Sarcoplasmic Hypertrophy vs. Myofibrillar Hypertrophy: What’s the Difference?

When people talk about “building muscle,” they often think it’s one single process. In reality, there are two distinct types of hypertrophy—sarcoplasmic and myofibrillar. Both increase muscle size, but they do so in different ways.

Sarcoplasmic Hypertrophy

• What it is: An increase in the volume of sarcoplasmic fluid inside the muscle cell.
• Effect: Muscles look bigger and fuller, but without a significant increase in strength.
• How to train for it: Higher reps (8–15+), moderate weight, shorter rest periods. Common in bodybuilding programs.

Myofibrillar Hypertrophy

• What it is: An increase in the number and density of myofibrils—the contractile fibers of muscle.
• Effect: Strength and power gains, with more compact size compared to sarcoplasmic growth.
• How to train for it: Lower reps (3–6), heavier weight, longer rest periods. Common in strength and powerlifting programs.

Which Is Better?

Neither is “better” — they serve different goals.

• Bodybuilders aim for sarcoplasmic hypertrophy to maximize muscle size and appearance.
• Powerlifters/athletes lean on myofibrillar hypertrophy to maximize strength and performance.
• A balanced program can give you some of both.

Takeaway

If you want size: train with volume.

If you want strength: train with heavy weight.

For overall growth: combine both approaches.