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Complementary effect of a combined exercise and dietary supplement intervention in individuals with knee osteoarthritis: study protocol for a randomized, double-blind, placebo-controlled trial

Čeh T, Završnik J, Šarabon N

Trials, 2026

Abstract

Background: Osteoarthritis is a common joint disease, especially among individuals aged 50 and older, leading to symptoms such as pain, stiffness, and functional limitations, particularly in weight-bearing joints like the knees. Knee osteoarthritis (KOA) is increasingly prevalent, making effective treatment strategies critical. Exercise and dietary supplements are commonly used to manage symptoms, but the combination of these two approaches has not been widely studied. This study aims to evaluate the effects of combining exercise with dietary supplements on pain, physical function, and quality of life in individuals with KOA.

Methods: This trial will involve KOA patients, aged 55 and older. Participants will be assigned to one of three groups: (1) dietary supplement, (2) exercise with dietary supplement, (3) exercise with placebo dietary supplement. Randomization and double-blinding apply only to the dietary supplement in the exercise groups, while the supplement-only group serves as a non-randomized group. The exercise regimen will consist of resistance training, conducted under supervision. The dietary supplement will be a combination of glucosamine and collagen. The primary outcomes include pain levels and physical function, which will be assessed through questionnaires (WOMAC, SF-36), numeric rating scale, and various physical function tests (30 s chair stand test, 40-m fast-paced walk, timed up and go test, star climbing test, 6-min walk test, static balance, and…

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Evidence Hub reads this as a randomized trial, done in people. Its evidence level is 2 of 5 (High · randomized trial). Randomized trials of a reasonable size are the strongest single-study design.

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