1999 年 23 巻 2 号 p. 171-174
[Purpose]We attempted to investigate the characteristics of the concentric and eccentric contraction of the internal and external rotators of the shoulder joint after modified Bristow and Bankart procedure.
[Materials and Methods]The sublects were 17 cases(14 males and 3 females)with a mean age of 23.6years (range from 15 to 30 years). Using a BIODEX dynamometer, the strength of the rotator muscles of the shoulder was measured at concentric contraction (CC) and eccentric contraction (EC). Angle velocity was set at 60 and 120 deg. /sec. in CC and 20 and 60 deg. /sec. in EC.
[Results]The muscle strength of the intemal rotators during CC and EC gradually increased after surgery. But there was no statically significant difference in the peak torque between preoperaion and 6 months after surgery. The peak torque of the external rotators during CC at 6 months after surgery was smaller than that of preoperation. However external rotators strength at 1 year after surgery was statically higher than preoperative strength. The peak torque of the external rotators during EC gradually increased after surgery, but there was no statistically significant difference between preoperation and 6months after surgery. E/C (eccentric torque/concentric torque) ratio at 60 deg. /sec. velocity gradually decreased in the internal rotators, but gradually increased in the external rotators.
[Conclusion]The muscle strength of the internal and external rotators recovered at 1 year after surgery.