Most of the people using treadmill stick to the same speed and takes their body to a steady state which burns fewer calories. But if interval training is practiced on treadmill it makes the person stronger and faster because of the development of strong muscles and burning out of fat.
As the interval training on treadmill is a high intensity exercise it improves the cardiovascular activities and avoids the boredom of doing treadmill. While doing interval training on treadmill one can either choose different speeds or different elevations with constant speed.
High intensity exercises leads to the development of fast twitch muscle fibers which require more energy to function as compared to the slow twitch muscle fibers which are developed due to steady state exercises. Hence high intensity exercises helps to burn more calories and more fats.
Before initiating interval training exercise on treadmill, steady state exercises should be regularly followed for at least six months. High intensity training should be preceded by warming up the body for 10 minutes at 3.0 mph speed. This makes the muscles to become flexible and loose and avoids the risks of injury during high intensity training.
Then identify a base speed which should be higher than the warm up speed and ideally it can be 4.0 mph. This will be the speed that the person should return to during recovery periods. Walk on the base speed for two minutes, then increase the speed to 4.5 mph for one minute and return to 4.0 mph for recovery and again increase the speed to 5.0 mph for one minute to return to 4.0 mph for another one minute.
Similarly increase the speed limits to 5.5, 6, 6.5 in every other minute and return to 4.0 mph for recovery. This pattern should last for about 10 to 20 minutes depending on the stamina of the person. Now cool down the body for another 10 minutes at 3.0 mph.
High intensity training can also be done by varying the inclination of the treadmill. In this pattern start warm up exercise at a lower elevation of 1.0 for 10 minutes and then increase the elevation to 1.5 for a minute and return to the former elevation of 1.0.
For the next minute, increase the elevation again to 2.0 and return to 1.0 for recovery and again increase the elevation to 2.5, 3, 3.5 and so on in every other minute while maintaining the recovery period at elevation of 1.0. Once you are through with all the exercises, stop the exercise with cool down exercise at an inclination of 1.0.
The length of high intensity intervals can vary as per the stamina of the practitioner and for a beginner it can be even 30 seconds and the recovery period can be extend up to 2 minutes. Once the practitioner becomes fit then increase length of the high intensity exercise period up to 2 minutes and keeps the recovery period for 1 minute as more fitter the person becomes, the quicker will be the recovery and hence requires only shorter recovery period.