Is there a difference between running outside and on a treadmill?

ChrisSmith asked sport scientists Dan Gordon whether you get the same benefits from hammering along the pavement as you can from jumping on a treadmill in the gym.

Dan - In the broadest sense, yes. In the broadest sense you will get cardiovascular adaptations and so on and so forth. Actually, if we look at it metabolically, there’s quite a big difference. If you run on a treadmill and you just use a treadmill in the gym and run at the same speed, so let’s say you monitor you speed with a GPS watch outside, the amount of work that's being undertaken by the muscle is quite significantly different because the treadmill is doing quite a bit of the work for you.

What we find is that there’s an increase in what’s called the eccentric phase of the muscle action, that’s the lengthening of the muscle whereas when you’re running outdoors, that phase is reduced. Why is that important? Well, the eccentric phase of the muscle actually uses almost no energy. One of the ways you can combat that is set your treadmill gradient at 1%. A 1% gradient increases the metabolic costs. There was a beautiful study done back in the late 90s where they compared outdoor running to treadmill running and they found the same metabolic cost if it was on a 1% gradient.

However, that only works if you’re running for a short period of time because once you beyond ‘X’ amount time you now start getting to issues of thermoregulation, because when you’re outdoors of course, one of the thing you’ve got is the ability to dissipate heat into the environment. When you're in a gym and you're on a treadmill that heat dissipation is much much  harder because you’re already running in a warmer room and we haven’t got the ability to remove the heat. So the net result is that although you’ll get the grand cardiovascular responses if you run because you’re just running and you’re running at the same relative speed, actually there are significant effects on muscle recruitment patterns between the two and significant differences for thermoregulation, and even potential for things like dehydration between the two.

Chris - Would you advocate then: save your money, just use the free gym called the stairs, park, the road?

Dan - Yeah. I mean I think it’s quite an interesting one. It’s often made me wonder why do people go to the gym to walk on a treadmill? I can understand it to a certain degree because I think there’s obviously a social side to doing it. But actually, I think in the end yeah, it’s free and the overall response is going to be better if you don’t use the treadmill.