The purpose of this study was to investigate the characteristics of body composition and force generation capacity in college Sumo wrestlers (N = 13, age= 19.8 ± 0.3 yr stature = 178.5+ 1.6 cm, body mass = 111.2 ± 3.8 kg, X ± SE) in comparison with untrained males (N = 18, 20.3 ± 0.2 yr, 170..1 ± 1.7 cm, 59.2 ± 1.4 kg). The Sumo wrestlers had significantly higher average values in relative fat mass (24.8 ± 1.0 %) and fat-free mass (83.3 ± 2.0 kg), estimated by an underwater weighing method, than the untrained subjects (relative fat mass = 12.9 ± 0.1 %, fat-free mass = 51.5 ± 1.3 kg). Moreover, the Sumo wrestlers had 1.7 to 1.9 times greater cross-sectional areas (CSAs) of elbow flexors and extensors and knee extensors, determined by a B-mode ultrasound technique, compared to those of the untrained subjects. Force values produced during elbow flexion and extension and knee extensions tasks under isokinetic contraction mode at constant velocities of 1.05, 3.14 and 5.24 rad · s-1 were significantly higher in the Sumo wrestlers than in the untrained subjects. The force value in all test conditions was significantly correlated to the related-muscle CSA, r = 0.611 - 0.910 (p < 0.05). The difference between the two groups in force per unit CSA (F · CSA-1) during elbow flexion was not significant at all test velocities. However, the Sumo wrestlers showed significantly lower F · CSA-1 values in elbow extension at 5.24 rad · s-1 and in knee extension at all test velocities. Thus, the body composition of the Sumo wrestlers was characterized by a high fat content and a large fat-free mass. Moreover, the Sumo wrestlers had considerably larger muscle CSAs of limbs than the untrained subjects. For the Sumo wrestlers, however, force output of the muscles with a pennate structure were not proportional to their CSAs, particularly in knee extensors.
Key words
Fat-free mass - muscle cross-sectional area - B-mode ultrasound - isokinetic force - heavy-weight athletes
