It is my favorite piece of equipment due to it's versatility. I've had ages 5 to 80 ride the elliptical. Anyone with a limp can benefit from the elliptical to regain their fluidness of stride. I use the elliptical specifically for calf, quadricep, hamstring, and back strengthening. The elliptical machine is a great way to get aerobic training without the stress to the knee, hip, and back joints. It also helps tow wean back patients into a running program post injury.