question: why am i doing strength training if i can't build muscle operating in a calorie deficit?

I have always heard that you should incorporate some strength training into your workout, and not only do cardio.  This is to help maintian bone density and build lean muscle mass in order to boost resting metabolism.

I have ben reading the forums a bunch in the last week and I have seen several people write that you can't build muscle mass when you are eating a calorie deficit to lose weight.  Thus my question, why am I doing strength training if i can't build muscle mass?

To maintain the muscle mass you have.

My question too! I seem to be toning up all the same, but I've also read that that shouldn't be possible. Very strange...

just because you can't gain muscle doesn't mean you cant lose it, you weight train in order to prevent the muscle you've already built from deteriorating. as said by jewelsmcblah.

okay, that is helpful.  why am i getting sore if i am not building muscle?

i assume the additional definition i am seeing is losing fat from on top of the existing muscle?

you still work the muscle but there isn't any additional "supplies" in the form of nutrients from food to build extra muscle, so instead of the tears being strengthened and enlarged, the muscle simply tears and repairs itself with minimal growth if any at all. so you are sore because you are effectively tearing the muscle, as anyone who exercises does, but you are not building new muscle because there isn't enough food there to build with.

I don't see why you can't both lose fat and gain muscle.  I know I did (although I am no longer physically able to exercise) just by going to my cardio pulmonary rehab.  I got stronger and trimmer, and lighter too, so I assume I gained muscle and lost fat.  I just ate what the CC tools told me to eat, based on my activity level, and I did well.

Maybe this list of topics, from Ask Mary, will help you.

I especially liked this one:

I have been doing cardio everyday for a hour, and I was wondering if I added weights how quickly would I gain muscle? I was told by my school dietitian that with a low calorie diet you can't gain muscle, is that true?

You need to eat enough calories to spare protein for building muscle. Otherwise, you’ll burn the protein you eat to meet your calorie needs.  Weight-training is a good idea, but people build muscle at differing rates depending on their body type. In three months of training, a slender person might gain one pound of muscle, while a naturally muscular person could gain 4 times as much.  After you lift weights, eat some carbohydrate and protein to replenish the muscle glucose and build new muscle. It is also important to lift weights every other day because muscles grow during your day of rest.  Two to three days a week of lifting is all you need.

Another thing to keep in mind is that people who are new to strength training may be able to initially build some muscle even with a calorie deficit. However, no one is going to get Arnold huge without a serious calorie surplus!