1% Grade on Treadmill = Outdoor Running

Mike Prevost · 12-13-2008, 06:53 AM

Some chatter on the board about this. Thought I would post some research. Having run quite a bit on the road and treadmill, this fits with what I have anecdotally found. See study below:

J Sports Sci. 1996 Aug;14(4):321-7.

A 1% treadmill grade most accurately reflects the energetic cost of outdoor
running.

Jones AM, Doust JH.

Chelsea School Research Centre, University of Brighton, Eastbourne, UK.

When running indoors on a treadmill, the lack of air resistance results in a
lower energy cost compared with running outdoors at the same velocity. A slight
incline of the treadmill gradient can be used to increase the energy cost in
compensation. The aim of this study was to determine the treadmill gradient that
most accurately reflects the energy cost of outdoor running. Nine trained male
runners, thoroughly habituated to treadmill running, ran for 6 min at six
different velocities (2.92, 3.33, 3.75, 4.17, 4.58 and 5.0 m s-1) with 6 min
recovery between runs. This routine was repeated six times, five times on a
treadmill set at different grades (0%, 0%, 1%, 2%, 3%) and once outdoors along a
level road. Duplicate collections of expired air were taken during the final 2
min of each run to determine oxygen consumption. The repeatability of the
methodology was confirmed by high correlations (r = 0.99) and non-significant
differences between the duplicate expired air collections and between the
repeated runs at 0% grade. The relationship between oxygen uptake (VO2) and
velocity for each grade was highly linear (r > 0.99). At the two lowest
velocities, VO2 during road running was not significantly different from
treadmill running at 0% or 1% grade, but was significantly less than 2% and 3%
grade. For 3.75 m s-1, the VO2 during road running was significantly different
from treadmill running at 0%, 2% and 3% grades but not from 1% grade. For 4.17
and 4.58 m s-1, the VO2 during road running was not significantly different from
that at 1% or 2% grade but was significantly greater than 0% grade and
significantly less than 3% grade. At 5.0 m s-1, the VO2 for road running fell
between the VO2 value for 1% and 2% grade treadmill running but was not
significantly different from any of the treadmill grade conditions. This study
demonstrates equality of the energetic cost of treadmill and outdoor running
with the use of a 1% treadmill grade over a duration of approximately 5 min and
at velocities between 2.92 and 5.0 m s-1.

Mike ODonnell · 12-13-2008, 08:53 AM

I've heard 3% before....but then again I hate jogging.

Mike Prevost · 12-25-2008, 03:01 PM

Quote:

Originally Posted by Mike ODonnell

I've heard 3% before....but then again I hate jogging.

Not too much difference between 3% and 1% really. Just that 1% more closely matches running outdoors on a flat surface. 3% would not be that far off. Of course, when these studies are done, the % grade on the treadmill is always calibrated. You can't always count on the read out on the machine to be accurate.

Oh...I love running but I hate running on the treadmill, no matter what % grade!

Mike

Patrick Yeung · 12-26-2008, 02:26 PM

Quote:

Originally Posted by Mike Prevost

Not too much difference between 3% and 1% really. Just that 1% more closely matches running outdoors on a flat surface. 3% would not be that far off. Of course, when these studies are done, the % grade on the treadmill is always calibrated. You can't always count on the read out on the machine to be accurate.

Oh...I love running but I hate running on the treadmill, no matter what % grade!

Mike

Im with ya.

I tend to keep it within 1 mile, 1.5 at the most, at an increasing intensity. I dont think you can ever really match outdoor running with a treadmill, no mater the grade.

Treadmills pull your feet back for ya, and they run continuously underneither you. When im slowin down after a sprint, I do a couple bounds as it slows down and it just spins under me without me really doing anything other than jumping. Cant do that outside.

Not to mention, its rather linear in direction.

Ben Fury · 12-29-2008, 08:52 PM

Outdoor running on a not overly improved trail is real running. Running on a treadmill is a boring waste of time. Running on the cement or tarmac bike trail around the park is almost as bad.

Run on the turf at least! Or pick a steep enough grade that you don't even NEED to run up because just walking up it will make you pant!! Hiking a mountain is real world fitness... and it's pretty... and it's relaxing...

Running on a treadmill is boring torture. Get outside and get some Vitamin D and a life!

Craig Loizides · 12-30-2008, 08:31 PM

It depends on the speed and the treadmill. The biggest difference is lack of air resistance on the treadmill. As speed increases, the wind resistance increases. In the study above, slow speeds (about 6-7 MPH) corresponded to a 0-1 degree incline while the faster speeds (about 9- 11 MPH) corresponded to a 1-2 degree incline.

This doesn't mean that you should run on a treadmill at 1 degree incline all the time. The goal isn't to obtain the same energetic cost. Some variety is good.

Walking up a steep incline isn't all that similar to running. Actually, in a lot of ways it's more similar to biking.