Anyone who's raced hard has felt it - the moment that elephant jumps on your back and your speed begins to ebb away. Your breathing becomes laboured; limbs get heavy and start to burn; and the only way to temper the pain is to ease off and watch as other competitors disappear over the horizon, never to be seen again.
It can be a mentally scarring process but misjudging your pace is an inevitable part of your development as an endurance athlete. There are ways of keeping that scarring to a minimum though, and one of the most effective is to learn how to pace your run.
What are the different pacing strategies you could employ on the run leg?
Much like skinning a cat, there are many ways to pace your run. We'll focus on four main options of metering out your effort on the run but the general principles apply to all three disciplines and the event as a whole...
Go hard and hang on
Full of adrenaline, with the crowd screaming in your ear, it's highly likely you'll set out on the run at warp-factor five looking for a new PB. However, just around the corner lurks a gang of nasties including oxygen debt, lactic acid and cramp, all waiting to spoil your fun.
You may get lucky and manage to avoid them - this is what happens when you make a sudden breakthrough in performance - but 99 times out of 100 they'll get you. Then they nobble you and leave you to limp in, feeling extremely sorry for yourself.
Despite the staggeringly bad odds, the 'go-till-you-blow' strategy is immensely popular and is employed regularly with a depressing ratio of failures to successes. Really, the only time a fast start is advantageous in a triathlon run is when the course necessitates it (if there's a single track or lots of athletes trying to bundle through a small gap, for example) or if you want to psychologically break your opponents (risky, as you have to be physically far superior to pull this off without doing yourself in too).
Due largely to the sterling work of Sid Robinson at Indiana University in 1958, 'even pacing' has been acknowledged as the best method to tackle most endurance events. Robinson's landmark study (in which three well-trained runners ran 1,200m with either a fast start, a slower start with faster finish or an even pace) clearly demonstrated that even pace was quickest overall. Second place went to the slower starter and trailing in last was the chap who bolted from the gun.
So why doesn't everyone run even pace? Well, to achieve even pace during the run is tricky. Firstly, you must be aware of the pace you can hold for the duration. Secondly, you need to be able to monitor this pace with reasonable accuracy. Thirdly, with the jelly-legged feeling of running after cycling, it can take a while to establish a good rhythm. Finally, you need to be prepared for the fact that simply holding the same pace becomes more difficult as the run goes on.
Once you overcome these hurdles, though, for the vast majority this is the way to go.
What is a negative split?
Negative splits refers to running the second half of the run faster than the first. Running a negative split off the bike (particularly in a long race) is a difficult task, but can be devastatingly effective.
In most triathlons much of the field slows down throughout the run. Usually all but a few of the top competitors see their mile splits drop towards the end. If you can save sufficient energy in the first half of the run, you'll pass many of your rivals and take back huge chunks of time in the closing stages.
The key with a negative-split run is to make it subtle - there's little to be gained from jogging out and sprinting back. The difference in time should only be a few percent, not minutes.
Aiming for a negative split is often a very good way for novices to get close to even pace. By putting in more effort as the run progresses, you're more likely to at least sustain your initial pace for the whole course.
Surges of fast and slow pace are probably the least well-used strategy in running off the bike. It's really only applicable to highly competitive situations when you're racing head to head with athletes of similar ability. Surging and slowing down is disruptive to the steady-state rhythm that the body prefers during exercise - hence the idea of injecting pace mid-race to drop your rivals.
Making this approach work requires either a significant fitness advantage over those around you or some very specific training of your anaerobic ability to cope with it. It also requires total commitment once you start breaking away from others - it's not a tactic for the weak or faint-hearted!
The mixed-pace game is therefore only really relevant for fighting over positions and not useful when you're looking to cover the entire course in the shortest possible time.
How to get pacing right on the day
Having established that for most tri runs an even (or slightly negative) pacing strategy is optimal, get this plan firmly wedged into your brain before the start. Once the race gets under way, the adrenaline and emotions of the event can turn rational people into impulsive loonies with no recollection of their pre-race tactics at all.
This can be catastrophic as your mind does a very good job of disguising the level of effort you're putting in when you're excited (such as at the start of the run with supporters cheering you on). The knock-on effect is that you can make massive physical exertions that don't become apparent until it's too late and you've already blown your doors off.
How to create the perfect run pace plan for your race
Creating a plan for you starts well in advance of the event. Your first consideration is what pace you'll actually be aiming for. To do this you must set a target run time based on previous race splits, current training times and take into account what you want to achieve. It must be realistic, and as you get more experienced this becomes easier.
Obviously, from this total time you can work out the necessary mile/km split times to give intermediate goals for the event. Write these down and memorise them, so that on the day you'll know exactly where you should be at any given point on the run and can adjust your pace according to the feedback you get on the course.
When you have these target mile/km times, training at and around them repeatedly is critical to get your mind and body accustomed to the feelings associated with that pace. One brilliant training session to enhance this is an acceleration run. As an example, an Olympic-distance racer would run 6 miles, starting at a pace around 1min per mile slower than their race pace and increase the pace by 15secs per mile through the session. For example, target pace is 6mins per mile (approx 37mins for 10km). Start the acceleration run with a mile at 7mins, then 6:45, 6:30, 6:15, 6:00 (target pace) and try to finish the last mile off in 5:45mins.
This session is great because it creates an awareness of pace and effort, teaches your mind and body to respond to an increasing workload - as felt during the race - and also teases a little more speed out of your legs for the final mile. Running faster than race pace is possible here because your tri race pace will be a little slower than your 'fresh' 10km time. For longer races, a set of up to 10 miles would be ideal (increasing pace in smaller increments); for sprint racing, 3-4 miles would be sufficient.
As you become more experienced, you'll become better at pacing your run after the bike; learn from your mistakes and you'll become much more precise over time. The final top five tips to assist in this process are:
1. Accurately pre-plan your pace, check it during the early miles and stick to it.
2. Train with lots of even pace and negative-split run sessions on a measured route (a track is perfect for this) to get used to how your target pace feels.
3. Perform some of your pacing sessions in 'brick' (bike to run) format to help you get over the jelly-legged feeling.
Ignore what's going on around you early in the run and go at your own pace.
4. Remember that most others will slow down so be prepared to let them go and catch them later.
5. Save your biggest effort for the second half of the run and be prepared to go hard right to the end of the race.
Learn from the best
In 1967 Paul Hart, then a top-level youth cross-country runner from Dorset, lined up for the English Schools Cross Country Championships. The previous year he'd finished third in the same event, and the two chaps who'd been ahead were a year older and no longer in the same race. A lot of people therefore considered Hart the favourite and told him so.
Responding to this, as any ambitious young athlete would, he set off at a furious pace and took the lead ahead of several hundred runners. He ran the first 400m in around 59secs (3:56mins for 1 mile) and then proceeded to have an epic and painful struggle with fatigue through the rest of the race as oxygen debt inevitably caught up with him.
As a testament to his strong character and training, Hart did finish the event, but in four short miles was passed by more than 100 athletes to finish 103rd! It just goes to show what can happen to even the fittest athletes if their pacing strategy isn't in perfect working order before the start of the race.