Isokinetic strength training improves motor function in a Chinese classical dancer with knee injury: a case report

Background: The muscle strength around the knee is essential for maintaining the stability and function of the knee joint of the dancer. If the musculoskeletal system in dancers is imbalanced and weakness this can cause knee injuries. Isokinetic muscle strength training is a special muscle strength training, but scarce studies have explored the effect of the recovery of knee joint function and stability after Chinese classical dancers’ knee injury.Objective: The purpose of this study was to examine whether 10 weeks of isokinetic muscle strength training would improve the functional health status of knee joint injuries in a Chinese classical dancer.Materials and Methods: A male Chinese classical dancer (age, 22 years) diagnosed with chondropathy of the patella, meniscus injury, patellar tendon injury and patellar cartilage injury in the left knee was recruited. The patient underwent a total of 10 weeks of isokinetic strength training of the flexor and extensor muscles on the left leg. Visual analog scale (VAS) score, the peak torque (PT), the total work (TW), the PT ratio of flexors and extensors (hamstring-to-quadriceps strength ratio, H/Q) at the angle of 60°/s, and the Lysholm score were measured before and after 10-week of training.Results: The VAS score decreased from 6.5 to 2.5. The PT of flexors improved from 53.2 to 102.6, which increased by 93%, and the PT of extensors improved from 76.7 to 172.5, which increased by 125%. The TW of flexors improved from 56.6 to 124.9, and extensors improved from 75.8 to 165. The H/Q improved from 69% to 59%. The Lysholm score increased from 47 to 72.Conclusion: Isokinetic strength training of the flexor and extensor muscles on the leg improves motor function and stability of knee joint in the Chinese classical dancer.