Can You Do Treadmill HIIT At 100% Effort?

Blazing fast speed. Velocity. Acceleration. Can you do treadmill HIIT and still call it a true HIIT workout? Unfortunately, no, and here’s why.

As you know, high intensity interval training, or HIIT for short, is done for about 5, 10, or 15 minutes, using sprints for 30 seconds followed by a minute of rest, then repeated, until you are completely fatigued. These intervals provide some of the most intense conditioning workouts your body can do, and the fitness benefits are outstanding.

As such, people have sought to adapt intervals to various fitness machines with mixed results. They are easier to do on stationary bikes, spinners, and even some ellipticals.

But a treadmill? HIIT hits a wall when trying to do them on our favorite cardio machine. At best, you can run as fast as 10 or 12 mph on many treadmills, but that’s only about 80% of a full sprint speed for an athlete (or 52% for the fastest human running at 23mph).

Disadvantages of Treadmill for Intervals

So what are the drawbacks to doing HIIT on a treadmill? Can a treadmill even do this type of quick speed change exercise? Well, that depends on the machine.

Some have a one-button manual control to select a fast speed so that you don’t have to hold a button and scroll up to the speed. Most treadmills do not. Running sprints is easy to do on an outdoor running track, but nearly impossible on a treadmill if you have to worry more about holding down the speed control button while panting heavily and trying not to slip off the machine.

Furthermore, the belt cannot go from zero to 10 mph lickety-split, and HIIT requires explosive power to run all out for 30 seconds. It will take the belt about 20 seconds to hit max speed, and another 10 or 15 seconds to slow down for the “rest” period (without hitting the emergency stop). For example, Runner’s World declared the Landice L7 to be the fastest treadmill going from 0 to 10 mph in 16 seconds.

Another point: HIIT carries a great risk of injury because of the intensity and speed involved. While this is not a problem with the wide-open space of a running track, doing it on a 20x60-inch platform is dangerous.

And the last drawback is that treadmill decks aren’t designed for sprinting; you run heel-toe on a treadmill, while proper sprinting technique is only the ball of the foot hitting the ground.

A Modified Treadmill HIIT Solution

If you have a treadmill that can be programmed for customized intervals, or if it has Interval programs, you can use that to start a modified treadmill HIIT program. The speed won’t be as fast as you like, but pre-programmed Interval workouts on treadmills are actually safer and better designed for out-of-shape individuals to do.

For example, the Smooth 7.6 HR treadmill has two Interval programs: Incline and Speed. The first allows you to select a level from 1 through 12 with the higher levels pumping the heart.

The incline level changes every 2 minutes during the 24-minute workout (which can be adjusted higher or lower in 4-minute segments). The Speed interval on the Smooth treadmill is more traditional, doing adjustments of belt speed.

Nevertheless, treadmill HIIT is not true high intensity interval training. By its nature, HIIT is blasting 100% maximum velocity for up to 30 seconds, alternated with rest/recovery, then going all out again.

Treadmills can do 12 mph and give an incredible fast-paced workout, but true high intensity intervals are simply not possible, practical, or safe.

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