Myth: Treadmill Running is Equal to Free Range Running
Posted Jan 07 2013 7:08pm
The treadmill is a beautiful piece of cardio machinery but I can't help but feel like some overgrown gerbil when I'm on one. There are many different kinds of designs. The high end gym models cost upwards of 9k. It is the most popular piece of equipment in health clubs for a reason, it burns a lot of calories and produces a great workout. However it is not equal to running outdoors. Biomechanically these are two very different activities. In fact, when comparing similar speeds and grades, some studies show outdoor running burns more calories.
Running on the treadmill is like running place. The belt rolls underneath your feet causing you to run directly down, not forward. It is common for the belt to 'grab' your feet and pull them back as you are running which increases the stress on your knees, back and hips. Whereas free range running is a type of controlled forward falling. Literally all your stabilizing muscles around your joints have to struggle to keep you from face planting. Outdoor ground surfaces are no where near a homogeneous (flat) as a treadmill's smooth belt. Running on uneven surfaces taxes the stabilizing muscles and increases your gross neural demand (metabolic and caloric output). Varied road conditions offer your joints some relief (wear patterns are more diverse- which is a good thing) and optimizes proprioception while strengthening the muscles in your feet, legs and core.
Outdoor running also exposes you to air resistance. Have you ever run into a head wind and felt you were hardly moving (this is a recurring dream of mine!)? How about running with the wind at your back giving you the feeling you could beat Prefontaine? These things don't happen on the treadmill, unless you put your treadmill outside! Having to overcome variable wind and weather conditions increases the neuromuscular and caloric demand of the routine. Moreover, the air quality and oxygen content is usually better when running outdoors, not to mention the copious amounts of healthy vitamin D radiating from the sun.
The treadmill is not without its benefits: absolute control of your pace and incline; consistent environment - no freak hail storms to out run; no traffic or bears to encounter; you can watch TV; large real time data in front of you; and it may be a time saver (you don't have to leave the house) and the most important benefit is you can stop whenever you want and won't be miles from your home (in the rain). A 2008 study comparing running outdoors and treadmill running at the same speed confirmed what earlier studies concluded: Treadmill running typically produces shorter strides with increased frequency. Furthermore earlier studies found an increased period where the foot is in contact with the treadmill belt. Shorter and more frequent strides has been associated with less impact forces. However, since the treadmill belt 'gives' unlike the hard road, the indoor workout has a smaller amount of healthy skeletal impact - which is needed to increase bone density. So you take the good with the bad.
A recommendation of a 1% grade while running on a treadmill will more accurately reflect the energy cost of outdoor running. The treadmill is a great tool to use while at the gym or home but for the serious athlete it should not be a total replacement for free-range running .
1- Riley, P. O., Dicharry, J. A. Y., Franz, J., Croce, U., Wilder, R. P., & Kerrigan, D. C. (2008). A kinematics and kinetic comparison of overground and treadmill running. Medicine & Science in Sports & Exercise, 40 (6), 1093. 2- Schache, A. G., Blanch, P. D., Rath, D. A., Wrigley, T. V., Starr, R., & Bennell, K. L. (2001). A comparison of overground and treadmill running for measuring the three-dimensional kinematics of the lumbo-pelvic-hip complex. Clinical Biomechanics, 16 (8), 667-680. 3- Frishberg, B. A. (1983). An analysis of overground and treadmill sprinting. Medicine & Science in Sports & Exercise, 15 (6), 478. 4-Heiderscheit, B. C.; Chumanov, E. S.; Michalski, M. P.; Wille, C. M.; Ryan, M. B., Effects of Step Rate Manipulation on Joint Mechanics during Running. Medicine & Science in Sports & Exercise 2011, 43 (2), 296-302. 5-Jones, A. M., & Doust, J. H. (1996). A 1% treadmill grade most accurately reflects the energetic cost of outdoor running. Journal of sports sciences, 14 (4), 321-327.