We are not big fans of treadmills, elliptical machines or steppers. Don't get us wrong, we love that they will help a person get healthier and obtain a modicum of fitness. In the absence of ANY other way to improve health, these will do.
The problem is, the fitness you might obtain on one of these won't transfer.
You can spend hours and hours on one of these machines all winter long. Come Spring, when you want to go out and use some of that fitness (running, hiking, whatever...) you've got NOTHING. Stair steppers, treadmills, and elliptical machines (plus others) do not mimic actual work or play very closely. Forward propulsion, impact from movement and core strength (very REAL functional considerations) are not simulated closely enough on a typical "cardio machine" to build functional fitness. If you spend a lot of time on one of these, when you go out to use that fitness you are simulating, it'll feel like starting over. This can lead to frustration, poor results and even injury.
At GPP we don't relish the thought of doing a lot of wheel spinning. None really. When we exercise, we want to get the most bang for our buck. Where it is possible, combining movements, muscle systems and energy pathways is preferable to doing each separately.
This is not to say we don't find benefit in treadmills, stair steppers, or elliptical machines. We do. We can use them to great effect. It becomes a problem however when one comes to rely on these types of exercise to the exclusion of other, more efficient modalities (running, sprinting, jogging, box jumps).