Managing knee osteoarthritis: the effects of anti-gravity treadmill exercise on joint pain and physical function
Knee osteoarthritis (OA) is a degenerative joint condition characterized by progressive joint pain, swelling, and loss of muscle and joint function for which there is no known cure. Current research indicates that the most important modifiable risk factor for the development and progression of knee OA is obesity, a condition that is increasingly common in older adults. Established treatment guidelines for knee OA recommend regular exercise for disease management. However, for obese patients weight-bearing exercise elicits large joint forces that can exacerbate symptoms and influence disease progression. Using a new anti-gravity treadmill capable of generating a lifting force called lower body positive pressure (LBPP), obese patients with knee OA can engage in regular physical activity while minimizing joint loading. The aim of this study was to assess the effect of a 12-week, anti-gravity treadmill walking (AGTW) program on knee pain and function in obese older adults with knee OA. The alternate hypothesis was that there would be a difference between Knee Injury and Osteoarthritis Outcome Score (KOOS) results before and after the anti-gravity treadmill walking program. A group of 25 participants with a mean (SD) age of 64.2 (6.1) years and BMI of 33.0 (6.8) kg/m2 completed AGTW twice per week for 12 weeks at a body weight percentage that minimized knee pain. Knee symptoms and function (KOOS), knee pain during full weight-bearing treadmill walking (FTW), isokinetic quadriceps and hamstring muscle strength, cardiovascular fitness (YMCA submaximal cycle ergometer test), general health status (SF-12), and activity level (average daily pedometer readings) were assessed at baseline and following the completion of the 12-week program using paired t-tests and Wilcoxon signed rank sum tests (α = 0.05). Improvements between baseline and outtake were found in all KOOS subscales, as well as hamstring and quadriceps thigh muscle strength. Knee pain during full FWB and AGTW decreased following the 12-week program. No significant differences were found in cardiovascular fitness, SF-12 scores, or average daily pedometer readings. The results of this study suggest that anti-gravity treadmill walking increases thigh muscle strength, reduces knee pain, and increases functional capacity during daily activities, including FTW in older, obese individuals with knee OA. Anti-gravity treadmill technology has the potential to improve the health and functional capacity of at-risk knee OA individuals, and advance current methods of rehabilitation and long-term management of chronic symptomatic knee OA.
osteoarthritis, obesity, lower body positive pressure, knee pain, treadmill exercise