Résumé
This study examined age-related changes in dynamic balance (DB) ability, and the relationship between DB ability and isometric knee extension strength (IKES). Subjects were 100 females who regularly performed some light gymnastic exercises at a gymnastics club once or twice a week. Subject ages ranged from 20 to 85 years old. The measured items were height, body weight (BW), IKES, and DB ability. Results were as follows: 1. The average DB ability tended to gradually decrease as the subjects got older. There were some significant differences in the average DB ability between the 20 to 29 and 60 to 69 age groups, and between the 20 to 29 and over 70 age groups. 2. It was shown that there was a significant negative correlation between age and DB ability (r=0.471, p<0.001). 3. There was a significant negative correlation between age and IKES/BW (r=0.579, p<0.001). 4. It was shown that there was a significant positive correlation between IKES/BW and DB ability (r=0.368, p<0.001). 5. There was a significant negative correlation between BMI and DB ability (r=0.370, p<0.001). This study showed that DB ability rapidly decreased over 60 years old, and also the value tended to be higher in persons with a higher knee extension strength and lower BMI. Therefore, it was suggested that it is important to increase the knee extension strength and maintain an appropriate BMI in order to maintain DB ability.
Résumé
This study examined peculiarities in both muscle strength and cross-sectional area (CSA) among soccer players in comparison with those of archers as contrasting athletes. Subjects were 15 male soccer players and 9 male archers at N University. Measurement items were height, body weight (BW), isokinetic muscle strength (knee extension, knee flexion, hip extension, hip flexion) and CSA (psoas muscles). Isokinetic muscle strength (30, 120, 240°/sec.) was measured by Cybex6000 (Lumex Co.), and the psoas muscle CSA was determined using magnetic resonance imaging (Hitachi, Japan). Results were as follows : 1. There was no significant difference in isokinetic knee extension and flexion strength/BW at all angular velocities between soccer players and archers. 2. On isokinetic hip flexion strength/BW, the average values of soccer players were significantly higher at all angular velocities than those of archers. However, there was no significant difference in the average values of isokinetic hip extension strength at all angular velocities between the two groups. 3. The average value for the psoas muscle CSA in soccer players was significantly higher than that of archers. In this study, the biggest difference in muscle strength between soccer players and archers was hip flexion strength, and the CSA of the psoas muscle in soccer players, which is the main component of hip flexion, was significantly larger than that of archers. These findings showed the peculiarity of soccer players due to the constant demands of movements involved in ball kicking and running during practice and competition.