Activity self-tracking technologies have become a popular tool for monitoring physical activity, used to assist individuals in increasing physical activity. Previous findings, however, are inconclusive on whether standalone activity self-tracking, alone or in combination with a step goal, is efficient in encouraging physical activity behavior. This study aimed at investigating the effects of mere activity self-tracking and activity self-tracking with a daily 10,000 steps goal on physical activity levels in a randomized-controlled parallel group trial (N = 150; mean age= 24.66, standard deviation = 4.75), using a publicly available fitness tracker and associated smartphone application. Two experimental groups, one of which without and the other with step goal, recorded daily physical activity (daily step count) via a fitness tracker wearable and associated smartphone application and via daily self-reports of activity over the course of 6 weeks. An unequipped control group recorded physical activity only via daily self-reports. Both experimental groups were compared against each other based on step count data, and against the control group based on daily self-reports of activity. Results of mixed-effect multilevel analyses suggest that activity tracking using fitness trackers and externally assigned goals do not drive greater physical activity behavior. Rather, results indicate substantial individual differences that should be targeted in future studies to better understand individual behavioral processes boosting or hindering daily activity.

In response to the Coronavirus Disease 2019 (COVID-19) pandemic, various measures were taken to contain its spread, including restrictions on physical education and sports clubs. These measures substantially limited children's physical activity behaviors and may have compromised their motor development. Such compromising effects may be particularly prevalent among children from lower socioeconomic background (SEB) who tend to be less physically active than higher SEB peers. In this study, the impact of COVID-19 pandemic-related restrictions on children's motor development was investigated with respect to children's SEB within the PESCov DFG project. Data from 68,996 children from a metropolitan region in Germany (Age: 8.83 years +- 0.56, range: 6.4-13 years, 35,270 female, 51.1 %) assessed between 2011/2012 and 2022/2023 were analyzed as part of the longitudinal cohort study “Berlin hat Talent”. Assessment took place before and after the onset of the pandemic using the German Motor Fitness Test. The test includes assessments of various motor skills covering endurance, strength, coordination, and flexibility. Demographic variables (e.g., age, gender) were collected via questionnaires. SEB was derived on school level, which was determined using the official school type classifications of the state of Berlin. Cross-classified linear mixed effect models were fitted to account for hierarchies in the data, with individual test values (level 1) being nested in motor domains (level 2a) and in participants (level 2b) and participants being nested in schools (level 3b). Outcome measure was motor skill performance transformed from German reference percentiles to z-scores per motor skill. The effects of Time (pre, post LD I, post LD II), Motor Domain, and SEB (continuous, -2 - 2) were estimated while controlling for Age, Gender, and Secular Trends. Main effects of Motor Domain, Time, and SEB were significant. Further, a significant Time x Motor Domain interaction revealed that motor skills differentially developed from during the pandemic. Coordination, strength, and flexibility decreased, while endurance increased. SEB had a negative effect on overall motor development of third graders. However, this effect varied between motor domains (coordination = endurance > strength > flexibility). Totally, motor skills were on average about 4 percentile points lower after lockdown I, and the effect of the pandemic was stronger after controlling for secular trend. Results suggest highly differential effects of the pandemic on children's motor development, which should be considered when recovering motor skills in the post-pandemic era. To avert these trends and the lifelong consequences of impaired motor development in childhood, comprehensive monitoring of children’s motor performance levels is needed as well as support programs for children with compromised motor performance, particularly for children from low SEBs.

This study further validates the sport-specific Mental Rotation Test – Basketball (MRT-BB) in which participants solve 24 items regarding basketball plays. The task of each item consists of comparing four alternative stimuli with a criterion stimulus and identifying the two “correct” alternatives. A total of 203 participants (101 females) took part in this experiment in which they solved the original MRT and the MRT-BB. The results replicate the findings of Weigelt and Memmert (2021 ). The number of items attempted declined toward the end of each set, with participants solving more items in the second set and men outperforming women. While participants solved more items on the MRT-BB, performance in both tests was positively correlated. Our replication of the previous results supports the validity of the MRT-BB. The correlation supports the notion that the mental rotation of the sport-specific stimuli is based on more general mental rotation skills.

Childhood obesity is associated with various adverse health outcomes. Restrictive measures to contain the spread of the Coronavirus Disease 2019 (COVID-19) pandemic, like lockdowns and school closures, affected children’s daily structure, physical activity, dietary habits, and sleep quality, possibly exacerbating risk factors for childhood obesity and higher body mass index (BMI) in children. In particular, as poor socioeconomic conditions tend to favor obesogenic environments, children from lower socioeconomic backgrounds (SEBs) may have been at relatively higher risk for elevated BMI levels following pandemic measures. In this study, the impact of measures related to the COVID-19 pandemic on the BMI of third graders was investigated with regard to children’s SEB. Data from 41,728 children (8.84 ± 0.56 years, 20,431 female) were collected in the context of the longitudinal cohort study “Berlin hat Talent” and analyzed as part of the PESCov DFG project. Children were tested either before the pandemic (preCOVID: Sept2017 - March2020, n = 26,314), or following the first (post_"LD I" : Aug2020 - Dec2020, n = 6,657) or second lockdown in Germany (post_"LD II" : Aug2021 - Jan2022, n = 8,757). Demographic variables were collected via questionnaires. SEB was based on the official school type classification of the state of Berlin. Linear mixed effect models were computed to account for the hierarchical nature of the data, i.e. children (level 1) nested in schools (level 2). Outcome measures were age- and sex-adjusted BMI standard deviation scores (SDS). Independent variables were Time (preCOVID, post_"LD I" , post_"LD II" ), SEB (continuous, -2 - 2), and the interaction thereof. Covariates were Age, Gender, and Month of Test. Significant effects of Time (p < .05) and SEB (p < .001) revealed elevated BMIs in post_"LD I" and post_"LD II" compared to preCOVID cohorts and higher BMIs for children with lower SEB. A significant Time x SEB interaction (p < .01) indicated that the effect of SEB on children’s BMI increased in response to lockdowns, especially in post_"LD II" . Results suggest that the COVID-19-related measures lead to increased BMI in children, and that children of lower SEB were at particular risk for higher BMIs following lockdowns. These findings denote an alarming trend and emphasize the necessity for countermeasures to reduce lockdown-related BMI increments in children, particularly in low SEB areas. Authorities are called into action to promote physical activity of children and establish post-pandemic offers to counteract the risk of increasing rates of childhood obesity and related adverse health outcomes.