Differences between the sexes in athletes' body composition and lower limb bioimpedance values

Abstract

Introduction: The differences between the sexes in body composition are well established, although sports activity at an elite level seems to reduce them. The aim of this study is a comparison of the sexes in terms of athletes' body composition with a three-compartment model and a localized bioimpedance analysis in elite soccer players.

Methods: 18 female and 18 male elite soccer players of the same age were matched (female=26.2±2.4, male 26.9±2.5; p=0.87). An assessment of body composition was performed through the integration of anthropometrics parameters, skinfold thickness and bioimpedance data. The evaluations were carried out in the morning on a group of athletes who were in a rested condition, having not exercised in the previous 12 hours and having fasted for breakfast.

Results: A body composition assessment shows higher values in females for hip circumference/ height (female: 0.55±0.03, male: 0.52±0.02; p<0.01) and fat mass index (female: 3.7±0.7 kg/m², male: 2.4±0.4 kg/m²; p<0.001), while there is no difference between the genders in the extra cellular mass index (female: 7.1±1.2 kg/m², male: 7.6±0.4 kg/m²; p=0.11). A localized bioimpedance analysis describes well-defined differences in the thighs, while in the calves these differences are reversed for the reactance values.

Conclusion: Sports activity seems to slightly reduce differences in the whole body. The different adaption at the same physical effort appears to be mainly related to cellular mass. This study shows for the first time localized bioimpedance values in female athletes.

Level of evidence: II b.

Keywords: L BIA; body composition; extracellular mass; soccer players.

Figure 1

Sexes differences in body composition with three compartments model indexed by body weight, percentage of body weight and by kg/m². a. On the left side, body composition analysis with three compartments model divided by kg of body mass; b. on the middle, body composition analysis with three compartments model divided by % of body mass; c. on the right side, body composition analysis with three compartments model divided by kg/m². Measurement error = difference between the sum of three compartment data of body composition and body weight or percentage of body weight or kg/m². * Sex differences with p < 0.05.

Figure 2

Whole-body BIVA point graphs. a. On the left side, the female sample plotted on the tolerance ellipses of the reference population; b. on the middle, the male sample plotted on the tolerance ellipses of the reference population; c. on the right side, the male sample plotted on the tolerance ellipses of the male, elite level, soccer reference population. R/h, height-adjusted resistance; Xc/h, height-adjusted reactance.

Figure 3

Whole-body BIVA mean graph. a. The 95% confidence ellipses for the whole-body mean impedance vectors of the female sample (dark dashed line ellipse) and the reference population (dotted line ellipse with vector) are shown; b. The 95% confidence ellipses for the whole-body mean impedance vectors of the male sample (dark dashed line ellipse), the reference population (dotted line ellipse with vector) and the soccer reference population are shown; c. the 95% confidence ellipses for the whole-body mean impedance vectors of the female sample (dotted line ellipse) and the male sample (dark dashed line ellipse) are shown. R/h, height-adjusted resistance; Xc/h, height-adjusted reactance.

Figure 4

Muscle-localized BIVA mean graph. The 95% confidence ellipses for the muscle-localized mean impedance vectors of the female and male samples are shown. Q, quadriceps (dotted line ellipse); H, hamstrings (dark dashed line ellipse); C, calves (solid line ellipse); R/L, segment length-adjusted resistance; Xc/L, segment.