed by multiple linear regression, with mediation as a function of PHV.

RESULTS

CRF exhibited transversal associations with reaction time in congruent (β = -0.004; p = 0.001) and incongruent (β = -0.005; p = 0.004) stimulus-responses. Meanwhile, the variation in VO_2max over the three year-study had a significant impact on the reaction time of congruent (β = -0.006; p = 0.001) and incongruent (β = -0.006; p = 0.012) responses at follow-up. However, PHV did not show a significant association with the cognitive functions, indicating no mediating role.

CONCLUSIONS

Although the associations between CRF and the cognitive functions exhibited great transversal and longitudinal impacts, somatic maturity did not affect the cognitive control functions, associating exclusively with CRF.

Assessment of physical fitness during pregnancy: validity and reliability of fitness tests, and relationship with maternal and neonatal health - a systematic review

Objectives

To systematically review studies evaluating one or more components of physical fitness (PF) in pregnant women, to answer two research questions: (1) What tests have been employed to assess PF in pregnant women? and (2) What is the validity and reliability of these tests and their relationship with maternal and neonatal health?

Design

A systematic review.

Data sources

PubMed and Web of Science.

Eligibility criteria

Original English or Spanish full-text articles in a group of healthy pregnant women which at least one component of PF was assessed (field based or laboratory tests).

Results

A total of 149 articles containing a sum of 191 fitness tests were included. Among the 191 fitness tests, 99 (ie, 52%) assessed cardiorespiratory fitness through 75 different protocols, 28 (15%) assessed muscular fitness through 16 different protocols, 14 (7%) assessed flexibility through 13 different protocols, 45 (24%) assessed balance through 40 different protocols, 2 assessed speed with the same protocol and 3 were multidimensional tests using one protocol. A total of 19 articles with 23 tests (13%) assessed either validity (n=4), reliability (n=6) or the relationship of PF with maternal and neonatal health (n=16).

Conclusion

Physical fitness has been assessed through a wide variety of protocols, mostly lacking validity and reliability data, and no consensus exists on the most suitable fitness tests to be performed during pregnancy.

PROSPERO registration number

CRD42018117554.

O3-7 Prenatal predictors and physical fitness in Spanish Youth: the UP&DOWN study

Background

Physical fitness outcomes are considered major health biomarkers to assess and monitor exercise-based interventions across the lifespan. Recent studies provide evidence that many adult and childhood chronic diseases should have their origins in gestational or fetal life. To date, a few pioneering studies have showed associations between prenatal predictors and selected physical fitness tests (strength and cardiorespiratory). Nevertheless, there is a lack of knowledge about the influence of prenatal factors on childhood performance on a comprehensive fitness test battery including speed and coordination. The innovative purpose of the current study is to analyse the relative weight of prenatal predictors on schoolchildren's physical fitness outcomes.

Methods

We obtain data from1188 children (571 girls) aged 6-11 years and 1020 adolescents (495 girls) aged 12-17 years. Prenatal predictors (gestational anemia, gestational diabetes and length of gestation) were self-reported from offspring's mothers. The ALPHA fitness test battery for youth was used to assess offsprinǵs physical fitness (muscular strength, motor fitness and cardiorespiratory fitness). Regression analysis were performed to predict the different physical fitness outcomes.

Results

The main findings of the present study indicate that the presence of gestational anemia significantly predicted lower scores of lower-body explosive muscular strength (standing long jump) and motor fitness (4x10-m shuttle run) and predicted moderately lower scores of upper-body isometric muscular strength (handgrip strength test). (p>.005; p>.008; p>.075 respectively). Moreover, gestational anemia better predicted lower scores of muscular strength and motor fitness in children than in adolescents (standing long jump, handgrip strength test, 4x10-m shuttle run) (p>.001; p>.051; p > 0.18, respectively). While gestational age and length of gestation (>34- ?42 weeks) predict better cardiorespiratory fitness (20 m shuttle-run test) (p>.023; p>.023 respectively) and motor fitness (4x10 m shuttle; moderately for length of gestation). (p>.020; p > 0.55 respectively).

Conclusion

This evidence suggests that preventive strategies by health-care institutions, policy makers and technicians must be two-fold: a) to effectively reduce gestational anemia in order to prevent offsprinǵs predisposition to low levels of physical fitness, and b) to intervene with toddlers and children at risk to provide tailored physical activity programs and regular physical fitness evaluation.

Reliability of Field-Based Fitness Tests in Adults: A Systematic Review

BACKGROUND

Physical fitness is a powerful predictor of morbidity and mortality, and is therefore a useful indicator for public health monitoring. To assess physical fitness, field-based tests are time-efficient, inexpensive, have minimal equipment requirements, and can be easily administered to a large number of individuals.

OBJECTIVE

The objective of this systematic review was to examine the reliability of existing field-based fitness tests used in adults aged 19-64 years.

METHODS

A systematic search of two electronic databases (MEDLINE and Web of Science) was conducted from inception to 8 June 2021 by two independent researchers. Each study was classified as high, low, or very low quality according to the description of the participants, the time interval between measurements, the description of the results, and the appropriateness of statistics. Three levels of evidence (strong, moderate, and limited) were established according to the number of studies and the consistency of their findings. The study protocol was registered in the International Prospective Register of Systematic Reviews (PROSPERO reference number, CRD42019118480).

RESULTS

Of 17,010 records identified, 129 original studies examining the reliability of field-based fitness tests in adults were considered eligible. The reliability was assessed of tests of cardiorespiratory fitness (33 studies: 30 of high quality), musculoskeletal fitness (92 studies: 78 of high quality), and motor fitness (22 studies, all of high quality). There was strong evidence indicating: (i) the high reliability of the cardiorespiratory fitness tests: 20-m shuttle run, 6-min step, and 6-min walk; (ii) the high reliability of the musculoskeletal fitness tests: handgrip strength, back-leg strength, Sorensen, trunk flexion sustained, 5-reps sit-to-stand, sit-and-reach and toe-touch, and moderate reliability bilateral side bridge and prone bridge tests; and (iii) the moderate reliability and low reliability, respectively, of the motor fitness tests T-test and single-leg stand. We found moderate evidence indicating the moderate or high reliability of the following tests: Chester, sit-up, partial curl-up, flexion-rotation trunk, timed stair ascent, pull-up, bent-arm hang, standing broad jump, hop sequence, trunk lift, timed-up-and-go, and hexagon agility. Evidence for the reliability of balance and gait speed tests was inconclusive. Other field-based fitness tests demonstrated limited evidence, mainly due to there being only few studies.

CONCLUSIONS

This review provides an evidence-based proposal of the more reliable field-based fitness tests for adults aged 19-64 years. Our findings identified a need for more high-quality studies designed to assess the reliability of field-based tests of lower and upper body explosive and endurance muscular strength, and motor fitness (i.e., balance and gait speed tests) in adults.

Validity and Reliability of the International FItness Scale (IFIS) in preschool children

OBJECTIVES

Examine the validity and reliability of parent-reported International FItness Scale (IFIS) in preschool-age children.

METHOD

A cross-sectional study of 3051 Spanish preschoolers (3-5 years). Fitness was measured by PREFIT fitness test battery and reported by parents using an adapted version of the IFIS. Waist circumference was evaluated, and the waist-to-height ratio (WHtR) was calculated. Seventy-six parents of randomly selected schoolchildren completed the IFIS twice (two weeks apart) for a reliability assessment.

RESULTS

ANCOVA, adjusted for sex, age and WHtR, showed that preschoolers who were scored by their parents as having average-to-very good fitness had better levels of measured physical fitness than those preschoolers who were classified as having "very poor/poor" fitness levels (18.1laps to 22.1laps vs 15.6laps for cardiorespiratory fitness; 6.6 kg to 7.5 kg vs 5.3 kg for muscular fitness-handgrip-; 71.7 cm to 76.4 cm vs 62.0 cm for muscular fitness-standing long jump-; 17.2s to 16.2s vs 18.2s for speed/agility; and 11.2s to 15.6s vs 8.7s for balance; p < 0.001). The weighted kappa for concordance between parent-reported fitness levels and objective assessment was poor (κ ≤0.18 for all fitness measures). Overall, the mean values of the abdominal adiposity indicators were significantly lower in high-level fitness categories reported by parents than in low-level fitness categories (p < 0.05). The test-retest reliability of IFIS items ranged from 0.46 to 0.62.

CONCLUSIONS

The reliability of the parent-reported IFIS are acceptable, but the concordance between parents reported and objectively measures fitness levels is poor, suggesting that parents' responses may not be able to correctly classify preschoolers according to their fitness level.

The Effect of the COVID-19 Lockdown on the Position-Specific Match Running Performance of Professional Football Players; Preliminary Observational Study

The COVID-19 pandemic interrupted professional football in the 2019/2020 season, and football experts anticipate that the consequences of lockdown measures will negatively affect the physical performance of players once competition restarts. This study aimed to evaluate position-specific match running performance (MRP) to determine the effect of COVID-19 lockdowns on the physical performance of professional football players. Players’ MRPs (n = 124) were observed in matches before and after the COVID-19 lockdown in the 2019/2020 season of the highest level of national competition in Croatia and were classified according to player position: central defenders (CD; n = 42), fullbacks (FB; n = 20), midfielders (MF; n = 46), and forwards (FW; n = 16). The MRPs were measured using Global Positioning System, and included the total distance covered, low-intensity running (≤14.3 km/h), running (14.4–19.7 km/h), high-intensity running (≥19.8 km/h), total accelerations (>0.5 m/s²), high-intensity accelerations (>3 m/s²), total decelerations (less than –0.5 m/s²), and high-intensity decelerations (less than –3 m/s²). The results indicated that, in matches after the COVID-19 lockdown, (i) CDs and FBs featured lower running and high-intensity running (t-value: from 2.05 to 3.51; all p < 0.05; moderate to large effect sizes), (ii) MFs covered a greater distance in low-intensity running and achieved a lower number of total accelerations, and total and high-intensity decelerations (t-value: from –3.54 to 2.46; all p < 0.05, moderate to large effect sizes), and (iii) FWs featured lower high-intensity running (t-value = 2.66, p = 0.02, large effect size). These findings demonstrate that the physical performances of football players from the Croatian first division significantly decreased in matches after the COVID-19 lockdown. A combination of inadequate adaptation to football-specific match demands and a crowded schedule after the competition was restarted most likely resulted in such an effect.

Mediation Role of Physical Fitness and Its Components on the Association Between Distribution-Related Fat Indicators and Adolescents' Cognitive Performance: Exploring the Influence of School Vulnerability. The Cogni-Action Project

Background: Physical fitness and fatness converge simultaneously modulating cognitive skills, which in turn, are associated with children and adolescents’ socioeconomic background. However, both fitness components and fat mass localization are crucial for understanding its implication at the cognitive level.

Objective: This study aimed to determine the mediation role of a global physical fitness score and its components on the association between different fatness indicators related to fat distribution and adolescents’ cognitive performance, and simultaneously explore the influence of school vulnerability.

Methods: In this study, 1,196 Chilean adolescents participated (aged 10–14; 50.7% boys). Cardiorespiratory fitness (CRF), muscular fitness (MF), and speed-agility fitness (SAF) were evaluated, and a global fitness score (GFS) was computed adjusted for age and sex (CRF + MF + SAF z-scores). Body mass index z-score (BMIz), sum-of-4-skinfolds (4SKF), and waist-to-height ratio (WHtR) were used as non-specific, peripheral, and central adiposity indicators, respectively. A global cognitive score was computed based on eight tasks, and the school vulnerability index (SVI) was registered as high, mid or low. A total of 24 mediation analyses were performed according to two models, adjusted for sex and peak high velocity (Model 1), and adding the school vulnerability index (SVI) in Model 2. The significance level was set at p < 0.05.

Results: The fitness mediation role was different concerning the fatness indicators related to fat distribution analyzed. Even after controlling for SVI, CRF (22%), and SAF (29%), but not MF, mediated the association between BMIz and cognitive performance. Likewise, CRF, SAF and GFS, but not MF, mediated the association between WHtR and cognitive performance (38.6%, 31.9%, and 54.8%, respectively). No mediations were observed for 4SKF.

Conclusion: The negative association between fatness and cognitive performance is mitigated by the level of adolescents’ physical fitness, mainly CRF and SAF. This mediation role seems to be more consistent with a central fat indicator even in the presence of school vulnerability. Strategies promoting physical fitness would reduce the cognitive gap in children and adolescents related to obesity and school vulnerability.

Criterion-Related Validity of Field-Based Fitness Tests in Adults: A Systematic Review

We comprehensively assessed the criterion-related validity of existing field-based fitness tests used to indicate adult health (19–64 years, with no known pathologies). The medical electronic databases MEDLINE (via PubMed) and Web of Science (all databases) were screened for studies published up to July 2020. Each original study’s methodological quality was classified as high, low and very low, according to the number of participants, the description of the study population, statistical analysis and systematic reviews which were appraised via the AMSTAR rating scale. Three evidence levels were constructed (strong, moderate and limited evidence) according to the number of studies and the consistency of the findings. We identified 101 original studies (50 of high quality) and five systematic reviews examining the criterion-related validity of field-based fitness tests in adults. Strong evidence indicated that the 20 m shuttle run, 1.5-mile, 12 min run/walk, YMCA step, 2 km walk and 6 min walk test are valid for estimating cardiorespiratory fitness; the handgrip strength test is valid for assessing hand maximal isometric strength; and the Biering–Sørensen test to evaluate the endurance strength of hip and back muscles; however, the sit-and reach test, and its different versions, and the toe-to-touch test are not valid for assessing hamstring and lower back flexibility. We found moderate evidence supporting that the 20 m square shuttle run test is a valid test for estimating cardiorespiratory fitness. Other field-based fitness tests presented limited evidence, mainly due to few studies. We developed an evidence-based proposal of the most valid field-based fitness tests in healthy adults aged 19–64 years old.

Objectively measured physical activity and academic performance in school-aged youth: The UP&DOWN longitudinal study

To examine the longitudinal relationships between objectively measured total volume and specific intensities of physical activity (PA) with academic performance in a large sample of youth aged 6-18 years. A longitudinal study of 1046 youth (10.04 ± 3.10 years) from Spain was followed over 2 years. PA (volume and intensity) was measured by accelerometry. Academic performance was assessed through grades reported on the transcript at the end of the academic year (Mathematics, Language, an average of these two core subjects, and grade point average [GPA]). Longitudinal relationships between PA and four indicators of academic performance were examined using covariance and regression analyses, adjusted for a variety of confounders. Youth Quartile 2 for PA volume at baseline obtained better scores than those who participated in Quartiles 1 or 4 volumes of PA in GPA 2 years later (p = 0.006). There were generally no longitudinal associations between specific PA intensities and any of the academic performance indicators (all p > 0.170). However, a change in light PA over 2 years was inversely associated with three academic indicators in youth (β_range , -.103 to - 090; all P < 040). Findings suggest that participants in Quartile 2 volume of PA had a better GPA in comparison with Quartiles 1 and 4 volumes of PA during youth, but there was no association with changes in PA volume over time. PA intensity was generally unrelated to academic performance during youth. However, there was an inverted u-shape relationship between light PA changes and GPA.

Mediation role of cardiorespiratory fitness on the association between fatness and cardiometabolic risk in European adolescents: The HELENA study

PURPOSE

This study was aimed to analyze the mediation role of cardiorespiratory fitness (CRF) on the association between fatness and cardiometabolic risk scores (CMRs) in European adolescents.

METHODS

A cross-sectional study was conducted in adolescents (n = 525; 46% boys; 14.1 ± 1.1 years old, mean ± SD) from 10 European cities involved in the Healthy Lifestyle in Europe by Nutrition in Adolescence study. CRF was measured by means of the shuttle run test, while fatness measures included body mass index (BMI), waist to height ratio, and fat mass index estimated from skinfold thicknesses. A clustered CMRs was computed by summing the standardized values of homeostasis model assessment, systolic blood pressure, triglycerides, total cholesterol/high-density lipoprotein cholesterol ratio, and leptin.

RESULTS

Linear regression models indicated that CRF acted as an important and partial mediator in the association between fatness and CMRs in 12-17-year-old adolescents (for BMI: coefficients of the indirect role β = 0.058 (95% confidence interval (95%CI): 0.023-0.101), Sobel test z = 3.11 (10.0% mediation); for waist to height ratio: β = 4.279 (95%CI: 2.242-7.059), z =3.86 (11.5% mediation); and for fat mass index: β = 0.060 (95%CI: 0.020-0.106), z = 2.85 (9.4% mediation); all p < 0.01).

CONCLUSION

In adolescents, the association between fatness and CMRs could be partially decreased with improvements to fitness levels; therefore, CRF contribution both in the clinical field and public health could be important to consider and promote in adolescents independently of their fatness levels.

Development of cardiorespiratory fitness standards for working memory using receiver operating curves in 15-year-old adolescents

Background

Working memory performance is associated with better academic achievements in children and adolescents, and it is positively related to CRF. However, what level of cardiorespiratory fitness (CRF) discriminates higher working memory performance is not known. The purpose of this study was to identify CRF thresholds linked to working memory in adolescents.

Methods

Data of 141 adolescents (53.2 % girls) were collected (14.9 years) from a cross-sectional study during the year 2019. CRF was assessed by the 20-m shuttle run test, and maximal oxygen uptake was calculated using the Mahar´s equation. Working memory was evaluated by the Corsi blocks test and performance was classified by percentiles. Receiver operating characteristic (ROC) curve analysis was used to identify CRF thresholds.

Results

The ROC analysis indicated that CRF could be used to discriminate working memory in adolescents. CRF thresholds of ≥45.03 ml.kg^− 1.min^− 1for boys and ≥36.63 ml.kg^− 1.min^− 1for girls were found to be indicative of “normal” working memory performance.

Conclusions

CRF could discriminate low and normal working memory performance in 14-16- year-old adolescents. These thresholds could allow for earlier identification and intervention of low working memory performance using CRF.

Fitness, waist circumference and their association with future blood pressure in youth: The UP&DOWN Longitudinal Study

OBJECTIVES

The aim was to determine the independent associations of muscular fitness (MF), cardiorespiratory fitness (CRF) and waist circumference (WC) with blood pressure (BP) levels over 2 years in children and adolescents.

METHODS

1089 children (517 females) and 787 adolescents (378 females) with complete data on fitness, WC and BP (systolic [SBP] and diastolic [DBP]) were included. Upper MF was assessed through the handgrip strength test, and lower MF using the standing long jump test. The 20-m shuttle run test was used to assess CRF. WC was obtained following standardized methods. Different regression models were fitted by introducing fitness and WC at baseline and their changes as exposures and BP at follow-up and their changes as outcomes.

RESULTS

WC at baseline was positively and independently associated with each BP variable at follow-up in children and adolescents (β=0.094-0.260; p≤0.05), and CRF was negatively associated with DBP in adolescents (β=-0.096; p=0.034). WC changes were associated with BP variables 2 years later in children (β=0.121-0.142; p<0.01). In adolescents, changes in upper MF (β=-0.116; p=0.001) and WC (β=0.080-0.098; p<0.05) were associated with SBP at follow-up. WC changes were independently associated with changes in each BP variable in children (β=0.111-0.145; all p<0.05) and SBP changes in adolescents (β=0.103 to 0.117; all p<0.01).

CONCLUSIONS

WC, but neither MF nor CRF, is independently associated with BP and its changes over 2 years. The attainment or maintenance of optimal fatness levels in the pediatric population should be highly encouraged for the prevention of future hypertension.

Physical Fitness and Self-Rated Health in Children and Adolescents: Cross-Sectional and Longitudinal Study

Self-rated health (SRH) is an independent determinant for all-cause mortality. We aimed to examine the independent and combined associations of components of physical fitness with SRH at baseline (cross-sectional) and two years later (longitudinal) in children and adolescents. Spanish youth (N = 1378) aged 8 to 17.9 years participated at baseline. The dropout rate at 2-year follow-up was 19.5% (n = 270). Participants were categorized as either children (8 to 11.9 years age) or adolescents (12 to 17.9 years age). The ALPHA health- related fitness test battery for youth was used to assess physical fitness, and SRH was measured by a single-item question. Cumulative link, ANOVA and ANCOVA models were fitted to analyze the data. Cardiorespiratory fitness, relative upper body isometric muscular strength, muscular strength score, and global physical fitness were positively associated with SRH in children (OR, 1.048; 95% CI, 1.020–1.076; OR, 18.921; 95% CI, 3.47–104.355; OR, 1.213; 95% CI, 1.117–1.319, and OR, 1.170; 95% CI, 1.081–1.266, respectively; all p < 0.001) and adolescents (OR, 1.057; 95% CI, 1.037–1.076; OR, 5.707; 95% CI, 1.122–29.205; OR, 1.169; 95% CI, 1.070–1.278, and OR, 1.154 95% CI, 1.100–1.210, respectively; all p < 0.001); and motor fitness was positively associated with SRH only in adolescents at baseline (OR, 1.192; 95% CI, 1.066–1.309; p < 0.01). Cardiorespiratory fitness and global physical fitness were positively associated with SRH in children two years later (OR, 1.056; 95% CI, 1.023–1.091; p < 0.001; and OR, 1.082; 95% CI, 1.031–1.136; p < 0.01; respectively). Only cardiorespiratory fitness was independently associated with SRH in children and adolescents at baseline (OR, 1.059; 95% CI, 1.029–1.090; and OR, 1.073; 95% CI, 1.050–1.097, respectively; both p < 0.001) and two years later (OR, 1.075; 95% CI, 1.040–1.112; p < 0.001; and OR, 1.043; 95% CI, 1.014–1.074; p < 0.01, respectively). A high level of cardiorespiratory fitness at baseline or maintaining high levels of cardiorespiratory fitness from the baseline to 2-year follow-up were associated with a higher level of SRH at 2-year follow-up in children (p < 0.01) and adolescents (p < 0.05). These findings emphasize the importance of cardiorespiratory fitness as strong predictor of present and future SRH in youth. Intervention programs to enhance cardiorespiratory fitness level of the youth population are urgently needed for present and future youth’s health.

Changes in the school and non-school sedentary time in youth: The UP&DOWN longitudinal study

The aims of this study were (i) to examine the sedentary time (ST) during different time periods [i.e., weekend, out-of-school weekdays hours, school hours, recess, physical education classes (PEC)] in children and adolescents; (ii) to identify 2-year longitudinal changes in the ST for these periods; and (iii) to examine if ST at baseline is associated with ST 2 years later. This was a 2-year follow-up study with 826 (51.9% boys) children and 678 (50.7% boys) adolescents. Accelerometers were used to assess ST. Students spent more than 60% of their weekend, out-of-school hours and school hours in ST. During these periods, girls and adolescents were more sedentary than boys and children, respectively (p < 0.05). Over 2-year follow-up, ST increased during the weekend, out-of-school hours, school hours and recess in all subgroups studied (p < 0.001). ST during PEC declined 2% per year in children (p < 0.001) but it increased in adolescents (p < 0.05). ST during the periods analysed at baseline was lowly associated with ST during these periods 2 years later (intraclass correlations from <0.001 to 0.364). Interventions in these settings may be adequate if the intention is to avoid ST increase in students.

Inflammation and fatness in adolescents with and without Down syndrome: UP & DOWN study

BACKGROUND

The main objective of this study was to describe the inflammatory status of adolescents with Down syndrome (DS) and their relationship with adiposity.

METHODS

Ninety-five adolescents with DS (44.2% girls) and a control group of 113 adolescents (47.8% girls), aged between 11 and 18 years old, from the UP & DOWN study were included in this substudy. Serum C-reactive protein, C3 and C4 complement factors, total proteins, interleukin-6, tumour necrosis factor-α, insulin, cortisol, leptin, adiponectin, galactin-3 and visfatin were analysed; homeostatic model assessment index was calculated. In order to evaluate adiposity, we measured the following body fat variables: weight, height, waist circumference and skinfold thicknesses. Birth weight was obtained by questionnaire. In addition, body mass index, waist-to-height ratio (WHtR) and body fat percentage (BF%) were calculated.

RESULTS

Down syndrome group showed higher levels of body mass index, WHtR, waist circumference, BF% and lower birth weight than controls (P < 0.001). In the general linear model in the total sample, WHtR was positively associated with C3 and C4 (P < 0.001) as well as with leptin levels (P = 0.015). BF% was positively associated with total proteins (P = 0.093) and leptin levels (P < 0.001). DS was positively associated with total proteins (P < 0.001), C3 (P = 0.047) and C4 (P = 0.019). Despite the higher levels of adiposity found in DS group, no direct association was found between BF% and leptin levels, comparing with the control group.

CONCLUSIONS

These findings suggest that abdominal obesity should be controlled in adolescents because of its relationship with acute phase-inflammatory biomarkers but especially in DS adolescents who may show a peculiar metabolic status according to their relationship between adiposity and inflammatory biomarkers.

High Levels of Physical Fitness Are Associated With Better Health-Related Quality of Life in Women With Fibromyalgia: The al-Ándalus Project

BACKGROUND

Physical fitness is a marker of health and is associated with health-related quality of life (HRQoL). Identifying which components of physical fitness are associated with HRQoL in people with fibromyalgia may contribute to the development of more specific therapeutic strategies.

OBJECTIVE

The 2 aims of this study were to examine the association of different components of physical fitness (ie, flexibility, muscle strength, speed and agility, and cardiorespiratory fitness) with HRQoL and to determine the extent to which any association between the components of physical fitness and HRQoL were of clinical relevance to women with fibromyalgia.

DESIGN

A cross-sectional design was used.

METHODS

This study included 466 women with fibromyalgia from southern Spain (Andalusia). The Senior Fitness Test battery and the handgrip test were used to assess physical fitness, and the 36-Item Short-Form Health Survey (SF-36) was used to assess HRQoL. Tender points, cognitive impairment, anthropometric measurements, and medication usage were also measured. First, multivariate linear regression was used to assess the individual relationship of each physical fitness test with the 8 dimensions of the SF-36. Second, a standardized composite score was computed for each component of physical fitness (flexibility, muscle strength, speed and agility, and cardiorespiratory fitness). A 1-way analysis of covariance to assess the differences in each of the 8 dimensions of the SF-36 across each physical fitness composite score was conducted. Forward stepwise regression was performed to analyze which components of physical fitness were independently associated with the SF-36 physical and mental component scales.

RESULTS

Overall, higher levels of physical fitness were associated with higher levels of HRQoL (regardless of the SF-36 subscale evaluated). The effect sizes for HRQoL between participants with the lowest and the highest physical fitness levels ranged from moderate to large (Cohen d = 0.53-0.90). The muscle strength composite score was independently associated with the SF-36 physical component scale, whereas the flexibility composite score and cardiorespiratory fitness were independently associated with the SF-36 mental component scale.

LIMITATIONS

A limitation was that the cross-sectional design precluded the establishment of causality. Additionally, only women were included in the study, because fibromyalgia predominantly affects women.

CONCLUSIONS

High levels of physical fitness were consistently associated with better HRQoL in women with fibromyalgia; clinically relevant differences were demonstrated between those at extreme physical fitness levels. Muscle strength, flexibility, and cardiorespiratory fitness were independent indicators of HRQoL. These results warrant further prospective research on the potential of fitness to predict HRQoL in this population.

Reliability and Concurrent Validity of Global Physical Activity Questionnaire (GPAQ): A Systematic Review

This study aimed to systematically review previous studies on the reliability and concurrent validity of the Global Physical Activity Questionnaire (GPAQ). A systematic literature search was conducted (n = 26) using the online EBSCOHost databases, PubMed, Web of Science, and Google Scholar up to September 2019. A previously developed coding sheet was used to collect the data. The Modified Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies was employed to assess risk of bias and study quality. It was found that GPAQ was primarily revalidated in adult populations in Asian and European countries. The sample size ranged from 43 to 2657 with a wide age range (i.e., 15–79 years old). Different populations yielded inconsistent results concerning the reliability and validity of the GPAQ. Short term (i.e., one- to two-week interval) and long-term (i.e., two- to three-month apart) test–retest reliability was good to very good. The concurrent validity using accelerometers, pedometers, and physical activity (PA) log was poor to fair. The GPAQ data and accelerometer/pedometer/PA log data were not compared using the same measurements in some validation studies. Studies with more rigorous research designs are needed before any conclusions concerning the concurrent validity of GPAQ can be reached.

Study protocol and rationale of the "Cogni-action project" a cross-sectional and randomized controlled trial about physical activity, brain health, cognition, and educational achievement in schoolchildren

BACKGROUND

Education and health are crucial topics for public policies as both largely determine the future wellbeing of the society. Currently, several studies recognize that physical activity (PA) benefits brain health in children. However, most of these studies have not been carried out in developing countries or lack the transference into the education field. The Cogni-Action Project is divided into two stages, a cross-sectional study and a crossover-randomized trial. The aim of the first part is to establish the associations of PA, sedentarism, and physical fitness with brain structure and function, cognitive performance and academic achievement in Chilean schoolchildren (10-13 years-old). The aim of the second part is to determinate the acute effects of three PA protocols on neuroelectric indices during a working memory and a reading task.

METHODS

PA and sedentarism will be self-reported and objectively-assessed with accelerometers in a representative subsample, whilst physical fitness will be evaluated through the ALPHA fitness test battery. Brain structure and function will be assessed by magnetic resonance imaging (MRI) in a randomized subsample. Cognitive performance will be assessed through the NeuroCognitive Performance Test, and academic achievement by school grades. In the second part 32 adolescents (12-13 year-old) will be cross-over randomized to these condition (i) "Moderate-Intensity Continuous Training" (MICT), (ii) "Cooperative High-Intensity Interval Training" (C-HIIT), and (iii) Sedentary condition. Neuroelectric indices will be measures by electroencephalogram (EEG) and eye-tracking, working memory by n-back task and reading comprehension by a reading task.

DISCUSSION

The main strength of this project is that, to our knowledge, this is the first study analysing the potential association of PA, sedentarism, and physical fitness on brain structure and function, cognitive performance, and academic achievement in a developing country, which presents an important sociocultural gap. For this purpose, this project will use advanced technologies in neuroimaging (MRI), electrophysiology (EEG), and eye-tracking, as well as objective and quality measurements of several physical and cognitive health outcomes.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03894241 Date of register: March 28, 2019. Retrospectively Registered.

Concurrent validity of supraclavicular skin temperature measured with iButtons and infrared thermography as a surrogate marker of brown adipose tissue

Brown adipose tissue (BAT) thermogenic activity is commonly assessed with a positron emission tomography with computed tomography scan (PET/CT). This technique has several limitations and alternative techniques are needed. Supraclavicular skin temperature measured with iButtons and infrared thermography (IRT) has been proposed as an indirect marker of BAT activity. We studied the concurrent validity of skin temperature measured with iButtons vs. IRT and the association of supraclavicular skin temperature measured with iButtons and IRT with BAT. We measured skin temperature upon a shivering threshold test with iButtons and IRT in 6 different regions in 12 participants (n = 2 men). On a separate day, we determined supraclavicular skin temperature with an iButton and IRT after 2 h of a personalized cooling protocol. Thereafter, we quantified BAT volume and activity by PET/CT. We observed that the absolute differences between the devices were statistically different from 0 (all P < 0.05) after the shivering threshold test. Moreover, we did not find any association between supraclavicular skin temperature measured with iButtons or IRT and BAT ¹⁸F-FDG activity (r = -0.213; P = 0.530 and r = -0.079; P = 0.817). However, we observed a negative association of supraclavicular skin temperature measured by IRT with BAT ¹⁸F-FDG volume (r = -0.764; P = 0.006), but not with supraclavicular skin temperature measured with iButtons (r = -0.546; P = 0.082). In light of these results, we concluded that the measurement of skin temperature obtained by iButtons and IRT are not comparable. Furthermore, it seems that supraclavicular skin temperature is not associated with BAT ¹⁸F-FDG activity, but it appears to be negatively associated with BAT ¹⁸F-FDG volume in the case of IRT.

Convergent validation of a questionnaire to assess the mode and frequency of commuting to and from school

AIMS

The purposes of this research were to study the convergent validity of the Mode and Frequency of Commuting To and From School Questionnaire using objectively assessed steps and time spent in different physical activity intensities and to compare the self-reported versus objective journey time in Spanish youths.

METHODS

Three hundred and eighty-nine Spanish youth aged 7-19 years were asked to complete the questionnaire and wore an accelerometer for five days. The objective commuting distance and time from home to school were estimated using Google Maps^TM.

RESULTS

There were significant differences between passive and walking participants on step numbers, sedentary time and physical activity levels (except for vigorous physical activity in children). For children, a mean difference of -4.03 minutes between objective measured and self-reported journey time was found (95% limits of agreement were 13.55 and -21.60 minutes). For adolescents, the mean difference was -1.39 minutes (95% limits of agreement were 15.23 and -18.02 minutes).

CONCLUSIONS

The findings indicated that the Mode of Commuting To and From School Questionnaire showed a convergent validity to assess this behaviour in Spanish youths. Self-reported journey time for walking is comparable to Google Maps^TM in adolescents but not in children.

Muscle strength is associated with lower diastolic blood pressure in schoolchildren

Cardiorespiratory fitness (CRF) provides protection against the elevated blood pressure in overweight youth. Less is known regarding any similar protective effect of muscular fitness. We investigated how handgrip strength, an easy to implement measure of muscular strength, interacted with CRF and BMI to determine blood pressure in youth. We measured systolic (SBP) and diastolic (DBP) blood pressure, handgrip strength (HG), CRF and body mass index (BMI) in n=7329 10-16year-olds (47% girls). We defined elevated blood pressure as >91st percentile and Good HG as >33rd percentile. Participants were classified as Fit or Unfit and as Normal or Overweight/Obese based on international standards. The prevalence of elevated SBP was 23%, and 44% of participants had elevated DBP. In unfit participants Good HG was associated with lower SBP (z=0.41 (95%CI: 0.20-0.61) and DBP (z=0.29 (95%CI: 0.12-0.47). In Overweight/Obese participants, DBP was z=0.24 (95%CI: 0.14-0.34) lower in the Good (versus Low) HG group. Overweight/Obese participants with Good HG also had a 32% lower risk of elevated DBP (OR: 0.68, 95%CI: 0.57-0.82). This association was attenuated but remained important after adjusting for BMI (20% risk reduction, OR: 0.80, 95%CI: 0.63-1.01). Muscular fitness appears to play some protective role against the risk of elevated blood pressure; particularly for the more prevalent measure: elevated DBP (44%). Effects may be restricted to Overweight / Obese or unfit youth, who have an increased risk of elevated BP and also may be less likely to engage in traditional cardiorespiratory fitness training. Research to determine the effects of muscular fitness training on blood pressure is warranted in these subgroups.

Physical fitness as a mediator between objectively measured physical activity and clustered metabolic syndrome in children and adolescents: The UP&DOWN study

BACKGROUND AND AIMS

The extent to which physical fitness (PF) attenuates or modifies the association between physical activity (PA) and clustered metabolic syndrome risk factors (CMetSRF) is controversial. We aimed: i) To examine the independent and combined association of objectively measured PA and PF with CMetSRF in children and adolescents; ii) To test the mediating effect of PF in the association of PA with CMetSRF.

METHODS AND RESULTS

A total of 226 children and 256 adolescents participated. Levels of PA (light, moderate, vigorous and moderate-to-vigorous [MVPA]) and PF were measured by accelerometry and ALPHA battery, respectively. Cardiorespiratory and muscular fitness values were combined in a global PF variable. A CMetSRF was computed by assessing the following variables: waist circumference, systolic blood pressure, high-density lipoprotein cholesterol, triglycerides and glucose. In children, the highest vigorous PA (β = -0.193; P = 0.003) and MVPA (β = -0.149; P = 0.025) were individually associated with lower CMetSRF, but these associations were not independent of global PF. In adolescents, the association of moderate (β = -0.123; P = 0.046) and MVPA (β = -0.147; P = 0.024) with CMetSRF was independent of PF. Among unfit adolescents, the higher time they spent in MVPA the lower CMetSRF levels were found (P = 0.032).

CONCLUSIONS

The results are suggestive of a full mediation of global PF in the association of MVPA and vigorous PA with CMetSRF in children. In adolescents, the association of higher moderate and MVPA with lower CMetSRF was independent of levels of PF, and mediation analyses suggest only a partial mediation of global PF in the association of MVPA with CMetSRF.

Parental educational level and psychological positive health and health complaints in Spanish children and adolescents

BACKGROUND

Interest on the impact of socioeconomic differences on youth's health is growing. The aim of the present study was to examine the association of parental educational level with psychological positive health and health complaints in Spanish children and adolescents.

METHODS

Parental educational level, psychological positive health indicators (perceived health status, life satisfaction, quality of family relationships, quality of peer relationships and academic performance) and health complaint index (headache, stomach ache, backache, feeling low, irritability or bad temper, feeling nervous, difficulties getting to sleep, feeling dizzy) were self-reported using the Health Behavior in School-aged Children questionnaire in 685 (366 boys and 319 girls) children and adolescents.

RESULTS

Children reporting parents with non-university studies (father, mother or both) had significantly higher odd ratio of having lower academic performance, lower life satisfaction, perceiving their health status as otherwise (vs. excellent) and having health complaints sometime than their counterparts reporting parents with university studies (father, mother or both).

CONCLUSION

Current results provide evidence that children having parents with a university degree (father, mother or both) are more likely to have higher psychological positive health and lower health complaints than children reporting parents with non-university studies. This is particularly important for the welfare policy that must pay attention for implementing programs for helping population to access to university studies by their impact on youth health.

The association of total and central body fat with pain, fatigue and the impact of fibromyalgia in women; role of physical fitness

BACKGROUND

The relationship between estimates of total and central body fat with fibromyalgia pain, fatigue and overall impact has not been fully described. We aimed to assess the individual and combined association of body fat (total and central) with pain, fatigue and the overall impact in fibromyalgia women; and to study the possible mediation role of physical fitness in these associations.

METHODS

A total of 486 fibromyalgia women with a mean (standard deviation) age of 52.2 (8.0) years participated. Pain was measured with self-reported measures and algometry, whereas fatigue with the Multidimensional Fatigue Inventory. The impact of fibromyalgia was measured with the Revised Fibromyalgia Impact Questionnaire (FIQR) total score. Total and central body fat were assessed by means of bioelectrical impedance and waist circumference, respectively. The Functional Senior Fitness Test battery and the handgrip strength test were used to assess physical fitness.

RESULTS

Total and central body fat were positively associated with pain- and fatigue-related measures and the FIQR total score (β from 0.10 to 0.25; all, p < 0.05). A combined effect of total and central body fat was observed on pain (FIQR and 36-item Short-Form Health Survey), general and physical-related fatigue and FIQR total score (all, overall p < 0.05), so that the group with no total and central obesity had more favourable results than those with total and central obesity. Cardiorespiratory fitness partially mediated (between 22-40% of the total effect) the associations between total and central body fat with pain, general fatigue, physical fatigue and reduced activity, and largely mediated (80%) the association of central body fat with the FIQR total score.

CONCLUSIONS

Physical fitness might potentially explain the association between obesity and fibromyalgia symptoms.

Television viewing, psychological positive health, health complaints and health risk behaviors in Spanish children and adolescents

AIM

The aim of this study was to study the correlation of television viewing with positive and negative health in youth.

METHODS

The present cross-sectional study comprised a total of 680 children and adolescents aged 6-17.9 (46% girls) representative of the province of Cádiz (south Spain). We used the Health Behavior in School-aged Children questionnaire to assess television viewing, positive and negative health.

RESULTS

It was found that correlations between television viewing >2 hours and several outcomes were inconsistent. No effects were found for quality of family relationships, quality of peer relationships, perceived academic performance and health risk behaviors in children, or with perceived excellent health status, excellent life satisfaction, quality of peer relationships, perceived academic performance and health risk behaviors in adolescents. However viewing >2 hours of television was correlated with lower quality family relations in adolescents, and lower perceived excellent health status, lower life satisfaction and higher health complaints index in children. Correction for multiple comparisons would render all television relationships as non-significant.

CONCLUSION

Our results suggest that negative television influences on children and adolescents are minimal. However excessive television viewing may be symptomatic of other underlying mental health problems for some children.

Independent and combined influence of neonatal and current body composition on academic performance in youth: The UP & DOWN Study

BACKGROUNDS

Unhealthy body composition is a cause for concern across the lifespan.

OBJECTIVE

The objective of this study was to examine the independent and combined associations between neonatal and current body composition with academic performance among youth.

METHODS

This cross-sectional study was conducted with a total of 1557 youth (745 girls) aged 10.4 ± 3.4 years. Birth weight and length at birth were self-reported. Current body composition was assessed by body mass index (BMI), waist circumference (WC) and percentage of body fat (BF%). Academic performance was assessed through schools records.

RESULTS

Birth weight was related to all academic variables in boys, independent of potential confounders, including BMI; whereas WC, BMI and BF% were related to all academic performance indicators in both boys and girls, independent of potential confounders, including birth weight (all P < 0.05). In addition, the combined adverse effects of low birth weight and current overweight on academic performance were observed in both boys and girls for grade point average (GPA) indicator. Boys in the group with none adverse effect had significantly higher scores in GPA (score +0.535; 95% confidence interval, 0.082-0.989) than boys in the group of both adverse effects (P < 0.007); among girls, GPA score was higher in the group with none adverse effect than in the groups with one or two adverse effects (P for trend = 0.029).

CONCLUSIONS

Neonatal and current body composition, both independently and combined, may influence academic performance in youth.

Validity and reliability of the 1/4 mile run-walk test in physically active children and adolescents

We investigated the criterion-related validity and the reliability of the 1/4 mile run-walk test (MRWT) in children and adolescents. A total of 86 children (n=42 girls) completed a maximal graded treadmill test using a gas analyzer and the 1/4MRW test. We investigated the test-retest reliability of the 1/4MRWT in a different group of children and adolescents (n=995, n=418 girls). The 1/4MRWT time, sex, and BMI significantly contributed to predict measured VO2peak (R2= 0.32). There was no systematic bias in the cross-validation group (P>0.1). The root mean sum of squared errors (RMSE) and the percentage error were 6.9 ml/kg/min and 17.7%, respectively, and the accurate prediction (i.e. the percentage of estimations within ±4.5 ml/kg/min of VO2peak) was 48.8%. The reliability analysis showed that the mean inter-trial difference ranged from 0.6 seconds in children aged 6-11 years to 1.3 seconds in adolescents aged 12-17 years (all P.

Reliability of the ALPHA health-related fitness test battery in adolescents with Down syndrome

The Assessing Levels of Physical Activity (ALPHA) health-related fitness test battery is a set of reliable, valid, and feasible tests to assess health-related physical fitness in children and in adolescents. The aim of this study was to examine the reliability of this battery in adolescents with Down syndrome (DS). The extended ALPHA health-related fitness test battery was performed twice within 1 month in 17 apparently healthy adolescents, aged 12-18 years, with DS who had an intelligence quotient ≥ 35. Intraclass correlation coefficient (ICC) was used to determinate test-retest reliability, and nonparametric Wilcoxon signed rank test was used to compare mean differences between measurements. With the exception of subscapular skinfold test, which obtained a moderate agreement (ICC = 0.64), all tests had a very high reliability: the 20-m shuttle-run test (ICC = 0.86), the right handgrip strength test (ICC = 0.86), the left handgrip strength test (ICC = 0.86), the standing broad jump test (ICC = 0.85), body mass index (ICC = 0.95), waist circumference (ICC = 0.98), triceps skinfold (ICC = 0.85), and the 4 × 10-m shuttle-run test (ICC = 0.92). There were no significant differences (all p > 0.05) in any of the tests. The ALPHA health-related fitness battery is reliable for measuring health-related components of fitness in adolescents with DS.

Reliability and feasibility of physical fitness tests in female fibromyalgia patients

The aim of the present study was to determine the reliability and feasibility of physical fitness tests in female fibromyalgia patients. 100 female fibromyalgia patients (aged 50.6±8.6 years) performed the following tests twice (7 days interval test-retest): chair sit and reach, back scratch, handgrip strength, arm curl, chair stand, 8 feet up and go, and 6-min walk. Significant differences between test and retest were found in the arm curl (mean difference: 1.25±2.16 repetitions, Cohen d=0.251), chair stand (0.99±1.7 repetitions, Cohen d=0.254) and 8 feet up and go (-0.38±1.09 s, Cohen d=0.111) tests. Intraclass correlation coefficients (ICC) range from 0.92 in the arm curl test to 0.96 in the back scratch test. The feasibility of the tests (patients able to complete the test) ranged from 89% in the arm curl test to 100% in the handgrip strength test. Therefore, the reliability and feasibility of the physical fitness tests examined is acceptable for female fibromyalgia patients.

Impact of a physical activity program on cerebral vasoreactivity in sedentary elderly people

AIM

The aim of the present study was to determine the effect of a physical activity program on the hemodynamic response of the brain (vasoreactivity) in elderly people.

METHODS

Eighteen men and 25 women (aged 62-67 years) were randomly assigned to an experimental (EXP, N.=22, 12 women) and a control (CON, N.=21, 13 women) group. Subjects in EXP group were required to complete a 7-month program based on aerobic training (3-4 sessions/weekd, 50 min/session, 3-4 sessions/week, at 70% maximum heart rate). Transcranial Doppler ultrasound was used to examine the cerebral blood flow response to hypercapnic and hypocapnic stimuli. We also determined blood pressure, total serum cholesterol, HDL and LDL cholesterol, and triglycerides, and conducted an aerobic capacity test (the 2.4-Km walking test). RESULTS.Brain vasomotor reactivity improved in the EXP group, reflected by a higher blood flow velocity in the middle cerebral artery (MCA) in both cerebral hemispheres in response to hypercapnia (induced by breath holding) (P<0.05). Subjects in EXP group also improved the cardiovascular profile aerobic physical condition (P<0.001) in terms of reduced arterial pressure, total cholesterol and triglyceride levels.

CONCLUSION

Our findings indicate that cerebral vasoreactivity in elderly may be improved by undertaking an aerobic exercise program.

Criterion-related validity of field-based muscular fitness tests in youth

AIM

The purpose of the present study was to analyze the association between isokinetic strength and field-based muscular fitness tests in youth.

METHODS

One hundred twenty-six adolescents (14.4±1.7 y) participated in the study. Upper and lower body isokinetic strength were measured at preset angular velocities of 90 º/s and 60 º/s, respectively. Muscular fitness was also assessed by means of field-based tests: handgrip strength, bent and extended arm hang tests, standing long jump, squat jump, countermovement jump and Abalakov jump. Height, weight and skinfold thickness were used to estimate body composition.

RESULTS

All field-based tests were significantly associated with isokinetic peak torque and power (P<0.001 in all cases). Handgrip strength and standing long jump showed the highest associations with the isokinetic parameters (0.61≤r≤0.87; 0.39≤R2≤0.76). Weight-bearing field tests increased on average 20 % their association (R2) with isokinetic parameters when standardized by individual's body weight (test score × weight), while the average increase was 16 % when standardized by fat-free mass (test score × fat-free mass).

CONCLUSION

Handgrip strength and standing long jump tests seem to be the most valid field-based muscular fitness tests when compared to isokinetic strength. These tests can be useful to assess muscular fitness in young people when laboratory methods are not feasible.

Substance abuse and health self-perception in Spanish children and adolescents

OBJECTIVE

The aim of this study was to analyze substance abuse and health self-perception in children and adolescents from the province of Cádiz (Spain).

METHODOLOGY

Participants were 738 students, 50.9 boys and 49.1% girls, from elementary school to high school (1st to 12th grade, mean age 12.2. years), who responded a Spanish adaptation of the Health Behavior in School-aged Children Inventory.

RESULTS

No difference was observed in percentage of boys and girls reporting to smoke or drink alcohol. Smoking and drinking habits increased with age, being higher in 11th and 12th grade students. Significant differences were observed among the percentage of smokers and non smokers recognizing to have parents, older brothers or friends who smoke. Rates of drug abuse were generally low, being cannabis the most frequently consumed illicit drug. Most respondents had a perception of excellent or good health, with no significant gender differences. About half of subjects considered that health exclusively depends on self behavior, but an important percentage also gave a relevant role to luck. Stomach-ache was the most frequent physical complaint, followed by headache. Psychological complaints mainly corresponded to nervousness and bad temper. Only a small percentage of subjects declared the use of medicines or tablets without prescription. No significant difference in the percentage of respondent who perceived an excellent or good health was observed among substance users and non users.

CONCLUSIONS

Substance abuse and health self-perception in children and adolescents are the result of the interaction of a complex series of individual and social factors. Activities aimed to improve health focusing on partial aspects of adolescents' lifestyle most probably will have limited results, and global programs are required.

Reliability of field-based fitness tests in youth

The objective of this systematic review was to study the reliability of the existing field-based fitness tests intended for use with children and adolescents. The medical electronic databases MEDLINE, SCOPUS and SPORTS DISCUS were screened for papers published from January 1990 to December 2009. Each study was classified as high, low or very low quality according to the description of the participants, the time interval between measurements, the description of the results and the appropriateness of statistics. 3 levels of evidence were constructed according to the number of studies and the consistency of the findings. 32 studies were finally included in the present review. The reliability of tests assessing cardiorespiratory fitness (9 studies), musculoskeletal fitness (12 studies), motor fitness (3 studies), and body composition (10 studies) was investigated. Although some fitness components warrant further investigation, this review provides an evidence-based proposal for most reliable field-based fitness tests for use with children and adolescents: 20-m shuttle run test to measure cardiorespiratory fitness; handgrip strength and standing broad jump tests to measure musculoskeletal fitness; 4×10 m shuttle run test for motor fitness; and height, weight, BMI, skinfolds, circumferences and percentage body fat estimated from skinfold thickness to measure body composition.

Percentile values for running sprint field tests in children ages 6-17 years: influence of weight status

The aim of this study was to provide percentile values for six different sprint tests in 2,708 Spanish children (1,234 girls) ages 6-17.9 years. We also examined the influence of weight status on sprint performance across age groups, with a focus on underweight and obese groups. We used the 20-m, 30-m, and 50-m running sprint standing start and running start tests to assess sprint performance. We calculated body mass index (BMI) using and categorized participants according to the BMI international cut-off for underweight, normal weight, overweight, and obese. Boys had significantly better scores than girls in all tests, except for the 30-m running sprint standing start and running start tests in the 6-7 year-old group. The underweight group had significantly better scores than their obese counterparts, whereas there were similar levels between underweight and normal weight individuals. The normal weight group showed a significantly better performance than their overweight and obese counterparts. Overweight boys had significantly better performance than their obese counterparts. In conclusion, the percentiles values of six running tests varied by age and gender The findings indicated that underweight youth did not have poorer sprint performance, and the obese group had lower scores than their leaner counterparts.

[Health behaviour of school children at the province of Cádiz]

OBJECTIVE

The aim of this study was to analyze some characteristics of health-related behaviour in school children at the province of Cadiz, centering on engagement in sports and physical activity, and on dietary habits.

METHODOLOGY

Participants were 738 students, mean age 12.2 years, from primary school o high school. 50.9% were boys and 49.1% girls, who responded a Spanish adaptation of the Health Behavior in Schoolchildren Inventory.

RESULTS

Sex differences were observed in the percentage of subjects not engaged in sports, which was higher in girls. Boys practiced sports and physical activity at a higher intensity and more time than girls. A large number of subjects considered good or normal their physical fitness, with only and small percentage describing it as regular. More than half of participants felt a support by parents, and to a smaller extent by brothers and friends. An important part of the subjects did not have breakfast every day, and some even never. A high percentage of the sample ate candies 1 to 3 days per week, being also high the intake of chips, nuts, hamburgers and sausages. Near a quarter of subjects reported not to consume vegetables.

CONCLUSIONS

Results obtained confirm the necessity of an adequate lifestyle habits education and the development of intervention programs in children and youth, counseling on diet and physical activity and targeting on girls, who are less physically active and on risk of serious disorders.

Criterion-related validity of sit-and-reach and modified sit-and-reach test for estimating hamstring flexibility in children and adolescents aged 6-17 years

The purpose of the present study was to examine the criterion-related validity of the sit-and-reach test (SRT) and the modified sit-and-reach test (MSRT) for estimating hamstring flexibility in children and adolescents as well as to determine whether the MSRT is more valid than the SRT. A total of 87 (45 boys and 42 girls) children (6-12 years old) and adolescents (13-17 years old) performed the SRT and the MSRT. Hamstring flexibility was measured with goniometry through the passive straight-leg raise test. Regression analysis was performed to study the association of SRT and MSRT with hamstring flexibility (criterion measure). The SRT was associated with hamstring flexibility in both children (beta=1.089, R (2)=0.281, p=0.001) and adolescents (beta=0.690, R (2)=0.333, p=0.004). The MSRT was also associated with hamstring flexibility in both children (beta=1.296, R (2)=0.298, p<0.001) and adolescents (beta=0.588, R (2)=0.243, p=0.027). It is concluded that the criterion-related validity of the SRT and the MSRT for estimating hamstring flexibility is weak. The present data do not support that the MSRT is a more valid method than the SRT in children and adolescents.

Criterion-related validity of field-based fitness tests in youth: a systematic review

The objective of this systematic review was to comprehensively study the criterion-related validity of the existing field-based fitness tests used in children and adolescents. The studies were scored according to the number of subjects, description of the study population and statistical analysis. Each study was classified as high, low and very low quality. Three levels of evidence were constructed: strong evidence, when consistent findings were observed in three or more high quality studies; moderate evidence, when consistent findings were observed in two high quality studies; and limited evidence when consistency of findings and/or the number of studies did not achieve the criteria for moderate. The results of 73 studies (50 of high quality) addressing the criterion-related validity of field-based fitness tests in children and adolescents indicate the following: that there is strong evidence indicating that the 20 m shuttle run test is a valid test to estimate cardiorespiratory fitness, that the hand-grip strength test is a valid measure of musculoskeletal fitness, that skin fold thickness and body mass index are good estimates of body composition, and that waist circumference is a valid measure to estimate central body fat. Moderate evidence was found that the 1-mile run/walk test is a valid test to estimate cardiorespiratory fitness. A large number of other field-based fitness tests presented limited evidence, mainly due to a limited number of studies (one for each test). The results of the present systematic review should be interpreted with caution due to the substantial lack of consistency in reporting and designing the existing validity studies.

Predictive validity of health-related fitness in youth: a systematic review

The objective of the present systematic review was to investigate whether physical fitness in childhood and adolescence is a predictor of cardiovascular disease (CVD) risk factors, events and syndromes, quality of life and low back pain later in life. Physical fitness-related components were: cardiorespiratory fitness, musculoskeletal fitness, motor fitness and body composition. Adiposity was considered as both exposure and outcome. The results of 42 studies reporting the predictive validity of health-related physical fitness for CVD risk factors, events and syndromes as well as the results of five studies reporting the predictive validity of physical fitness for low back pain in children and adolescents were summarised. Strong evidence was found indicating that higher levels of cardiorespiratory fitness in childhood and adolescence are associated with a healthier cardiovascular profile later in life. Muscular strength improvements from childhood to adolescence are negatively associated with changes in overall adiposity. A healthier body composition in childhood and adolescence is associated with a healthier cardiovascular profile later in life and with a lower risk of death. The evidence was moderate for the association between changes in cardiorespiratory fitness and CVD risk factors, and between cardiorespiratory fitness and the risk of developing the metabolic syndrome and arterial stiffness. Moderate evidence on the lack of a relationship between body composition and low back pain was found. Due to a limited number of studies, inconclusive evidence emerged for a relationship between muscular strength or motor fitness and CVD risk factors, and between flexibility and low back pain.