I respectfully have to say I think you misread my post. I believe this was my exact statement
"You need to be in as good if not better shape for EMS as the demands are on a regular and consistent basis, not occasional like in the fire service."
Meaning you are going to be exposed to the same high level of stresses on a regular basis (multiple times a day) as opposed to occasionally as in a fire where you work very hard no doubt and alot of stress is placed on that time, but even in busy fire hall's it is not usually multiple times a day every day. Think of it in these terms - EMS is more a repetitive stress job - the injuries you'll likely see are from the same stresses over and over wearing on the body. Biggest complaint in EMS that ends careers besides burnout - back injuries and it's from frequent lifting, turning, etc. That eventually causes significant wear and tear on the body and repetitive injuries much similar to those experienced by those who do factory work, etc. It's still going to happen to some degree, but if properly conditioned, it's going to be significantly reduced prolonging your career. Fire however, is more likely to be a traumatic injury - also due to deconditioned body, but more from the fact your body wasn't adequately prepared initially for the job rather than daily wear and tear. This I suspect is the largest reason that MI's are a huge cause of death within the fire service. If you look at it in that aspect, no one is harder than the other, but the effects it has on the body differ in the injury causes. I have worked both urban and rural fire and ems so I think I can make a fair comparison.
As far as the demands placed on EMS - it really varies where you work. Some rural places deal with a different situation and have to pack people out for long distances (hunters, hikers, etc in wooded areas). Some urban people are frequently packing people down multiple flights of stairs because the building is so old it doesn't have an elevator. Each says their job is hard, make them switch places and they'll respect the other side. It's just a different game whatever area you are and you have to condition your body to the needs of the job you perform and the area you serve. That's the ideal way we prevent injuries, not sitting here debating who's job is harder, better, or more dangerous.