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Not all muscles are created equal!

Happy Monday, all! (Or whatever day you end up reading this!!!!!!

Last week I wrote about the best way to structure a workout. In case you missed it, click here!

One of the things I mentioned multiple times was the fact that sets, reps, and rest periods are determined by multiple factors. Individual factors set aside - there are 4 primary phases you should rotate between for optimal health, muscle size and strength, and cardiovascular function. Not only does this lead to better aesthetics (meaning you'll look better) and a body that functions better, but it also helps break monotony of working out. And it ensures you gains make more gains!

This pertains to ALL walks of fitness. Some athletes and high-level fitness competitors will spend more time in certain phases than others....but all are important nonetheless.

1. Adaptation.

2. Muscle building.

3. Muscle strengthening.

4. Conversion.

Next week I will explain each phase and how to set up a workout for each!

But first you need to understand the 2 main types of muscles in your body. This will help you better understand why it's important to micro-manage things like sets, repetitions, and rest periods!

Here are the most important things to know about slow twitch, or Type I, muscle fibers:

1. These are the endurance muscles. They have mitochondria which use oxygen to produce ATP (aka energy), so they are classified as aerobic. (So if you've ever wondered "Why is it called aerobic class" - that's why!). Because they produce their own energy they can sustain force for extended periods of time. However, they are unable to generate a significant amount of force.

2. Endurance training can help increase mitochondrial density which improves the efficiency of how the body uses oxygen to produce ATP.

3. These muscles are smaller and less defined.

4. The muscles responsible for maintaining posture are mostly type I.

Here are some tips for training Type I muscles:

1. Isometric contraction exercises (exercises with little to no joint movement) keep the Type I fibers under stress for an extended period of time. A few example exercises include: front plank hold, superman hold, or single-leg balance hold.

2. Resistance training exercises should include lighter weights with slower movements for an extended amount of time (longer than 15 seconds). Think low weight, high reps.

3. Circuit training (which involves moving from one exercise to the next with little to no rest) and body weight exercises with high repetitions are two effective ways of challenging the mitochondrial capacity.

4. Rest intervals should be 30 seconds or less to challenge the body's ability to quickly convert oxygen to energy.

Here are the most important things to know about fast twitch, or Type II, muscle fibers:

1. These are the power muscles. They generate more force than Type I muscles. Type IIa use oxygen to convert glycogen to ATP. (What's glycogen?). Type IIb rely on ATP stored in the muscle cell.

2. They have a high threshold and are only activated for heavy loads which the Type I muscles can't handle.

3. They are much quicker to fatigue, and generally only function at highest capacity for 3-15 seconds.

4. They are the responsible for the size and definition of a muscle (but don't worry, they won't get "bulky" unless trained in a VERY specific manner with the right fuel intake).

5. High strength and power training can increase the number of Type II muscle fibers.

6. The muscles responsible for movement of the body are primarily Type II.

Here are some tips for training Type II muscles:

1. Resistance training with heavy weights stimulates these muscles to grow and recruit more fibers. The heavier the weight, the better.

2. Explosive power-based exercises, whether it is with a barbell, kettlebell, dumbbells, or body weight, is another effective method. (IE jumping lunges, squat jumps, jumping pushups, etc).

3. They fatigue quickly, so focus on lifting as heavy as you possibly can for 2-6 repetitions.

4. Because they use such high amounts of energy they take longer to "recharge", so rest periods between sets should be 90+ seconds (during some workout phases 3-5 minutes is the required rest period).

So basically, Type IIb get you going powerfully, Type IIa keep you moving powerfully for about 15 seconds, and Type I keep you going for anything longer than 15 seconds.

There you have it! Share this with someone who needs to know their body better!

And check back next week for tips on how to best train each muscle fiber type in the adaptation phase!

Have a great week!

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