Is it best to do cardio before or after weights? Why? I have been doing 45 minutes on the tredmill at 2.9mph and a 3-5% grade and then doing weights and seem to be at a stall on my weight loss I need help! Any suggestions on what machines to do to add in loss?

There have been several threads on this topic both here and in the Exercise thread, and the consensus seems to be that you should do the weights first, then cardio. That being said, you also need to warm up before doing weights, and I find that about 5 minutes on the treadmill or elliptical is perfect to just warm my muscles. THen you can do your weights without being tired from cardio. When you're tired, it's harder to keep your form and to lift as much as you can. You might want to do a little less cardio after weights, esp if you do a lot of leg work. Good work though.

As to a stall in your weight loss, if you're doing that much cardio (you didn't say how many times a week), you might look at your eating. Maybe you're eating too much, or maybe too little for the amount of exercise.

Really good point Pat about being too tired to have good form after cardio. I never thought of it that way, i just new i preferred to do weights first cause i was too tired after cardio, but good point.

About the stall, if you have been doing the same thing for a while it might be time to mix it up a bit. Your muscles get used to the same ol' routine. If you are limited to a treadmil i would try running/walking combo or just lay off it completely for a couple of months and pick up tennis, just something to get your muscles woke up. When my muscles get tired of my elliptical i do tae bo or badminton. it works like a charm to get you out of that platueau.

Personally, I believe it's good to alternate the days you lift and the days you do cardio. Or, I might do cardio in the morning and weightlifting when I come home in the afternoon.

I usually do cardio first. however weight training done correctly is excellent cardio, at least too me. If your weight is stalled checked your caloric intake and the type of foods you eat and then increase the intensity of the exercise a little. I wish you well.

I agree on the alternating days if you can, especially if you are doing 45 minutes of cardio after weights. I tried to do both on the same days to save time (and not have to go to the gym EVERY day), but on days I did both I ended up starving and ravenous, and usually ended up eating a couple hundred more calories on those days anyway. Killing myself for nothing. When I started alternating (upon the suggestion of all the ladies here ) I noticed a big difference.

As far as the stall on your weight loss, how long has it been? And are you still hitting your target heart rate while on the treadmill? For me over the last couple of weeks, I've had to change my speed and incline to get to the same heart rate, because my body has gotten used to the exercise. Does the machine you use have a "random" or "hill" setting? Try changing it up a little, or use a different machine like an ellyptical or exercise bike just to break up your routine. I was also disappointed in my scale, but I did go down a clothing size recently without losing any weight-so check your measurements, too, before you get too discouraged. The old "muscle weighs more than fat" saying really is true, and a trainer at my gym told me that some people actually gain or don't lose any weight for a while when starting a program that includes weight training, but you should lose inches, which in my opinion are just as wonderful.
As far as what machines to use to speed up your loss, I don't know what you are already using-but my gym has circuit training set up, to work all muscle groups. The more muscle you build/tone, the higher your metabolism will be. I don't think any particular muscle work will make you lose more or less weight, the thing is to aim for all over improvement.

You might want to increase the intensity of the cardio. I'm finding that even though I'm doing a lot of cardio (or maybe because of), I can increase the speed and incline without having a huge impact on my heart rate (I'm still in the zone but probably sweating more and having more impact on my muscles). I've been raising my cardio almost every workout.