Most of us have been acquainted with treadmills in one way or another. Motorised treadmills at the time of this writing is still the most accessible treadmill to most people; in gyms ,clinics, hospitals and homes. Motorised treadmills are what we call treadmills where the “treads” that you stand on will move with its own motor and the goal of the equipment is to run/walk on the treadmill to stay on top of its treads, otherwise you will be pushed backwards with the treads. This short post will point out the main differences between motorised treadmill and “real” running.
The invention of the motorised treadmill brings about significant improvement in conveniences, especially in running. This allows people to exercise and run indoors, away from the elements and bad weather. No more excuses because of the external environment. Which is also promotes its inclusion for gyms and clinics due to convenience. It is however still an “artificial” running equipment. It does not replicate running on the ground 100%.
DIRECTION OF FORCE
The basics of running applies in all terrains - if you want to run forward, push the ground backward and the ground will apply an equal and opposite reaction force onto your body: forward. Whether you are in the air or touching the ground does not matter, as long as there is more forward momentum, you will move forward more. Upwards momentum brings you more “air time”, but does not actually bring you forward. Backward momentum will also slow down your forward progress, commonly caused by poor running technique (e.g. hard heel strike).
THE TREAD RUNS
The main difference between a motorised treadmill and “real” running is that the treads run, and with its own motor. What a runner is actually doing on top of a treadmill is to stay on top of it - no matter how. Intuitively, if the tread is “running” backwards at 10 km/h, the runner must be “running” forward at 10km/h right? This can be the case, but not always. In walking this is true because the walker is always in contact with the treads, so the only way to counteract 10 km/h backwards it to walk 10 km/h forwards.
In running, you are not always in contact with the tread, so the runner can counteract the 10km/h backwards of the tread by being “off” the tread -increasing the “air-time” of his running. This is putting upwards momentum into his body by pushing the ground downwards, pushing you upwards in the air, instead of forwards. A way to commonly observe this are people who run “bouncing” up and down significantly. In real life, this upwards motion does not push you forward, but in a motorised treadmill, it counts as your distance, calorie and speed, because the tread - still runs at the same speed.
TREADMILL VS “REAL” RUNNING
Now onto comparisons.
The treadmill is still a very useful tool, convenient for exercise, but it does not replicate real running perfectly. The fact that the tread is running, as mentioned, “rewards” the runner with “distance covered” by upward movement. In real running, upward movement does not bring you forward. If you are running on the treadmill without intention to translate that to running on solid ground, this may or may not be an issue.
However, if running on solid ground is the goal, the treadmill will not directly translate to that. It is artificial and may promote upwards movement, which can come in many forms, such as overstriding, pushing upwards or hard heel-striking. While such running techniques may not be an issue on a motorised treadmill, it will result in a less efficient running economy when running on solid ground. In other words, the motorised treadmill allows for too much freedom or movements that counts towards forward distance that in real running it would not.
To conclude, while treadmill running is convenient as a replacement for running outdoors, it is not a direct one-to-one replacement of running on solid ground. It allows for a lot of movement to be counted as forward movement where real running would not. There are differences which may or may not be significant, depending on your training goals. However, as a runner, coach, athlete, clinician, these factors must be considered when running on treadmill is used as an exercise or assessment - they are different from running on actual solid ground. It does not mean motorised treadmills shouldn’t be used, but if you want to run on solid ground, don’t just train on motorised treadmills.