Running indoors or outdoors has long been a debate in the running community and it’s often met with very varying opinions.

Some say pavements will damage your knees, while others will say that the treadmill won’t give you the training you need. So which is better?

We’ve got the lowdown on why both are important when training for a race.

Indoors

1) It’s technically easier

Simply by its design, a treadmill assists with leg turnover as you initiate each stride. Coupled with a lack of wind resistance, this means that treadmill running is, theoretically, easier. Research also suggests that setting the treadmill to a 1% grade accurately reflects the energy costs and simulates outdoor running.

2) There’s less impact on your knees and feet

One of the major benefits of treadmills is that the force is absorbed from your foot with every bounce of the belt, so runners exert a smaller push-off force than they would outside on a trail or pavement, lessening the impact on joints.

3) It’s more convenient

For those prepping for a competitive endurance run, the treadmill is a great way to perfect your fluid and carbohydrate intake before race day. A tempo or long run on the treadmill allows you to practice eating and drinking without slowing down to see how your body reacts to different hydration products and intervals.

4) Consistency

When running outside, you have to be mindful of other pedestrians on your path and stop at crossings, gates or other obstacles – and you’ll automatically vary your pace or slow down over time. A treadmill, on the other hand, will only slow down or stop if you make the change. Running at a consistent, unwavering pace can help maintain training while improving your stamina over set distances and time.

Outdoors

1) A better test of balance, mobility and flexibility

Outdoors, the ground is rarely flat, and the terrain varies and is often uneven. Changing surfaces from pavement to road, grass, muddy path, or hillside is more likely to improve your balance and spatial awareness when running. Being able to cope with sudden changes in the surface is also incredibly important to competitive events where you may be jostled in a race or tightly packed alongside other competitors and have to adjust for footing and stride.

2) Actual races

Running outside is a real-life example of what your actual race will be like. Running outdoors can therefore prepare you for races and long-distance running in ways that a treadmill just can’t. Whether it’s managing frosty air in the dead of winter or pushing yourself the extra mile with the help of the pack and pacemakers, you don’t want to get to the start line of any running event not having run a good distance outdoors.

3) Accuracy

Running outside will give you better accuracy on how you’ll perform come race day. You may very well do well in a specific time on the treadmill, but technically, everything on the treadmill is your ideal condition for a run – the perfect pace, the right gym temperature, the ideal elevation and no one close to you to jostle you. Race day conditions will never be perfect and there may be factors that will affect your run that you wouldn’t take into account on a treadmill. Having a few outdoor runs before your race will give you a more accurate idea of how you’ll do and how you’ll react and adjust accordingly should something like a tree root, wind on the day or a higher elevation than you’re used to coming up.