Good Shock Absorption: You want to purchase a treadmill with good shock absorption. Why? You want to buy a treadmill with good shock absorption because good shock absorption will make running on a treadmill easier on the knees. Many people injure their knees running on cement or on treadmills of poor quality because of the lack of shock absorption.
Sturdiness: You want to make sure that the treadmill you purchase is sturdy, not only for safety reasons, but for durability. Everyone who buys a treadmill does not weigh only 125 pounds. Some people weigh 300 pounds, and so it is important to look for treadmills that specifically state their weight capacity.