The first questions asked by patients with a new diagnosis of Amyotrophic Lateral Sclerosis (ALS) often include: "Does exercise help slow the progression of the disease?", "Is there any harm in exercising?", or "What type of exercise (endurance or resistance) is most appropriate?" At this time, however, there is a lack of answers for people who suffer from an illness that affects their strength above all else. Yet the beneficial effects of exercise in both healthy people as well as people with other diseases have been extensively studied and resulted in recommendations about the types of exercise that are beneficial. In this study the investigators will ask participants with ALS to exercise in one of three ways: weightlifting (resistance exercise), stationary bicycling (endurance exercise), and range of motion exercise (the current "standard of care" for ALS patients). The investigators will use several different types of tests to determine whether one type of exercise is tolerated better and is safer than another. The investigators will also collect information about how the body responds to exercise in ALS. This study will help in the development of a larger national study to understand how exercise can be combined with other treatments to potentially improve strength and alter the course of the disease.