(To alternate between forcing the pace and resting, with the intention of wearing out other riders. Riding hard for relatively short periods).
With interval training, you alternate short, fairly intense spurts of exercise with periods of relatively easy exercise. For example, say you're out bicycling. After warming up for 15 minutes or so, you may try cycling all-out for 30 seconds and follow this with a few minutes of easy pedaling until your heart rate slows down a little, to about 120 or fewer beats per minute. Then you do another tough 30-second interval, and so on. In essence, you're switching between the low and high ends of your target zone.
When you first try interval training, keep the high-intensity periods short — 15 to 30 seconds. Follow these periods with at least three times as much active rest (so, 45 to 90 seconds). Active rest means that you keep moving between intervals instead of stopping dead. So after you do that 30-second bike sprint, pedal slowly for about 90 seconds. You may need even more recovery than that, especially if you're a beginner. As you become more accustomed to higher levels, you can increase the length of the high-intensity intervals as you decrease the length of the low-intensity intervals. Eventually, you can aim for a 1:1 hard-to-easy ratio, measuring intervals in terms of time or distance.
This charming word means "speed play" in Swedish. Fartlek is basically interval training without an exact measure of time or distance. You just do your intervals whenever you feel like it. You may try sprinting to every other telephone pole. Or set your sights on that horse standing in the field down the road and pick up your pace until you reach him.
You can add hills to walking, biking, running, or skating workouts. You have to work harder when you come to a hill, but ultimately you're rewarded with extra strength and stamina. As a bonus, going uphill can burn twice as many calories as exercising on flat land. One fun drill is to do hill repeats. Find a long, fairly steep hill and then sprint up it and jog down it, repeating this sequence four to eight times.
Goal: Increase your climbing lactate threshold
Where: A road with a long steady climb
(I didn't have one of those but a shorter, steep climb that I did 3 times in a row)
How: Focus on continuous riding without interruptions for the length of the prescribed interval. Riding intensity should be in the 78 percent to 83 percent range of your maximum heart rate (...) The length of the workout should range from 5 to 15 minutes and recovery time between repeats should be 5 to 10 minutes.