You've probably heard that you can get a better workout on the treadmill by increasing the incline. True, says Rick Morris, a Colorado running coach who wrote the book Treadmill Training for Runners, but he adds that many people attempt to sprint up steeper hills on the treadmill than they would consider tackling outdoors. Pitching the incline too steep for your fitness level can put excess stress on your back, hips and ankles as you lean far forward. Morris says if you typically run 3 to 10 miles three or more times per week, you should stay below 8 percent; new runners or those who train on flat terrain should stick to a 5 percent incline, max.
Be safe: This basic ladder workout from Morris' book will take you gradually up to a moderate incline. After your warm-up, run for two minutes at a 1 percent incline. Then increase the incline to 2 percent, and run for 45 seconds. For each interval, increase the incline by one percentage point and decrease the sprint by 10 seconds, so you'll run 35 seconds at a 3 percent incline, 25 seconds at 4 percent and 15 seconds at 5 percent. That's the top; now work your way back down to 1 percent. Jog one minute and repeat.