One‐Year Effects of the FIT FIRST 20 High‐Intensity and Multisport Physical Education Program on Physical Fitness and Psychological Outcomes in Early Adolescents: A Cluster‐Randomized Controlled Trial

ABSTRACT We evaluated the 1‐year effectiveness of FIT FIRST 20, a high‐intensity multisport physical education (PE) program, on physical fitness and psychological outcomes in 4–6 grade schoolchildren (10–13 years). A cluster‐randomized controlled trial was conducted across 82 classes from 30 Danish schools ( n  = 1652 pupils; 49% girls). Schools were allocated to either three weekly 40‐min FIT FIRST 20 sessions (intervention) or standard curriculum PE (control) over approximately 40 weeks. Outcomes were assessed at baseline and post‐intervention; 2‐year follow‐up results will be reported separately. The primary outcome was cardiorespiratory fitness, assessed using the Yo‐Yo Intermittent Recovery Test Level 1 (children's version). Secondary outcomes included agility, lower‐body muscular power, postural balance, handgrip strength, body composition, blood pressure, resting heart rate, health‐related quality of life, physical self‐concept, motivation for physical activity, and satisfaction of basic psychological needs. Intervention effects were analyzed using linear mixed‐effects models adjusted for sex, baseline sport participation, age, body mass and height. The latter two were excluded from models predicting psychological outcomes. Compared with the control, the intervention arm showed significantly greater improvements in cardiorespiratory fitness (54.90 m, 95% CI [8.35, 101.40], p  = 0.021), along with significant gains in agility and lower‐body muscular power. No interaction effects were observed for other physical fitness and psychological outcomes, although significant overall effects of time were observed for several outcomes. Overall, FIT FIRST 20 appears to be a feasible school‐based strategy for improving selected physical fitness outcomes in 10–13‐year‐olds. Further modifications may be needed to strengthen the effects on psychological outcomes. Clinical Trial Registration: ISRCTN14624515