In the last 30 years, there was a tremendous development in the aerobics, fitness and gym. During the 70s there were only very few hospitals that were equipped with them for the treatments. At that period there were no comparisons between ellipticals and treadmills as treadmills were the only available equipment at that time. Theoretically speaking, both treadmills and ellipticals work with the same principle and hence the same medical result can be obtained from both. But ellipticals offers a safer environment when compared to treadmills. ellipticals are good for treating cardiovascular problems usually associated with old age. So the old aged people will not feel comfortable with something moving under their feet. So the treadmills are suited for bodybuilding workouts.
Now-a-days treadmills are very common in gyms and in households. So the manufacturing of treadmills has increased tremendously in the last decade. On the other hand, ellipticals have not gained much popularity even among the average bodybuilders as they are specialized gear. So when we compare treadmills and ellipticalss, the first point that stands out is the impact of ellipticals on one's health whereas the treadmills offer a much natural running experience. This is the main reason why a professional runner prefers to use treadmills for training rather than the ellipticals.
When treadmills and ellipticals are compared based on medical points, ellipticals has the upper hand as it was recently found that the ellipticals can burn the same amount of calories as with treadmills with much lesser effort. There are many elderly persons suffering from knee problem. They can be treated by the unique design of ellipticals. The other advantage of ellipticals is its reversible pedal. This reversible pedal allows the motion in the opposite direction which acts as a unique exercise which is not possible with the unidirectional treadmills.
Both ellipticals and treadmills have their own advantages and disadvantages. So before buying either, one need to complete analyze the purpose for which he is buying it and choose accordingly.