Gainer type: training by muscle fiber type
Gainer type helps explain why the same program gives one person rapid progress and another barely visible change. Here is a simple way to assess whether your muscle handles a short, heavy set or longer higher-rep work better.
Compiled and summarized by Janar Rückenberg. The core idea is practical: before arguing about sets and reps, it is worth looking at how your muscles actually respond to training load.
Why does gainer type matter at all?
Skeletal muscles contain different types of muscle fibers. Some fibers are better suited to powerful, explosive work, others to prolonged effort. That doesn’t make anyone a good or bad lifter. It simply explains why one person grows well on 4-8 reps while another needs more like 10-15 reps for the same muscle.
In one experiment, the approach was quite simple. 87 men and women first determined their 1-rep max on a Nautilus 10-degree chest machine. After a five-minute rest, they performed reps to failure at 80% of their 1RM.
Most landed between 8 and 13 reps. This can be seen as the average type, with type I and type II fibers fairly mixed. Those who did fewer than 8 reps were more likely to be type II dominant, while those who managed more than 13 reps leaned toward type I, or slow-twitch, fibers. Admittedly, this isn’t a lab test, but it gives a good hint for planning your training.
How to determine your gainer type
The idea behind the test is simple: take one big compound exercise, find the maximum weight you can lift for one correct rep, then see how many reps you can do at 80% of that weight. The tempo should stay controlled and comparable. The translator’s recommendation was 3 seconds on the negative and 2 seconds on the positive, or concentric, phase.
- In each chosen exercise, determine your repetition maximum.
- After resting 4-5 min, perform the maximum number of reps at 80% of your 1RM.
- Compare your result with the table and determine your gainer type.
In English-language bodybuilding and sports literature, the word Gainer is used. A fast gainer builds mass more easily with training, a slow or hard gainer with more difficulty, and an average gainer falls in between. Because these terms sound awkward in Estonian, the original English words are used here.
| Reps performed at 80% of 1RM | Standard deviation from the mean | Endurance level | Gainer type |
| 4 or fewer | -3 | very, very low | Fast Gainer |
| 4-6 | -2 | very low | |
| 6-10 | -1 | low | |
| 10-13 | mean | average | Average Gainer |
| 13-17 | 1 | high | |
| 17-21 | 2 | very high | |
| 21 or more | 3 | very, very high | Slow Gainer |
An important clarification: fiber distribution can differ from one body part to another. If the share of type II fibers in the quadriceps is 85%, in the deltoid it might be only 40%, for example. That’s why you shouldn’t draw big conclusions about your whole body from a single chest test.
Gainer type and exercise selection
The most sensible approach is to test the larger muscle groups separately. Use exercises you can perform with proper technique. If your form breaks down, you end up measuring your ego rather than the muscle’s work capacity.
- Quadriceps – barbell squat
- Pectorals (chest) – bench press
- Latissimus dorsi – wide-grip pull-up or behind-the-neck pulldowns
- Deltoids – seated behind-the-neck press
- Biceps – standing barbell curl
- Triceps – lying triceps extension (skull crusher) or cable pushdown
As you can see, the emphasis is on compound exercises. They give a better picture of how the larger muscles work than small isolation exercises do. Still, keep in mind that no exercise works in complete isolation. If you train chest, shoulders and triceps together, the presses you do for chest already load the shoulders and triceps too.
Gainer type and recovery
Recovery is where this topic becomes genuinely useful. If a muscle needs more days after heavy sets, there is no point stubbornly overtraining it. On the other hand, a muscle with greater endurance may need more work in order to grow.
Slow Gainers should perform 10 or more sets per muscle group with 10-15 reps. Red muscle fibers dominate in Slow Gainers.
| Light day | Medium day | Heavy day | |
| Large muscle groups | 3 days | 4 days | 5 days |
| Thighs | |||
| Lower back | |||
| Medium-sized muscle groups | 2 days | 3 days | 4 days |
| Chest | |||
| Upper back | |||
| Biceps | |||
| Triceps | |||
| Shoulders | |||
| Small muscle groups | 1 day | 2 days | 3 days |
| Abs | |||
| Calves | |||
| Forearms |
Average Gainers should do 5-8 sets per muscle group of 10-12 repetitions. Average-type Gainers have a mix of white and red muscle fibers.
| Light day | Medium day | Heavy day | |
| Large muscle groups | 4 days | 5 days | 6 days |
| Thighs | |||
| Lower back | |||
| Medium-sized muscle groups | 3 days | 4 days | 5 days |
| Chest | |||
| Upper back | |||
| Biceps | |||
| Triceps | |||
| Shoulders | |||
| Small muscle groups | 2 days | 3 days | 4 days |
| Abs | |||
| Calves | |||
| Forearms |
Fast Gainers should do 3-5 sets per muscle group of 4-8 explosive repetitions. In Fast Gainers, white muscle fibers dominate.
| Light day | Medium day | Heavy day | |
| Large muscle groups | 5 days | 6 days | 7 days |
| Thighs | |||
| Lower back | |||
| Medium-sized muscle groups | 4 days | 5 days | 6 days |
| Chest | |||
| Upper back | |||
| Biceps | |||
| Triceps | |||
| Shoulders | |||
| Small muscle groups | 3 days | 4 days | 5 days |
| Abs | |||
| Calves | |||
| Forearms |
The simple truth: the table won’t write your program for you. It gives you a starting point. If a muscle isn’t recovering, cut the sets or take a longer break. If progress stalls and recovery is good, add work cautiously.
FAQ: Gainer type in training
Does my Gainer type determine my entire training?
No. It’s a tool, not a final diagnosis. Look at your repetition results, recovery and technique, and at whether your strength and muscle mass are actually moving.
Do I need to test each muscle separately?
For the larger muscle groups, it makes sense. Fiber distribution can differ, as shown by an example where the share of type II fibers was 85% in the quadriceps but only 40% in the deltoid.
Is the test suitable for a beginner?
A beginner should learn proper technique first. Testing a 1-repetition max requires control and a good feel for the lift. If your technique isn’t solid, get a coach’s help or put the test off.
Translator’s note: I haven’t tried this way of determining fiber composition myself. It looks good in theory, but I can’t say whether it works in practice. If you have experience with it, or feel like giving it a go, let us know your results in the comments!
In my translation I have partly used materials from Dr. Squat’s “Finding the Ideal Split”.
Author: Janar Rückenberg
Come and train! ArtGym
