Exercise! - Efficiency varying between machines?

So, when you look at it, the elliptical is basically a treadmill without the impact of running, right? So long as you're using it at about the same speeds, that is.

But I've discovered, after a little trial-and-error, I don't get anywhere NEAR as good a workout on the elliptical as I do on the treadmill. On the treadmill, my heartrate is at the peak of my acceptable zone, and it's really feeling like a workout when I'm done. On the elliptical, however, I barely get past the halfway of my target zone, and it just...feels easier. When I'm done, I'm only sweating a bit, and just feeling slightly warm and out of breath. Whereas I'm really sweaty after basically the same interval workout on the treadmill, and significantly more out of breath. Definitely higher on the exertion scale.

So does anyone know why that is? I'm doing essentially the same workout, only on two different machines and the only difference I can think of is the impact versus no-impact.

The elliptical does a portion of the work for you...on a treadmill, you have to lift your feet and push them forward. On an elliptical, your feet are sort of propelled forward by the elliptical motion.

However, you can make the ellipticals a harder workout than a treadmill, or at least I can, by upping the resistance...provides a whole new level of leg workout over a treadmill.

I hadn't really thought of it like that, Mandalinn. Thanks for pointing that out. You're right about upping the resistance on the elliptical, however, for my purposes that's not ideal. I'm trying really to get a good cardio workout and especially to increase my endurance. I'm on week 1 of C25K right now, actually, hoping to go from "can jog 30 seconds before getting severely out of breath" to "can jog 30 minutes without having to stop". So while the elliptical on a higher resistance setting would work my legs harder, it wouldn't stretch my cardio endurance the way running does.

Anyway, sorry for rambling. Thanks for the explanation!

Nikaia - I get my heartrate up to the top of my max with a significant incline and resistance. If you're working your muscles in addition to the running motion, your heart rate will DEFINITELY get up there, which will improve your cardiovascular conditioning. To mimic the running motion, though, your better bet would be the treadmill, because it'll also condition your joints to take the impact of running.

I use the elliptical as a "cross trainer" on my days off from running. I get a great workout even on Level 1, which is where I live on the elliptical. I challenge myself to speed up for particular intervals and try to reach certain distances by the end of fifteen minutes, a half hour, etc. I generally do an hour on the elliptical and am definitely pooped by the time I finish!

Kara