Your muscles grow when they recover from heavy stress that you put on them in the gym. Your body 'thinks' that you were fighting for your life and nearly made it. It builds some extra muscle to make your chances better next time. The same story in other words: when you stress your muscle to the limit, it gets micro-injured. When it repairs the damage, having enough time and building material, it overdoes a little, to prevent a micro-injury in the future.

If you want your muscle to grow, you should give it as much stress as possible in the gym, then provide it with everything it needs to recover and grow - time and food.

Do not stress the same muscle every day - it will not have enough time to recover and grow. If you work out regularly the last 6 months or more, you should pump really heavy weights, as heavy as you can take. In this case your muscles will need more time to recover, more than they needed when you started working out. Recovery time depends on your metabolism rate. Most people need 48 hours of "leisure time" for a heavily exercised muscle.

Just started working out? For the first couple of weeks or a month (depending on your shape) take it easy, do not push yourself to the limit, otherwise you can easily injure yourself. If you work out regularly only the last 6 months or less, it is a good idea to do a whole body workout in one day, without splitting your routine. Start your workout with larger muscles, and move to smaller ones. For example: legs-back-chest-arms-calves-abs. Work out 2-3 days a week, but not 2 days in a row.

After the first 6 months, your workouts should be short (about one hour) and very intensive.

Most people achieve their best results in muscle building with 2-4 exercises for the target muscle, 2-4 sets per exercise, 5-8 reps per set. Larger muscles, like legs, require more exercises or sets. In any case, each set should have 4-10 reps. More reps will not help you in muscle building.

There are compound and isolation exercises. Compound exercises allow you to use heavier weights - they are more effective for muscle growth than isolation exercises. Bodybuilders use isolation exercises mostly to achieve better muscle definition, when they already have a lot of mass. To give a good stress to a target muscle, you may start with 3-4 sets of a compound exercise, then do other 2 compound or isolation exercises (2-3 sets each).

Warm up to improve performance and prevent injury! Warm up for 5-15 minutes prior to the actual workout. You should begin to sweat. The whole purpose of your warm up is to increase body temperature by one or two degrees. Let only a few minutes elapse from completion of the warm up until the actual workout. A warm-up will not cause early fatigue or hinder performance. On the contrary, warm-ups will increase your performance. For a good warm-up, try 5-7 minutes of jogging followed by stretches. Start every weight-lifting exercise with one or two warm-up sets. Use a weight that is one-third to two-thirds of the goal weight you will be lifting that day.

Try this pattern.

• First do one warm-up set with a light weight (10-15 reps). Then do 10 reps with your goal weight. Increase the weight and do 8 reps. Increase it again and do 6 reps. Do the last 2 sets to failure - use help of a sparring partner when necessary. This means that you should use such weight that you cannot do one extra rep, even if your life depends on it. Rest 60-120 seconds between sets (30-60 sec for small muscles, more for larger ones), 2-3 minutes between exercises.
• Increase the reps to 12-10-8 when you are comfortable with 10-8-6 reps.
• Increase the load after you did 12-10-8 reps for a few days. Start with your 10 reps set, then do your 8 reps set, then increase the weight and do one more set. For the last set, use such weight that allows you to do only 4-6 reps. Train with these weights until you can do 12-10-8, then increase weights again. Remember, you have to stress your muscles very hard to make them grow. You will not achieve that with light weights. Some experts recommend rotating a strength building routine (4-8 sets of 2-5 reps with extremely heavy weights) and a mass building routine (2-4 sets of 5-10 reps). Follow each routine until you see some progress, it usually takes weeks.

Use the proper form of an exercise, otherwise you will rob the target muscle of the required stress, and can injure yourself. Learn the proper form and stick to it.

Change your exercises. Your muscles get used to the same movements and it becomes harder and harder to push them to the limit. Time to time (say once a month or every 2 months) switch to different exercises for the same muscle group. Use supersets and other advanced techniques to 'surprise' your muscles in order to stress them more than you can with regular exercises. Supersets put a lot of stress on your body, do not do them every workout.

Avoid overtraining. Overtraining is a situation when you stress your muscles more often than they can recover. It doesn't do any good to your muscles. Remember, stressing them is only one half of muscle building, the second half, when muscles actually grow, is recovery. If your muscles don't have enough recovery time or food, but you keep pushing, they will actually lose mass. Overtraining is bad not only for your muscles, but also for your health in general. Some signs of overtraining: feeling chronically tired, having trouble sleeping, being sick all the time with colds and flues or feeling depressed. To avoid overtraining, concentrate on resting, eating and sleeping as hard as on pushing iron :)

Split your routine. If you are doing 2-4 exercises per muscle group, 2-3 sets each - the whole body workout will not fit in one hour. You'll have to split your routine. You can split it into 2 or 3 days. If you split it into 3 days, you'll have to work out more often. Do not exercise the same muscle 2 days in a row. Check the list of all involved muscles in the exercise popup window.

Eat a lot. Eat, rest, and then eat again! Avoid animal fat, sugar and salt. Eat more protein (lean meat and poultry, fish, milk, egg whites) and complex carbohydrates. Your food should have a lot of complex carbohydrates. Eating 100% protein all the time would be a big mistake. Proteins are the building material for your muscles, carbohydrates are the primary source of energy. Complex carbohydrates are pasta, potatoes, grey and whole-wheat bread, corn, bananas, and other food with starch. Simple carbohydrates are sugar and very refined white flour. Simple carbohydrates tend to turn your food into your fat.

For muscle growth, you would need about 1g (some sources say more) of protein for a pound of your weight every day. Calculate how much protein you can eat with natural food, and take the rest with supplements. Eat natural food 3-4 times a day and take supplements in between. Also, take at least one pill of multivitamins and minerals a day. Drink at least 8 glasses of pure water a day, by small portions during the day - it improves your metabolism and helps your muscles to recover.

And the last, but not the least, work out regularly! It is very important. Your muscles are very fast to forget what they've become.