Body Composition in Physically Active Male Students Assessed Using Multi-Frequency Bioelectrical Impedance Analysis

Body composition is strongly influenced by physical activity and dietary habits. Male students enrolled in Physical Education and Sport programs represent a distinct population because their curricula include systematic physical activity that directly affects physiological characteristics. This study aimed to establish a representative body composition profile of physically active male Physical Education and Sport students using a multi-frequency bioelectrical impedance analyzer (BIA) and to evaluate the reliability and consistency of measurements across two assessments. A total of 108 male students aged 19–25 years participated in the study. Body composition was assessed using ten indicators: body fat percentage, visceral fat index, body mass index (BMI), muscle mass, skeletal muscle mass, sarcopenic index, total body water, body weight, height, and phase angle. Descriptive statistics, paired-samples t-tests, effect size analysis (Cohen’s d), and Bland–Altman analyses were used to evaluate agreement, reliability, and measurement consistency between pre- and post-test assessments. No statistically significant differences were observed between assessments for any parameter (p > 0.05). Effect sizes were trivial across all indicators, indicating negligible changes between measurements. Bland–Altman analysis revealed bias values close to zero and relatively narrow 95% limits of agreement, confirming good measurement reliability and reproducibility. Physically active male students exhibited a stable and reproducible body composition profile. The obtained values may serve as reference data for body composition assessment in similar populations. Although the BIA method demonstrated high reliability, it appears more sensitive to moderate-to-large changes than to very small individual physiological fluctuations.