Characteristics of physique and composition in junior sumo wrestlers: changes in body composition with weight gain over 6 months

Abstract

Purpose: Childhood obesity has become a global health issue causing obesity‒related health problems in children. Sumo is a sport that requires wrestlers to increase their physique, starting from childhood, to improve performance. Herein, we aim to assess the body composition of junior sumo wrestlers who are presumed to have high fat‒free mass, and evaluate the changes associated with weight gain.

Participants and Methods: Participants included male sumo wrestlers (n=12; average age, 15.1±1.4 years) belonging to a local sumo club. We compared and examined changes in their anthropometric indices and body composition over 6 months.

Results: The average body weight was found to be 99.7±18.1 kg and the body fat percentage was 38.9± 6.6％ at the baseline. Over the six months, they gained an average weight of 2.4 kg, but their body fat percentage dropped significantly to 35.6±6.7％ (p < 0.05 each). The amount of fat‒free mass increased significantly by 3.1 kg in the trunk and 1.4 kg in the upper and lower limbs. Body fat significantly reduced by 2.6 kg in the upper and lower limbs. However, it did not decrease in the trunk. The amount of weight gain and change of trunk fat were related (r=0.949, p < 0.001).

Conclusion: Junior sumo wrestlers had a high body fat percentage with 51.5％ of the body fat mass distributed in the trunk. Despite gaining weight for over 6 months, their body fat percentage decreased. Since body fat and muscle distribution increased only in the trunk, it became clear that both fat‒free and fat were distributed in the trunk with weight gain. To continue competing while maintaining health, regular observation of body composition and nutritional education are desired for junior sumo wrestlers.