Abstract:

BACKGROUND: The shoulder joint is the most flexible joint, but there are rare studies for the developmental characteristics of children shoulder joint muscle.
OBJECTIVE: To analyze the development characteristics of flexor and extensor strength of the shoulder joint in 10-year-old children by using isokinetic test.
METHODS: Totally 59 10-year-old children’s flexor and extensor muscle of bilateral shoulder joints at 60 and 120 (°)/s speeds were tested by Kinitech isokinetic measuring system.
RESULTS AND CONCLUSION: The comparison of homonymous muscle between male and female at the same speed showed that the peak torque (PT) and maximum power rating (MT) of extensor and flexor muscle between left and right shoulders had no significant difference (P > 0.05). On the left shoulder joint, male PT/body mass (BW) was higher than female’s at 120 (°)/s speed (P < 0.05); male extensor value was higher than female’s at the speed of 60 (°)/s and 120 (°)/s (P < 0.01 or P < 0.05). The maximum power (MP)/BW of male flexor was higher than that of female at 6 (°)/s speed (P < 0.05), while the MP/BW of male extensor was higher than that of female at the speed of 60 (°)/s and 120 (°)/s (P < 0.05 or P < 0.01). On the right shoulder joint, PT/ BW of male extensor was higher than that of female at the speed of 60°/s and 120 (°)/s (P < 0.05); MP/BW at the speed of 60 (°)/s and 120 (°)/s had no significant difference between male and female flexor (P > 0.05). MP/BW of male extensor was higher than that of female at the speed of 60 (°)/s and 120 (°)/s (P < 0.01 or P < 0.05). These findings suggest that in terms of 10-year-old children, different genders had no influence in the development of flexors and extensors of shoulder joints; in the same person, the extensor muscle strength is better than the flexor muscle and the ratio of flexor and extensor is in a reasonable range.