Localized Bicep Tissue Bioimpedance Alterations Following Eccentric Exercise in Healthy Young Adults

Objective: The localized bicep tissue bioimpedance was measured from participants who completed an eccentric exercise protocol with one arm and no exercise with the other arm to compare changes that occur as a result of the exercise protocol over a 96h observation period. Methods: The localized bicep bioimpedance, bicep circumference, and self-reports of bicep pain were collected from 6 volunteers at pre, post, 24h, 48h, 72h, and 96h timepoints after completing an eccentric exercise protocol of the elbow flexor muscles. Results: The unexercised bicep showed no statistically significant differences between the pre-exercise and post-exercise measures at any timepoints for all impedance measures and circumference. The exercised bicep showed statistically significiant decreases (p < 0.01) for 10 kHz, 50 kHz, and 100 kHz impedance (resistance and reactance) and increases of bicep circumference at the 72h and 96h post-protocol timepoints, compared to the pre-protocol measurements. The self-reports of pain of the exercised bicep also showed statistically significant increases (p < 0.01) at the 48h and 72h timepoints compared to the baseline reports. Conclusion: Completion of the eccentric protocol resulted in increases of bicep circumference and decreases in the magnitude of resistance and reactance components of the localized tissue bioimpedance; with maximum changes of swelling and impedance occurring at the same post-protocol timepoints. These changes support that localized tissue bioimpedance is sensitive to the changes that occur as a result of the exercise protocol with the potential to quantify tissues for exercise induced changes. Significance: Localized tissue bioimpedance is sensitive to the changes that occur from eccentric exercise and may be a potential method to non-invasively quantify tissues for changes due to exercise, fatigue, injury, and recovery.