Completing the Race in Under 2 hours, 30 minutes
If you can complete an Olympic Distance race in under 2.5 hours, then your race plan is pretty straightforward – go like heck! During the swim, the goal should be to avoid as much chaos at the beginning as you can and settle into a steady pace as quickly as possible. So, when the gun goes off, my suggestion is to swim as hard as you can for 200-400 meters while keeping in mind you're swimming a mile. If the pecking order hasn't been established by then, back off and settle into a pace you can hold steady for the remainder of the swim. The initial high-intensity burst will push you right into an anaerobic state and your body will be burning with lactate. But so will everyone else. It is better to burn rubber at the beginning than get clubbed for the entire swim. When you finally settle into your steady pace, you should be in single file behind someone, swimming very close to their feet when you put your hands in the water in front of you. Likewise, someone will probably on your feet to catch the draft. During the initial sprint, your HR could reach the 90-96% range, but you should settle into an effort at 76-86%. When you finish the swim, you should be somewhat tired but also feel like you could have swum another mile at the same effort and pace. If you're staggering up the beach, you swam too hard.
Physiologically, the hardest part of any triathlon is the transition from swim to bike. You are going from a prone position where you mostly use your arms to immediately standing up and fully engaging the legs as you run to your bike. The blood that was in your arms and head gets directed to the legs, but your body needs to keep enough blood in your head so you don't pass out. Thus, your HR and blood pressure both get jacked up to compensate for the abrupt change in body position – prone to standing. Avoid panicking. Stay calm and regroup before you get on your bike.
Once on the bike, the idea is to get into your groove as quickly as possible. For the majority of the bike leg, your HR should be toward the upper end of the 76-86% range. The goal is to hold a steady pace that is challenging but not debilitating. If you biked the 40k on a velodrome, then your 10k splits should be dead even or should get slightly faster. If you start out too hard on the bike or push too hard the first half, then you'll get slower and slower as the miles pass. During the second half of the bike, your HR will probably drift up into the 84-92% range. That's OK. This is the HR range which closely corresponds to your Lactate Threshold (LT). Your LT will most likely fall into the 88-93% range if you are well trained (regardless of how fast/slow you are). If you are well trained, then you should be able to sustain a steady effort near/at your LT for about an hour. So, if your HR drifts into this range (84-92%) during the latter half of the bike, your level of effort is close to ideal.
As you transition to the run, your upper body will again demand some of the blood that is pooled in the legs. This can lead to “heavy legs” at the beginning of the run. Best strategy is to be patient. Start out with a shorter stride than normal to keep your stride rate high and to minimize the shock of starting yet another sport. Allow your stride to slowly and naturally lengthen over the course of the first .5 to 1.5 miles. Your HR on the run should be in the 84-92% range from the start. Pick a level of effort that you know you can hold for 6-8 miles. This will help you avoid starting out too fast on the run. While you are definitely building up lactate in your muscles, you are not doing so at a greater rate than your body's ability to process it – as long as you keep your HR below your LT. Once you jack your HR above your LT, you have a very limited amount of time to sustain that level of effort before the accumulated lactate is too much for your body to handle. Think of it as sensory overload. Your body will shut you down and reduce you to a very humbling end. The goal of your 10k should, as on the bike, to either even split or negative split it. If at Mile Four you are feeling strong, then push the pace and bring your HR into the 90-96% range – you're close enough to the finish where you should be able to sustain that level of effort to the end (about 10-20 minutes).
Completing the Race in More Than 2 hours, 30 minutes
If your finish time for an Olympic Distance race is going to be longer than 2.5 hours, then you have to be more careful with how you utilize your energy. The more time beyond 2 hours, the more you need to keep the reins in and avoid pushing your HR above 84%. Think of your race as more of a stair step with your effort rather than a straight line. On the swim, you can still sprint the initial several hundred meters and let your HR creep into the 90-96% zone. But when you do settle into your steady pace, shoot for 70-78%. This may be easier than you are accustomed to swimming in a race, but it will leave you with more energy for the remaining legs. Once on the bike, start out at 70-78% for the first half. If you're feeling strong and like you have a fairly full tank, then push your effort up to 76-86% for the last 10-20k. Do this gradually rather than abruptly. A sudden spike in effort by you will cause a negative knee jerk reaction by your body – not as immediate but potentially devastating to your results.
Once back on your feet and into the run, follow the same principles as your speedier brethren. Start the run with a shorter stride and let it lengthen naturally. Don't force anything. Your HR should be in the 76-86% range to begin with. If you can run the 10k in under an hour, then you can push yourself early into the 84-92% range. If it feels good to do so, go for it! If it feels labored, back off to below 84% and try again a mile later. Your goal on the run is to negative split it – make the second half faster than the first half. When you are about 10-15 minutes from the finish, if you're feeling strong then give it everything you've got. Get the HR into the 90-96% range (and equivalent effort to a fresh 5k run). Push yourself through that finish chute and pat yourself on the back for a job well done!
For faster athletes, for the most part, the level of effort should feel consistent from start to finish, aside from the swim start and your final push on the run to the finish line. So, consider your general level of effort as a flat line. However, as your effort remains consistent, your HR will drift – or rise – as your body fatigues and you continue to push yourself. As the race progresses, it will require a greater level of effort to hold your pace consistent. This is defined as “cardiac drift”. So, if you begin your race, or any leg of the race, at too high an intensity you run the risk of severely limiting your performance. In the end, we can only ignore the discomfort for so long before the body takes control and slows us down. For slower athletes, think of your race effort as series of stair steps. Push yourself a little bit harder as you enter a new leg of the race. At the end, you should be pushing yourself just as hard (according to HR) as the top athletes. If you've utilized your energy properly, you'll be able to do this and feel strong doing so.
If you find yourself petering out during the course of the 10k run, you completed the first 2 legs too hard. But, if you feel strong during all three legs and find that you can actually speed up the second half of the run, then congratulations! You've meted out your energy successfully and my guess is that the race result will be one of which you can be proud.
Final Word on Sprint Races
Sprint races can be a fun diversion from the regular routine of racing. For those athletes who can complete an Olympic distance race in less than 2.5 hours, the strategy is simple. Go as hard as you can at an effort you can hold for 60-75 minutes. In terms of HR, this translates to the 84-92% range for the swim and bike legs, and the beginning of the run leg. As the run progresses, if you have meted out your effort wisely, you can bump your HR into the 90-96% range – or similar to fresh 5k effort. Once your HR is consistently above 90%, you've got about 15 minutes in your tank before your body shuts you down, so best to save that level of effort for the majority of the run. Jack your HR too soon and you'll be slowing down instead
of speeding up for the finish.
If you think you will be finishing a sprint race in more than 75 minutes, you have to be more careful with your level of effort. You can hold your HR at 84-92% at a consistent speed and level of effort for about an hour. It would be best to settle into a pace at 76-86% for the swim – after the initial sprint from the gun – and then bring your HR up into the 84-92% range for the bike leg. Settle into a solid yet sustainable pace. Get off the bike and keep your HR under control for the first half or 2 miles of the run (for a 5k). At that point, if you're feeling strong, push harder and bring your HR up into the 90-96% range all the way through the finish.