Chronic Kidney Disease (CKD) affects more than 20 million adults in America. CKD may affect the normal functioning of skeletal muscle, leading to fatigue, weakness, and changes to the way the body processes nutrients. The main purpose of this study is to understand how CKD affects muscle mitochondria, an essential component of skeletal muscle cells. We are enrolling 150 people who have CKD and are between the ages of 18-90 years old. Participants will undergo a specialized, non-invasive MRI test on their hand muscle that will measure mitochondrial function. Also, participants will complete health-related questionnaires, undergo a brief physical examination, and provide blood and urine samples.