Standing, Walking or Running?

The best answer depends on what you’re trying to accomplish

It may seem obvious that doing as little as possible during the recovery period will allow you to run faster during the next rep. And it’s true that a slow walk will best allow your muscles to recharge their stores of phosphocreatine, the instant fuel that powers the first 10 seconds or so of a sprint. For that reason, passive recovery is the best choice for workouts where you’re focusing on your sprint speed, like 8 x 300m with 90 seconds rest.

Having to jog during your precious recovery period, on the other hand, may seem like a cruel punishment. But it can actually help you run faster in the next rep: active recovery keeps blood circulating through your muscles, clearing away lactate and other fatigue-related metabolites that built up during the previous rep. A 2014 study from researchers at St. Mary’s University College in Britain found that it took about two minutes for the benefits of active recovery to kick in with lowered lactate levels compared to passive recovery. That means jogging is the best option for hard aerobic workouts like 6 x 1,000m with 2:00 rest.

Of course, the ultimate goal isn’t simply to run your next rep as fast as possible; it’s to build your fitness so that you can race faster. During a workout like 10 x 400m with 1:00 rest, the recovery period isn’t long enough for lactate clearance to matter, so walking the rest would help you run the workout faster. But if the goal is to develop your aerobic fitness, it’s better to jog the rest so you’re relying more on your aerobic energy sources instead of phosphocreatine. A bit more short-term discomfort (and possibly slower interval times) will translate into greater fitness in the long term.

To ramp up the aerobic demands of the workout even more, you can try a third option for interval recoveries. A “f loat” recovery involves running at a pace that’s just barely slow enough to allow you to get your breathing back under control before the next interval. Workouts with f loat recoveries teach your body to recover on the f ly, which is a key skill for racing over hilly terrain and for responding to surges when racing against other people. Try 4– 6 x 800m at 10k race pace, alternating with 800m f loat recoveries that are 30 to 60 seconds slower. Of course, none of these rules are unbreakable. Your body responds best to new and different challenges, so now and then try jogging the recoveries during a workout where you usually walk, or vice-versa. And most importantly, make sure you’re earning your recoveries by hammering the intervals: there’s no yin without yang. Alex Hutchinson is one of the most respected endurance sports writers in the world. He is a contributing editor at Canadian Running. Read his regular column, ‘The Science of Running,’ on p.38.