A treadmill or running machine provides low impact indoor exercise, with less resistance such as rain, wind, ice, snow. There is less chance of injury on a treadmill compared to running outside as running machine have a smooth even surface, that absorbs shock better than pounding the road. The treadmill runner does not have to worry about weather, traffic, traffic lights, running alone at night or other safety concerns, making it more convenient than running outside. Treadmills allow you to jog, run, sprint, climb hills, and resistance train by easily and accurately varying grade and speed of the running machine, with out having to plan your route to fit your running requirements in.