No matter how well your training is going, you may doubt your ability to hit your goal time on race day. How can you be confident that your hard work is paying off? The answer is a benchmark workout, done a few weeks before race day. ‘Being able to predict your time has many potential benefits, including enhanced mental preparation, informed goal setting, nutrition planning and fluid planning,’ says Dr Eloise Till, who researched a marathon-predictor workout for a recent study.
But marathoners aren’t the only runners who can benefit: there are workouts you can do before your 5K, 10K or half marathon, says running coach John Henwood. ‘These workouts give you a good indicator of what you’ll be capable of on race day,’ he says.
There are also simple formulas that don’t involve a workout that can give you an idea of your race potential. Legendary coach Frank Horwill observed that, most runners’ paces decrease by about four seconds every 400m as they move up from one race distance to the next. For example, a 25-minute 5K equates to 120 seconds per 400m. Using the four-second rule, this translates to 124 seconds per 400m for 10K (a time of 51:40), or 128 seconds per 400m for a half marathon (1:52:00).
The workouts assume you are doing the necessary training and they are only estimations to give you an idea of your potential, rather than predict your finishing time to the second – they can’t factor in the course profile or climatic conditions (such as heat, humidity or a strong wind) you might encounter.
1/ Magic mile
Why: Devised by coach Jeff Galloway, it’s a simple way to estimate race times.
How: After a warm-up, run a mile as fast as you can, pacing yourself as evenly as possible. You should finish feeling you couldn’t now run more than 100m at the same pace. Add 33 secs to your mile time for your pace for a 5K; multiply it by 1.15 for your 10K pace; by 1.2 for half-marathon pace; and by 1.3 for marathon pace. On subsequent efforts, try to beat your previous time.
2/ 5K baseline
Why: If you’ve never run the 5K distance, you might not know your pace.
How: Run two miles at conversation pace and speed up in the final mile to a speed at which you can only say a few words at a time. A few days later, run three one-mile repeats at the pace you ran your third mile, jogging 800m between each. If your third repeat is at least as fast as the first, your baseline pace is ideal. But if you slow down, use the average pace of the three mile repeats.
3/ 5K predictor
Why: ‘It’s a very good indicator of whether you can handle five kilometres at a certain pace even with rest in between, since a 5K is less about endurance and more about short bursts of energy,’ says Henwood.
How: Two or three weeks before race day, run 5 x 1000m at your 5K goal race pace, with a 400m recovery jog between each interval. Take the average of your five single kilometre times and multiply it by five to get your predicted time.
4/ 4 x 800s
Why: For new and intermediate runners, half-mile repeats help you gauge your speed without worrying about pacing yourself over a longer distance.
How: After a warm-up, run 800m at a comfortably hard pace. Adjust pace in the next three reps depending on how you feel (take a 5-min walk between each). Take the average pace of your reps to find your 5K goal pace. Over three months, increase the reps to five or six, or decrease recovery.
5/ 10K predictor
Why: ‘A mile is long enough to tap into the endurance you need in the 10K race, so it’s a good predictor,’ says Henwood.
How: Do this workout two or three weeks before race day. Run 5 x 1 mile at your 10K goal race pace, taking a 400m or two-minute slow recovery jog between each repeat. Work out what your average pace was across the five mile repeats and then multiply the result by 6.2 to get an approximate idea of your 10K finishing time.
6/ 13.1 predictor
Why: ‘A 10K is great because it has that endurance aspect of a half marathon but doesn’t require you to run too much so close to race day,’ says Henwood.
How: Three to five weeks before race day, run 10K at 80 per cent effort (a ‘comfortably hard’ level of exertion). Take this 10K time in minutes (for example, a 55:30 is 55.5) and add 0.93. Multiply the result by 2.11. Using this formula, a 50-minute 10K at 80 per cent effort predicts around a 1:47 half marathon at race effort.
7/ 5K repeat tempos
Why: A half marathon demands speed and endurance. Because you’ll be running just below your lactate threshold, longer (3-6K) tempo efforts at pace are the best way to train the body to sustain pace without tiring.
How: After warming up for a few kilometres, run three sets of 5K at goal half-marathon pace, with a 5-min recovery jog between each. If you can get through the final repeat feeling challenged but in control, your goal pace is about right.
8/ 26.2 predictor
Why: ‘Long runs are great marathon predictors because a marathon is just one really long run,’ says Henwood.
How: Run at your marathon pace for 10-14 miles of a 20-mile long run. Take the average mile time from your race-pace miles and multiply it by 26.2. Do this run five weeks before race day for intermediate runners; and a second time two weeks later for advanced runners. (Beginners should skip this workout and use their long run pace as a goal race pace.)
9/ Yasso 800s
Why: Invented by Bart Yasso from Runner’s World US: take your goal marathon time and then try to run that time over 800m – using minutes and seconds rather than hours and minutes.
How: If your aim is a four-hour marathon, your Yasso goal time is four minutes. Earlier in your schedule, start with six reps at your goal time, with a recovery time equal to the rep (in this case, four minutes). Repeat the workout regularly and add reps, up to a maximum of 10, a few weeks out from your race.
10/ The simulator
Why: Created by coaching brothers Keith and Kevin Hanson, the aim is to simulate a marathon as closely as possible without overtaxing the runner.
How: Run 26.2 kilometres (just under 16.3 miles) at goal marathon pace three or four weeks out from your race. This is long enough to test your ability to sustain your marathon pace and let you know if it’s realistic (and it will also boost confidence), but not so long that it will deaden your legs for days.