You probably prefer one over the other, but there are pros and cons to each of these.

When you ask an avid runner which they prefer, you can bet they’ll have some strong feelings about one over the other. The debate might be as old as the treadmill itself, and we can understand why. Running can be a daunting task for a lot of people so you would want to make sure you maximize the time you spend sweating.

You’ll want to know answers for:

What’s better for fat loss? 

Which burns more calories?

What’s better for my joints?

You’re not wrong for choosing one modality over the other but they each have their own pros and cons and understanding them can help you make the decision that’s best for you!

Outdoor Running

The people who are fans of outdoor running love to point out that nothing can beat sunshine and fresh air – which is true, you can’t replicate that on the treadmill. There are more pros to outdoor running than just that though!

Outdoor running will get you more muscle activation because your feet actually have to grab the floor to propel you forward whereas some of that work gets done for you on the treadmill as the belt moves underneath you. 

There is also greater muscle activation depending on the type of environment you’re running in too!

If you’re running down a crowded sidewalk you have to dodge traffic side-to-side to keep going forward. Doing that makes use of different parts of your quads, glutes, and hamstrings as well as your adductors and abductors which don’t get used as much on a treadmill. 

When you run on uneven surfaces/trails you also make use of different stabilizing muscles around your hips, knees, and ankles to keep you balanced which also improves your proprioception leading to lower risk of injury over time. 

Running on stiffer surfaces like concrete or asphalt has also been found to improve your bone density. This is because you create more ground forces compared to a treadmill or a softer surface which leads to better reinforcement of your bones. 

Outdoor running has also been shown to improve your gait since you aren’t restricted by the confines of a treadmill; you can more freely extend your stride to its natural length.

Running outside also gives you access to the greatest source of Vitamin D around – THE SUN! With Vitamin D deficiency being a common diagnosis nowadays, running outdoors is a great way to get your Vitamin D and burn calories at the same time.

Treadmill Running

Treadmill running has lots of training benefits as well, although it can never truly replicate training outside you can still find a lot of uses for it.

Treadmills have a lower rate of perceived exertion, meaning that you don’t find the activity of running as difficult as you would outdoors. 

For instance, if you’re outside and running uphill you’ll likely perceive that to be more challenging than if you were running at the same incline and speed on your treadmill. Although the physical exertion – heart rate, vO2, and caloric expenditure would be the same – you’d mentally fatigue sooner running outdoors because you perceive the activity to be more difficult. This can lead you to give up sooner than you would on a treadmill.

With treadmill running, you also don’t have to work against the elements. You don’t have wind/air resistance or weather factors working against you so you don’t get worn out as quickly, which also impacts the perceived effort being placed. 

Treadmills also tend to have softer surfaces than most outdoor environments making it easier on the joints than outdoor running which can be advantageous for people with pre-existing joint injuries or looking to ease into running in general.

Treadmills are also much better at helping you maintain your pace than outdoor running. You have no choice but to run at the speed the belt is going at with a treadmill whereas you can slow down with outdoor running and not realize it for several minutes. This is great for maximizing the time you spend running as well as performance if you’re training for a race or other performance-based activity.

The treadmill also has much more versatility. Most people find them more enjoyable because you can run on a treadmill at any time. You can even multi-task on treadmills by watching your shows, reading, babysitting, waiting for your dinner to finish cooking, just to name a few – which can make it more enjoyable for most people and makes it easy to adhere to a running schedule!

Injury Risk

As with any type of exercise, there will be some injury risk involved with both modes of running. 

When running outdoors you are at risk for knee, ankles,and foot injuries as a result of unpredictability with the terrain and because you’ll be running downhill (which isn’t possible with most treadmills). This adds stress to the knees. Not to mention you are also faced with more hazards – falling, cars, cyclists, dogs, etc – which just add to the unpredictability of outdoor running.

Treadmills are generally considered safer than outdoor running but there are still an alarming 24,000 treadmill-related injuries in the US each year including sprains, falls, and head injuries. You are also more likely to suffer an overuse injury such as muscle strains, spasms, tendonitis (runner’s knee), and sprains because of the lower perceived effort you can push yourself longer without realizing that your body doesn’t want to. 

In any case, you can always reduce your risk of injury by implementing a proper mobility routine before and after your run!

Conclusion

There’s an argument to be made for each case and they can be useful for different goals or applications.

At the end of the day, the most important factor for choosing what’s better for you is what you prefer and what you can stick to doing for the long run (haha I made a pun)!