Muscle Hypertrophy and Hyperplasia - How Muscles Grow?

Muscle Hypertrophy and Hyperplasia or how muscles grow is something that many trainees see as 'go to the gym, lift a little bit (in order not to bulk up too much), have beach body in no time'.

Well, to tell you the truth - building an athletic body takes time and effort. You have to lose fat and build muscle, one at the time, or even at the same time.

For muscles to grow, body needs to be in anabolic state (simplified - surplus of calories and good nutrients in general) and muscles have to be stimulated with proper exercises. If you want to lose fat, you have to be in caloric deficit. So, if you want to gain muscles and lose fat at the same time, you have to balance between two of them - eat around your maintenance level, eat more on training days, especially around workouts and body will (very simplified!) compensate needed calories for muscle growth by burning body fat, up to a point determined by genetics, age, current nutrition etc.

Muscle Hypertrophy is increase in size of muscle cells. Don't confuse it with muscle hyperplasia (formation of new muscle cells). There are two different types of muscle hypertrophy - myofibrillar and sarcoplasmic (pictures are very simplified, just to show two opposite types of muscle hypertrophy).

hypertrophy-myoDuring myofibrillar hypertrophy contractile proteins increase in number and thus increase muscle strength with slight increase in muscle size.
hypertrophy-sarcDuring sarcoplasmic hypertrophy, volume of sarcoplasm increase in muscle cells with no increase in muscle strength.

hypertrophy-myo-sarcSarcoplasmic and myofibrillar hypertrophy occur almost always together as result of exercise - volume of sarcoplasm increase in muscle cells and contractile proteins increase in number.

Which form of hypertrophy (or adaptation to exercise) will be more pronounced depend on many things, mostly on selection of sets and reps during exercises. More exercises with smaller weights and higher reps per sets - sarcoplasmic hypertrophy. More exercises with bigger weights and lower reps per sets - myofibrillar hypertrophy. Good exercise programs combine both to achieve best and biggest gains in both strength and size - unless something specific is requested.

Powerlifting programs give priority to myofibrillar hypertrophy, but stronger muscles means that more volume can be done with more ease. Bodybuilding programs usually give slight advance to sarcoplasmic hypertrophy, but as one lift weights with higher number of reps per sets one also gets stronger. Also types of muscle fibers play role in type of hypertrophy.

Hyperplasia is increase in number of (muscle) cells. It happens under influence of hormones in human body (insulin-like growth factor 1 - IGF-1 and human growth hormone - HGH). Different exercises (gym workouts, cardio) and nutrition promote secretion of these and other hormones (insulin for example in PWM) that help these new cells to mature in size and strength.

Since the abundance of IGF-1 and HGH in childhood, any sport activity in that period makes more permanent impact on human body when compared with sport exercises in adults. That is one of the reasons why approach to children play and exercise must be careful - long story short - don't force your kids, let them play, run, jump, climb, that way they will do more volume with more intensity then you can imagine :o)

For muscles to grow, body needs to be in anabolic state (simplified - surplus of calories and good nutrients in general) and muscles have to be stimulated with proper exercises. If you want to lose fat, you have to be in caloric deficit. So, if you want to gain muscles and lose fat at the same time, you have to balance between two of them - eat around your maintenance level, eat more on training days, especially around workouts and body will (very simplified!) compensate needed calories for muscle growth by burning body fat, up to a point determined by genetics, age, current nutrition et