Originally Posted by 25hz

Ellipticals don't smooth out the stroke, in fact, they do the exact opposite. For the same ground speed, when the elliptical approaches the large diameter of the ring, the crank speed slows down. As the ring then passes the large diameter and rotates toward the smallest diameter, the crank speed increases. For the entire pedal rotation, the foot speed is constantly slowing and speeding up. It's noticeable at first, but you quickly get used to it. The more exaggerated the ellipse, the more of the change in pedal speed. Some people have knee problems if the pedal speed change is too much because as the pedalsslow for the high spot, the loading also increases, which can be too much for some knees. The ellipticals are most noticeable for people with bad technique who grind because the acceleration and easing through the dead spot is most noticeable. Ellipticals can help anyone though and the benefits are not diminished with proper pedal technique. While the power output using round rings during a complete pedal rotation would produce something like a sine wave with the actual pedal speed looking like a relatively flat/straight line, using elliptical rings would still produce a power sine wave but the peaks would be longer while the valleys would be shorter. At the same time, it would change the pedal speed line from pretty much flat, to a sine wave also.