Avoiding injury is important but don't let it determine what you lift. If you want to do heavier weights, then a good 30min cardio and even plyometrics routine before you start lifting is a good way to warm up your muscles, get the blood flowing and minimise risk of injury.
Another way to reduce risk, and this is just as important if not more than warming up, is good form. Actually, you want to go for near perfect form in some of the back involved excersises. This will also help you target the muscles you are trying to specifically work out.
3x10 is a standard lifting routine and you are correct to try to go to failure at the 4th or 5th set if you wish. While I'm not an expert at losing weight while gaining lean mass I know that a complete transformation will come in stages. You might start with weights and cardio and go heavy after an intitial 'gym break-in' but later I'm guessing you'll simply want to maintain mass and enhance definition by doing higher reps and focus more on cardio to meet your goal.
What I can say about going heavy is that it will increase your free testosterone if you don't burn yourself out (don't overdo it) and it will help you therefore to gain that lean mass muc faster and in a natural way.
This is purely on the weight side of things. For cardio, which I don't usually do much of (I'm here more for the nutrition) I would say high intensity interval training? anyone agree? I believe it is recommended to help burn as much fat as possible while keeping lean mass.
You might want to try compound exercises mainly and or main muscles group excercises, because this will develop the biggest muscles and you'll burn more calories doing it. So don't do 3 different sets on calves and then be so sore you can't run or ride for the next 3 days (I've done this :P).
There is a lot of information on the web for this but you are at a reasonable starting point. I would say change up your excerise routine every 2 months as well, otherwise your body will just adapt to the routine and you wont gain as much (lean mass).
Don't forget to eat clean. As well, don't cut your caloric intake too much from what you burn in a day, having too much of a deficit will mean you body starts burning muscle too, set a reasonable loss target and adjust calories for that.
Last edited by rrross; 03-26-2010 at 03:03 AM.