Firstly, the treadmill targets speed and incline, helping your running, walking, and cardiovascular endurance. Although, it can cause a lot of pressure on the knees, ankles, and hip joints. That is why, as an alternative, the elliptical trainer tends to be a much better cardio equipment, as it is a low-impact machine and give a total-body. It also works forward and backward which allows you to engage more muscles.