Cross-Train (xt): Whether it's a swim, bike ride, gym workout, or exercise class, this is the day to do anything but run. Maintain an easy to moderate effort for these sessions.

Easy: This is a comfortable, conversational pace that's best for short, easy runs; long, slow runs; and warmup and cooldown jogging--almost all of the running you'll do while marathon training. During weekend long runs, beginners can take walk breaks.

Quality: This is harder running, performed over short distances with rest intervals of jogging or walking between. If you aren't breathing hard and leaving your comfort zone, you're not running hard enough.

Tempo: On these even-paced, moderately hard runs, the effort should be hard enough that conversation is somewhat difficult. Run hard, but in full control. (See "Perfect Tempo," page 37, for more.) Note: The distances shown on tempo-run days include a 1.5-mile warmup jog and 1-mile cooldown jog, so subtract 2.5 miles to determine the tempo-pace segment of that run.

Advertisement - Continue Reading Below: Every tempo run and quality workout should begin with a warmup jog of about 1.5 miles (or 15 minutes) and end with a cooldown jog of about one mile (or 10 minutes)--longer if you need it. The warmup jog should begin at a very easy pace or a walk and the cooldown jog should end that way.