Is Running On A Treadmill More Difficult Than Running Outside?

I've had patients travelling this past couple of weeks during their kid's school holidays. The only time they could run was on a treadmill in the hotel. A few of them have asked me why they found running on a treadmill more tiring than on the road or track. 

I thought this was strange as running on a treadmill should not be more difficult than running outside and looked it up. 

And true enough, I found an article in which runners were asked to run on a track and then asked to rate how difficult the exercise felt. They then went on a treadmill without a display unit of the speed they were running and told to set the treadmill at the same pace they thought they had just ran. Almost all the runners chose a speed that was much slower. 

Researchers have found that for most people, running biomechanics are similar whether running on a treadmill or outside (Riley et al 2008).

In fact, running on a treadmill is less jarring than running on the ground outside. A 2014 study (Kaplan et al, 2014) showed that we strike the ground with about 200 percent of our body weight while running on an outside track. This was reduced to 175 percent of our body weight when running on a treadmill. 

Evidence suggest that the hard work associated with treadmill running is psychological. Many studies show that people experience less fatigue, more vitality and greater pleasure waling outside compared to walking on a treadmill. 

Personally I feel it is definitely nicer to exercise outdoors. I don't like running on the treadmill too much. I'd much prefer running outdoors any time. I feel like a caged hamster going on and on in a wheel when I'm running on a treadmill. 

Picture from giphy

However, after my accident, I'm very happy just being able to do any exercise. A run is a run, whether outdoors or on a treadmill.

References

Kaplan Y, Barak Y et al (2014). Referent Body Weight Values In Over Ground Walking, Over Ground Jogging, Treadmill Jogging, And Ellipticall Exercise. Gait Posture. 39(1): 558-562. DOI: 10.1016./j.gaitpost.2013.09.004.

Kong PW, Koh TM et al (2012). Unmatched Perception Of Speed When Running Overground And On A Treadmill. Gait Posture. 36(1): 46-48. DOI: 10.1016./j.gaitpost.2012.01.001.

Riley PO, Dicharry J et al (2008). A Kinematics And Kinetic Comparison Of Overground And Treadmill Running. Med Sci Sports Ex. 40(6): 1093-1100. DOI: 10.1249/ MSS.0b013e3181677530.

Thompson CJ, Boddy K (2009). Does Participating In Physical Activity In Outdoor Natural Environments Have A greater Effect On Physical And Mental Wellbeing Than Physical Activity Indoors? A Systematic Review. Environ Sci Technol. $5(5): 1761-1772. DOI: 10.1021/es102947t.