There is a long-standing debate in the running world between running outside and running on a treadmill–especially in winter, when conditions may send you into the gym more often than usual. Some runners and triathletes refuse to step foot on the ‘mill, while others appreciate a good indoor session now and again. Each option has its merits, but is there a clear winner in the battle between outdoor and treadmill running, in terms of the benefit to your training?
Pros and cons of running outside
There’s something invigorating about hitting the pavement or trails and feeling the wind on your face. Outdoor running provides a direct connection to your environment. The constantly changing scenery and exposure to natural elements can boost our mood and overall sensory experience. Running outside also introduces irregular terrain and natural inclines and declines, which can provide an extra challenge and potentially improve your fitness.
Rain, snow, ice or extreme heat or cold can sometimes make heading outside unpleasant at best and dangerous at worst.
Pros and cons of running on the treadmill
Running on a treadmill offers a controlled environment that eliminates the unpredictable factors of outdoor running. Treadmills allow you to easily customize your workout, adjusting the speed, incline and duration to specific training goals. This controlled setting is particularly useful for those recovering from injuries or seeking a consistent surface to lessen the impact on your joints.
Perhaps the biggest argument against treadmills is that they can be boring. The absence of natural scenery and lack of fresh air may feel monotonous, making it harder to stay motivated to complete your running sessions.
Are there physical differences between outdoor and treadmill running?
Sports science journalist and author Alex Hutchinson of Toronto says that, for the most part, there are no differences in training effects between outdoor running and the treadmill.
“There have been a whole bunch of studies analyzing how running on a treadmill is different from running outdoors,” he says. “They do pick up some subtle differences in things like the angle of your knee, but overall these biomechanical differences are pretty negligible.”
The biggest difference between is the lack of air resistance on a treadmill, since you’re not moving forward in space. To counteract this, Hutchinson says runners can set the treadmill incline to 0.5 or 1 per cent, to mimic the effort you’d be putting in outdoors.
“Despite the lack of air resistance, a lot of studies find that treadmill running feels harder when you’re running fast,” he says. “This is probably less to do with physiology than psychology: it’s kind of nerve-wracking to be pushing close to your limits on a fast-moving treadmill, where one false step could send you shooting off the back. That might raise your heart rate a little, but should be less of an issue if you do a lot of treadmill running and get comfortable with the feeling.”
So what’s the verdict?
In the end, declaring one option as definitively better than the other would overlook the unique advantages each brings. Outdoor running stimulates the senses, while treadmill running offers control, convenience and consistency. If you’re training for an outdoor race, you should probably do at least some of your training outside, but both types of running are valuable. Variations in training goals, weather conditions, time constraints and personal preferences should dictate the choice between outdoor or treadmill running.