Running on Elliptical Machine for Cardio Fitness

Running on an elliptical machine is an excellent alternative when you must abstain from high-impact activities like jogging and highly active group fitness classes. The duration of your elliptical session depends on your goal. The length of your workout should closely mimic your normal routine such as the duration of a soccer game, a road race or a jog around the block.
Sprint Intervals
The physiology of sprint intervals is very similar to playing basketball, soccer or simply working in a quick, highly intense aerobic session when you are short on time. This type of training burns a tremendous amount of calories after the workout session as your body returns your heart rate, breathing rate, body temperature, blood circulation and energy production back to resting levels. To do sprint intervals on an elliptical you would alternate between intervals of fast running and slower walking for 20 to 25 minutes. The challenging intervals of your sprint workout must be so hard that you simply cannot exercise for longer than 20 to 25 minutes. Individual sprints should last between 30 and 45 seconds while walks can be two to three minutes.
Fat Burning
At any given moment your body utilizes a mixture of glucose and body fat to fuel your activities including your runs on an elliptical machine. However, it takes about 20 to 30 minutes for your body to use primarily stored body fat as the preferred source of fuel compared to carbohydrates or glucose. You should run on an elliptical for 60 to 90 minutes to enhance your body's fat-burning capacity. Exercising for this duration stimulates adaptations inside your muscle cells to make you a better fat-burning machine. Such adaptations include a greater concentration of cell structures that process body fat, a greater concentration of enzymes that break down body fat and a greater density of capillaries to deliver oxygen and fat molecules.
Leg Endurance
In a normal run on a treadmill or outside, you run only against gravity, wind resistance and the force of your body weight against the ground. The elliptical is an excellent tool you can use to build the muscular endurance of your leg muscles because you can run against a greater level of resistance. The duration of your elliptical run should be slightly greater than your typical outdoor run or a race you might be training for. For instance, if you normally run 30 minutes, your elliptical workout should be 35 to 40 minutes; if your race lasts for one hour, your time on the elliptical should be about 70 to 80 minutes.
Considerations
Running on an elliptical should not be a complete substitute for running outside unless you have injuries that may be exacerbated from a regular run. If you are training for a specific event, your elliptical workout must last as long as that event if you are to perform optimally. However, if you are exercising simply to improve your health and fitness, consider incorporating short, moderate and long-duration elliptical runs. Vary the duration of your elliptical run every week as part of a well-rounded fitness or conditioning program.