Caloric Balance

People new to weight lifting have this wonderful gift; the body is adapting by building muscle and lysing fat. In time, you'll find that that ability will fade.

 

Additionally,
It might be worth noting that you can gain strenght without adding new muscle mass.
Your existing muscles have certainly become stronger, but you have probably not really added much (if any) new muscle mass if your body has been in a caloric defecit.
Your biceps may appear larger because there is less fat over the top of the muscle.

Just a thought

 

Christopher, strength is a function of efficiency. Your muscle is composed of groups of innervated cells called motor units. Each motor unit can either fully contract or not contract at all. It is the combination of motor units that generates force. For example, 8 units contracting together at once will generate more force than 2 units contracting together at once. Your muscles are not 100% efficient and you never contract all motor units at once.

Strength is called a neurological (rather than physiological) response because in general, you can gain strength simply by training your central nervous system to become more efficient at contracting more motor units simultaneously. This allows you to generate more force without more mass.

It is a myth that strength and mass go hand in hand. They do not - they impact each other but not to the greater extent. Some of the strongest power-lifters in the world have smaller muscles than many bodybuilders, and some of the biggest bodybuilders have weak bench press and squats.

It is true that gaining muscle requires a caloric surplus and losing fat requires a caloric deficit. People who just start out have an adaptive response and can gain muscle while losing the fat. After your first several months, however, you are pretty much in that mode.

Most people who lose fat and gain muscle within a given period - for example, bodybuilders preparing for a competition - are doing it in waves, i.e. a few higher calorie days and a few lower calorie days, so they are in a surplus/deficit within smaller units of time. Even people who consume constant nutrition and pull this off tend to manipulate cardio and nutrition so if you look at a "window" of time, they are doing one or the other (surplus or deficit) but it averages to a net effect over time.

Jeremy

 

Mass is simply more muscle fiber, not necessarily the ability to use it. It does create leverage, which improves strength, but no so much as training FOR strength. This is why periodization is so important, i.e. not sticking to a single rep range, because when you add more muscle mass, it is a good decision to train in a way to train that new mass to function.

Jeremy

 

Chris, take a look at the lightweight lifters at the Olympics. You'll see guys and girls putting a lot more weight over their head than some huge bodybuilders will ever think about.