How To Build Fast Twitch Muscle Fibers

Want to unlock the power of your fast-twitch muscle fibers for better strength and performance?

It all boils down to incorporating explosive movements, heavy power exercises, resistance training, plyometrics, and sprinting into your routine.

But hey, there's more to it than just the basics! Keep reading for a detailed breakdown of each approach and expert advice on creating a balanced workout routine that lets your fast-twitch muscle fibers shine.

Understanding Muscle Fibers

To understand how to maximize the power of fast-twitch muscle fibers, it's important to first grasp the basic knowledge of what muscle fibers are, how they function, and the difference between fast-twitch and slow-twitch muscle fibers.

So, let's dive into the world of muscle fibers and see how our genetics can play a role in our muscle composition.

Difference between fast-twitch and slow-twitch muscle fibers

Our muscles are composed of two main types of fibers: fast-twitch and slow-twitch.

Picture these as the gears in your car: they function differently and are used for different purposes.

Slow-twitch muscle fibers (Type I): These are the marathon runners of your body.

They have high endurance, are resistant to fatigue, and are primarily used for long-lasting activities like running a marathon or doing an hour of yoga.

They aren't as large or powerful as their fast-twitch counterparts, but they can sustain activity for a longer time as they rely on oxygen to generate fuel for muscle contractions.

Fast-twitch muscle fibers (Type II): These are the sprinters of your body.

They are larger, more powerful, and store a ton of carbohydrates for quick energy.

Fast-twitch muscle fibers are great for short, intense bouts of activity where you need to exert a lot of force, like lifting heavy weights or sprinting.

There are two subcategories: Type IIa fibers are more resistant to fatigue than Type IIb, but they still tire more quickly than slow-twitch fibers.

Knowing this distinction can help you train more effectively.

For instance, if you're a sprinter or weightlifter, focusing on exercises that target your fast-twitch fibers can help you build strength and speed.

On the other hand, if you're a distance runner or enjoy endurance activities, working with your slow-twitch fibers can increase your stamina.

The role of genetics in muscle fiber composition

Our genetics have a say in the ratio of fast-twitch to slow-twitch muscle fibers in our bodies.

Some people may naturally have more of one type, predisposing them to be better at either power-based activities (fast-twitch dominant) or endurance-based activities (slow-twitch dominant).

However, don't be discouraged if you find you're not naturally inclined towards the activity you love.

While our genetic makeup provides a baseline, research has shown that with specific, consistent, and well-designed training, we can influence our muscle fibers to some extent.

For instance, some of our muscle fibers, known as intermediate fibers, can take on the characteristics of either slow-twitch or fast-twitch fibers depending on how we train them.

The Power of Fast-Twitch Muscle Fibers

Fast-twitch muscle fibers pack quite the punch.

They're key players in activities that require power and speed, like sprinting or weightlifting.

But what is it about these fibers that make them so powerful?

Let's dive into the nitty-gritty of how fast-twitch muscle fibers contribute to strength and the role carbohydrates play in this process.

Explanation of how fast-twitch muscle fibers contribute to strength and power

Fast-twitch muscle fibers, also known as Type II fibers, are the superheroes of strength and speed.

When you need to generate a lot of force quickly, like when lifting a heavy weight or sprinting to catch a bus, you can thank your fast-twitch fibers for coming to the rescue.

Here's the science behind it: these fibers have a lower concentration of mitochondria and blood vessels compared to slow-twitch fibers, which means they aren't as efficient at using oxygen to generate energy.

Instead, they're geared towards anaerobic metabolism, a process that provides quick bursts of energy but isn't sustainable in the long run.

This is why these fibers are excellent for short, high-intensity efforts but fatigue quickly.

Their size also plays a role. Fast-twitch muscle fibers are larger than slow-twitch fibers, which allows them to generate more force.

They also contract more quickly than slow-twitch fibers, which means they can produce a high level of power in a short amount of time.

This makes them the perfect candidate for activities requiring a lot of strength or speed.

The role of carbohydrates stored in fast-twitch muscle fibers

As we discussed, fast-twitch fibers are designed for quick, powerful actions, and they need a readily available energy source for this. This is where carbohydrates come into play.

Carbohydrates, when consumed, are broken down into glucose.

This glucose is then stored in the muscles and liver as glycogen. Fast-twitch muscle fibers have a higher capacity to store glycogen compared to slow-twitch fibers.

This glycogen is what fast-twitch fibers draw on during those short, intense bursts of activity, providing a quick, albeit limited, energy source.

This storage capacity is one of the reasons why athletes performing high-intensity activities often have diets high in carbohydrates.

Ensuring adequate carbohydrate intake can help to maximize glycogen stores in fast-twitch muscle fibers, allowing these fibers to work at their best during high-intensity activities.

Training Fast-Twitch Muscle Fibers: An Overview

Building fast-twitch muscle fibers isn't about performing a secret set of exercises known only to a handful of fitness gurus.

It's about incorporating specific types of exercises that target these power-packed fibers.

So, let's get straight into understanding the various ways we can train and build our fast-twitch muscle fibers.

First, a fundamental principle to remember is that fast-twitch muscle fibers respond to high intensity, explosive movements that demand a lot of power in a short amount of time.

This means incorporating exercises that make your muscles work hard and fast.

Here are some types of exercises that can help you target and train those fast-twitch fibers:

1. Explosive Movements: Exercises like box jumps, jump squats, and kettlebell swings are great for training fast-twitch muscles. These activities require a rapid, powerful movement that's perfectly suited for fast-twitch fibers. Remember, the key here is the intensity and speed of the movement, not the duration.

2. Heavy Power Exercises: These are exercises that involve lifting heavy weights for fewer repetitions. Examples include power cleans and back squats. The aim is to lift as heavy as you safely can, forcing your fast-twitch fibers to engage to handle the load. Always prioritize form over weight to avoid injury.

3. Resistance Training: This is another effective way to engage your fast-twitch muscle fibers. The trick is to perform the exercises at a faster rate, without sacrificing form, or to include power exercises, like snatches and clean and jerks, in your routine.

4. Plyometrics: Plyometric exercises involve a quick, explosive movement that's ideal for training fast-twitch muscle fibers. Examples include jump squats, box jumps, and lateral jumps. The focus is on executing the jump as powerfully as possible.

5. Sprinting: Finally, sprinting is a great way to engage your fast-twitch muscle fibers. It involves short, intense bursts of running, which is just what fast-twitch fibers are built for. Incorporating sprints into your workouts can help train these fibers effectively.

Remember, while fast-twitch muscle fibers are built for high-intensity activities, it's essential to balance this training with rest to prevent overuse and injury.

Incorporate these exercises into your routine, but always give your muscles time to recover.

Explosive Movements

Explosive movements – those quick, high-intensity activities that get your heart pumping and muscles working – are a fantastic way to train your fast-twitch muscle fibers.

Here, we'll take a closer look at box jumps, jump squats, and kettlebell swings, three classic explosive exercises that can help you supercharge your fast-twitch muscle training.

Box Jumps

Box jumps are a classic plyometric exercise that involves jumping from the floor onto an elevated platform, like a plyo box.

This is an exercise that combines strength, speed, and coordination.

Here's how to perform a box jump:

  1. Stand in front of a sturdy box or platform. Make sure it's a safe height – not too low that it's easy, but not so high that it risks injury.
  2. Drop into a half-squat position, swinging your arms back for momentum.
  3. Explode upward, swinging your arms forward and driving your knees up to assist the jump.
  4. Land softly on the box, absorbing the impact with your legs.
  5. Stand up straight to complete the movement, then step or jump back down and repeat.

This explosive jump followed by a controlled landing is excellent for training fast-twitch fibers, as it requires a lot of force to be generated in a short amount of time.

Jump Squats

Jump squats are another high-intensity exercise that is effective for training fast-twitch muscle fibers.

As the name suggests, it involves performing a squat followed by an explosive jump.

Here's how to do a jump squat:

  1. Stand with your feet shoulder-width apart.
  2. Lower into a squat position, keeping your chest up, back straight, and knees behind your toes.
  3. Push through your heels and explode upwards, jumping as high as you can.
  4. Land softly, absorbing the impact with your legs as you immediately sink back into the squat position.
  5. Repeat the movement.

Like box jumps, the explosive nature of the jump squat demands a lot of power in a short amount of time, making it ideal for training fast-twitch fibers.

Kettlebell Swings

Kettlebell swings are a total-body exercise that requires strength, power, and coordination.

This movement can target your fast-twitch muscle fibers thanks to its explosive nature.

Here's how to perform a kettlebell swing:

  1. Stand with your feet hip-width apart, holding a kettlebell in both hands in front of you.
  2. Hinge at your hips, bending slightly at the knees, and swing the kettlebell back between your legs.
  3. Quickly stand up, explosively driving your hips forward and swinging the kettlebell up to about shoulder height.
  4. Let the kettlebell swing back down between your legs, using the momentum to begin the next swing.
  5. Repeat the movement.

The power for the kettlebell swing should come from your hips, not your arms.

This explosive hip drive recruits your fast-twitch muscle fibers, making it a fantastic exercise for building power and strength.

Heavy Power Exercises

Heaving lifting is no easy feat. It requires strength, precision, and a good amount of grit.

But did you know that it's a highly effective way to train your fast-twitch muscle fibers?

Power cleans and back squats are two powerlifting exercises that can help you achieve this.

Let's delve into the specifics of each exercise and understand how they influence fast-twitch muscle fibers.

Power Cleans

The power clean is a complex, compound movement that requires precision, strength, and power.

It's a classic Olympic weightlifting exercise that involves lifting a barbell from the floor to your shoulders in one swift, clean movement (hence the name).

To perform a power clean, follow these steps:

  1. Stand with your feet hip-width apart and the barbell positioned over the middle of your feet.
  2. Bend at the hips and knees to grasp the bar with an overhand grip. Your hands should be just wider than shoulder-width.
  3. Lower your hips, look straight ahead, and keep your chest up and back flat.
  4. Lift the bar off the floor by powerfully extending your hips and knees.
  5. As the bar rises to your knees, jump upwards while pulling the bar up with your arms.
  6. Quickly drop under the bar, catching it on your front shoulders as you move into a squat position. Your elbows should be pointing forward, with the bar resting on your fingers and front deltoids.
  7. Stand up to complete the movement.

Power cleans are great for training fast-twitch muscle fibers because they require a high level of force to be generated quickly.

This explosive power targets your Type II muscle fibers, helping to build strength and power.

Back Squats

Back squats, a staple in many strength training programs, are another excellent exercise for engaging fast-twitch muscle fibers.

The back squat involves holding a barbell across your back and squatting down before standing up again.

Here's how to perform a back squat:

  1. Stand with your feet shoulder-width apart, toes pointed slightly outward.
  2. Position the barbell across your upper back, holding it with an overhand grip.
  3. Bend your knees and push your hips back to lower into a squat, keeping your chest up and back straight.
  4. Squat down until your thighs are at least parallel with the floor.
  5. Push through your heels to stand back up, extending your hips and knees.
  6. Repeat the movement.

The heavy load in a back squat demands a significant amount of force to be generated in a relatively short amount of time, especially when you're standing up from the bottom position.

This makes it an excellent exercise for training fast-twitch muscle fibers.

Both power cleans and back squats are complex movements that require proper form to be effective and safe.

If you're new to these exercises, consider getting guidance from a fitness professional to ensure you're performing them correctly.

As you incorporate these exercises into your routine, remember that quality trumps quantity every time.

It's better to do fewer reps with excellent form than more reps with poor form.


Jumping right into the world of fast-twitch muscle fibers, we find ourselves encountering plyometrics.

Plyometrics is an exercise methodology that includes jumping and rebounding, aimed to improve power and speed.

By working muscles to their maximum in short intervals, plyometrics predominantly engages fast-twitch muscle fibers.

Let's spring into the nitty-gritty of plyometrics and uncover how it helps in strengthening these powerhouse fibers.

Plyometric exercises work on the principle of the stretch-shortening cycle.

This cycle involves rapidly stretching a muscle (an eccentric contraction) and then immediately shortening it (a concentric contraction).

This process enhances muscle power and helps improve performance in activities that require speed and force, which is the specialty of fast-twitch muscle fibers.

Here are some plyometric exercises that can help engage and strengthen your fast-twitch muscle fibers:

1. Jump Squats: Stand with your feet shoulder-width apart.

Start by doing a regular squat, then engage your core and jump up explosively.

When you land, lower your body back into the squat position to complete one rep.

The power required to propel your body upwards is a fantastic way to target those fast-twitch muscle fibers.

2. Box Jumps: Stand in front of a box or platform.

Swing your arms and hinge your hips back, bending your knees for momentum, then explosively jump onto the box.

Carefully jump back down to start and repeat.

Box jumps require considerable force exertion in a short amount of time, hence they work your fast-twitch muscle fibers.

3. Lateral Jumps: Stand beside a box or an object of a similar height.

Bend your knees slightly and jump sideways over the object, landing softly on the balls of your feet.

Immediately jump back over to the starting position.

Lateral jumps engage the fast-twitch muscle fibers, enhancing their ability to exert force rapidly.

Remember, plyometric exercises demand a high level of effort.

Therefore, they should be performed after a thorough warm-up to prepare your muscles and joints for the high-intensity activity.

Also, these exercises involve a higher risk of injury compared to some other forms of exercise, so always prioritize form and safety over the intensity of the exercise.

Finally, keep in mind that recovery is crucial. Fast-twitch muscle fibers need more time to recover compared to slow-twitch fibers.

Make sure to give your body ample rest in between your plyometric sessions to allow for optimal muscle recovery and growth.


If you're in search of a pure, uncomplicated, and highly effective way to engage your fast-twitch muscle fibers, sprinting could be your answer.

With the wind in your hair and the ground beneath your feet, sprinting is not just exhilarating, but also a great way to tap into the power of your fast-twitch muscle fibers.

Let's lace up those running shoes and explore how sprinting helps build these powerhouse fibers.

Sprinting is a high-intensity exercise that involves running over a short distance in the shortest amount of time.

This activity calls for a rapid burst of speed and power, which is precisely what your fast-twitch muscle fibers are designed for.

When you sprint, you push your body to its limit in a short period, which directly engages these fibers.

Initially, when you start sprinting, your body recruits the Type IIa fast-twitch fibers.

As you continue to sprint and increase your intensity, your body calls upon the larger, more powerful Type IIb fast-twitch fibers.

By targeting these fibers, you're effectively training them to become stronger and more efficient, thereby improving your power and speed.

Here are some ways you can incorporate sprinting into your workout routine:

1. Track Sprints: Find a local track or a long stretch of flat, open space.

After a good warm-up, sprint for 100m, then walk or jog back to the start to recover.

Repeat this 5-10 times, depending on your fitness level.

2. Hill Sprints: If you're up for a challenge, try hill sprints.

Find a moderate to steep hill and sprint up it as fast as you can.

Walk back down for recovery and repeat.

3. Interval Sprints: On a treadmill or a flat outdoor surface, sprint at maximum effort for 30 seconds, then walk or jog for a minute or two to recover.

Repeat this cycle for 10-20 minutes.

Remember, sprinting is a high-impact, high-intensity activity that places a considerable amount of stress on your muscles and joints.

Therefore, it's crucial to ensure you have a proper warm-up before you start sprinting.

Stretching, jogging, and performing mobility exercises can prepare your body for the upcoming intensity.

Just as important is your cool-down phase.

After sprinting, take a few minutes to cool down by walking or jogging slowly, followed by some light stretching.

This helps your body recover and can reduce the risk of injury and muscle soreness.

Also, listen to your body. Sprinting can be demanding, and it's vital not to overdo it.

Start slow, progress gradually, and give your body ample time to rest and recover.

Fast-Twitch Muscle Fiber Training Tips

Now that we've explored the fascinating world of fast-twitch muscle fibers and discovered various ways to train them, let's delve into some practical tips to maximize your training and to do it safely and effectively.

Whether you're a seasoned athlete or just getting started on your fitness journey, these tips can be your guide to successfully build and strengthen your fast-twitch muscle fibers.

1. Warm-Up and Cool-Down: Like any high-intensity workout, training fast-twitch muscle fibers requires a thorough warm-up and cool-down session.

A warm-up helps prepare your body for the exercise ahead and reduces the risk of injury.

It could involve light cardio, mobility exercises, or dynamic stretches.

Similarly, a cool-down helps your body return to its normal state, aids in recovery, and reduces post-workout soreness.

2. Hydration and Nutrition: Fast-twitch muscle fibers store a lot of carbohydrates, and they use these stores for fuel during high-intensity exercises.

Consuming a balanced diet rich in carbohydrates can help fuel your workouts.

Post-workout protein is crucial too, as it aids in muscle recovery and growth.

Staying hydrated is also essential, especially during intense exercises like sprinting or plyometrics.

3. Rest and Recovery: Fast-twitch muscle fibers take a longer time to recover than slow-twitch fibers.

Overworking these fibers can lead to fatigue and hinder your performance.

Therefore, it's important to have rest days in between your high-intensity workout sessions.

4. Incorporate Variety: To target your fast-twitch muscle fibers effectively, incorporate a mix of explosive movements, power exercises, resistance training, plyometrics, and sprinting into your routine.

Varying your workouts also helps prevent overuse injuries and keeps your workouts exciting.

5. Don't Neglect Slow-Twitch Fibers: While you're focusing on your fast-twitch muscle fibers, don't forget about your slow-twitch fibers.

These fibers play a key role in endurance and help you perform for longer durations.

A balanced fitness routine should involve both high-intensity, short-duration exercises for fast-twitch fibers and low-intensity, long-duration exercises for slow-twitch fibers.

6. Professional Guidance: When starting a new exercise routine, especially one that involves high-intensity activities, it's beneficial to seek guidance from a fitness professional.

They can provide proper form, ensure safety, and create a customized workout plan based on your fitness goals.

7. Listen to Your Body: Lastly, it's important to listen to your body. If an exercise doesn't feel right, or if you're experiencing pain or discomfort, take a step back.

It's okay to modify exercises or take extra rest days as needed.


In a nutshell, understanding and training your fast-twitch muscle fibers can give you the edge in power and speed.

By mixing up your workouts with explosive movements, heavy power exercises, resistance training, plyometrics, and sprinting, you'll tap into your body's innate potential.

Remember, balance is key, and the journey will require dedication and smart training.

So, lace up those shoes, fuel up, and get ready to hit those fitness goals.