Can non-invasive electrical brain stimulation improve exercise rehabilitation outcomes in people with hip osteoarthritis?

Transcranial direct current stimulation (tDCS) devices (Brain Premier tDCS E1 Plus) will deliver a weak current [</=2 milliamps (mA)] from a 35x35mm anodal electrode [that increases cortical excitability] on the scalp at the vertex (overlying primary motor cortex of the more symptomatic limb) to a cathodal electrode placed over the deltoid tubercle on the upper arm. The physiotherapist will also train the participant in how to self-perform tDCS on non-supervised days, but will be nearby to provide any assistance if needed. Real tDCS will be performed at 2mA for 20 minutes whilst completing exercise rehabilitation. The exercise rehabilitation intervention will be identical between groups and will be reported as per the Consensus on Exercise Reporting Template (CERT). Participants will be provided an 8-week gym membership at the provider physiotherapy clinic. The intervention will involve 8 weeks of physiotherapist-supervised exercise, consisting of three in-person visits/ week in which participants receive tDCS during each session. Exercise will be based on templates, sent via Physitrack®, however these will be individually adapted as able and progressed when participants can complete the prescribed exercise. Reporting items from CERT. 1. The majority of exercises will use body weight resistance, however the following additional equipment will be utilised: knee extension machine, hamstring curl machine, leg press machine, circular TheraBand. 2. All exercises will be prescribed by a qualified physiotherapist, with greater than five years of experience in managing chronic hip pain. 3. Exercises will be prescribed individually and performed individually, however there may be other rehabilitation patients and clinicians in the rehabilitation gymnasium at the same time. 4. Participants will receive 1:1 supervision by a physiotherapist for one rehabilitation session per fortnight (which will include progressing exercises). All other rehabilitation sessions will be unsupervised. 5. Attendance at the rehabilitation centre will be recorded via private practice standard booking system. 6. Participants will receive reminder text messages about physiotherapy consultations. 7. All exercises will be prescribed so they are either pain free or have minimal pain (=2/10 on a numerical rating scale of pain) when performed. Exercises will be progressed when all sets and repetitions can be performed. 8. The exercise progressions will be based on patient function but must include: • A single joint exercise for each of the following muscle groups: lumbar extensors; abdominals; hip extensors; hip flexors, hip abductors; hip adductor; knee flexors; knee extensors; ankle plantar flexors. • A multi joint squat pattern (e.g., squat) and bend pattern (e.g., deadlift) movement. • one balance-based exercise (e.g., star excursion balance). 9. Adverse events will be reported to all study staff as they occur. 10. Exercises will be performed in a physiotherapy rehabilitation gymnasium. 11. Participants will be provided double leg single joint exercises (e.g., double leg bridge), before being progressed to single leg single joint exercises (e.g., single leg bridge) and then more highly loaded single leg single joint exercises (e.g., single leg hip thrust). Sets and repetitions will be based on endurance repetitions (e.g., 3 x 15 reps) and performed three times per week. 12. Exercises will follow the description above but will be individually tailored to the participant and progressed as able. 13. Exercises will be progressed when participants can perform 3 x 15 repetitions or regressed if they are causing pain > 2/10. 14. All participants will be commenced with double leg single joint exercises and progressed as able. 15. Adherence will be determined as the number of sessions attended across the 8-week intervention divided by the number of prescribed sessions.