Slovenia is a pioneer in the systematic monitoring of physical fitness in children and adolescents. In 1969, a national system for monitoring physical and somatic development, called the Sports Educational Chart, was developed and later revised in 1987. Since 1987, all Slovenian primary and secondary schools complete three anthropometric and eight physical fitness measures to assess child development on the population level. The results are processed by the Faculty of Sport, University of Ljubljana, Laboratory of Physical and Motor Development. The Laboratory provides feedback to every schoolchild, class and school. In recent years, advanced IT support was upgraded and renamed as the SLOfit system. Registered users of SLOfit, consist of PE teachers, parents, children, and physicians, who are able to use the on-line application My SLOfit. Through My SLOfit, individuals can follow their development, assess health risks or get advice. The web platform facilitates cooperation between the educational and health system enabling a holistic approach to developmental difficulties. The My SLOfit application works as a powerful communication tool with other platforms, including a website (www.slofit.org), and Facebook. This article presents the basic features of the SLOfit surveillance system and highlights its development as a support tool for efficient, holistic data use.

This study analyses the changes of moderate-to-vigorous physical activity (MVPA) in a cohort of boys and girls aged 11 (n = 50) and 14 (n = 50). Physical activity was assessed with Bodymedia SenseWear Pro Armband monitor for 6 days in October 2013 and October 2016, considering 90% of daily wear time (21h and 40min). The initial sample (n = 160) included the children who wore the monitors at age 11 but the final analyzed sample included only those children from the initial sample (n = 50), whose data fulfilled the inclusion criteria at age 11 and 14. Physical fitness and somatic characteristics of the final sample (n = 50) were compared to a representative sample of Slovenian schoolchildren at ages 11 (n = 385) and 14 (n = 236) to detect possible bias. Changes in MVPA were controlled for maturity using the timing of adolescent growth spurt as its indicator. The average MVPA decreased more than one quarter (34.96 min) from age 11 to age 14. Children were significantly more active at age 11 than at age 14 (p < 0.01, d = 0.39). The timing of puberty onset in girls was significantly earlier (12.01 ± 1.0 years) (p < 0.01) than in boys (13.2 ± 0.75 years) (p < 0.01, d = 1.35). There was a significant gender difference in moderate-to vigorous physical activity at age 14 (p < 0.05, η 2 = 0.12) and between moderate-to vigorous physical activity at age 11 and 14 (η 2 = 0.11). After controlling for the timing of adolescent growth spurt the girls at age 11 showed significantly higher level of physical activity than at age 14 (p < 0.01, η 2 = 0.17). Early adolescence is crucial for the development of physical activity behaviours, which is especially pronounced in girls. The significant decline of MVPA between ages 11 and 14 in Slovenia are likely influenced by environmental changes since the timing of adolescent growth spurt did not prove as a factor underlying the decline of MVPA.

The aim of this study is to describe trends in overweight and obesity among Slovenian youth for the period 1989–2018. Nearly all schoolchildren in Slovenia had their height and weight measured annually, which lead to a total of 6,738,510 data-points during the 30-year period. The IOTF cut-off points and Joinpoint regression were used to examine annual percent change (APC) in overweight and obesity prevalence across 3 age groups (7–10, 11–14 and 15–18 years). Obesity approximately tripled, while overweight doubled between 1989 and late 2000s in both genders. Since then overweight has been steadily decreasing in all 3 age groups for boys and in 7–10-year-old girls. Obesity has also been declining since 2009, but only in the youngest boys and girls (APC = − 1.9, 95% CI = − 3.2 to − 0.6 and APC = − 1.6, 95% CI = − 3.0 to − 0.2, respectively). Unfavourable trends were noted only in 15–18-year-old girls, with obesity rising at an unchanged rate over the past 30 years (APC = 4.8, 95% CI = 4.5–5.1). Overweight and obesity among Slovenian youth has increased dramatically over the last 3 decades. Still, during the last decade this rise has been reversed or at least stopped. This reversal of trends was more marked in boys than in girls, and in young children compared to adolescents.

A systematic search of the literature was performed to compare the effects of interventions that targeted sedentary behaviours or physical activity (PA) or physical fitness on primary prevention of obesity in 6-to 12-year-old children. The search identified 146 reports that provided relevant data for meta-analysis. Point estimates in % body fat were higher for fitness interventions compared with PA interventions (standardized mean difference = −0.11%; 95% CI = −0.26 to 0.04, and −0.04%; 95% CI = −0.15 to 0.06, respectively). Including sedentary behaviour to a PA-or fitness-oriented intervention was not accompanied by an increase in intervention effectiveness, as the point estimates were slightly smaller compared with those for PA-or fitness-only interventions. Overall, the effects tended to be larger in girls than in boys, especially for PA + sedentary behaviour interventions. There was some evidence for inequality, as the effects on body mass index were seen when interventions were delivered in the general population (standardized mean difference = −0.05, 95% CI = −0.07 to −0.02), but not in groups of disadvantaged children (standardized mean difference = −0.01, 95% CI = −0.29 to 0.19). In conclusion, school-based PA interventions appear to be an effective strategy in the primary prevention of childhood obesity among 6-to 12-year-old children, but targeting sedentary behaviour in addition to PA or fitness does not increase the effectiveness of the intervention.

Low physical fitness has been found to be associated with many chronic diseases and medical conditions. Knowledge of secular trends in physical fitness is important to initiate countermeasures for addressing negative trends. The aim of this study was to analyze secular trends in health‐related muscular fitness in Slovenian children and adolescents between 1983 and 2014. Data were collected as part of “The Analysis of Children's Development in Slovenia (ACDSi)” study in 1983, 1993/94, 2003/04, and 2013/14. Anthropometry (body weight, height, BMI, and triceps skinfold) and muscular fitness (standing long jump, bent‐arm hang, and sit‐ups 60 s test) of 18730 (9168 female) students from primary and secondary schools were recorded. The secular trend was analyzed considering anthropometry. The results showed that anthropometric measures had an increasing trend and overall muscular fitness had a decreasing trend. Leg muscle power decreased over the decades in all age groups (relative difference between −1.5% and −2.6%), being more pronounced in boys. Arm muscle strength decreased in two younger age groups (range −21.1% to −42.7%, 6–10, and 11–14 years), but not in the oldest group (15–19 years), where the increase occurred in both genders (0.4% to 9.3%). In terms of decades, the largest negative changes (−30.1%) occurred from 1993/94 to 2003/04 and the smallest changes (−4.2%) from 2003/04 to 2013/14. The overall trend in repetitive core strength surprisingly increased (1.1% to 18.3%). There is a need to promote healthy lifestyles, raise parental awareness and use all government resources to redirect the negative trend in physical fitness.