Background: Knee loading, muscle co-contraction, and pain are increased in knee osteoarthritis (OA). Exercises decreased pain in knee OA, yet OA is a mechanical disease and biomechanical changes need to be explored as
well. Therefore, this study aims to investigate the effectiveness of an exercise programme on these outcomes in people with medial knee osteoarthritis.
Methods: Cohort pilot study design. Nineteen participants with knee OA attended group exercise sessions, integrated with self-management education, once a week for six weeks, with additional home exercises.
Outcomes assessed pre- and post-exercise programme were: External Knee Adduction Moment (EKAM), Knee Adduction Angular Impulse (KAAI), knee antagonist muscle co-contraction during gait, and the pain-subscale
of the Knee injury and Osteoarthritis Outcome Score (KOOS).
Results: Fourteen participants completed the study. Post-exercise intervention, the EKAM and KAAI did not change significantly (p= 0.21–0.7, p = 0.56, respectively). Muscle co-contraction between the vastus-lateralis
and biceps-femoris muscles decreased in early-stance (64.78 (44.35) compared to 38.10 (23.10), p = 0.01) andmid-stance (27.62 (32.12) compared to 14.94 (17.40), p=0.04). A corresponding significant pain reduction
was seen (p = 0.00) with a median and range of 51.50 (47.00–62.50) at week six compared to 34.50 (29.25–41.25) at baseline.
Conclusion: This is the first knownstudy to explore the effect of an exercise programmeon knee loading andmuscle co-contraction in knee OA. Although EKAMdid not change, the findings suggest a reduction in vastus-lateralis
and biceps-femoris co-contraction might be a mechanism by which pain is reduced in knee OA.