Bioelectrical impedance analysis as a means of quantifying upper and lower limb asymmetry in youth elite tennis...

This study aimed to examine side-to-side differences in phase angle (PhA) in both upper and lower limbs of youth elite tennis players. Among other outcomes, PhA was directly determined using segmental multifrequency bioelectrical impedance analysis (BIA) in 26 tennis players (11.6 ± 1.1 years, 54% boys) and compared against a sex- and age-matched reference population. Significant upper limb asymmetry in PhA (p < 0.001), with a higher value on the dominant side of the body, was observed in the tennis players. At lower limb level, the tennis players showed a tendency towards a significantly higher PhA in the contralateral compared to the ipsilateral limb (p = 0.089). Using vector analysis (BIVA), a significant degree of PhA asymmetry (p = 0.002) was only reflected in the tennis players' upper limb. Additional segmental outcomes also demonstrated a significant degree of upper limb asymmetry in terms of tennis players' lean mass (p < 0.001), total segmental water (p < 0.001), fat mass (p < 0.001), extracellular water (p < 0.001) and extracellular water ratio (p < 0.001), whereas lower limb asymmetry was only observed in tennis players' fat mass (p = 0.037) and extracellular water (p = 0.001). This is the first study to report significantly more pronounced BIA-based side-to-side differences in youth elite tennis players compared to a non-athletic reference population at the upper limb level, whereas no significant between-group differences in the lower limbs were found. This explorative study should trigger future research to further scrutinize the role of BI(V)A as a promising field-method in monitoring bodily asymmetries in youth elite tennis players in view of sport performance and athletic health.HighlightsBioelectrical Impedance Analysis is a promising field-method to monitor side-to-side asymmetry in youth elite tennis players.Youth elite tennis players displayed a more pronounced degree of BIA-based side-to-side differences compared to a non-athletic reference population at the upper limb level, whereas whilst between-group differences appeared to be less evident in the lower limbs.Future research is warranted to scrutinize whether and to what extent these degrees of segmental bodily asymmetry may be related to injury risk (prevention) and athletic development of (pre)adolescent tennis players.