The treadmill versus the great outdoors
Experts are as divided as runners on the question of outdoor versus indoor running. Peta Bee examines the evidence
There are two types of runner — those who like treadmills and those who don’t. As someone who falls firmly into the second category, I simply can’t bear the hamster-wheel confinement of a mechanical running belt. Outside, blissfully unaware of how quickly (or slowly) I am moving, I can keep going for anything up to an hour. Put me on a treadmill and I barely manage five minutes. I become fixated on the screen that tells me the distance I have covered and the number of calories I have used. I get bored. Others insist they find the treadmill reassuringly familiar. Nothing ever changes — no wind, no rain, no traffic — so they know exactly what to expect.
But, for producing results, does your running preference really matter? Experts seem as divided in their opinions as runners. Studies have shown that indoor running burns about 5 per cent fewer calories than running outdoors, partly because of the lack of wind resistance and partly because the treadmill’s motorised belt propels you slightly.
Phil Hayes, of Northumbria University, says that fewer calories are also used while running on harder surfaces. “Run on muddy, sandy or grassy ground and your leg muscles need to work harder to push upwards and forwards for each stride,” he says. “There is none of that extra effort on a treadmill.” Studies by Professor Jonathan Doust, of the University of Brighton, show that treadmill users who want the same calorie-burning effects as running outdoors need to set the machine at a permanent 1 per cent incline.
It is not just the energy cost of running that changes with location — the way you run can alter, too. Dr Sharon Dixon, of the University of Exeter, says that treadmill runners often alter their technique without realising it, sometimes moving more slowly or with shorter strides. Some researchers have shown that runners also adopt a more upright posture on indoor equipment, resulting in less energy being available for forward momentum.
“There are distinct differences in style,” Dixon says. “On a treadmill, they hit the ground much more flat-footed, while on the road or grass they land on the heel and roll to the mid-foot, which offers more cushioning from the impact.”
Such adaptations don’t necessarily mean that you are more likely to be injured. In fact, newcomers to running may well experience fewer problems if they start out on a treadmill, which offers more “give” than concrete or a road surface. A 2003 study in the British Journal of Sports Medicine found that pavement running led to a significantly higher rate of bone strain and tension among road runners compared with treadmill runners. That strain can raise the risk of stress fractures by more than 50 per cent, the authors concluded.
Stick solely to the treadmill, though, and over time your susceptibility to injury will rise. “Running outside exposes your body to the unpredictable,” Dixon says. “There are changes in terrain, undulation and direction that force you to use different muscles all the time. On a treadmill you use the same running style all the time, which means that you are loading the same muscles and body parts that could eventually become prone to stress-related injuries, particularly if your style is not that good in the first place.”
Hayes adds that variations in terrain and conditions outside can improve a runner’s proprioception — the ability of the neuromuscular system to make changes to body position and muscle use in response to the different surfaces and challenges encountered. “This is a really important factor, because the more the body is tested unawares, the more it improves balance, power and running efficiency,” he says. “Treadmill running removes that aspect of training.”
It is not all bad news for those who prefer running indoors. A recent study published in the journal Medicine & Science in Sport & Exercise showed that watching their reflection in a gym mirror while running helped novice runners to run more smoothly. “What we see influences how we co-ordinate our limbs,” says Professor Daniel Eaves, of the University of Teesside, who led the study. “If you are just getting into running, gym mirrors may be ideal for developing your style and performing a less demanding run.”
However, as people became fitter, Eaves found that the benefits of monitoring their reflection tailed off. So does all this mean that you are better off abandoning the treadmill if you want to get the most out of your daily run? Dixon says that the ideal scenario for those who like the treadmill would be a combination of running indoors and out, but that running only on the treadmill will still make you fitter than many other forms of exercise.
“There are pros and cons to each and it really does boil down to personal choice,” she says. “A lot of people just don’t feel safe running outside when it’s dark or they feel self-conscious about running in the park or down the street. For them, treadmills are a source of security. It’s better to run indoors all the time than to not run at all.”
The treadmill versus the great outdoors – Times Online5 10 2009