Levi muscle index, a new bioimpedance parameter for the evaluation of muscle mass in soccer players

Purpose: The assessment of muscle mass in athletes is used because it directly correlates with sports performance. Vector bioimpedance assessment is a growing method of assessing body composition in athletes because it is independent of predictive formulas containing body weight, ethnicity, age, and sex. The study aims to propose a new parameter (Levi Muscle Index, LMI) that evaluates muscle mass through raw bioelectrical data. Methods: 664 male footballers underwent bioimpedance assessment during the regular season. LMI was correlated with body cell mass (BCM) and phase angle (PA) to establish efficacy. Results: The footballers were 24.5 ± 5.8 years old, 180.7 ± 5.9 cm tall and weighed 76.3 ± 7.1 kg. The relationships were: LMI-BMI: r = 0.908, r2 = 0.824, p\0.001; LMI-PA: r = 0.704, r2 = 0.495, p = 0.009 and PA-BCM: r = 0.491, r2 = 0.241, p\0.001. Conclusions: The results obtained confirm that LMI could be considered a new parameter that provides reliable information to evaluate the muscle mass of athletes. Furthermore, the higher LMI-BCM relationship than PA-BCM demonstrates specificity for muscle mass evaluation in athletes regardless of body weight, ethnicity, age, and sex.