In Greece it's the same. The point is, though, that what is most important is the military training you get. And whether you get that training at 18 or 35, it's pretty much the same. And it's not the running and the push ups, but rather how to use a weapon, how to bandage a wound, how to camouflage, how to wear a chemical suit, etc etc. Sure an 18-year old will have more stamina than a 35-year old when it comes to the running and climbing and push ups, but that matters more when there's a war. And when there's a war everyone from 18-50 will serve, not just the ones in their prime. Doing your military service during peacetime in your prime is just a waste of your prime, especially if you're an elite athlete.