PART I: Treadmill vs Outdoor Running

Do you get bored running indoors on a treadmill?  I do.  When I gave up outdoor running during winter I started to get really bored during the months of January, February, and March.  My solution…I found a way to add variety and fun into treadmill workouts by including speed intervals, incline running, distance running, and moderate intervals.  I usually rotate through a schedule of different types of runs that allows me to set goals, stay motivated, and achieve new personal bests in different categories.

I’m sure some of you are dedicated outdoor runners, but even if you do minimal running on a treadmill, it’s helpful to know the differences between outdoor and treadmill running.  One main difference is in caloric expenditure.  Typically caloric expenditure is lower on a treadmill than with outdoor running.  While the treadmill allows you to maintain constant speed, there is no wind resistance when running on the treadmill, reducing overall energy expenditure by about 7%.  Research suggests that an incline of 1% will compensate for lack of wind resistance as it relates to energy expenditure.

Another difference when using a treadmill instead of outdoor running is the moving belt.  The belt pulls your foot backwards as it lands compared to push forward off of a solid surface when running outdoors.  I haven’t come across recent research on this subject but in my opinion the moving belt also reduces total caloric expenditure by a certain amount as well.

When it comes to the moving belt, something to keep in mind is the impact of a constant speed moving belt on muscles when running at high speeds.  The belt does not slow down even when muscles are fatiguing.  As muscles fatigue the neuromuscular system will not be able to fire the muscles in the same sequence at the same rate but the belt will continue to pull your foot back at the same pace.  This can increase risk of muscle pulls, especially when the runner is extremely fatigued.

Summary of Benefits to Running on the Treadmill:

  • Speed is constant and controlled
  • Shock absorbing deck reduces impact on joints
  • No unexpected terrain to navigate
  • Can’t skip your run due to bad weather  😉

As you can tell, there are benefits and drawbacks to both treadmill and outdoor running.  The key is to choose which type of running works best for you, motivates you to stay consistent, and keeps you safe from injuries.  Once you have that in mind you can build a program that includes variety and challenge no matter if it’s indoors or outdoors.  Next week I plan to review the difference in workload for incline treadmill workouts and I’ll also share a simple incline workout with you so you can try it on your own.  If you have any questions, be sure to email me at!