Strengthening exercises have led to improvements in strength and motor functions in patients with primary muscular weakness and weakness related to inactivity in cases of mild to moderate Parkinson’s disease. Patients perform exercises when at their best, 45 minutes to one hour after medication. An 8-week resistance training study geared towards the lower legs found that patients with Parkinson's Disease gained abdominal strength, and improved in their stride length, walking velocity and postural angles. Also, due to the forward flexed posture and respiratory dysfunctions in advanced Parkinson’s disease, deep diaphragmatic breathing exercises are beneficial for improving chest wall mobility and vital capacity. Exercise may correct constipation.