Types of Hypertrophy (Muscle Growth)

Sooooo, weight training!

When dealing with weight lifting, things are not as clean cut as “lifting weights = getting bigger and stronger”

You have to have a clear understanding of what your goals are ie:

  • Pure Size
  • Strength
  • Endurance

Only once you’ve figured out what you want to achieve with your training can we delve deeper into the basic mechanics of how to train!

When it gets to Muscle Hypertrophy (Increased muscle mass), there are 2 types of muscle hypertrophy.

  1. Myofibrillar Hypertrophy
  2. Sarcoplasmic Hypertrophy

Both types increase muscular size, but are not the same!


Myofibrillar Hypertrophy is when the actual myofibril size and amount increases (Increase in muscle fiber and amount of muscle fiber). This type of muscle is extremely dense and hard! A muscle consisting of mostly myofibrillar hypertrophy feels as hard as rock in a contracted state.  This increases your strength exponentially as the amount of muscle fiber is increased and muscle fiber size is increased.

Myofibrillar hypertrophy usually occurs withing the 6 – 8 rep range (Using a weight that you are only just able to complete 6 – 8 reps per set)

Sarcoplasmic Hypertrophy is when the muscles sarcoplasm ( Fluid within the cell membrane) increases. There is no increase in myofibril (Muscle fiber) size and no new myofibrils created. The only thing that increases is the sarcoplasm (Fluid within the cell) volume per cell.

Sarcoplasmic hypertrophy does increase the overall size and appearance of muscles (Even at a resting state the muscle appears to be much larger and blown up), but there are no strength gains as the muscle fibers have not increased or become bigger! A muscle consisting of mostly sarcoplasmic hypertrophy feels very soft and puffy in a contracted state, as there are no new or larger muscle fibers to recruit and only sarcoplasm. This type of Hypertrophy will mostly occur withing the 9 – 15 rep range per set.

Any rep range above 15 reps per set will start working on your muscles endurance ability and start becoming an Aerobic  exercise rather an Anaerobic. Any rep range between 1 – 5  per set increases your one rep maximum strength as your body adapts to the higher amount of weight used and is able to recruit almost all the muscle fiber available (Neuromuscular Efficiency). There is no size gain or endurance gain within the low rep range though!

The above demonstrates the importance of having a varied rep range to train with. We don’t want to be all SIZE and no power, but we also don’t want to be able to lift a ton once and then have nothing else left in reserve!

The 6 – 8 rep range per set (We’re talking each set to failure) is the ideal rep range to train in most of the time  as you get very good strength increases along with size and endurance gains, but as long as you don’t neglect the higher and lower rep ranges as you will be shortchanging yourself if you don’t get to train in these rep ranges as well.

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