Cross-education in people with Parkinson's disease, a short-term randomized controlled trial

Introduction: People with Parkinson's disease usually have a major impairment on one side of the body. It is hypothesized that unilateral resistance training may improve strength on the most affected limb when compared to bilateral resistance training. Aim: 1) To confirm that short-term unilateral resistance training improves strength on the most affected limb in people with PD. 2) To investigate if short-term unilateral resistance training reduces asymmetry. Methods: Seventeen individuals with Parkinson's disease were randomly assigned to unilateral resistance group (UTG, n = 9) and bilateral resistance group (BTG, n = 8). Twenty-four sessions of resistance training were performed. The nine-hole peg and box and blocks tests were performed to assess motor control of the upper limbs. The handgrip strength and isokinetic dynamometry were performed to assess the upper and lower limbs strength, respectively. All tests were assessed unilaterally at baseline (T0), during (T12), and at the end of the intervention (T24). Friedman's ANOVA was used to determine within group differences across the three time-points. In the event of significance, post-hoc analyses were performed using the Wilcoxon signed rank test. The U Mann-Whitney was used to determine between group differences at a specific time point. Results: The BTG was significantly better than the UTG group at T24 compared to T12 with respect to peak torque at 60°/s and 180°/s (p < 0.05). Conclusion: Short-term bilateral resistance training is better than unilateral resistance training to improve strength for lower limbs most affected in people with Parkinson's disease.