To study the feasibility of a large randomised controlled trial (RCT) evaluating the effectiveness of physiotherapy in Parkinson's disease (PD), 173 patients were asked to participate in a study with random allocation to best practice physiotherapy, or to no physiotherapy. The primary outcome measures were the Parkinson's disease questionnaire-39, the Parkinson activity scale, and a patient preference outcome scale (PPOS). Only 14% of the patients could be included in the study. The PPOS showed the largest effect size (0.74) with a significant group effect (p<0.05). Specific alterations to the study design to ensure successful RCTs in this field are recommended.