I do 20 rep Squats. With a challenging weight they are as tough as any grappling contest. Although you do need to rest between reps (to get a breather), you hold the bar on your back until all 20 are finished.
Before you pick the bar up pull your shoulder blades back. This should tense your "traps". The bar then rests on your traps instead of being too high, near your neck. With practice the bar can be balanced quite well there, and it avoids getting lumps on you vertebrae (like some body builders get).
Another option is to buy a product called the Manta Ray. It fits over your shoulders to help cushion the bar and keep it in place. Search some Bodybuilding Product Sites for further. Try
www.hardgainer.com site. These people are weight trainers who concentrate on safety and they are very anti steroids.
With regards stationary bikes/treadmills as opposed to the real thing I don't think it matters, as long as you work hard enough to increase your fitness.
Good luck!