Abstract
Phase angle (PhA) is the relationship between reactance (Xc) and resistance ratio (R) current that flows through the cellular tissue, which can be measured via Bioelectrical Impedance Analysis (BIA) when measuring body composition. Due to the availability and ease of use, phase angle has been adopted and used in clinical nutrition to track various disease states, from malnutrition to cancer cachexia, and other muscle-wasting diseases. Since PhA reflects cellular water content and rapid changes in cellular health, applications for athlete performance tracking have shown promise. Resistance training is highly effective for enhancing PhA when adopting high-intensity volumes and durations for programs. Normative data on healthy and/or athletic populations remains inconsistent. Previous research on Rugby Union players found no significant differences based on player positions. However, longitudinal studies examining the changes in PhA, specifically among college-aged athletes, are needed. PURPOSE: To examine changes in PhA and lean body mass (LBM) during an off-season 6-week resistance training cycle (i.e., mesocycle) in a subset (N=21) of a collegiate club male rugby team. METHODS: Body composition was measured via multi-frequency bioelectrical impedance analysis (MF-BIA) (Seca mBCA 514) and Dual-Energy X-ray Absorptiometry (DXA) (Hologic, Horizon W) at the end of the spring competitive season (T1) and the beginning of the fall standard union match season (T2). Athletes were required to fast a minimum of eight hours, abstain from exercise for 24 hours, and void their bladder within 30 minutes of data collection. A paired T-test analysis was conducted via statistical software (SPSS 29.0.2.0) for changes in PhA and LBM over the two (T1 – T2) time points. RESULTS: A significant difference was found in LBM (M = 0.897 g, SD= 1,476 g) (p>0.001, a = 0.05). No significant differences were found in PhA (M = 0.117 degrees, SD = 0.22 degrees) (p>0.001, a = 0.05) at T2 when compared to T1. CONCLUSION: During the six-week resistance training program, there was no change in PhA and a significant increase in LBM was shown. While these results are not surprising, the level of change did vary for LBM (1,323± g), but not for PhA (6.87± degrees) among the participants. PhA and LBM provide insight into skeletal muscle health and readiness to participate in high-level competition. Phase angle has shown to be a reliable measure of cellular health in aging and disease populations. However, a short-term resistance training program (6 weeks) implemented during the summer did not show a change in phase angle. LBM could better indicate training effects during short term training in rugby athletes.
Recommended Citation
Rodriguez, Alexis; Large, Brandon; Large, Tyler; Hughes, Jmya; and Spillane, Micheil
(2025)
"Changes in Phase Angle and Lean Body Mass During 6-Week Offseason Mesocycle in Collegiate Club Rugby Players,"
International Journal of Exercise Science: Conference Proceedings: Vol. 2:
Iss.
17, Article 190.
Available at:
https://digitalcommons.wku.edu/ijesab/vol2/iss17/190
