Treadmill training: yes or no for outdoors performance?

What they found

When the results were analyzed, it was found that muscular activity was similar when running overground and on a treadmill across all conditions. However, the muscle activity was most similar for the thigh muscles at a grade of 1% and for the ankle stabilizing muscles at a grade of 2%. Put simply, athletes performing training sessions on treadmills can rest assured that they are using their running muscles in a similar manner as to when running overground as they normally would.

Interestingly, stride time was more variable during overground running as compared to running on a treadmill. This finding is intuitive to anyone that has spent time on a treadmill, as any misstep or adjustment in stride can be quite jarring, discouraging variation in stride parameters. In contrast, when running overground, these variations are handled relatively seamlessly as there is no pressure to conform to a pre-determined belt speed. This has potential implications for training decisions as we’ll explore below.

Getting practical

For most athletes, whether they like it or not, they’ll be spending some time on the treadmill, especially as temperatures get colder. While it’s pretty obvious that running on treadmill is not exactly the same as running overground, it appears that those differences are much smaller than one would expect, at least when it comes to activation of the key muscles involved in running. If you plan to race or compete overground, it makes sense to ensure that you’re training overground with some regularity. However, when that’s not possible or feasible, be assured that training on a treadmill is still bringing your closer to your goals. 

It’s important to note that running on a treadmill wasn’t identical to running overground, and these differences should be considered when performing a large amount of running on the treadmill. The study demonstrated that muscle activation of the thigh muscles was most similar to overground running at a grade of 1%. As such, it makes sense to perform at least some of your treadmill work with a 1% gradient. Likewise, muscle activation of the ankle muscles was most similar to overground running at a grade of 2%. To ensure appropriate muscle activation of these muscles, a portion of the training volume should be performed with a 2% gradient as well.

The researchers also found that variation for stride time was significantly large when running overground, particularly at higher speeds. This makes sense, as the treadmill tends to lock you into a more rigid striding pattern. However, having some variability in the stride is beneficial for both health and performance. If you’re going to perform a significant amount of work on a treadmill, consider changing your running speed with some regularity during the course of a training session. These can and should be small changes, with the idea being to promote greater variability in the striding pattern, which will likely help you avoid loading the exact same tissues in the exact same way, which in turn can help you avoid unnecessary injuries.

When performing the occasional training session on a treadmill however, you shouldn’t sweat these details. But if treadmill running is going to comprise a large part of your training load, these are adjustments well worth making. Rest assured that treadmill training is a productive component of any training program, and with some carefully applied adjustments, it can be even more productive.

References

1. Med Sci Sports Exerc. 2022 Oct 14. doi: 10.1249/MSS.0000000000003055. Online ahead of print.