THE BENEFITS OF INTERVAL RUNS

Always running at one pace is a common mistake. Ironman legend Mark Kleanthous recommends high-intensity intervals

Long, low- to moderate-intensity run sessions are great for increasing aerobic capacity and your ability to make the most of your near-endless supplies of fat for fuel, but they don’t prepare you for competing at race pace. That’s where run intervals come in.

High-intensity running followed by a brief rest period allows you to repeat run efforts at high speed, which will pay off come triathlon race day. Improved performance derives from a number of physiological adaptations conducive to optimal speed.

One of the key ones is increasing your ability to recycle lactic acid at a faster pace. Instead of lactic acid accumulating in your blood, bringing with it hydrogen ions, raised acidosis and subsequent slowdown, repeated intervals ensure your body can break down lactic acid and use it as fuel, which is particularly important at sprintand Olympic-distance racing.

The result of this is that you raise your lactic threshold; in other words, when you race at the same intensity as a pre-interval programme, you’re faster. Interval training also increases VO2 max, as well as strengthening your heart.

For many triathletes, one run interval session a week is fine. Just remember that running is one-third of your sport. To maximise speed, you should also pencil in swim and bike interval sessions; in fact, you could swim two or three intervals a week as there’s less effort placed on your upper body during the bike and run sets.

As for bike, a weekly time-trial effort potentially followed by an easy 20min run is a good idea.

“High-intensity running followed by brief rest periods will allow you to run at high speed on race day”