Both the physical self-concept and actual motor competence are important for healthy future physical activity levels and consequently decrease overweight and obesity in childhood. However, children scoring high on motor competence do not necessarily report high levels of physical self-concept and vice versa, resulting in respective (in-) accuracy also referred to as (non-) veridicality. This study examines whether children’s accuracy of physical self-concept is a meaningful predictive factor for their future physical activity. Motor competence, physical self-concept and physical activity were assessed in 3rd grade and one year later in 4th grade. Children’s weight status was categorized based on WHO recommendations. Polynomial regression with Response surface analyses were conducted with a quasi-DIF approach examining moderating weight status effects. Analyses revealed that children with higher motor competence levels and higher self-perceptions show greater physical activity. Importantly, children who perceive their motor competence more accurately (compared to less) show more future physical activity. This effect is strong for underweight and overweight/obese children, but weak for normal weight children. This study indicates that an accurate self-perception of motor competence fosters future physical activity beyond single main effects, respectively. Hence, the promotion of actual motor competence should be linked with the respective development of accurate self-knowledge.

The measurement of physical fitness (PF) is an important factor from many different perspectives. PF is a determinant of healthy child development as it is related to several health outcomes. However, existing taxonomies of the construct and frequently used fitness assessments vary concerning their theoretical assumptions and practical implications. From a theoretical perspective, the construct of physical fitness covers a variety of motor domains, such as cardiovascular endurance, strength, coordination, or flexibility (eg, Caspersen et al., 1985). However, most fitness assessments provide a single (composite) score including all items as test outcome. This implicitly relates to a one-dimensional structure of physical fitness, which has been shown for other motor performance assessments in early childhood (eg, Utesch et al., 2016).This study investigated this one-dimensional structure for 6-to 9-year-old children within the item response theory framework (Partial Credit Model). Seven fitness subtests covering a variety of motor dimensions (6-minute run, pushups, sit-ups, standing broad jump, 20 m sprint, jumping sideways, and balancing backwards) were conducted to a total of 790 six-year-olds, 1371 seven-year-olds, 1331 eightyear-olds, and 925 nine-year-olds (48.2% females). Each item was transformed into five performance categories controlling for sex and age. This study indicates that a one-dimensional testing of PF is feasible across middle childhood. Furthermore, for 6-and 7-year-olds, all seven items including balancing backwards can be accumulated to one factor. From the age of about 8 and 9 years balancing backwards seems to become too easy. Altogether, analyses show no diversification of PF across childhood. K E Y W O R D Sitem response theory,

Though it is well-established that self-esteem develops from childhood well into old age, little is known about the processes that influence this change, especially among young populations. This international, cross-sequential study examined the development of self-esteem in 1599 second-graders (Age MT1 = 7.99, SDT1 = 0.52 years; 52% male) in the Netherlands and Germany over three years. Multilevel models revealed that mean-level trends in self-esteem were stable across time among all demographic groups, but that males and students in the Netherlands consistently had higher self-esteem than females and students in Germany. Further analyses examining the role of social support in self-esteem development demonstrated that individuals with better peer and family social support tended to have higher levels of self-esteem and that within-person changes in social support were directly related to changes in self-esteem level, providing support for sociometer theory. These findings suggest that demographic factors as well as social support are important predictors of self-esteem as early as middle childhood.

In recent years anti-doping organizations have implemented various measures to deter elite athletes from using performance-enhancing drugs. One of the main challenges in the fight against doping is that the effectiveness of these anti-doping measures is still unknown. Since the effectiveness of the measures depends primarily on the athletes’ perception, this study focuses on the following four objectives: (1) How effective do top-level athletes perceive individual anti-doping measures to be? (2) Are the results stable across different sports and (3) genders? (4) How can the anti-doping measures be structured into appropriate categories? To address these issues the perceived effectiveness of 14 anti-doping measures was surveyed among 146 top athletes from Germany (Cycling: N = 42; Athletics: N = 104) who are members of at least the National Testing Pool. Results reveal significant differences in the perceived effectiveness of the anti-doping measures. Improved diagnostics were considered to be the most effective remedy for doping, followed by increased bans and the implementation of an anti-doping law. In contrast, fines and a leniency program were considered significantly less effective. Second, with the exception of indirect detection methods and increased use of an Anti-Doping Administration and Management System, results were consistent across cyclists and track and field athletes. Third, no significant gender difference was observed. Finally, an exploratory factor analysis showed that all anti-doping measures can be classified into the three categories risk of detection (e.g., control frequency and efficiency), punishment (e.g., fines and bans) and communication (e.g., education program). The results of this study provide a guideline for future research and for anti-doping and sport organizations when developing strategies against doping and allocating their anti-doping budget.

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