Everything You Need To Know About Running Outside or on a Treadmill

"Both treadmill and outdoor running have their benefits, and the choice between the two largely depends on individual preference and circumstance", David Jou, DPT, said.

"One of the main differences between running on a treadmill versus outside is the running mechanics (also known as form or technique) required for each", Yusuf Jeffers, NASM, CPT, said.

"When it comes to running outdoors, you have to create the necessary force to propel your body forwards, which requires strong and efficient backside mechanics, aka maintaining proper form", he explained. "Efficient backside mechanics also relates to what's happening with the muscles on the back side of your body like your hamstrings, glutes and calves, which help you create power", he added.

On a treadmill, some of this posterior work is done for you, since the belt automatically moves underneath you. One limitation of treadmill running is that, because the power is being generated by you and the treadmill, it may shorten your stride and potentially reduce the range of your front-side mechanics, specifically, how your form looks at the front of your body, and what's happening in relation to ankle dorsiflexion, hip flexion, knee flexion and your pelvis position, which should be neutral.

"Treadmills are a great tool in a running repertoire", Jeffers said. He added that the key benefits of running on a treadmill include that they are often located in a climate-controlled room and they enable you to dictate and access variables that may not be readily available outside—such as controlling speed and adjusting the incline.

In addition, treadmill belts provide a level of cushion that the ground may not, which can help preserve bone and joint health over time. You can also walk on a treadmill as a form of active recovery.

"Running on a treadmill may be easier on your joints because the surface is typically flat and consistent, and the structure of the belt makes it lower-impact relative to running outdoors", Jou said. "More specifically, running on a treadmill is advantageous if you're recovering from injuries, or experience joint dysfunction and pain", he added.

"If you have cardiovascular conditions, balance issues, vertigo or dizziness, or are recovering from an operation or lower-body injury, consult a healthcare professional for guidance on whether running on a treadmill is the best option for you", Jou said.

"Treadmill running is considered a low-impact activity, but individual factors including—but not limited to—poor fitting footwear, pre-existing health conditions, and your running mechanics can influence the likelihood of getting injured", Jou said.

"Runner's knee, shin splints, stress fractures, Achilles tendonitis, plantar fasciitis and muscular imbalances can be exacerbated due to the repetitive nature and decreased variability of the terrain on the treadmill relative to road running", Jou said.

"Additionally, performing running workouts on a treadmill can be helpful for new runners because they're able to customise the incline and speed; control the pace and intensity of the workout which, in part, makes it easier to maintain a consistent speed; or practise interval training", Jou said. Not to mention, training in a controlled environment enables you to devote energy towards your workout as opposed to focusing on unpredictable external factors like the weather. "This, in theory, can result in more successful workouts", Jou added.

However, due to the belt's flat and consistent surface, running on a treadmill may not challenge certain muscle groups as effectively as running outside. Because of how linear and stable running on a treadmill is, you may not be prepared for the differences in the terrain outdoors. Before running outdoors, make note of the texture of the path, inclines and declines, and varying temperatures.

Due to variations of the outdoor terrain and inclines on the road, the ankle and foot stabilisers—including the anterior tibialis (the front part of your shin)—the calf muscles, and the hip abductors and adductors will be used differently than when running on the treadmill.

"While treadmill running can be a good starting point for runners, running outdoors engages a wider range of muscles, particularly in the legs, as you navigate uneven terrain and varying inclines", Jou said.

Additionally, people who exclusively run on the treadmill may have underdeveloped hamstrings, glutes, calves, hip stabilisers, and adductors and abductors (the muscles responsible for moving your legs in and out laterally) due to the homogeneity of running on a treadmill, specifically the flat surface of the belt, according to Jeffers.

"It is important to note that certain factors associated with running on a treadmill, like hip flexor tightness from the repetitive forward motion and weak glutes and a decrease in core activation from the lack of variation and demand of balance and stabilisation, can contribute to or worsen muscular imbalances such as lower cross syndrome", Jou said.

"To make a treadmill-run level of effort comparable to outdoor running demands, consider increasing the incline to 1.0", said Jason Machowsky, CSCS, RD, and exercise physiologist.

"Conversely, running outdoors may help you become a stronger runner, given that you have to create the force between yourself and the ground in order to generate speed and power, versus relying on the treadmill to do this for you", Jeffers said.

"Running outdoors can also offer a greater sense of mental stimulation because you're experiencing varying scenery, nature, people and obstacles", Jou said. In general, exercise has been found to enhance cognitive function. What's more, research has also found that nature improves cognition and mental health. In fact, research has suggested that outdoor exercise has more benefits for the brain than exercising indoors. These benefits include improved attention, memory and inhibitory control—which involves controlling automatic urges like behaviour, thoughts and emotions.

Outdoor running may also set the scene for social interaction. For instance, you may choose to jog with a partner, friends or even a local running group. A 2022 study found that as the number of running partners significantly increases, so does the number of running sessions. And when runners were able to name a key co-runner, they reported that they received more social support to run and had a positive basis for social comparison.

In addition, training outdoors can help to prepare for any races you may have planned. To toe the starting line ultra-prepared, consider simulating the course of an upcoming race. For example, you can train for any long hills or sharp turns, Machowsky said, and depending if the race is close by, you can even train on different parts of the course, albeit safely—leave any road running for race day when streets are closed.

On the flip side, running outdoors can be challenging depending on where you're located. Additionally, learning how to pace yourself outdoors can be harder initially because you can't programme your pace as you would on a treadmill, and the terrain is constantly changing, but once you nail it, your runs will become more efficient. "Running outdoors on hard surfaces like concrete or tarmac can lead to joint and bone injury if you aren't strong enough or prepared for the workload", Jeffers said.

If you're concerned about joint and bone injury, Machowsky suggested running on soft outdoor surfaces such as grass, a turf field, running track or trail.

"You may also want to consider environmental challenges with outdoor running, which include changes in the terrain, wind and temperature, which could all impact your pace, workout intensity and performance overall", Jou said.

To help prevent joint and bone injury, try these two exercises Machowsky recommended.

"Overall, both treadmill running and outdoor running can be effective forms of training, and the best choice for you depends on your goals and personal preferences", Jou said.

If you're unsure, Jou recommended working with a licensed physiotherapist specialising in sports performance, a running coach or a combination of both, to determine what's best for you.

Another path to identify the optimal modality for you? Assess your strengths and weaknesses—working with a run coach or physiotherapist can be especially useful here. Don't forget to focus on your strengths and weaknesses to be a well-rounded runner.

It's also important to consider your short-term and long-term goals. "For example, if you're a beginner training for a 5K and new to learning how to pace yourself, practising shorter intervals on the treadmill could help you learn what it feels like to run at a consistent pace", Jeffers said. If you're more experienced, you may want to work on uphill and downhill repeats outside to improve your power and running efficiency.

Jeffers said he generally recommends implementing both outdoor and treadmill running for most runners, "especially those runners who exclusively choose outdoors or treadmills while avoiding the other". For beginners, he typically recommends running outdoors for speed work and utilising the treadmill to build up your mileage. "There's no one-size-fits-all prescription to this, which is great in and of itself", Jeffers said.

For Machowsky, "getting the work in is kind of the most important thing", and then you can get more nuanced in terms of training location and determine what makes the most sense in terms of your goals, he added.

Finally, Jou recommended utilising what you have access to in order to stay motivated, emphasising that, in general, it's beneficial to incorporate both types of running into your routine to maximise overall fitness and performance.

Words by Tamara Pridgett