With machines set up in rows to encourage competition, many ordinary gyms cater to men's bodies and psychology. At Curves, estrogen-touting exercise mavens move around a circuit of hydraulic resistance machines that have been designed to work with women's bodies and promote weight loss, protect against osteoporosis, and deal with arthritis. An experienced trainer is always nearby to help manage machine maneuvering and muscle making. Instead of fiddling with weight stacks and losing momentum, the hydraulic machines use body weight and fitness level to create resistance that matches abilities, decreasing the risk of soreness or injury. Because traditional lift-and-lower motions create bulky muscles, each machine uses push-and-pull motions to create toned, lean muscles perfect for crushing a grapefruit without looking like you can. The Curves Circuit with Zumba Fitness incorporates the Curves philosophy within the moves of Zumba, a Latin-inspired dance-fitness program that focuses on free-form movement instead of belligerently counting reps over the music.