TL;DR: Sarcoplasmic hypertrophy is an increase in sarcoplasmic fluid volume in the muscle cell without an increase in strength. Myofibrillar hypertrophy is the increase in myofibrils, the part of the muscle that contracts.
Hypertrophy refers to the growth or expansion of an organ or tissue owing to an increase in the size of its cells, in this case we're talking about muscle.
There are two types of muscular hypertrophy; sarcoplasmic and myofibrillar hypertrophy. They are two completely different types of muscle growth, caused by different types of training.
In this article, I'll discuss the differences between these two types of muscle hypertrophy, how to train for one of the other, and why you may want to.
Table of Contents:
Sarcoplasmic Hypertrophy
Sarcoplasmic hypertrophy is where the amount of sarcoplasmic fluid in a muscle cell increases without an increase in myofibrils or improvement in muscular strength.
When it comes to bodybuilding and getting as big muscles as possible, bodybuilders prefer to concentrate on this kind of hypertrophy.
Sarcoplasm is the fluid and energy resources that surround your muscles' myofibrils. ATP, glycogen, creatine phosphate, and water are all present in this sarcoplasm fluid.
Sarcoplasmic hypertrophy is defined as an increase in the amount of sarcoplasmic fluid in your muscle cells.
Muscles adapt to survive longer with less of a requirement for maximal strength and speed in shorter durations as a result of sarcoplasmic hypertrophy.
This would increase muscle volume but not muscular fibres, resulting in reduced functional mass and relative strength since less usable bodyweight would be added overall.
Sarcoplasmic hypertrophy occurs when the sarcoplasm develops faster than the myofibrils, resulting in a larger relative space taken up by the sarcoplasm.
The myofibrils might have grown, but the sarcoplasm developed at a quicker rate. Alternatively, the myofibrils may have developed at a slower rate than the sarcoplasm.
How to Train for Sarcoplasmic Hypertrophy
If you just want to train for sarcoplasmic hypertrophy, you should perform high-volume sessions with rest intervals of 60 seconds or less.
Reps should be between 8 and 15, and sets should be around 3-4 minutes long.
When you exercise for sarcoplasmic hypertrophy, you'll probably notice that your muscles recover fast and that your workouts aren't too taxing on your nervous system.
As a result, at least twice a week, you should exercise each muscle group. Consider a push/pull/legs split or an upper/lower split.
Myofibrillar Hypertrophy
Myofibrillar hypertrophy occurs when myofibrils and sarcoplasm develop at the same rate, resulting in the myofibrils and sarcoplasm taking up the same amount of space.
Actin and myosin contractile proteins increase in number and add to the actual strength of a muscle, as well as a small increase in muscle size, when training for myofibrillar hypertrophy.
This is because the body treats micro tears and damage in the muscle fibres as injuries, repairing and strengthening them with more proteins.
How to Train for Myofibrillar Hypertrophy
Strength will be the primary emphasis of your training for myofibrillar hypertrophy. This means your rep ranges will be between 1 and 5, and your rest periods will be around 3-5 minutes.
You will, however, be performing more sets, around 5-10.
The majority of your time will be spent doing multi-joint, compound exercises including overhead presses, bench presses, deadlifts, squats, rows, etc.
Myofibrillar Packing
Myofibril packing occurs when the myofibrils develop faster than the sarcoplasm, resulting in a larger relative space taken up by the myofibrils.
One interesting aspect of myofibrillar packing is that it's possible that myofibrils develop, yet do not increase a muscle fibres cross-sectional area.
Nonetheless, myofibrillar packing may enhance muscle fibre cross-sectional area in two ways.
Myofibrils may develop to the point where they press against the outside wall of a muscle fibre, increasing the cross-sectional area.
The sarcoplasm grows in tandem with the myofibrils, resulting in an increase in the cross-sectional area of muscle fibres.
Although the sarcoplasm increases, myofibril development outpaces sarcoplasm growth in this situation, since this follows the myofibrillar packing criteria.
Essentially, myofibrillar packing is accelerated growth of myofibrils compared with the sarcoplasm of a muscle.
Can You Train for Both at the Same Time?
It is possible to train for both types of hypertrophy at once, instead of focusing on one specific type of hypertrophy, combining the two types of training can enhance both myofibrillar and sarcoplasmic hypertrophy.
This will enhance your overall strength while increasing muscle size and endurance at the same time, giving you the best of both worlds.
Written by Billy White
Billy White is a qualified Kinesiologist and Personal Trainer. He is an aspiring bodybuilder, fitness enthusiast, and health and fitness researcher.
He has multiple years of experience within the fitness, bodybuilding and health space. He is committed to providing the highest-quality information.
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