Have fitness questions? Fitz has your answer. Our ThatsFit.com fitness expert -- and now your own virtual personal trainer -- will help you get fit, increase your overall health and do it in a fun way. Drop your questions here in the Comments section below and we'll choose two per week to publish on That's Fit! Learn more about Fitz here.

Q. Dear Fitz, I know that most people are trying to lose weight, but I am trying to gain. Gain muscle, that is. I am going to the gym three to four times per week. I'm using the weight machines there, but It doesn't seem like I am gaining any muscle. Could you give me some advice? What types of healthy food should I eat? Should I be doing more reps with less weight or fewer reps with more weight? Any help would be appreciated. Thanks, Lea Rettig

A. Hey Lea, your question is superb, and the answer thank goodness is quite simple. Strength training should be challenging. Funny enough, my clients always seemed shocked and follow up that feeling of shock by giving me dirty looks when I pass them the dumbbell I'd like them to lift. Along with that dirty look, I receive chronic cries of, "Fitz! That's heavy!" Well, yes. Yes it is. The purpose of strength training is to get stronger, and yes ... build muscle. If I were to give them weights they could already lift comfortably ... they wouldn't be getting any stronger!

Lifting weight that does not make you grunt may help you build a certain amount of endurance, but that's not what you are trying to accomplish. Lea, find a weight that feels heavy to do for each of your exercises. Not dangerously heavy. But, choose a weight that you could not lift more than 10 times if your life depended on it. The first few reps might not seem so bad, the middle few should make you wince, and the last few should make you grunt, groan and wince. Challenge yourself! I recommend training with a weight you can do no more than three sets of eight or 10 with. Once you've trained a particular muscle group, make sure you allow it at least 48 hours to rest, repair and rebuild as well.

As far as nutrition goes, protein of course is key in building muscle. A recent study I found in the Journal of the International Society of Sports Nutrition states that "protein intakes of 1.4 – 2.0 g/kg/day for physically active individuals is not only safe, but may improve the training adaptations to exercise training." Spread your protein consumption throughout the day. You needn't obsess over it though. More important, strive for a balanced diet full of fruit, vegetables, lean protein, lean dairy, healthy fats and plenty of water. Lean meat, eggs, nuts, and beans are great sources of protein.

Lea, creating a strong athletic physique takes work. I happen to love lifting weights, and think it's a lot of fun too. Having said that ... I do not have overly large 'mannish' muscles. They're just strong and lean. Strength training not only helps make you strong, it creates curves, burns fat more efficiently, promotes healthy bone density and simply makes you a more resilient person. Now go get yourself a pair of weight lifting gloves and prepare to grunt, groan and sweat. Choose weights that are actually heavy to you and you'll get where you want to go in no time.

Punches & Kicks,