Sarcoplasmic hypertrophy is an increase in muscle cell fluid within the sarcoplasm. Imagine grabbing a handful of liquorice vines. Each liquorice vine represents a bundle of muscle fibres. Between the bundles is a fluid-filled space called the sarcoplasm. During sarcoplasmic hypertrophy, the sarcoplasmic fluid volume increases, but the muscle fibre mass does not, essentially creating larger, less dense muscles. No actual muscle growth occurs and no strength is really gained, but the muscle itself appears much larger.
Sarcoplasmic hypertrophy occurs from higher rep schemes (10-15+ reps) associated with bodybuilding, where building muscle size is the main goal.
It is why some people in the gym appear large and muscular but are relatively weak.
For most athletes, training for sarcoplasmic hypertrophy is not beneficial. Only high-impact sport athletes like football and rugby players should add this type of training to their programs—to gain the additional benefit of size to help reduce injuries due to impact.
Myofibrillar hypertrophy is essentially muscle fibre growth. A myofibril is the contractile portion of a muscle fibre. Without myofibrils, our muscles could not move. When myofibrillar hypertrophy takes place, the number of myofibrils in a muscle increases, which in turn increases the muscle fibre density and strength.
Using the example of liquorice vines, if you have 5 vines in your hand, each one representing a myofibril within a muscle fiber, you have five contractile units within that muscle fibre. Now add 3 more pieces of liquorice, or 3 more myofibrils. This represents myofibrillar hypertrophy. The muscle fibre itself has grown by adding more contractile units, making it bigger and stronger.
Myofibrillar hypertrophy occurs from heavier loads and lower rep schemes (3-5 reps).
Because it involves the addition of more contractile units to the muscle cells, myofibrillar hypertrophy is more beneficial than sarcoplasmic hypertrophy. More myofibrils means greater strength and power production.
Sample lower-body training routine designed to prioritize myofibrillar hypertrophy for added power, strength and muscle density with some sarcoplasmic hypertrophy focus to increase overall muscle volume.
- Dynamic Warm-Up
- Power Clean – 4×3
- Squat – 3×5 at 80% max
- Walking Lunges – 3×10 each leg
Written By Ryan Sprague