Increase in BMI and Negative Muscular Strength Trends in Adolescents in 1990 and 2020: Results from the Regional Observatory of Motor Development in Southern Italy

In the last decades, low levels of physical activity and sedentary lifestyles were associated with the progressive decline in physical fitness in children and adolescents. The present cross-sectional study aims to assess the evolution of muscular strength in adolescents in an Apulia province (Italy), comparing motor performance in 1990 and 2020. The sample consists of 107 adolescents attending secondary school in Lecce in 1990, and 118 attending the same school in 2020 (11–12 years old). After dividing the sample according to gender and BMI, muscular strength was assessed with Standing Long Jump (SLJ) and Medicine Ball Throw 2 kg (MBT). Statistical analysis included ANOVA to highlight significant differences in motor performances in 1990 and 2020 according to gender and BMI, and linear regression to investigate the variance explained by BMI on SLJ and MBT. The results showed (a) lower motor performance in 2020 compared to 1990, (b) the increase in the percentage of overweight-obese from 1990 to 2020, and (c) a negative association between BMI and the SLJ in 2020. Findings suggest the need to assess and monitor physical fitness—as a health status indicator—in adolescents, and promote further opportunities to encourage and expand the time spent in physical activity in Apulia.