burning fat

I think running is better because there is not much strain on the back.Also, running conditions your cardiac muscles so you can stay young and healthy.

I think your best bet would be to alternate resistance training with cardio training. Your body uses fat for fuel/energy. If you are eating enough to give you the energy to exercise, and not over eating, you will lose bodyfat by doing both. If I had to pick one, I would choose resistance (weight) training. The more muscle you have, the more calories & fat your body uses. Both would be the best choice.

It depends on your body. Everyone is different. honestly, a huge percentage of your results will come from your diet. Personally, resistance training works best for me. I do a lot of core training and a moderate amount of cardio. I used to do lots of cardio, but I have found that it doesnt work for my body as well as resistance training. Both are important. The more muscle (or lean mass) you have, the more calories you burn. Your body uses fat for fuel. If you use more calories than you take in and you exercise, you will lose fat.

Running 1 hour is enough. Even fast/brisk-walking for 1 hour is enough. Any repetitive activity done more than 30 minutes can burn fat. On the 30th minute your aerobic/oxygen centers open up. Oxygen burns your fat. So I suggest doing it for more than 30 minutes so that on the first 30 minutes you get to open the oxygen centers and on the 2nd half you are burning the fat.