Concentric versus combined concentric-eccentric isokinetic training: Effects on functional capacity and symptoms in patients with osteoarthrosis of the knee

Objective: To compare the effects of concentric and coupled concentric-eccentric isokinetic resistance training on functional capacity and symptoms of patients with osteoarthrosis (OA) of both knees. Design: Repeated measures. Setting: A university exercise physiology laboratory. Participants: Twenty-three volunteers, ages 41 to 75 years. Patients were randomly assigned to 3 groups: concentric (CON, n = 9), concentric-eccentric (CON-ECC, n = 8), and nontreatment (NONTX, n = 6). Interventions: The CON group performed 12 concentric contractions of each knee extensor and flexor muscles; the CON-ECC group performed 6 concentric and 6 eccentric contractions of each knee muscle group by using a spectrum of angular velocities ranging from 30degrees/s to 180degrees/s with 30degrees/s intervals, for both sides, 3 days a week for 8 weeks. Main Outcome Measures: Functional capacity (rising from a chair, walking, stair climbing and descending,) and pain during rest and activities, peak torque, and cross-sectional area (CSA) of knee muscle groups of subjects were tested before and after training. Results: Both training groups showed marked decreases (P < .001) in pain scores and increases (P < .001) in functional capacity together with increases (P < .05-.01) in peak torque and CSA of knee muscles. However, the NONTX group did not display these marked changes after the 8-week period. The, results also indicated that concentric-eccentric training has a greater influence on functional capacity, especially stair climbing and descending, than that of concentric training when compared with NONTX group; however, the improvements in pain measurements were better in the CON group compared with the CON-ECC group after the training. Conclusions: The results suggest that with the isokinetic resistance training used in this study, it is possible to improve functional capacity and decrease pain in patients with OA of the knee. The results also showed that extensive training involving a high number of repetitions and eccentric contractions was safe, effective, and well tolerated for the patients with knee OA.