Assessment of amplitude-frequency characteristics of postural sway at the pressure centers of the contralateral lower limbs of young athletes

BACKGROUND: The development of instrument-based methods for the functional diagnostics of adaptive body changes in children engaged in sports activities is a currently relevant area of research. AIM: This work examined the amplitude characteristics of postural sway at the pressure centers of the contralateral lower limbs in young athletes in motionless standing positions across a frequency range. METHODS: Amplitude-frequency characteristics were analyzed during motionless standing in 18 children aged 7–10 years, of both sexes, who regularly participated in track and field. The postural sway parameters of the pressure centers under both feet were recorded using two stabilometric platforms. Measurements were collected in the low-frequency range (up to 1.0 Hz) for 20 seconds and the high-frequency range (1.0–6.0 Hz) for 1 second. The deviation angle α (°) of the sway axis of the lower limbs from the midline axis was determined. The first peak amplitudes and frequencies of sway were measured: а1, а2, and а3 (mm) and f1, f2, and f3 (Hz) in the low-frequency range, respectively; and А1, А2, and А3 (mm) and F1, F2, and F3 (Hz) in the high-frequency range. The control group comprised 18 children with typical daily physical activity levels. RESULTS: In young athletes, more favorable amplitude-frequency characteristics of postural sway at the low- and high-frequency ranges were identified compared with age-matched peers not engaged in sports and leading sedentary lifestyles. This effect was manifested by a frequency shift in sway, a reduction in all peak sway amplitudes at both the low- and high-frequency ranges, lower asymmetry of sway amplitudes, and the stable synchronization of pressure center oscillations across the entire frequency spectrum. CONCLUSION: Amplitude-frequency parameters of postural sway at the pressure centers of the contralateral lower limbs should be considered while training younger school-aged children for sports to prevent neuromuscular imbalance due to fatigue, and injuries.