Hypertrophy refers to the growth of the cross sectional area of skeletal muscle.  


It is caused by the muscle adapting to overload, which in this case is an increased weight being lifted.

This post will explain the types of hypertrophy and the process needed to follow to achieve it.

Hypertrophy occurs when the muscle is required to lift more weight than can comfortably be lifted.  This overloading will cause the muscle to become damaged and over time and through training it will rebuild with more strength and size in order to overcome the weight.

 The 2 types of hypertrophy are Myofibrillar and Sarcoplasmic.

Myofibrillar hypertrophy occurs when a weight lifted causes damage and overloading to the muscle causing the body to recruit more muscle fibers and more importantly more Myofibrils.  These are the contractile part of the muscle and contain the active protein Actin and Myosin.  The muscle will increase the density and number of these myofibrils which will in turn increase the strength of the contraction and the size of the muscle belly.

Sarcoplasmic hypertrophy occurs as a result of training or lifting to fatigue.  When a weight is lifted for a number of repetitions that lasts longer than 10 seconds the fuel in the muscle is spent.  This fuel and energy is contained in the sarcoplasm (fluid part) of the muscle and will be increased in volume in order to maintain a contraction for a longer period.  This increase in sarcoplasmic volume will lead to increased muscle belly size and improve time to fatigue because more fuel available.

The easiest way to visualize the difference between the 2 types is to compare a body builder to a powerlifter.  They are both muscular in shape but possess different weight lifting abilities.  A power lifter will require Myofibrillar hypertrophy to complete powerful fast movement of heavy weight.  Their aim is lifting the maximum weight possible.

A body builder will need to lift less heavy weight but for sets to failure in order to increase size of muscle rather than maximal strength.  The aim is to increase size not necessarily strength.  This would require sarcoplasmic hypertrophy.

Always bear in mind that neither form of hypertrophy will be possible without a good nutrition regime and a well-designed training program. 

If you are aiming for powerlifting strength and size plan your training on the following basis:

 ·      Lifting weight that is 85-90% of your 1 Rep max

·      Lifting for 5-8 reps

·      Resting for 60+ seconds per set

 If you are aiming for bodybuilder sized muscles then try this:

 ·      Lifting weight that is 70-75% of your 1 Rep Max

·      Lifting for 10-15 reps- Aiming to fail on the last rep

·      Resting for up to 60 seconds per set

 But what gives you the complete package of strength and size?

 ·      Lifting weight that is 75-85% of your 1 Rep max

·      Lifting for 8-12 reps

·      Resting for 30-60 seconds per set

 This is a very brief overview of what hypertrophy is and how to apply it to training programs.

To conclude, hypertrophy is the process by which the muscle belly increases in size due to increased exertion or weight lifted.  The 2 types differ where sarcoplasmic hypertrophy increases the volume of sarcoplasm to delay onset of fatigue and myofibrillar hypertrophy increases the maximal strength of the muscle.  Both however will increase the size of the muscle belly over time and with effective training and nutrition.