Most people think training for a marathon is just about building up the miles so you've got the stamina to run 26.2 miles on race day. That's important, but if you want to run a FASTER marathon, you'll need to incorporate speed training into your routine. The good news is that speed training can be fun and different — and it helps break up the monotony of marathon training all while helping you achieve your time goal. Here are some of the common terms used to describe various speed-training workouts.

Fartleks: During a fartlek, you speed up and slow down at varying, nonuniform intervals. For example, run hard for two minutes, then run easy for three minutes, then run hard for four minutes and so on. You can also improvise fartleks. Run hard to that tree in the distance, jog to the next trash can, then sprint to the next tree, etc.

Tempo Runs: Different runners, and different training plans will define a tempo run in different ways. In general, it is a run done at a slightly uncomfortable pace. Sometimes they are runs done at the pace of a previous 5K or 10K. They can also sometimes be done at your projected marathon pace.

Intervals: Interval training is a proven way to increase endurance by adding intensity at set points in your run. Run a set distance at top speed, then a set distance at a slower pace to recover and repeat. Common intervals for marathon training are 800 meters, 1200 meters or 1 mile.

Hills: Improve your speed by running locals hills. Run up and down the same hill over and over again. This can be done on a treadmill using incline settings.

Pace Runs: Pace runs are workouts done at the pace you hope to use to complete the marathon.