Body Composition Analysis in Runners Using Bioimpedance Technique

Sex-based differences in body composition are well documented, though sports practice may reduce them. This study aims to: 1) provide baseline body composition data acquired via bioelectrical impedance analysis (BIA) for competitive male and female runners (sprinters and long-distance); 2) evaluate which training protocol more effectively improves body composition; and 3) outline a methodological approach for future research. Thirty-six athletes (13 females (F), 23 males (M)) are assessed: 22 sprinters (10F, 12M) and 14 long-distance runners (3F, 11M). BIA measurements are taken under standardized conditions. Initial assessments show that both sexes fall within normal fat mass (FM) ranges: M average 19.32%, F 25.65%. FM is higher in females than in males, and lower in long-distance runners than in sprinters. After a three-month training period—sprinters follow high-intensity, low-volume workouts with biweekly strength sessions; long-distance runners emphasize endurance and weekly strength training—a second assessment reveals improved body composition and hydration in both groups. Long-distance runners improve their body composition between the two tests and show, on average, the best overall body composition values. However, sprinters exhibit the highest percentage improvements, as they begin with less favorable values and respond strongly to the training stimulus. Notably, the most trained female athletes display excellent values, in some cases comparable to those of their moderately trained male counterparts.