Arc Trainers Alternative-motion cross trainers that offer inviting workouts for a wide range of exercisers. The 21 incline adjustments result in motions that mimic gliding, striding and climbing and exert less stress on the knees than walking. A versatile trainer for a wide range of exercisers. Stationary arms are ideal for those looking to improve power and strength. LOWER BODY ARC TRAINER A versatile alternative motion cross-trainer that appeals to a wide range of exercisers and exerts less stress on the knees than walking. With 21 incline levels, exercisers can choose the type of workout they want and work different muscle groups. The lower-body version has stationary arms that allows exercisers to focus on power, HIIT training and calorie burn.