Acute aquatic treadmill exercise improves gait and pain in people with knee osteoarthritis

Objective: To examine the acute effects of aquatic and land treadmill exercise on gait kinematics as well as the level of disease-specific and movement-related pain for individuals with osteoarthritis.

Design: Quasi-experimental crossover design.

Setting: Biomechanics laboratory.

Participants: Participants (N=14; age, 43-64y) diagnosed with osteoarthritis at the knee (n=12), osteoarthritis at the knee and ankle (n=1), or osteoarthritis at the knee and hip (n=1).

Interventions: Participants performed 3 exercise sessions separated by at least 24 hours in 1 week for each mode of exercise (aquatic treadmill and land treadmill).

Main outcome measures: Gait kinematics and pain were measured before and after each intervention.

Results: The angular velocity gain score during stance for left knee extension was improved by 38% after aquatic treadmill exercise (P=.004). Similarly, during swing, the gain scores for angular velocity were also greater for left knee internal rotation and extension by 65% and 20%, respectively (P=.004, P=.008, respectively). During stance, the joint angle gain score for left hip flexion was 7.23% greater after land exercise (P=.007). During swing, the angular velocity gain score for right hip extension was significantly greater for aquatic exercise by 28% (P=.01). Only the joint angle gain score for left ankle abduction during stance was significantly higher after land exercise (4.72%, P=.003). No other joint angle gain scores for either stance or swing were significantly different for either condition (P=.06-.96). Perceived pain was 100% greater after land than aquatic treadmill exercise (P=.02). Step rate and step length were not different between conditions (P=.31-.92).

Conclusions: An acute training period on an aquatic treadmill positively influenced joint angular velocity and arthritis-related joint pain. Acute aquatic treadmill exercise may be useful as a conservative treatment to improve angular speed of the lower-extremity joints and pain related to osteoarthritis.