European fitness landscape for children and adolescents: updated reference values, fitness maps and country rankings based on nearly 8 million test results from 34 countries gathered by the FitBack network.

OBJECTIVES: (1) To develop reference values for health-related fitness in European children and adolescents aged 6-18 years that are the foundation for the web-based, open-access and multilanguage fitness platform (FitBack); (2) to provide comparisons across European countries. METHODS: This study builds on a previous large fitness reference study in European youth by (1) widening the age demographic, (2) identifying the most recent and representative country-level data and (3) including national data from existing fitness surveillance and monitoring systems. We used the Assessing Levels of PHysical Activity and fitness at population level (ALPHA) test battery as it comprises tests with the highest test-retest reliability, criterion/construct validity and health-related predictive validity: the 20 m shuttle run (cardiorespiratory fitness); handgrip strength and standing long jump (muscular strength); and body height, body mass, body mass index and waist circumference (anthropometry). Percentile values were obtained using the generalised additive models for location, scale and shape method. RESULTS: A total of 7 966 693 test results from 34 countries (106 datasets) were used to develop sex-specific and age-specific percentile values. In addition, country-level rankings based on mean percentiles are provided for each fitness test, as well as an overall fitness ranking. Finally, an interactive fitness platform, including individual and group reporting and European fitness maps, is provided and freely available online (www.fitbackeurope.eu). CONCLUSION: This study discusses the major implications of fitness assessment in youth from health, educational and sport perspectives, and how the FitBack reference values and interactive web-based platform contribute to it. Fitness testing can be conducted in school and/or sport settings, and the interpreted results be integrated in the healthcare systems across Europe.

Twitch contractile properties of plantarflexor muscles in young and middle-aged recreationally physically active and non-active women.

BACKGROUND AND AIMS: This study examined the effect of recreational physical activity on the contractile properties of skeletal muscles in middle-aged vs young women. METHODS: A total 74 young (20-29-year-old) and middle-aged (45-54-year-old) women participated. The subjects were distributed into four groups: 1) young recreationally physically active (RPA) (n=19), 2) young recreationally physically non-active (RPN) (n=21), 3) middle-aged RPA (n=23) and 4) middle- aged RPN (n=16). RPA women exercised regularly in groups of recreational gymnastics 2-3 times per week. Isometric twitch of the plantarflexor muscles was evoked by supramaximal electrical stimulation of the tibial nerve in resting and post-activation potentiation state. RESULTS: A greater resting twitch maximal rate of force development (RFD), and potentiated twitch peak force (PF) and maximal rate of relaxation (RR) were observed in the young RPA women compared with the two middle-aged women groups. In young RPN women, these characteristics were greater than in the middle-aged RPN women, whereas they did not differ significantly when compared with the middle-aged RPA women. A shorter resting and potentiated twitch contraction time, and a greater potentiated twitch maximal RFD were found in the young compared with the middle-aged groups. There were no significant differences in twitch characteristics between RPA and RPN women of similar age. CONCLUSIONS: The recreational gymnastic type of physical activity did not have a marked effect on twitch contractile properties in young and middle-aged women. A reduced speed of isometric twitch contraction was found in middle-aged women, which was more pronounced in the post-activation potentiation state.