In other words, your training should closely model the various circumstances of racing, because only by doing this can you stimulate the physical adaptations needed to prepare your body for an optimal race effort.
The principle of specificity should shape your entire training program. But in this article, I would like to discuss five special race-preparation measures that are underutilized even among triathletes who train sensibly overall.
Race pace workouts
The body tends to adapt to the precise work intensities it is challenged to maintain in workouts. The more time you spend training at a given intensity level (up to a point), the more efficiently your body will be able to work at this level.
So, in order to adapt optimally to your goal race pace in each leg of a triathlon, you should do a certain amount of training at this pace.
For example, suppose you are training for an Olympic distance triathlon and your target splits are 28 minutes for the 1.5K swim (1:52/100m), 1:15 for the 40K bike (20 mph), and 45 minutes for the 10K run (7:15/mile).
In the last six weeks before the race, you might do one workout per week in each discipline that emphasizes this pace. Cover 80-100% of the race distance at this pace, but break it up into at least two separate intervals with active recovery between them.
In the case of the swim, a good format would be a main set of 4 x 300m at 1:52 per/100m.
A great way to prepare mentally for a triathlon in the final weeks is mental rehearsal, or visualization. This entails finding some quiet time to sit or lie down, close your eyes, and imagine yourself swimming, cycling and running with strength and confidence in the context of your upcoming race.
Try to make these meditations as concrete and sensorially detailed as possible - an effort that will be helped greatly if you have some familiarity with the course, but which is still feasible if you do not.
While you want your mental rehearsal to be positive, don't make it unrealistically so. For example, rather than imagining that you feel no fatigue, even at the end of the race, imagine yourself fighting through fatigue and staying focused despite discomfort.
Take yourself through the entire race, start to finish, in condensed form. Play some inspirational music, if you like. (I like to choose a "theme song" for each important race I prepare for.) Do this at least several times, and as often as every night, right up until race eve.
Practice swim starts, exits, and transitions
The final two weeks before a race is a good time to rehearse race transitions and swim starts and exits, especially if you're relatively inexperienced in triathlon racing.
You can get a solid, race-specific swim workout by simulating the first and last 100 yards of the swim several times. Put on your wetsuit -- if you'll be racing in one -- and simply charge from the beach into the water, break through the surf (if there is surf), and swim hard for roughly 100 yards. Then turn around, swim back to shore, and run onto the beach.
To practice transitions, set up a makeshift transition spot just as you plan to set it up for the coming race. First practice your swim-bike transition several times. You can combine your swim exit practice with your swim-bike transition practice, if you wish. Then practice your bike-run transition several times.
There is a big difference between running on fresh legs and running off the bike in a triathlon. In order to be prepared to do the latter, you need to practice it regularly in training.
I recommend doing at least one "brick" (bike-run) workout every other week. Mix it up, sometimes doing a shorter ride followed by a longer run, other times doing the opposite, sometimes doing both parts at a moderate intensity, other times doing either the bike or the run or both parts at a higher intensity, and so forth.
Simulating race conditions
Lastly, you should also make an effort to simulate the terrain and conditions of your upcoming race in training. If the bike course is very hilly, ride on hills. If the race will take place in an area that is hotter than your local area, try to do some of your training during the hottest part of the day.
You get the idea. I also recommend that you do at least the occasional workout at the same time of day as your race start.
Even such small measures can make a difference!
Matt Fitzgerald coaches runners and triathletes and is the author of "Triathlete Magazine's Complete Triathlon Book" and "Runner's World Guide to Cross-Training."