Interval Vs duration cardio-Is it so obvious?

Recently there has been a growth in interval cardio, with statements like “It melts fat”, “Just look at sprinters, compared to distance runners”. These have encouraged many people to move away from traditional cardio & to try out HIIT (High Intensity Interval Training) protocols in the hope of burning fat more quickly & in less time.
First I’d like to say I’m not saying that HIIT style training won’t burn fat, it’s just some of the observations used to reach those conclusions are, when you think about it, obviously faulty.
Let’s start with the usual statement “Just look at sprinters, compared to distance runners”. When you look at runners, yes sprinters look ‘jacked’, while the distance people looked thin, but why is that? First of all think about what you need to be a sprinter, & what you need to be a distance runner.

A sprinter: High power to weight ratio. This means that they need to generate a huge amount of power quickly, while carrying as little weight as possible. This means ectomorphs (the naturally thin) won’t have enough muscle to generate enough power, & endomorphs (naturally fatter) will be carrying too much weight, so the successful sprinter will naturally tend to be a mesomorph (naturally fairly low in fat, but with good muscular development), so we have a naturally strong, low fat looking person tending towards being the most successful in the sport of sprinting.

A Distance runner: Low weight is the priority here. Power is a secondary concern; you need to carry as little as you can, so your energy can be saved. You just need enough muscle to keep a steady pumping of the legs, anything else is wasted muscle & just extra weight to drag around the course. Here the ectomorph has an advantage over both the endomorph & mesomorph. So, naturally they would have a thinner build than a sprinter.

“But,” you’ll say “sprinters upper bodies are great too! All big & pretty well defined”. Yes & why is that? Because they do weights! & as mesomorphs muscle comes easily without too much fat, so in no time they get that ‘jacked’ look. If an ectomorph did exactly the same, would the results be the same? I doubt it, they’d need a different dietary & training routine to achieve a similar look (or as near as they could get).




Don’t believe me, well here’s a couple of pictures of guys doing 100 yard dash from the early 20th century, when they thought weight training would slow them down, these guys still ran what would be considered pretty fast times, but note the lack of upper body development compared to today’s sprint athletes. The added muscle mass of today’s athletes allows greater acceleration & top speeds, so outweighs the added mass they carry.

It may well be that HIIT will work for you as a fat burning tool, infact I do recommend that both interval & duration cardio are worked regularly, so you cover all the bases in your training. But, bear in mind a lot of what is said about HIIT is actually hype & if duration is your preference, then you will get results (as has been shown by gyms all over the world), HIIT is just another tool in your training box, not ‘the answer’ to your fat burning, cardio health goals.