Strength Training and Arthritis Trial Grant uri icon

abstract

  • Abstract Exercise (both aerobic and resistance) is a safe intervention in knee osteoarthritis (OA) patients, with few contraindications or adverse events. Indeed, from a public health perspective, few treatments can be delivered to such a large proportion of OA patients with so little adverse risk. Loss of muscle and gain in fat contribute to disability, pain, and morbidity that is associated with knee OA, and quadriceps weakness is an independent and modifiable risk factor for it. However, while all published treatment guidelines, supported by Level 1 evidence, recommend muscle strengthening to combat sarcopenia and improve muscle quality in knee OA patients, previous strength-training studies either used intensities or loads below recommended levels, or were generally short in duration, lasting 6 to 24 weeks. These studies had low to modest effect sizes, inadequate length to detect changes in disease progression, did not address the underlying mechanisms of OA, and provided little lasting clinical benefit that is derived from longer term structured exercise, even years after supervised treatment is terminated. The effectiveness of more intense strength training exercise to improve OA symptoms, slow disease progression, and affect underlying mechanisms has not been examined, the unsubstantiated belief that intense strength training might exacerbate symptoms. Our exciting preliminary data, however, clearly show excellent tolerance for high-intensity strength training, as well as reduced pain and increased function. We now propose an 18-month, high-intensity strength training intervention for older adults with knee OA with the primary focus to improve thigh composition (more muscle and less fat). We will evaluate initial short-term clinical benefits; however, combining greater duration with high intensity should sufficiently alter thigh composition (more muscle and less fat) to attain long-term changes in knee joint forces, decreased inflammatory cytokines, lower pain levels, and a slowing of OA progression that are not achievable with shorter interventions. Participants (age = 55 yrs; BMI = 25 kg/m2 and = 40 kg/m2) will be randomized to one of 3 groups: high-intensity strength training; low-intensity strength training; or attention control. The 18-month intervention will provide sufficient time to determine whether high-intensity training reduces the rate of disease progression, which has yet to be convincingly demonstrated for any OA treatment. The study sample will consist of 372 (124/group) ambulatory, community-dwelling persons with: (1) mild-to-moderate medial tibiofemoral OA (KL = 2-3); (2) knee varus malalignment (varus angle = 2 degrees and = 10 degrees); and (3) no participation in a formal strength-training program for more than 30 minutes per week within the past 6 months. The primary clinical aim is to compare the interventions? effects on knee pain, and the primary mechanistic aim is to compare the effects on knee joint compressive forces during walking, a mechanism that affects the OA disease pathway. Secondary aims are to compare the intervention effects on: additional clinical measures of disease severity (function, mobility); disease progression as measured by MRI; thigh muscle and fat volume as measured by CT; components of thigh muscle function, including hip abductor strength and quadriceps strength, power, and proprioception; additional measures of knee joint loading; and inflammatory and OA biomarkers. This study is innovative in three ways. First, it tests the efficacy of a high-intensity strength training protocol suitable for an older population with knee OA. Second, it considers both clinical and mechanistic outcomes. Third, it combines exercise intensity and duration to identify a non-pharmacologic therapy capable of improving clinical symptoms and slowing disease progression with mi

date/time interval

  • September 2011 - August 2018