HIIT: Train less for better results

Why you should add high-intensity interval training to your running schedule



by Garth Fox

running fast

What's the basic concept?

The idea is that 15 minutes of high-intensity interval training (HIIT) can deliver the same physiological benefits (such as improved endurance, and reduced risk of heart attack, stroke and diabetes) as three hours of long, slow running.

It seems that short bursts of high intensity exercise – 30-second all-out sprints with a work-to-recovery ratio of around 1:6 – may stimulate the same cellular pathways as long, steady state aerobic exercise. In other words: the same health gains of running but in a fraction of the time. But, of course, there’s a catch: as lead researcher Martin Gibala says, “Those short bursts hurt.” 

What’s the risk?

HIIT sessions require maximal, or close to maximal, efforts. This means you rely primarily on your anaerobic system for energy. If the aerobic system uses oxygen on a ‘pay as you go’ basis, the anaerobic system generates an oxygen ‘debt’, which needs paying off as soon as you back off from the full-on effort. (That is why heartrate monitors aren’t particularly good for gauging the intensity of HIIT intervals: your heartrate continues to climb sharply during recovery as the body pays off the oxygen debt.)

But as long as you have the OK from your doctor to exercise, this is entirely safe. Just remember that maximal exercise of any sort puts considerable stress on your muscles and connective tissues. There’s no further benefit to be had from doing more than two days of HIIT per week. And you need time to recover, so allow at least one full day of recovery between sessions. Prioritise longer, low-intensity sessions in your training week, and include strength and conditioning work to help prevent injury. 

Endurance is more important to me than explosive speed. Can I still benefit?

Yes. There’s no doubt that long, slow runs are the most effective means of training for an endurance race. They boost the fatigue resistance of slow-twitch muscle fibres; HIIT has its greatest impact on fast-twitch fibres. So why should you include HIIT sessions in a distance training programme?

One good reason is that although the fast-twitch fibres may not be as fuel-efficient or resistant to fatigue, they join in the action when leg muscles start to tire in the latter stages of a race. So you may get a boost to your overall muscular endurance.  

Do I have to run my HIITs?

No – HIITs work well on the elliptical trainer, stair climber or stationary bike. In Gibala’s study, the subjects used a bike: it’s not only a very time-efficient way of getting in a quality workout, but because cycling is non-weight bearing, it’s the mode of exercise least likely to cause – or exacerbate – injury.

As for whether the improvement in leg speed developed by cycling crosses over to improved leg speed during running, that’s up for debate. But it certainly won’t hurt! 

Three simple high-intensity sessions

On a track
Warm up with five laps at an easy pace - gradually speed up so that you end up running briskly. Then do 200m at maximal sprint effort followed by 400m gentle jog. Repeat six times.

On a treadmill
Set the incline to one per cent. Warm up by running gently, gradually building speed, for 10 minutes. On an effort scale of one to 10, you should be at five to six by the end. Run 30 seconds at close to maximal speed (which is at least 18km/h on the treadmill for most people); jog gently for three minutes. Repeat four to six times.

On a bike
Following a short warm-up, try four to six bouts of maximal sprint efforts, each lasting for 30 seconds, and follow with four minutes of easy spinning recovery. 


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Discuss this article

The article suggests it cannot hurt to gain leg speed from cycling. But from my experience, gaining too much strength in the quad muscles from cycling, although it doesnt effect your leg speed, it can limit your stride length as you have got to lift those heavy quad muscles. Also, I found it can lead to under developed core strength and stability. As you dont use these core muscles on a bike, precisely due to it being a non-weight bearing exercise. A session on the bike here and there may do more benefit than harm, but I would be careful about relying on it too much, as it will lead to over-developed quads and under-developed core muscles. What I have started now to counteract this is to do hill reps, pushing hard up hill is a less structurally demanding running way to do HIIT training, but it has the benefit of developing core muscles as well as leg speed, strength and stride length. Obviously it needs to be brought in gradually, as you will be using different muscles more than you are used to at first. (Another option is to do them on the grass, for less chance of heavy impact injuries)


Posted: 29/05/2013 at 22:40

Train less for better results. HIIT is all well an good if your a sprinter who doesn't know how to train properly. But for roadies its just stupid. Theres a reason elite kenyans do like 15x1000m for example.
Posted: 30/05/2013 at 10:05

I stopped doing HIIT training after about the 4th time getting injured (yes, I'm a slow learner). This is not a risk-free enterprise, as if you're not pushing your body to the max every rep, you're not doing it right, and in 30-second bursts you can push your body dangerously hard. I only got muscular injuries, but Evan Davies had a stroke doing HIIT.


Posted: 31/12/2013 at 12:46

Evan Davies? maybe Andrew Marr, but the stoke being caused by HIIT was hearsay, and he warns people off rowing machines rather than intense exercise! As a road runner steady miles and the occassional threshold and vo2max session is enough to meet my goals and contribute to general fitness.


Posted: 01/01/2014 at 09:35

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