Graduate Student Research Symposium 2026

Bioelectrical impedance analysis (BIA)-derived whole-body (WB) phase angle (PhA), a measure of fitness and cellular health, has become increasingly widespread. WB PhA is dependent upon segmental reactance (Xc) and resistance (R), yet there is an incomplete understanding of how segmental values change with training.

PURPOSE: To compare segmental metrics (PhA, R and Xc) after different types of training.

METHODS: Male subjects (24.8±4.7 years) were randomized to a 4-week program: endurance (ET, ran at 85% of critical speed for 30 min, n=8), strength (ST, 4 sets of 5 backsquats at 85% 1RM, n=8, 3x/week), or control (n=9). Standing BIA-derived metrics (Z, Xc, PhA) were measured pre- and post-training with a tetrapolar device (50 kHz). R was calculated for each segment (arms, legs, trunk).

RESULTS: CS improved in ET (5.2%, p<0.005) and strength increased in ST (12.9%, p<0.005). Trunk PhA was higher than limb PhA, while trunk Xc and R were lower than limb values.

CONCLUSION: Different training modes produced changes in Xc and R, suggesting BIA interpretation may require analysis of R and Xc, not PhA alone.