Localized bioelectrical impedance analysis: how useful is it in the follow-up of muscle injury? A case report

Aim. Lower limb muscle injuries are among the most common soccer injuries and account for nearly one third of all injuries in professional soccer. The four muscle groups most often involved are the flexors (37%), the adductors (23%), the quadriceps (19%), and the calf muscles (13%). Localized bioelectrical impedance analysis (BIA) is a noninvasive method to evaluate soft-tissue hydration and cell membrane integrity. Here we report the changes in bioelectrical parameters measured during the course of muscle injury healing. Methods. Using a tetrapolar bioimpedance analyzer (50 kHz), we took serial localized measurements of the right posterior thigh muscles to evaluate the flexors, and of the injured left posterior thigh muscles to evaluate the flexors before the injury and during recovery through to return-to-play in a professional soccer player. The aim was to determine the changes in BIA parameters (resistance [R], reactance [Xc], and phase angle [PA]) during healing and compare them with baseline values (non-injury). Results. As compared with baseline values, R, Xc, and PA were decreased at postinjury day 1 (R -2.1 Omega, Xc -0.5 Omega, PA -1 degrees) and at postinjury day 3 (R -2.6 , Xc -0.9 Omega, PA -2 degrees) and returned to baseline after physiotherapy and rehabilitation therapy. The results indicate that the decrease in R reflects localized fluid accumulation, while the decreases in Xc and PA reflect a disruption in cell membrane integrity and cell density during healing. Conclusion. Localized BIA of muscle groups is a practical, inexpensive, and noninvasive method to evaluate soft-tissue injuries to the lower limb.