Looking to knock out an intense workout in 30 minutes? This is one of my favorite treadmill workouts. It's perfect for mixing up my routine, increasing the intensity, and decreasing the duration.
I start with five minutes of easy jogging. Then I bump the incline up to a high hill (10%), and a walk speed that isn't too fast that I'll need to grab onto the handlebars. If you feel the urge to hold onto the handlebars, reduce the incline or the speed to the point where you are no longer holding on. After two minutes, I switch to the sprint interval in which I reduce the incline to a much lower hill (3.5%, I never go down to a full 0%) and go as fast as I can for 30 seconds.
This is definitely a more advanced workout, so if you're not used to running hills start with lower speeds and inclines and work your way up! For example, an easier set of intervals would be:
2 Mins Walk 5.0% incline; 3.5 mph
30 Sec Run 3.5% incline; 5.0 mph
Tweak it to YOUR personal level of fitness and push yourself!!