Association of regional bioelectrical phase angle with physical performance: a pilot study in elite rowers

Background : This study aimed to examine the association between regional Phase Angle (PhA) and physical performance in athletes where the use of specific body segments is required. Methods : Sixteen elite-level rowers (13 male aged 17.6±2.1 yr; 3 female aged (21.0±4.4 yr) participated in this investigation. Raw bioimpedance parameters were obtained with a phase-sensitive 50 kHz bioelectrical impedance analysis (BIA) device and fat-free mass, percentage of fat mass (FM%), and arms and legs lean soft tissue (ALST and LLST, respectively) were estimated using specific BIA-equation developed for athletes. The time (2000t) and the mean power (MP) expressed during the 2000 m test performed on a rowing ergometer were measured. Results : The major findings of the study were that upper hemisome PhA (UPhA) were more strongly related with 2000t (R 2 =0.35, p=0.015) and MP (R 2 =0.40, p=0.009) than whole-body PhA. Additionally, not only UPhA maintained a significant relationship with 2000t (p=0.001) and MP (p=0.001), even after adjustment for the co-variables sex, ALST, and FM%, but the explained variance increased to R 2 =0.72 and R 2 =0.78, respectively. Conclusion : These results suggest that the regional PhA might be used as a tool for evaluating performance related parameters in sports where specific body segments are involved, preferring it to the whole-body measured value.