The purpose of the study was to comprehensively characterise changes in indicators of physical fitness and functional capabilities of adolescent girls depending on the level of motor activity under the influence of aerobic loads. The study was conducted at the Pereyaslav Gymnasium No. 3 (Kyiv Oblast) during March 17 – May 25, 2025 and included an aerobic programme with two stages of measurement, which allowed analysing the dynamics of physical fitness and functional indicators of the cardiovascular system of adolescent girls with different levels of motor activity. It was found that in the high-activity group, the distance of six-minute running increased from 900 ± 100 m to 1,130 ± 90 m (+25.6%), while in the low-activity group – from 820 ± 95 m to 950 ± 85 m (+15.9%). The number of squats in 30 seconds increased by +45% (from 20 ± 4 to 29 ± 3) against +33.3% (from 18 ± 4 to 24 ± 3). The 4x9 m shuttle run performance improved moderately: -1.1 s in high-activity and -0.7 s in low-activity. Functional changes in the cardiovascular system were manifested by a decrease in the resting heart rate by -11.4% and -7.3%, respectively, an increase in recovery in the first minute by +54.5% against +44.4%, and a decrease in the Ruffier-Dixon Index by 29.7% and 21.6%, which reflects an improvement in the functional state. Correlation analysis confirmed that the level of motor activity was statistically associated with the scale of adaptive changes (r= 0.68-0.72;p< 0.01). Thus, the initial motor status determined the training sensitivity of adolescent girls and influenced the nature of changes in physical fitness and functional indicators. The obtained data can be used by physical education teachers, trainers, and specialists of health programmes to differentiate the load, taking into consideration the initial level of motor activity of girls
Panhelov et al. (Wed,) studied this question.