Do you know what fast twitch and slow twitch muscle fibres are?
Stronger, faster, more powerful.
When you’re in the gym, you want to be all those things. But by nature, you’re better at some athletic activities than others. You see this in children too: The children who do better in the mile run aren’t the same ones who crush a sprint where they have to change direction often. (The opposite is often true as well.)
Why? Because of muscle fibres, particularly the concentration of fast-twitch muscle fibres. Your fast-twitch muscle fibres, also known as Type II fibres, are the fibres responsible for explosive movements, things like vertical leaps, 40-yard sprints, and exercises like power cleans and dumbbell snatches.
Your body has a limited number of Type II muscle fibres, and research has shown that that’s somewhat determined by your genetics. With smart training, however, you can, to some extent, alter some of your other muscle fibres to essentially function as fast-twitch muscle fibres.
Looking to beef up your bench press, improve your sprint, or even dominate the cardio row? Then you want to create hone your explosive ability by developing as much fast-twitch muscle response as possible. And I’m going to show you how to do exactly that. Like Liam Neeson in Taken, your muscles were born with a particular set of skills. You can’t change those, but smart training can push your body where you want it.
What’s in a muscle?
A muscle is essentially a bundle of . . . bundles. Let’s start with muscle fibres. A bunch of muscle fibres are bundled into fascicles, which are then bundled together. A bundles of fascicles essentially comes together to form, say, your biceps, or any other larger muscle you can think of.
The best way to think about muscle composition is to think of a ponytail. That’s hundreds of thousands of tiny strands bundled together, but, by and large, all those hairs move together. The job of any one muscle (say, flexing your elbow, which is what your biceps do), is completed by those smaller muscle components working together.
Different Muscle Fibres, Different Purposes
Those smaller muscle components and muscle fibres break down into several different groups, each with different strengths and weaknesses.
We’ve been over these, and they’re the reason you’re reading this story. These are your explosive fibres, and they generally anaerobic power, without using oxygen.
There are two types of fast-twitch fibres: Type IIA and Type IIX. Type IIA fibres are intermediate, and help accommodate more intermediate capacity. They can also replicate some aerobic qualities of slow-twitch muscle fibres, although they still deliver higher power output than your slow-twitch fibres. Type IIX fibres are more powerful, but they’re found more frequently in animals, such as lions, than in humans.
Anything explosive is driven by your fast-twitch fibres. Think of a bench press, where you fire the weight up as quickly as you can (even if it’s moving slowly), or a power clean, where you’re exploding the weight up swiftly, or the explosive first steps of a sprint or speedy first minute on the Airdyne bike.
In general, you can’t change the quantity of Type II fibres, so you can’t hone your explosive ability that way. But stick with me for another few paragraphs, because you can train to become a more “fast-twitch athlete.”
Slow-twitch fibres, also known as Type I fibres, have a high resistance to fatigue, and a high aerobic capacity. Each slow-twitch fibre has more oxidative enzymes than fast-twitch fibres, as well as more mitochondria and more capillaries. That means higher aerobic function, which can power you through miles upon miles of long-distance run or an hour-long spin class. Any endurance event is relying on Type I muscle fibres.
Hybrid muscle fibres
A good percentage of your muscle fibres are hybrid muscle fibres, meaning they sit between Type I fibres and Type II. Muscle fibres can gradually change, based on your activity level. If you’re inactive, these hybrids tend to lie between slow-twitch and Type IIA fast-twitch, or between the two brands of fast-twitch, Type IIA and Type IIX.
If you’re active, however, those fibres become what you need them to be — and this is how you can make your body more explosive. Your body will allow these hybrid fibres to figure their roles. Don’t tap them for certain activities, and the body won’t push them to be anything more than hybrid. Push forward in your training, and you can shift them toward more direct tasks.
Your Fast-Twitch Muscle Training Plan
Research shows that it’s easier to train fibres toward Type II (fast-twitch) than Type I. However, there isn’t much research into the specific training protocols that can push you toward one type of fibre. Trainers are still figuring that out.
Your best bet, very often, is to train as explosively as possible. The trick, however, is that your body can only train explosively so often, so you have to space out that brand of training properly. Think of taking at least two days of rest between explosive workouts geared specifically toward shifting hybrid fibres into Type II territory.
With that said, here would be my personal recommendations for your training schedule Mix in two of these workouts twice a week to add explosion to your body:
Box Jump Plyos Workout
Why? Box jumps are a great way to work on explosive, fast-twitch ability and shift those hybrid fibres into fast-twitch territory. You’re forcing your leg muscles to contract quickly, and then explode upwards, and you can’t do that while using your slow-twitch, aerobic fibres. The best part: Even if you’re not shifting hybrid fibres into fast-twitch territory, you’re working on the coordination of jumping, which will make you better at each leap.
Directions: Stand with your feet shoulder-width apart. Bend at the knees and push your hips back, and throw your arms backward. From that position, explode upwards, driving your feet through the ground and your arms skyward. Land on the box, aiming to land with your feet shoulder-width apart.
Do 4 sets of 6 reps, focusing on the quality of each leap. You want to be as explosive as possible, even if that feels unnatural. Rest 2 minutes in between each set. Quality is better than speeding through (and fast-twitch muscle fibres also need more time to rest).
High-Intensity Steady-State Work
Why? “High-intensity steady-state” training is a term coined by the Institute of Motion, a group that studies human design, function, and performance. It holds a lot of practicality in performance. The ability to sustain a high intensity in your training over a short interval will hit those hybrid fibres solidly.
Directions: Do this barbell complex, completing 10 reps of each exercise without putting the bar down. Do 5 rounds, resting 2 rounds in between each.
Stand with a loaded barbell at your shoulders, feet about shoulder-width apart, core and glutes tight. Bend at the knees and push your butt back, lowering your torso until your thighs are parallel with the ground. Explosively stand back up. That’s 1 rep; do 10.
Barbell Shoulder Press
Stand with a loaded barbell at your shoulders, core and glutes tight, feet shoulder-width apart, hands slightly wider than shoulder-width. Keeping your core and glutes tight, press the barbell overhead, straightening your elbows and shoulders. Pause at the top, then lower with control to the start. That’s 1 rep; do 10.
Lower the barbell to your hips, letting your arms hang naturally, feet shoulder-width apart. Tighten your core. Keeping your spine tall, and keeping the barbell against your shins, push your but backward and hinge forward at the waist, lowering until you feel a stretch in your hamstrings. Stand back up, squeezing your glutes. That’s 1 rep; do 10.
Hinge at your hips and push your but backwards, until your torso is at a 45-degree angle with the ground; let your arms hang naturally. Bend your knees slightly for balance. Squeeze your shoulder blades and pull the barbell up to your ribcage. Pause, then lower to the start. That’s 1 rep; do 10.
Lower the barbell to the ground, near your feet. Set your feet about hip-width apart, and hinge at your hips, gripping the bar at about shoulder-width. Squeeze your shoulder blades and flex your lats. Lower your hips and squeeze your glutes. Keep your chest up and tighten your core. Drive your heels into the ground and pull the weight upward, standing up. Squeeze your glutes at the top. That’s 1 rep; do 10.
Battle Rope Speed Work
Why? Battle ropes are heavy enough to challenge you but light enough that you can always slam them down explosively. That explosive movement guarantees you’ll light up those hybrid fibres.
Directions: Stand with your feet shoulder-width apart in an athletic stance, one end of the rope in each hand. Use an overhand grip, arms in front of your torso, elbows slightly bent. Raise your left arm over your head, then slam the rope down. Repeat the process immediately with your right arm. Alternate slams for 30 seconds, then rest for 90 seconds. That’s 1 round; do 6 rounds.
By David Otey, C.S.C.S.