Does current behaviour predict the course of children's physical fitness?

Modeling the Dynamics of Children's Musculoskeletal Fitness

This study models children's musculoskeletal fitness (MSF) developmental trajectories and identifies individual differences related to effects of time-invariant, as well as time-varying covariates. A total of 348 Portuguese children (177 girls) from six age cohorts were followed for three years. MSF tests (handgrip strength, standing long jump and shuttle run), age, body mass index (BMI), socioeconomic status (SES), gross motor coordination (GMC) and physical activity (PA) were assessed. Data were analyzed using multilevel models. Between 5 and 11 years of age, boys outperformed girls in all three MSF tests (p < 0.05). Birth weight was positively associated with shuttle run performance (β = -0.18 ± 0.09, p < 0.05). BMI was positively associated with handgrip strength (β = 0.35 ± 0.04, p < 0.001) and shuttle run performance (β = 0.06 ± 0.01, p < 0.001), but negatively associated with standing long jump performance (β = -0.93 ± 0.23, p < 0.001). GMC was positively associated (p < 0.001) with all three MSF tests, while PA was associated with standing long jump (β = 0.08 ± 0.02, p < 0.05) and shuttle run (β = -0.003 ± 0.002, p < 0.05) performance only. No school environment effects were found, and SES was not related to any MSF tests. Children's MSF development showed a curvilinear shape with increasing age, with boys outperforming girls. Weight status and physical behavior characteristics predicted MSF development, while environmental variables did not. Examining potential longitudinal predictors of MSF across multiple dimensions is important to gain a more holistic understanding of children's physical development as well as to future interventions.

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.

Physical fitness development in relation to changes in body composition and physical activity in adolescence

The decline in adolescents' physical fitness (PF) in recent decades has raised concerns about current population's possible future challenges with health and physical functional capacity. This study explored the associations between body composition, physical activity, maturation, and PF development in adolescents. Furthermore, PF development of adolescents with low initial PF was assessed. A 2-year observational study was conducted between spring 2013 and 2015. Nine comprehensive schools and their 10- to 13-year-old students were invited to participate in the study (1778), and a total of 971 students (54.6%) agreed. Cardiorespiratory fitness (20-meter shuttle run), muscular fitness (push-ups), fundamental movement skills (5-leaps test), body composition (bioelectrical impedance analysis), moderate-to-vigorous physical activity (accelerometer), and pubertal status (self-assessment questionnaire) were measured at 1-year intervals. Latent growth curve modeling (LGM) was used to study PF development over time. Change in fat mass had the strongest and most coherent associations with PF development during adolescence. Fat-free mass, moderate-to-vigorous physical activity, and pubertal status were associated with PF development, although not systematically. Subgroup analyses showed that PF development in the low fitness group followed a similar pattern as the whole population. However, their PF remained significantly lower throughout the 2-year period. The findings suggest that fat accumulation is an essential detrimental factor for PF development during adolescence. Actions to prevent excessive fat accumulation might help to prevent future declines in functional capacity. Indications that low fitness levels sustain during adolescence highlight the relevance of detecting these individuals and providing interventions already before adolescence.

[Teacher-Based Health Promotion in Primary School Children in Baden-Württemberg: Effects on Endurance Performance and Incidence of Abdominal Obesity]

BACKGROUND

Health promotion has to start early. Many prevention programmes lack proof of effectiveness. A programme that promotes an active and healthy lifestyle for primary school children in Baden-Württemberg is "Join the Healthy Boat".

AIM

The effect of this one-year school-based intervention on endurance performance and incidence of paediatric abdominal obesity was investigated in a large cluster randomised study.

METHODS

Data of 1739 children (7.1±0.6 years) were available at baseline and follow-up. Background variables were assessed via parent questionnaires. Endurance performance (6-minute run) and anthropometric data were collected on-site. Children with waist-to-height-ratio (WHtR) ≥ 0.5 were classified as being abdominally obese. The difference in endurance capacity and the incidence of abdominal obesity between baseline and follow-up were calculated and analysed in simple and hierarchical regression models taking into account the school effect.

RESULTS

Adjusted for gender and grade level, the difference in completed meters in the intervention group after one year was significantly greater (70.5±128.6 vs. 59.2±106.6 m, n=1708). However, after taking into account data clustering of schools, the significance was lost. Odds for the development of abdominal obesity in the intervention group were more than halved after adjustment for gender, grade, baseline WHtR and no-breakfasts (odds ratio=0.48, 95% CI [0.25; 0.94], n=1535).

CONCLUSION

Children should learn to make healthy choices from an early age. With the prevention of abdominal obesity as an indicator, this intervention is characterised as an effective health promotion.

Long-term effect of migration background on the development of physical fitness among primary school children

BACKGROUND

Children with a low socioeconomic status and migration background are more likely to exhibit unfavorable health behavior patterns and higher BMI scores as well as lower physical activity and physical fitness.

AIM

To evaluate the effect of migration background on the development of physical fitness among primary school children from first to third grade.

METHODS

In this longitudinal study, height, weight, and physical fitness of primary school children from Tyrol/Austria were measured five times over a period of 2.5 years using the German motor performance test DMT 6-18 consisting of eight items testing different subdomains of physical fitness.

RESULTS

A total of 266 children (45% girls) participated in all five tests, of which 69 (26%) children reported to have a migration background (MB). Mixed-model ANOVA did not reveal a significantly different development of physical fitness (according to the mean total Z-score of DMT 6-18) over time, P = 0.883, partial ƞ²  < 0.01. However, children with MB showed significantly lower physical fitness compared to children without MB, P < 0.001, partial ƞ²  = 0.06. Controlling for BMI and age did not alter the interpretation of the results. Analyses of the single test items revealed significant differences in motor tests involving strength and endurance.

CONCLUSION

Primary school children with and without MB significantly increased their physical fitness over time in a comparable manner. However, children with MB showed a significantly lower physical fitness at all test time points, which was only partly explained by a higher mean BMI in children with MB. Children with MB outreached the mean baseline fitness level of children without MB not until the fourth test time point, that is after two years. Therefore, a special focus on physical fitness particularly including strength and endurance capacities should be directed to children with MB already in young ages.

Development of physical fitness in Austrian primary school children : A longitudinal study among overweight and non-overweight children over 2.5 years

Background

Physical activity and physical fitness play an important role in the prevention of overweight and obesity in childhood and adolescence and reduce the risk of becoming overweight or obese in adulthood.

Aim

To evaluate the development of physical fitness in overweight and non-overweight primary school children from the first to third grades.

Methods

Using a longitudinal study design, body height and weight as well as physical fitness of primary school children from Tyrol, Austria were measured five times during a period of 2.5 years using the German motor performance test (DMT 6–18).

Results

In total, 266 children (55% boys) with a mean age of 6.4 ± 0.5 years at baseline participated. The proportion of overweight children was 11% at baseline and 22% at the fifth time point. Overweight children showed a significantly lower physical fitness level (mean total z‑score of DMT6–18) at all 5 time points (Hedges g: 0.64–1.09). Repeated measurement analyses of variances showed a significant increase of physical fitness over time among overweight (partial η²: 0.12) and non-overweight (partial η²: 0.29) children. With respect to gender, physical fitness significantly increased over time among overweight (partial η²: 0.20) and non-overweight (partial η²: 0.28) girls, as well as among non-overweight boys (partial η²: 0.31) but not among overweight boys (partial η²: 0.07).

Conclusion

Overweight and non-overweight primary school children significantly increased their physical fitness over the study period; however, overweight children showed a significantly lower physical fitness level at all test time points and did not even achieve the mean baseline fitness level of non-overweight children. With respect to the increasing percentage of overweight children over the study period, evidence-based preventive measures to reduce overweight and increase physical fitness should be implemented at the earliest in primary schools with a special focus on overweight boys.