Progressive Resistance Training Compared to Neuromuscular Exercise in Patients With Hip Osteoarthritis

The primary aim of this randomized controlled trial is to investigate the effectiveness of 12 weeks of progressive resistance training (PRT) compared to neuromuscular exercise (NEMEX) on functional performance in patients with hip OA measured by the 30-seconds chair stand test. Secondary aims are to investigate; the determinants of improvement in physical function following PRT or NEMEX; the effectiveness of booster sessions in prolonging the effects of the initial interventions (12 months), the cost-effectiveness of booster sessions (12 months). We will test the hypothesis that PRT is superior to NEMEX in improving physical function measured with the 30s sit-to-stand test at 12 week follow-up.

This randomized controlled trial will be a multicenter trial involving hospitals and physiotherapy clinics across Denmark. Part 1: For the initial 12-week exercise intervention, participants will be randomized into two groups: PRT or NEMEX. Part 2: After the initial intervention, participants in each group will be randomized to booster sessions (PRT+B and NEMEX+B) or to receive no further treatment (PRT-B and NEMEX-B). Booster sessions will be provided at 4, 6, 8 and 10 months after baseline. Outcomes will be measured at baseline, after 12 weeks of intervention, and at 6-, 9- and 12-months follow-up.

The exercise interventions will be performed at the collaborating hospitals and physiotherapy clinics across Denmark. All sessions will be conducted in group sessions with one physiotherapist supervising the exercises. The duration and frequency of the interventions will be 12 weeks with 2 supervised sessions each week. If participants experience pain during exercise exceeding 5 out of 10 on a Visual Analogue Scale (VAS), the physiotherapist will modify the exercise, decreasing the exercise intensity (load) or modifying the range of motion. All unilateral exercises will be performed for both sides.

The NEMEX intervention will follow the NEMEX program as described by Ageberg et al. The sessions consist of a 10-minute submaximal warm up on an exercise bike followed by 50 minutes of NEMEX training with exercises focused on stability, postural function, postural orientation, lower extremity muscle strength, and functional exercises.

The PRT intervention will follow the same protocol for training frequency and duration as the NEMEX intervention. The sessions consist of a 10-minute submaximal warm up on an exercise bike followed by 50 minutes of PRT with exercises targeting the muscles of the hip and knee joints; leg press, hip extension, hip abduction, hip flexion and knee extension.

Eligibility Criteria:
Inclusion Criteria:

* Clinically diagnosed OA of the hip joint according to the National Institute for Health and Care Excellence criteria
* Have experienced pain of at least 3 out of 10 on the visual analog scale in the index hip within the last two weeks
* Age ≥ 45 years
* No surgery in the lower extremities six months prior to inclusion
* No comorbidity that prevents exercising
* Adequacy in written and spoken Danish
* Not being a candidate for total hip arthroplasty

Exclusion Criteria:

* BMI score \> 40
* Pregnancy
* Resistance training or neuromuscular training for the lower extremities for more than 12 sessions in the last 6 months or 6 sessions in the last 3 months (resistance training is defined by the American College of Sports Medicine guidelines while neuromuscular training is defined by exercises involving multiple joints and muscle groups performed in functional weight-bearing positions with emphasis on the quality and efficiency of movement, as well as alignment of the trunk and lower limb joints)
* Planned vacation for more than 14 days within the 12-week intervention period without the possibility of expanding the intervention accordingly