Effects of an acute hamstring stretch in people with and without osteoarthritis of the knee

Abstract

Objective To compare the effects of an acute stretching intervention on knee extension range of motion, passive resistive torque and stiffness in subjects with osteoarthritis of the knee, and to compare these variables with subjects without osteoarthritis. Design Cross-sectional experimental study. Setting Human performance laboratory. Participants A total of 55 participants were recruited: 28 subjects (males and females) with osteoarthritis of the knee joint and 27 subjects of a similar age without osteoarthritis of the knee joint. Intervention Using the Kincom dynamometer, three 60-second stretches with 60 seconds of rest between stretches were applied to the hamstring muscle group. Main outcome measures Peak knee extension range of motion, peak passive torque and stiffness in the final 10% of knee extension range of motion. Results A significant ( P < 0.05) increase in knee extension range of motion, peak passive torque and stiffness was observed in both groups. For knee extension range of motion, the mean difference for the osteoarthritis group and non-osteoarthritis group was 4.9 degrees [95% confidence interval (CI) 0.9 to 8.5] and 4.4 degrees (95% CI 1.8 to 6.8), respectively. For peak passive torque, the mean difference in the osteoarthritis group and the non-osteoarthritis group was 4.4 N m (95% CI 0.8 to 6.9) and 1.0 N m (95% CI −1.4 to 3.5), respectively. For stiffness in the final 10% of knee extension range of motion, the mean difference for the osteoarthritis group and the non-osteoarthritis group was 0.19 N m/degree (95% CI 0.08 to 0.3) and 0.04 N m/degree (95% CI −0.05 to 0.1), respectively. Stiffness in the final 10% of knee extension range of motion was significantly higher in the osteoarthritis group compared with the non-osteoarthritis group after stretching. Conclusions Elderly individuals with and without osteoarthritis of the knee are able to demonstrate immediate beneficial adaptations to a stretching intervention. This is important as stretching is often used in preparation for exercise programmes.