Free tool

Are you more fast-twitch or slow-twitch?

Find out your muscle fiber type with a simple gym test. Discover whether you respond better to heavy sets or high reps.

Exercise

How are you determining your 1RM?

I know my 1RM

Estimate my 1RM

Your 1RM (kg)

Weight (kg)

Reps

Enter the weight you're lifting and the maximum number of reps you can hit. We'll estimate your 1RM using the Epley formula.

Reps completed at 50% of your 1RM

Run this test in the gym: load 50% of your 1RM and do as many reps as possible to failure.

Fast-twitch (type II) Slow-twitch (type I)

1RM (estimated)

50% weight

Reps

Training advice

This is a field test, not a lab result. It gives you an indication you can use to optimise your training.

Want a training schedule built around your muscle fiber type?

Message Steev

How does the test work?

Your muscle fiber type determines how your muscles respond to training. Fast-twitch fibers (type II) are strong and explosive but fatigue quickly. Slow-twitch fibers (type I) produce less force but have a lot of endurance.

This test compares your maximum strength (1RM) with your endurance at 50% of that load. Can you hit a lot of reps at 50%? You probably have more slow-twitch fibers. Not many reps? Your fast-twitch fibers are likely dominant.

The ratio varies by muscle group and is partly genetic. But regardless of your type -- the right training makes the difference.

Are you more fast-twitch or slow-twitch?

Training advice

How does the test work?

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