That's one of the biggest problems I see as a personal trainer in the gym each day.

Many people want to build more muscle, but they do not strive to progress upwards in the amount of weight they lift. If that is the case, continually gaining lean muscle and strength can be prohibited.

I often speak with women who are fearful of lifting more weight because they do not want to build large muscles.

I explain to them that it's almost impossible for women to gain muscle mass like men can because of the lack of the amount of the sex hormone testosterone that creates this growth of muscle.

Since women do not produce enough testosterone, the likelihood of building large muscles is virtually impossible.

Women that you see on TV or in magazines with large, man-like muscles, either use muscle-enhancing substances (steroids) or they naturally produce more testosterone than most women.

It is very difficult for women to build bulky muscles.

You must strive to continuously increase your weights lifted over time. Muscle will only grow if it is forced, or coerced, into growing. You force it by lifting progressively heavier weight.

Muscle growth is simply a result of placing demand on your body. When you lift a weight that is heavier than you are used to, your body will start to add muscle to handle the extra demand (weight) you are placing on it.

As you continually lift heavier weights over a long period of time, your body will continue to adapt to the additional demand being placed on it, by building more muscle.

If you continuously lifted the same amounts of weight over time, the body would become used to that weight and new muscle growth would not need to occur. It has no reason to add more muscle because the muscle you currently have can handle the demand.

When you start lifting more weight, then your body needs new muscle to handle this additional demand, creating new lean muscle tissue to handle this demand.

Any new and additional muscle growth you achieve will have a direct impact on the number of calories you burn. So, for long term success in weight loss and fitness, continue to lift progressively heavier weights as you continue on in your program.

How do you know how much weight to lift?

If you are just starting a lifting program, keep it light and easy and learn proper form. As you progress, start to increase the weights you lift but decrease the amount of times (reps) that you lift the weight.

Something happens when you do this. If you lessen the amount of times you have to lift something, shouldn't the amount of weight you can lift increase?

Suppose if you had to lift 100 pounds 10 times. You manage it and it's not that difficult. Now, say you only have to lift it 6 times.

If you managed to do it 10 times at 100 pounds, shouldn't you be able to increase the weight if you only have to do it 6 times now?

So, as you progress into your weight training workout, begin to lessen the amount of reps and instead increase the weight.

Increase the weight to 150 pounds and lift it 6 times.

The more weight you lift, the more muscle you need to adapt to the additional weight. The more your body needs to adapt to more resistance, the more growth that will occur.

The more lean muscle tissue you have, the more calories burned and the more weight loss...see how weight lifting/resistance training has a direct impact on fat loss and weight management?

Six repetitions are a great number for you to shoot for.

A repetition is one movement. A set of movements is called a set. If you were to do a set of 10 repetitions, you would have to move the weight 10 times.

Start a particular weight lifting exercise (bench press, bicep curls) with a nice, easy set of 10 reps. The next set do eight, and the last two sets, do 6 reps.

Follow this for ALL exercises. When you can do more than six reps for that given weight, you simply add more weight and continue to shoot for six reps.

As you continue up in weight over time, that's proof that you are getting stronger and are adding more lean muscle to your body. This, in turn, is a future investment in burning off more calories.

So to build more muscle, you need to lift more weight.