Cross trainers are a popular piece of equipment found in gyms across the world. They offer a low-impact workout that is gentle on the joints, and they’re particularly popular with runners. They’re not just for those recovering from injury—cross trainers are an ideal way to burn calories on rest days, as they’re a lower impact exercise than running but work a lot of the same muscles. They can also help build complimentary muscles in the lower body that can help runners avoid injury from frequent stress on the ankles and shins.