Muscle Localized Phase Angle Is Related To Lower Limb Strength In Amateur Female Soccer Players

The relationship between the bioelectrical impedance phase angle (PhA) obtained at the whole-body level and muscular performance in athletes is well-established. However, it is still unclear whether the PhA obtained through localized muscle bioimpedance analysis (ML-BIA) may indicate muscular strength in a specific limb. PURPOSE: To verify if ML-PhA is a predictor of lower limb muscle strength (LLMS) in amateur female soccer players. METHODS: The sample comprised 15 amateur female soccer players (age: 19.7 ± 2.3) with a training frequency of at least 3 times a week. The lean soft tissue (LST) and fat mass (FM) of the right thigh were assessed by DXA. ML-BIA was performed on the anterior right thigh using a tetrapolar 50 kHz device. The electrodes were positioned 5 and 10 cm distally from the anterior-inferior iliac spine and proximally at the superior pole of the patella and 5 cm above. LLMS was assessed by a one-repetition maximum test (1RM) conducted on a horizontal leg press machine. Linear regression analysis was performed to test ML-PhA as a predictor of muscle strength, controlling for age and limb composition (LST and FM). RESULTS: ML-PhA was correlated with thigh FM (r = -0.66; p = 0.007) and LLMS (r = 0.65; p = 0.008). There were no correlations between LLMS with thigh FM and LST (p > 0.05). ML-PhA demonstrated a significant relationship with LLMS by itself, that remained significant even after controlling for age and FM (Table 1). CONCLUSION: The ML-PhA was positively related to LLMS and negatively to thigh FM, proving to be a significant predictor of LLMS even after controlling for age and thigh fat mass. ML-PhA appears to be an indicator of muscle strength. Future studies with larger samples are necessary to confirm ML-PhA as a potential performance marker in this population. Table 1. - Linear multiple regression to test ML-PhA as a predictor of 1RM-legpress (lower limb muscle strength). Lower Limb Muscle Strength B S.E β t p r2ajust p ML-PhA1 2,331 0,802 0,600 2,908 0,013 0,425 0,014 ML-PhA2 1,693 0,892 0,435 1,898 0,084 0,470 0,018 ML-PhA3 3,038 1,088 0,782 2,793 0,017 0,422 0,029 This study was financed in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - Brasil (CAPES) - Finance Code 001[Grant number: N.M. Oliveira: 88887.711500/2022-00