Author(s): SHIMIZU, K., YOSHIKAWA, A.2, YABUNO, N.2, HASHIMOTO, Y.2, INAMI, T.1,2, Institution: KEIO UNIVERSITY, Country: JAPAN, Abstract-ID: 941

INTRODUCTION:
Rhythmic gymnastics is an aesthetic sport characterized by high training loads, repeated jumping actions, and strict body shape management. These demands are associated with increased risks of low energy availability and impaired bone health in female athletes.Bone density reflects long-term skeletal adaptation to mechanical loading and nutritional status, whereas phase angle (PhA), derived from bioelectrical impedance analysis, reflects cellular membrane integrity and fluid distribution and is considered an indicator of short-term physiological condition. However, the relationship between bone density and PhA in rhythmic gymnasts remains unclear. Therefore, this study examined the associations among bone density, PhA, body composition, and jump performance in elite rhythmic gymnasts.
METHODS:
Ten elite female rhythmic gymnasts (18.6±1.96 years) competing at national level or higher were included. Body composition was assessed using InBody 270S. Phase angle at 5 kHz and 50 kHz was measured in the supine position using InBody M20.Bone density was evaluated at the calcaneus using ultrasound speed of sound (SOS). Jump performance was assessed by countermovement jump (CMJ) height and reactive strength index (RSI).
Associations among variables were examined using Spearman’s rank correlation coefficients (p<0.05).
RESULTS:
The mean values for each indicator were as follows: PhA5 kHz 2.8±0.36 degrees, PhA50 kHz 7.4±0.67 degrees, bone density (SOS) 1546.7±24.18 m/s, weight 47.4±3.30 kg, body fat percentage 17.8±5.04 %, skeletal muscle mass 21.1±1.26 kg, CMJ height 27.2±3.51 cm, and RSI 2.1±0.24.
Bone density showed no meaningful association with PhA50 kHz (ρ=−0.086) or body fat percentage (ρ=−0.086). In contrast, PhA demonstrated moderate associations with jump performance and body composition indicators.
CONCLUSION:
Bone density and phase angle appeared to represent different physiological dimensions in elite rhythmic gymnasts. Bone density, reflecting skeletal adaptation, was largely independent of PhA and body fat percentage.
In contrast, the associations between PhA and performance-related variables suggest that PhA may be more sensitive to short-term physiological condition. These findings indicate that bone density and PhA provide complementary information.
A combined evaluation of skeletal health and cellular-level indicators may enhance conditioning and health monitoring in aesthetic sports.