I found the link to this conversation in January. It really is the only ongoing conversation. You can't get this stuff from Nordictrack. I tried and their 3rd party support people sent me a cycle conversion. They admitted they did not have anything for the elliptical after I called them on it.

I recently got a 990 pro Audio Strider. Real nice system that gives a good workout. My search started because in the gym I use there is LifeFitness systems. Nice commercial item that measures in MPH and Miles (theoretical miles). They do meet at the 18inch stride setting so I thought it would be simple to find a way to figure this out. Key word “thought”.

I started with the basic 1760 strides count and realized pretty soon that this could not be right. I liked your calculation method but it still did not work for me 100%.

I had decided to just not worry about it and focus on effort and time. I guess us analytic types just can't.

So, I have taken some less than 100% accurate measurements to back into the Rotations Per Mile (2X = Strides). I have worked my way up to 40 minutes of solid work on both systems. During a recent LifeFitness session the indication was 3.59 miles total or 5.385 MPH. As I vary the resistance the first mile is faster 5.825 MPH. During the first mile I counted rotations for 2 minutes. I got an RPM of 67.

Basically what I calculated was 690 revolution = 1 mile. I used this to back into finding R and got 14.6 inches. Well the well is not that big. It's pretty much the same as the 990p system.

This 690 RPM doesn't translate directly to the 990p. I hit this many revolutions in much less than 10-11 minutes and I know I am not moving that much faster.

So then throw all that out. Differences in manufacturing styles kind of blow out comparing 2 systems. You can't count on the Pulse count on the systems either.

What I can say for sure is on the gym system my current effort gives me about 3.6 miles on 40 minutes. On the 990p I get about 4500 strides. Both of these get me to the point of needing to wring my shirt out and I need to stop.

If someone wants to get a pedometer (and I might) you need a good one. Consumer Reports likes the Omron Pocket Pedometer HJ-112 best. From reading about it you should get an accurate reading from walking as well as on the elliptical.

In the end we might forget all of this and focus on the cardio aspects. Getting your heart rate to your target (220-age) for 15+ minutes. Of course you will need a good pulse monitor.

Make any sense to you?

The reason that it is so hard to find a definitive answer to the “revolutions per mile” question concerning elliptical machines is because the answer is fairly complex. Most of the geometric calculations I've seen here on your blog are correct as far as they go but are a measure of “machine miles” rather than the actual equivalent miles a person with a normal stride would have run on level ground.

Elliptical machines only approximate a runner's stride – which is why most stride length measurements come up with really large numbers of revolutions per mile (1000+). If you were to adopt a stride on level ground like that of an elliptical you'd be taking really small steps. Movement on an elliptical machine is more akin to running uphill but with the ability to raise or lower gravity – so you can be running up something steep, with short strides, but with low resistance (if you choose).

A much better way to approximate your mileage, as has been suggested by others, is the”work equivalent” mile. The calculations involved in doing this are both laborious and will vary somewhat from person to person. This probably accounts for the difficulty in getting a straight answer from NordicTrack or other manufacturers concerning this issue. The upshot is that for most individuals on machines with a 20″ stride length (or average stride length if adjustable) the work equivalent revolutions per mile is between 700 and 800 revolutions.

I made these measurements on a NordicTrack Audiostrider 990. My body mass is about 92kg (205lbs) and I am 6'3″ tall.

I hope that this helps. This blog is one of the highest rated in a Google search (which is how I found it) so I hope that this helps other runners make sense out of the confusing data supplied by their elliptical machines.

As I've maintained since writing the post (now more than 2 years ago… hey!), I'm comfortable with my analysis & conclusion. Since the mileage travelled on an elliptical will always be theoretical only, there's no strictly right or wrong answer, and there's certainly no agreement on what to measure (ie.. what is rotating?)

I continue to be amused & slightly humbled that this post has emerged as the authoritative reference on this question. I say today, as always: use whatever measurement makes sense to you.

Enjoy.