Fast-Twitch vs. Slow-Twitch Muscle Fibers: What’s the Difference and Which One Should You Train?

Hey Angels and Alphas,

The two main types of muscle fibers are slow-twitch muscle fibers (also called Type I fibers) and fast-twitch muscle fibers (also called Type II fibers). Slow-twitch muscle fibers contract slowly but have plenty of endurance, while fast-twitch muscle fibers contract rapidly but have less endurance.

This doesn’t mean that your body can’t use both; they’re just suited to different kinds of activities and training regimens. Find out more about the differences between them and how you can train each type for optimal results.

The Three Main Types of Muscle Fibers

There are three types of muscle fibers, which are slow-twitch, fast-twitch A and fast twitch B. Slow-twitch fibers typically contract slowly but can last a long time while contracting. These muscles allow you to do activities that don’t require a lot of energy, such as walking up stairs or running a marathon.

Fast-twitch A is recruited when you need to generate force quickly but only for short periods of time before fatigue sets in.

Fast-twitch B is used during high intensity exercise where your muscles require more speed, power or strength than the other two types can provide alone so it helps you maintain those higher intensities for longer periods of time before fatigue sets in.

Different Types of Workouts

One type of workout is geared towards training fast-twitch muscles, another is geared towards training slow-twitch muscles, but which one should you train to get the most out of your time in the gym? The answer lies in understanding what each type of muscle fiber does.

Slow-twitch muscle fibers are more efficient at using oxygen to generate force for a sustained period of time (2 to 3 hours). Fast-twitch muscle fibers are used for explosive events that last less than 2 seconds. These muscles have a lower aerobic capacity but can produce greater amounts of force faster than slow-twitch muscles.

The Benefits of Doing Fast-Twitch Exercises

Fast-twitch fibers contract quickly with a lot of force, but they tire out quickly as well. They’re great for short bursts of strength, speed, or power—but not for endurance. That’s why athletes like sprinters train their fast-twitch muscle fibers by doing sprints, intervals on the track, and weightlifting exercises that focus on explosive power (like snatches).

Slow-twitch muscle fibers are usually found in large numbers in places like your legs and lower back because they burn fat to create sustainable energy through aerobic respiration.

They do this through anaerobic glycolysis, which converts glycogen into lactic acid; that lactic acid then generates more heat so you can keep going for longer.

If you want to improve your stamina during cardio activities like running or cycling, it might be time to focus on training slow-twitch muscle fibers rather than just focusing on building more fast-twitch muscles.

The Benefits of Doing Slow-Twitch Exercises

Slow-twitch muscle fibers are designed for endurance, which is why they’re typically used to maintain a steady pace for long periods of time. They’re also effective at conserving energy because they rely on oxygen instead of sugar as fuel, which means they can continue working even when our glycogen stores are depleted.

This makes them perfect for low intensity workouts like walking or light jogging that last more than an hour per session.

These types of exercises also don’t require any equipment, so you can do them anywhere at anytime—no excuses! Plus, slow-twitch muscle fibers are important for improving cardiovascular health by increasing the amount of capillaries in your muscles.

Slow-twitch muscle fibers use aerobic respiration (requires oxygen), whereas fast-twitch muscle fibers use glycolysis (doesn’t require oxygen). The Benefits of Doing Fast-Twitch Exercises: Fast twitch muscles are designed primarily for strength and power.