Prime Time

Rev up your warm up to prep your body for hard efforts.

You know the feeling. It’s the first repeat of an interval workout, you’re breathing like a steam engine, and your legs feel like they’re caught in quicksand. But you also know the second interval will feel a little better, and by the third, you will have settled into a rhythm. It’s called the priming effect – as your body adapts to the physiological demands of running hard, the effort feels easier. Learn to prime your body during your warm up instead of the first repeat, and you’ll run the entire speed session – or entire race – at your best effort.

When you first start running hard, your muscles immediately demand more oxygen. The rest of your body tries to respond with a higher breathing and heart rate, dilated blood vessels, and metabolic changes within the muscles that all speed the delivery of oxygen. But by the time these systems have ramped up, your oxygen-starved muscles have already dipped into anaerobic energy reserves (this is when you get that quicksand feeling). However, if you include a few minutes of strategic hard running as part of your warmup, you will bring your oxygen delivery system up to maximum efficiency while still allowing enough time for your anaerobic energy reserves to recover before the start of your repeats or race. In other words, here’s how to get those demoralising first kilometre blahs out of the way during your warm up – not during your workout.

To trigger the priming effect, you need to exceed your lactate threshold, which corresponds roughly to half-marathon pace, for at least a few minutes. Legendary coach Jack Daniels suggests two to three minutes at 10K pace. World record holder in the mile Hicham El Guerrouj would perform several 200-metre repeats close to mile race pace, jogging back to the start for recovery.

University of Alabama researchers recently studied three different warm up routines for swimmers. On average, the longest warm up produced the best performance – but results varied widely among the individual swimmers. In fact, half the swimmers swam slower when they tried the ‘best’ warm up protocol. The takeaway is that what’s best for the average runner may not be best for you. Experiment with the length, intensity and timing of your priming surge until you find a combination that works.

Aim to finish your priming about 10 minutes before the start of the race. You don’t have to get it exactly right; the effect lasts for up to 45 minutes, says British exercise physiologist Mark Burnley, Ph.D. A shorter break between priming and racing won’t hurt either. Logistics at the start of a big event can be complicated, so be flexible, and don’t fret if you have to adjust on the fly.

Ready to Go
The shorter and faster the race, the more important priming becomes

Mile (1600m): 2 x 400 metres at 5K pace; 1:00 rest
5K: 2:00 to 3:00 at 10K pace
10K: 4:00 starting at marathon pace and steadily accelerating to finish a bit faster than half-marathon pace
Half-marathon and longer: Skip it. For longer races, starting with full glycogen stores is more important than oxygen delivery.


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