The Effects of Direct Current Stimulation Combined with Exercise on Mobility, Strength, and Balance in People with Multiple Sclerosis (MS): A Randomised Controlled Trial

Arm 1 — Combined DC Stimulation and Exercise (Intervention)Arm 1 — Combined DC Stimulation and Exercise (Intervention) Participants will complete a supervised exercise program twice weekly for 8 weeks (16 sessions total), each session lasting approximately 45–60 minutes. Sessions will be delivered one-on-one in a face-to-face format at the ACU Exercise and Lifestyle Clinic, Strathfield Campus, by qualified exercise science researchers. The program comprises progressive resistance and functional training targeting lower limb strength, balance, and mobility, individualised according to participant capacity. Examples of exercises prescribed include leg press, leg extension, seated hamstring curl, hip flexion and abduction using a terminal hip machine, step-ups, and balance and gait retraining. Exercise intensity will be set at a moderate-to-vigorous level, monitored using the RPE scale (0–10), targeting a rating of 6–7 (hard), with a Repetitions in Reserve (RIR) of 2–3. Intensity will be progressively increased across the 8 weeks in accordance with each participant's tolerance and functional response. During exercise, pulsed direct current (DC) stimulation will be delivered via the Neubie device , applied bilaterally to lower limb musculature including the tibialis anterior, gastrocnemius, quadriceps (rectus femoris and vastus medialis), and hamstrings. Stimulation intensity will be individualised and titrated to a subjective intensity of 7/10 on a verbal rating scale, and will not exceed a VAS-Pain ceiling of greater than 4/10. Stimulation frequency will be periodised across the 8-week program: Stimulation frequency will be periodised across the 8-week program: Weeks 1–2 will use 100–160 pps to prioritise neuromuscular re-education and device adaptation, Weeks 3–5 will use 55–75 pps to maximise muscle activation for strength and hypertrophy, and Weeks 6–8 will use 40–75 pps to support progressive overload as training demands increase. Adherence will be monitored via session attendance checklists completed by the researcher at each visit, with attendance recorded as a proportion of the 16 scheduled sessions. Reasons for any missed sessions will be documented. Participants missing more than two consecutive sessions will be contacted to confirm continued eligibility and willingness to proceed.