As the U.S. population ages and the prevalence of osteoarthritis (OA) among older adults rises, the prevention of OA-associated disability is an important public health priority. Accordingly, efficacious interventions are needed to manage pain and maintain physical function among older adults with OA. Because skeletal muscle weakness is a primary contributory factor to the progression of pain and functional decline among persons with OA, optimal interventions are those capable of improving skeletal muscle strength. High-intensity resistance exercise is the best-known method of improving muscle strength; however high-compressive loads typically induce significant joint pain among persons with OA. Accordingly, current recommendations include the performance of low- or moderate-intensity physical exercise - despite the fact that these training paradigms are sub-optimal for enhancing muscle strength. This application proposes conduct a pilot study to investigate the potential of an innovative training paradigm with potential to stimulate improvements in skeletal muscle strength while utilizing low-intensity loads. This paradigm, known as KAATSU training, involves performing low-intensity exercise while externally-applied compression mildly restricts blood flow to the active skeletal muscle. The overarching objective of the present application is to evaluate the efficacy and feasibility of chronic KAATSU training for the improvement of skeletal muscle strength and physical function among persons aged > 60 years with symptomatic knee OA and mild to moderate physical limitations. Up to 72 participants will be recruited to participate in this three month intervention study. Participants will be randomly assigned to one of two intervention conditions: (1) a standard exercise intervention consisting of center-based, moderate-intensity resistance training, or (2) a KAATSU training program matched for overall workload. This study will provide novel information regarding the therapeutic potential of KAATSU training for improving strength and function as well as attenuating pain among these individuals. The study will also provide critical information regarding the long-term, clinical viability of the paradigm by evaluating participant safety, discomfort, and willingness to continually engage in the KAATSU training program.

Inclusion Criteria:

• Age 60 years and older
• Radiographic evidence of osteophytes
• Moderate to severe pain score (41-90 mm) recorded on 100-mm visual analog scale after 50-ft walk
• Bilateral standing anterior-posterior radiograph demonstrating Kellgren and Lawrence grade 2 or 3
• OA of the target knee
• Score ≤ 10 on the Short Physical Performance Battery, as an indicator of physical limitation
• Sedentary lifestyle, defined as <150 min/wk of moderate physical activity as assessed by CHAMPS questionnaire
• Willingness to participate in all study procedures

Exclusion Criteria:

• Failure to provide informed consent;
• Regular participation in resistance exercise training within the past 3 months
• Current involvement in supervised rehabilitation program
• Absolute contraindication(s) to exercise training according to American College of Sports Medicine guidelines
• Diagnosed peripheral vascular disease
• Ankle-brachial index < 0.95
• Resting office systolic blood pressure > 160 mm Hg or < 100 mm Hg
• Diastolic blood pressure > 100 mm Hg
• History or family history of thrombosis
• Resistant hypertension, defined by BP > 140/90 despite use of 3 or more antihypertensive medications
• Severe cardiac disease, including New York Heart Association Class III or IV congestive heart failure, clinically significant aortic stenosis, history of cardiac arrest or stroke, use of a cardiac defibrillator, or uncontrolled angina
• Deep venous thrombosis
• Known peripheral neuropathy
• History of rheumatoid arthritis
• Lower limb amputation
• Lives in a nursing home; (persons living in assisted or independent housing will not be excluded)
• Significant cognitive impairment, defined as a known diagnosis of dementia or a Mini-Mental State Examination exam score < 24
• Unable to communicate because of severe hearing loss or speech disorder;
• Severe visual impairment, which would preclude completion of the assessments and/or intervention
• Other significant co-morbid disease that would impair ability to participate in the exercise intervention
• Lives outside of the study site or is planning to move out of the area during the study timeframe
• Simultaneous participation in another intervention trial