Treadmill running vs outdoor running is an arguement that, pardon the pun will continue to run and run. It is a discussion that has legs.

People fall into two distinct running and fitness camps; those who love running in the great outdoors and wouldn't dream of running on a treadmill and those who visit the gym and see know reason why treadmill running shouldn't produce the same results as outdoor training.

Well, first things first ... doesn't treadmill running produce the same fitness benefits as outdoor running? The simple answer is no.

Treadmill running burns approximately 5% less calories than outdoor running. So running on a treadmill for 30 minutes is equivilent, in terms of outdoor running as running for 28 and minutes.

Also, the oxygen consumption (the amount of volume used during cardiovascular movement) on a treadmill is significantly less on a treadmill because whilst outdoor running requires the runner to propel themselves forward in each step (unless running downhill), treadmill running (unless on a high hill gradient) only requires the runner to, in effect, run on the spot. Less oxygen consumption means less stress on the heart and lungs, which in turn, means less health benefits when running on a treadmill.

However, is not all bad news for those who prefer treadmill running. A  study on the bone strain and tension during treadmill and outdoor running (British Journal of Sports Medicine, 2003) found that treadmill runners led to a significantly less bone strain and tension among compared with outdoor pavement runners. That strain of pavement running can increase the likelihood of injury by as much as 50%.

A study in Medicine & Science in Sport & Exercise also found that treadmill running in front of a mirror also reduced injury as watching their running style helped treadmill runners improve their running form by finding a smoother way to co-ordinate their limbs.

To conclude, running is one of the best forms of cardiovascular exercise and as such if you prefer to run either outdoors or a treadmill, as long as you stay injury free and challenge yourself periodically, you will gain significant fitness benefits, regardless of whether you jump on the treadmill or pull your trainers on for an outdoor run.