A frequent question I get asked is whether I like treadmill running, and if I think they are good/bad for running. My honest answer, it depends!
Have I run on a treadmill? Yes, loads of times! Have I run outside? Absolutely, and many more times than a treadmill.
So, why the answer, “it depends”?
Firstly, running on a treadmill is not quite the same, mechanically, as running outside. When you run outside, you push off the ground to move, whereas on a treadmill you are primarily moving your legs to keep up with the treadmill belt. Whilst running on a treadmill does have you pushing off the “ground” a little, the extent of this is far less than when running outside and pushing off the actual ground.
That said, there are huge benefits to treadmill running, and I mainly think these are environment based. Here in Dubai, we struggle with two key environmental factors. These being the lack of hill training and the summer heat. Unless you are willing to head to the mountains for your hill reps, it’s hard to feasibly manage them into your weekly training schedule due to the city being so flat. And whilst the summer heat has its benefits in training, we see runners have a drop in pace and increase in heart rate when the temperature increases outside. Having the treadmill as an option is a great way to control the environment and maintain some speed work once the temperatures soar.
What you might have noticed on the treadmill, is that long runs seem longer, and speed sessions seem slower/harder. Why? It’s thought that this is mainly psychological. The 2012 study by Kong et al explored the unmatched perception of speed running on a treadmill versus outside and found that paces slowed considerably when the experiment was put in place to test runners in 3-minute intervals outside and inside. It can be thought the same psychological impact occurs with the duration on a treadmill, as there is no end/finish line; meaning that treadmill runners often suffer from more mental exhaustion than outside runners.
Treadmills certainly have their place and are useful in a runner's portfolio of training options,. They also provide an excellent way to help with analysis of gait and form. But the boredom of running on a treadmill is real. Use them wisely!
Kong, Pui W et al. “Unmatched perception of speed when running overground and on a treadmill.” Gait & posture vol. 36,1 (2012): 46-8. doi:10.1016/j.gaitpost.2012.01.001