Inclines raise the front of the tread belt to simulate going uphill and provide greater resistance to the user. Less expensive treadmills may have a manually-adjustable incline, which requires to user to change the angle of incline while off the treadmill. Other treadmills have automatic, or "Power" inclines, that allow the user to adjust the incline while using the machine, through a separate motor inside the treadmill. A typical automatic incline increases the angle up to 12%, which requires quite a bit more effort from the user.

For more information on choosing a treadmill, see

How to Choose a Treadmill

Treadmill Buying Tips

Big Guy – Big Treadmill

What is iFit?