Precor makes a wide selection of fitness products for both the home and the gym. The 9.21i is an older Precor residential treadmill model; it is no longer available through Precor, but used units can be found for sale. The 9.21i is a low-impact treadmill featuring several built-in programs and heart rate control technology.
Integrated Footplant Technology
Integrated Footplant Technology by Precor offers a more fluid stride, which reduces fatigue when walking or running. The system collects information on motor and belt speed and uses the data to adjust the belt movement. When you are running on a hard outdoor surface, as your foot strikes the ground, the solid surface beneath you supports the acceleration of your foot as you push off. On a treadmill, because of the movement of the belt, as you strike the deck, drag is created, pulling your foot backwards. Integrated Footplant Technology eliminates this drag by adjusting the belt speed precisely as you make contact with it. According to the Precor website, the motor speed is adjusted up to 100 times per second.
Motor and Deck Specifications
The Precor 9.21i treadmill features a 2.0 horsepower motor that supports speeds from 0 to 10 mph. You can set the incline from zero to 15 percent. The running deck is 17 inches wide, providing a good-sized surface on which to run.
Several built-in programs and workout options offer you variety on the 9.21i treadmill. The manual setting allows complete control over the incline and speed settings of your workout. The interval, weight-loss and random settings automatically adjust the speed and incline settings for you. The Heart Rate Course will monitor your heart rate and adjust the treadmill's incline and speed, allowing you to keep your heart rate within a predetermined target zone.