This study examines the potential of using mental practice (MP) to promote the learning of 2 mobility tasks in persons with stroke. Twelve patients were trained with MP to increase the loading of the affected limb while standing up from a chair and sitting down. Vertical forces were recorded using force plates under each foot and the chair. Changes in the loading of the affected limb and in task duration, immediately after 1 training session and 24 h later, served as outcomes. After training, the loading of the affected limb had increased (P < 0.001) during standing up (16.2%) and sitting down (17.9%), and the improvement remained significant 24 h later, indicating a learning effect. In contrast, the duration of the performance did not change with training. The results indicate that, in the early stage of learning with MP, changes in limb-loading strategies are a more sensitive measure of performance than is speed.