Cardio before lifting weights or after?

I've always heard that you should do cardio before lifting weights to warm up. But, then I hear people that do it after lifting weights what's the difference and why do people do that. I am 24 yrs old, 5,1, and weight 105lbs, I am underweight, but the reason why I do cardio is to warm up and I am trying to get rid of these damn love handles...lol...So what is your suggestion. I am also confused on how much cardio I should do since I am already skinny and I dont want to burn muscle only fat. Thanks in advance for your answer =)
Answer:
after the weights.. cardio always comes after the weights. this way, you have more energy available when weight training, leading to a more effective workout, and secondly, you will have used alot of the stored muscle glycogen during the course of your weight workout, leading to a more effective fat burning effect from your cardio afterwards. you can safely do 30-40 minutes of cardio 3x-4x weekly without burning into muscle mass. cardio sessions that go over 45 minutes begin to sap you of muscle size. hope this helps, good luck

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According to the trainers at my gym, it doesn't matter which you do first.

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Do 5-10 minutes of warm up at a decent pace, then 15-45 minutes at the end when your muscles are depleted to lose fat. It will be hard, but push through it.It has something to do with all of the carbs in your system being burned up during your weight workout, so the cardio you do at the end only has fat to burn.Love handles have more to do with heredity than fat, so you could get even thinner and still have the appearance of love handles.

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Does not matter. Most people seem to like to do cardio first then weight lift because it 'warms up the muscles". This is false as the muscles are warmed up whenever you use them. So you can warm your muscles up perfectly fine by starting your exercise by lifting light weight. I actually prefer to lift first then do cardio. This is my personal preference because I hate cardio and I find if I do it first I tend to be wiped out for lifting, which is what I am really concentrating on.
You also can do cardio to help with those love handles. Don't worry about burning away muscle. Your body uses simple carbohydrates first for fuel, then begins to break down fat. Only after ATP can no longer be adequately provided from fat do you begin to break down proteins, which muscle is made out of. After that you start to break down your nucleic acids...you do not need to worry about that. Also lifting weights will help to burn those love handles because muscle requires much more energy to maintain itself than fat. By increasing muscle mass, you will be increasing your metabolism (specifically your catabolism which is the breaking down process)

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If you're thin, you need to eat good calories and train with weights. You need quality calories from good fats and protein. Tuna, Chicken, Steak, egg whites etc.Stretching or light weight sets prior to a full weight training session is what most body builders do to warm up. Cardio is left for after the workout (if at all). You burn calories during a good weight training workout. You can continue to burn calories after the weights if you want with cardio. In order to build muscle you need to lift weights and feed the muscles with good food (protein). Body builders "bulk" or gain as much muscle as they can. They try to gain as much muscle and as little fat as possible. Then increase the cardio, decrease the amount of calories when they prepare for a show. Cardio can be used to burn excess calories, but is usually used when trying to "cut" or lose weight.Cardio before weight training will make you tired. You will not be able to lift the weight you typically could without the cardio. You need to build up you muscle by lifting to your potential during your training sessions.

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After

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