Watch this impressive tempo workout by Ryan Hall prior to his Olympic Marathon Trials victory. Remember, Ryan is one of the best runners in the world, so don't try this by yourself!
Although interval training has been found to be a more effective VO2 booster, tempo training should not be abandoned completely. Mentally and physically, sustained race-pace runs give you the feel for racing like no other workout. Since your training is designed to help you run faster, it makes perfectly good sense to do a large block of your running at race pace or faster.
Along with long runs and interval training, tempo runs are the 3rd primary piece of the marathon training puzzle not to be overlooked. To start with, set aside one day per week, and after a 10-15 minute warm-up, get into your tempo (marathon pace) for 5 minutes, slow to a jog, and repeat.
Here is a sample weekly progression to help you introduce tempo training. As with intervals, you should be schedule an easy workout on the previous day. Remember, this is supposed to be done at marathon pace.
More advanced runners can continue to progress. For me, 60 minutes seems to be the upper limit for a good tempo run.
10 min jog.........5 min tempo, 5 min jog x 2..........10 min jog cool-down
10 min jog.........8 min tempo, 5 min jog x 2..........10 min jog cool-down
10 min jog........10 min tempo, 5 min jog x 2..........10 min jog cool-down
10 min jog........10 min tempo, 3 min jog, x 3..........10 min jog cool-down
10 min jog........15 min tempo, 5 min jog, x 2..........10 min jog cool-down
10 min jog........20 min tempo, 5 min jog, 10 min tempo,10 min jog cool-down
10 min jog....... 30 min tempo, 10 min jog cool down