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Updated: Jun 24, 2026
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Construction of Constant-Load (Isotonic) and Constant-Velocity (Isokinetic) Torque-Velocity-Power Profiles In vivo for the Rat Plantar Flexors
Published on: October 3, 2025
Changes in segmental bioimpedance following eccentric plantar flexor exercise taken to volitional failure
Carlo Rossi1,2, Kworweinski Lafontant2, Ecaterina Vasenina2,3
1Sport and Exercise Research Unit, Department of Psychology, Educational Science, and Human Movement, University of Palermo, Palermo, Italy.
Summary
Segmental bioelectrical impedance analysis (BIA) reveals significant changes in muscle recovery after eccentric exercise. Phase angle (PhA) and resistance (R) indicate localized cellular health shifts during the 72-hour recovery period.
Area of Science:
- Exercise Physiology
- Biomedical Engineering
- Sports Science
Background:
- Segmental bioelectrical impedance analysis (BIA) offers insights into cellular health, muscle, and fluid balance.
- Phase angle (PhA), resistance (R), and reactance (Xc) are key BIA parameters reflecting localized tissue status.
- Understanding BIA responses post-exercise aids in monitoring training adaptations and recovery.
Purpose of the Study:
- To investigate localized BIA parameter changes following eccentric plantar flexor exercise.
- To assess the time course of these BIA alterations during a 72-hour recovery period.
- To explore the utility of BIA in tracking muscle recovery and informing training/rehabilitation strategies.
Main Methods:
- Twenty male participants underwent unilateral eccentric plantar flexor resistance training.
- Segmental BIA measurements (ICW, ECW, R, Xc, PhA, Z, IR) were taken pre-exercise, immediately post-, and at 24, 48, and 72 hours post-exercise.
- A two-way repeated measures ANOVA analyzed leg-by-time interactions for BIA parameters.
Main Results:
- Significant leg-by-time interactions were observed for most BIA parameters (p<0.05).
- Immediately post-exercise, the intervention leg showed decreased R, increased impedance ratio (IR), and decreased Xc (p<0.001).
- Phase angle (PhA) decreased immediately post-exercise but was elevated at 24 and 48 hours compared to baseline (p<0.05).
Conclusions:
- Eccentric exercise induces significant localized changes in BIA parameters, reflecting muscle recovery.
- The observed BIA changes align with established muscle recovery timelines.
- Segmental BIA shows potential as a non-invasive tool for monitoring exercise recovery and guiding rehabilitation.
