Weight lifting

It depends. At the 15th rep are your muscles fatigued to the point you can't do any more? If not you may be using a lighter weight than you need. Once you go above half a dozen reps the most important thing is how does the muscle being worked feel. Does it burn? Are you able to push out another rep? Does the muscle ache a little for the next 24-48 hours? If so then you've done the required amount of exercise to stimulate muscle growth (Don't worry, you're not going to turn into Schwarzenegger in drag!), you'll also receive a small boost to your metabolism for several hours after the workout so you'll burn more energy when recuperating and any additional muscle will also cause your base metabolic rate to increase. But yes, lifting the weights will help.

Personally, unless its on legs (which I only increase after I reach 15 reps) I would increase the weight you use on any exercise when you are able to go to 10-12 reps. If you cannot perform 6 reps at the new weight then drop back down a bit. And as you are doing 3 sets I would recommend you do the first set very light just to get blood flowing to that muscle area, the 2nd set at a moderate weight to get your mind/muscle connection going (as you are performing the movement concentrate on the feel of the muscle during the contraction) and then for the 3rd set with the muscles sufficiently warmed up do them as heavy as you can safely perform to the required rep range. Try and do them at a steady even pace on the way up and on the way down and really feel the muscles working. And don't just give up at an arbitrary number. Only give up when you are unable to perform another repetition of the exercise, not because the muscle is burning. And I would recommend either doing your weight training before your cardio or do them at separate times.

I hope that helps you.

It depends. At the 15th rep are your muscles fatigued to the point you can't do any more? If not you may be using a lighter weight than you need. Once you go above half a dozen reps the most important thing is how does the muscle being worked feel. Does it burn? Are you able to push out another rep? Does the muscle ache a little for the next 24-48 hours? If so then you've done the required amount of exercise to stimulate muscle growth (Don't worry, you're not going to turn into Schwarzenegger in drag!), you'll also receive a small boost to your metabolism for several hours after the workout so you'll burn more energy when recuperating and any additional muscle will also cause your base metabolic rate to increase. But yes, lifting the weights will help.

Personally, unless its on legs (which I only increase after I reach 15 reps) I would increase the weight you use on any exercise when you are able to go to 10-12 reps. If you cannot perform 6 reps at the new weight then drop back down a bit. And as you are doing 3 sets I would recommend you do the first set very light just to get blood flowing to that muscle area, the 2nd set at a moderate weight to get your mind/muscle connection going (as you are performing the movement concentrate on the feel of the muscle during the contraction) and then for the 3rd set with the muscles sufficiently warmed up do them as heavy as you can safely perform to the required rep range. Try and do them at a steady even pace on the way up and on the way down and really feel the muscles working. And don't just give up at an arbitrary number. Only give up when you are unable to perform another repetition of the exercise, not because the muscle is burning. And I would recommend either doing your weight training before your cardio or do them at separate times.

I hope that helps you.

Great insight! I haven't began weight lifting yet but since I am 40lbs away from my true goal weight, I think its time. Thank you for this information