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Although risk factors for cardiometabolic diseases begin to present in young people, the association between physical fitness and adiposity with traditional and novel risk factors for cardiometabolic diseases across adolescence remains relatively unknown. Following ethical approval, fifty-two adolescents (age 11.6 ± 0.6 years; 32 girls) were recruited for a 2-years longitudinal study. Adiposity was assessed based on sum of skinfolds, waist circumference and body mass index, and physical fitness as distance run on the multi-stage fitness test (MSFT). Risk factors for cardiometabolic diseases (pro- and anti-inflammatory cytokines, plasma insulin, Homeostatic Model Assessment of Insulin Resistance - HOMA-IR, blood pressure) were measured following an overnight fast. Relationships between independent and response variables were analysed using multi-level modelling (final combined models were created using the stepwise backward elimination method). Plasma insulin concentration and HOMA-IR were positively associated with adiposity and inversely associated with distance run on the MSFT (all p

BackgroundSchool-based physical activity interventions are accessible to most adolescents and could enhance adolescent cardiometabolic health and cognition; yet the feasibility and success of school-based physical activity interventions is understudied.MethodsSixteen adolescent girls (age: 11.7 ± 0.3 y; height: 1.58 ± 0.07 m; body mass: 45.5 ± 9.2 kg) were randomized to either an intervention (2-weeks sprint training; n = 8) or control group (continuation of regular physical activity levels; n = 8). Following familiarization, all participants completed baseline measurements including fasted and postprandial capillary blood samples, a battery of cognitive function tests (Stroop Test, Sternberg Paradigm and Flanker Task), and an assessment of physical fitness (20 m sprint and multi-stage fitness test). The intervention group completed 2-weeks progressive sprint training (3 sessions per week: week one 6 × 10 s sprints, week two 8 × 10 s sprints). Follow-up measurements were completed 48 h after the final sprint training session. Data were analyzed via ANCOVA to examine between group differences at follow-up whilst controlling for baseline score.ResultsAccuracy in the intervention group during the three-item Sternberg paradigm was greater when compared with the control group (Intervention: 99.6 ± 1.1%; Control: 97.7 ± 2.2%, p = 0.046). BDNF concentration was also higher in the intervention group at follow-up than control group (Intervention: 39.12 ± 9.88 ng.ml−1; Control: 22.95 ± 9.13 ng.ml−1, p < 0.001). There were no differences at follow-up between the intervention and control group for measures of cardiometabolic health (fasted cytokine concentrations or postprandial glycaemic and insulinaemic responses) or on the Stroop Test or Flanker Task (all p > 0.05). However, the intervention group reported enjoying the sprint training and that they found the sessions valuable.ConclusionTwo-weeks sprint interval training in a school-setting enhanced working memory and increased concentrations of BDNF in adolescent girls. The intervention was deemed enjoyable and worthwhile by the adolescent girls and thus the longer-term implementation of such an intervention should be examined.

The present study examined if elite youth male association football (soccer) players aged 8–19 y (n = 2,875) from the English talent development system, who ultimately achieved professional status differed in stature, body mass, and physical performance (20-m sprint speed, slalom agility speed, vertical counter-movement jump with arm swing jump height, multistage fitness test distance) compared with their non-professional peers. The study also examined the longitudinal pattern of development of stature, body mass, and physical performance, and if this was different between future professionals and non-professionals, while considering the effects of playing position. Multilevel modeling of the 8,898 individual (player-occasion) data points suggested that from age 12.0, the future professionals performed better in a vertical counter-movement jump with arm swing test and slalom agility test than future non-professionals, and improved at a faster rate, so that by age 18.0 the differences in vertical counter-movement jump with arm swing and slalom agility performance were 1.7 cm (p < 0.001, d = 0.3) and 0.14 s (p < 0.001, d = 0.5), respectively. In addition, future professionals were faster (by 0.02–0.04 s on the 20-m sprint, p < 0.001, d = 0.2) and ran further in the multistage fitness test (by 47 m, p = 0.014, d = 0.2) than future non-professionals throughout their development, but there were no differences in stature or body mass during development between the groups. Whereas, multistage fitness test performance improved linearly with age, the development of all other physical characteristics was non-linear. There were inter-individual differences in the development of all characteristics, and there were differences between playing positions in the development of all characteristics. Thus, in summary, future professionals jump higher, are more agile, faster, and more endurance fit than future non-professionals as they age, and the pattern of development is different in professionals and non-professionals for vertical jumping and slalom agility performance.