Variation in sexual dimorphism in relation to physical activity

Area of Science:

• Human biology
• Anthropometry
• Exercise physiology

Background:

• Sexual dimorphism, the distinct physical characteristics between males and females, can be influenced by environmental factors.
• Physical activity is a significant environmental factor that may modulate sex differences in body composition and morphology.

Purpose of the Study:

• To investigate how physical activity levels affect sexual dimorphism in anthropometric traits.
• To compare the degree of sexual dimorphism in body composition between active and inactive young adults.

Main Methods:

• Anthropometric measurements of 542 young adults (20-30 years) were collected, including lengths, breadths, circumferences, and skinfolds.
• Body composition parameters such as fat-free mass (FFM), fat mass (FM), and arm muscular area (AMA) were calculated.
• The D index was used to quantify sexual dimorphism, with analyses including Principal Component Analysis (PCA) and univariate/multivariate statistics.

Main Results:

• A greater degree of sexual dimorphism was observed in the physically active group compared to the inactive group.
• Adjusted circumferences and skinfolds, along with derived body composition parameters, showed more pronounced sex differences in active individuals.
• Univariate and multivariate analyses confirmed increased sexual dimorphism in active participants.

Conclusions:

• Regular physical activity appears to enhance or reveal greater sexual dimorphism in anthropometric and body composition variables.
• These findings suggest that women may exhibit greater stability or resilience to environmental pressures like physical activity in terms of their physical characteristics.
• The study highlights the interplay between lifestyle factors and biological sex on human physical variation.