Treadmills come in two basic varieties—motorized and non-motorized. Your workout will be different depending on your choice. You will have to put more effort into a workout on a manual treadmill, but most motorized treadmills have better features and construction. The curved-belt manual treadmill is a newer subcategory. They rival some of the best motorized treadmills in terms of sturdy design as well as in having a high price tag. They have become a favorite among athletic trainers and you may see them at your local gym. Compare these categories and see which type of treadmill would work best to suit your needs.