Effect of High-Intensity Strength Training on Knee Pain and Knee Joint Compressive Forces Among Adults With Knee Osteoarthritis

Abstract

IMPORTANCE Thigh muscle weakness is associated with knee discomfort and osteoarthritis disease progression. Little is known about the efficacy of high-intensity strength training in patients with knee osteoarthritis or whether it may worsen knee symptoms.OBJECTIVE To determine whether high-intensity strength training reduces knee pain and knee joint compressive forces more than low-intensity strength training and more than attention control in patients with knee osteoarthritis.DESIGN, SETTING, AND PARTICIPANTS Assessor-blinded randomized clinical trial conducted at a university research center in North Carolina that included 377 community-dwelling adults (Ն50 years) with body mass index (BMI) ranging from 20 to 45 and with knee pain and radiographic knee osteoarthritis. Enrollment occurred between July 2012 and February 2016, and follow-up was completed September 2017. INTERVENTIONS Participants were randomized to high-intensity strength training (n = 127), low-intensity strength training (n = 126), or attention control (n = 124).MAIN OUTCOMES AND MEASURES Primary outcomes at the 18-month follow-up were Western Ontario McMaster Universities Osteoarthritis Index (WOMAC) knee pain (0 best-20 worst; minimally clinically important difference [MCID,2]) and knee joint compressive force, defined as the maximal tibiofemoral contact force exerted along the long axis of the tibia during walking (MCID, unknown). RESULTS Among 377 randomized participants (mean age, 65 years; 151 women [40%]), 320 (85%) completed the trial. Mean adjusted (sex, baseline BMI, baseline outcome values) WOMAC pain scores at the 18-month follow-up were not statistically significantly different between the high-intensity group and the control group (5.1 vs 4.9; adjusted difference, 0.2; 95% CI, −0.6 to 1.1; P = .61) or between the high-intensity and low-intensity groups (5.1 vs 4.4; adjusted difference, 0.7; 95% CI, −0.1 to 1.6; P = .08). Mean knee joint compressive forces were not statistically significantly different between the high-intensity group and the control group (2453 N vs 2512 N; adjusted difference, −58; 95% CI, −282 to 165 N; P = .61), or between the high-intensity and low-intensity groups (2453 N vs 2475 N; adjusted difference, −21; 95% CI, −235 to 193 N; P = .85). There were 87 nonserious adverse events (high-intensity, 53; low-intensity, 30; control, 4) and 13 serious adverse events unrelated to the study (high-intensity, 5; low-intensity, 3; control, 5).CONCLUSIONS AND RELEVANCE Among patients with knee osteoarthritis, high-intensity strength training compared with low-intensity strength training or an attention control did not significantly reduce knee pain or knee joint compressive forces at 18 months. The findings do not support the use of high-intensity strength training over low-intensity strength training or an attention control in adults with knee osteoarthritis.

Knee-extensor strength, symptoms, and need for surgery after two, four, or six exercise sessions/week using a home-based one-exercise program: A randomized dose-response trial of knee-extensor resistance exercise in patients eligible for knee replacement (the QUADX-1 trial)

“…This suggests that the intervention and associated exercise dosage needed to improve symptoms in patients eligible for knee replacement does not necessarily have to be either extensive or comprehensive. 49 This corresponds well to the results from the supplementary regression analyses and our recent meta-regression analysis indicating no dose-response between prescribed pre-operative knee-extensor exercise dosage and change in outcomes before scheduled knee replacement -although this was not a randomized comparison. 33 The objective assessment of exercise adherence showed that group 2 exercised half as much as group 4 and 6 (total sessions and TUT).…”

“…Firstly, larger exercise dosages do not seem to be more effective than smaller. 49 Secondly, an exercise intervention with one home-based exercise can lead to clinically relevant improvements in symptoms comparable to more comprehensive interventions in patients eligible for knee replacement. 22,49,50 Finally, a simple exercise therapy intervention using only one exercise, in a model of coordinated care, can prompt the majority of patients eligible for knee replacement to postpone surgery.…”

“…43,[80][81][82] Thus, patients eligible for knee replacement might not need large exercise dosages to improve their symptoms. 43,49,83 This suggests that one well-instructed home-based knee-extensor exercise is a viable treatment alternative to supervised exercise for patients with severe knee OA. For example, for patients who have a busy daily schedule, patients who live far from a clinic and patients who cannot afford or are not interested in attending formal group exercise sessions at a clinic at fixed times.…”

Benefits and Mechanisms of Exercise Training for Knee Osteoarthritis

“…Retrograde walking can significantly reduce pain, dysfunction, and improve quadriceps strength and performance ( Alghadir et al, 2019 ). Although the results of high-intensity and low-intensity aerobic exercise are consistent, low-intensity aerobic exercise is better for patients with severe KOA ( Messier et al, 2021 ). High-intensity aerobic exercise is effective for patients with mild KOA.…”

“…Strength training is indispensable for patients with KOA to restore muscle strength. The main functions of strength training are relieving pain, alleviating stiffness, enhancing muscle strength, improving physical function, and increasing the shock absorption ability of the lower extremity muscles during walking ( Li et al, 2016 ; DeVita et al, 2018 ; Chen et al, 2019 ; Messier et al, 2021 ). The types of strength training mainly include isokinetic exercise, isometric exercise, and isotonic exercise ( Malas et al, 2013 ; Sharma, 2021 ).…”