Thursday, August 22, 2013

Strength and Size Are Not Related (At First)

Contrary to popular belief, muscle size doesn't have as much to do with strength as we might think. For this article, I'd like to clarify how strength is developed and why it's different than just getting "big & bulky". In addition, we'll look at the physiological properties of strength and muscular size and how training programs can address each property individually.

What's Your Goal?

Everyone has different fitness goals. You know what your goal is and you have an ideal for what you want to accomplish. Maybe you want to lose weight and be able to run a 5k. Or perhaps you want to build functional strength after a surgery or injury. Maybe you want to improve your tennis serve or vertical jump. Heck, maybe you want to look like Hugh Jackman (The Wolverine, not Jean Valjean from Les Miserables, c'mon...).

No matter what your fitness goals, you'll get fast and efficient results by weightlifting. 

If the bar ain't bendin' you're just pretendin'
- Hugh Jackman (Twitter)

Unfortunately, many people carry negative connotations about weightlifting. Some people are afraid of building big, bulky muscles. Some people feel that weightlifting "slows you down." Yet the exact opposite is true. With a proper weightlifting program, you can build long, lean muscles and improve coordination, balance, and speed!

Understanding Muscles

Before we go any further, let's take a look at what we're working with. When talking about strength, we're talking about the ability of a muscle to contract. That is, the ability of an individual fiber to get smaller.

The word Muscle comes from the Latin Musculus, literally, "Little Mouse" because of how certain muscles (biceps) looked like little mice. Now, the Romans and Greeks didn't actually think mice lived under the skin, but they were relating the anatomy to something they could understand. When you look at a whole muscle, it kinda looks like a blob of meat. That's because it is. It's a blob of meat.

This muscle is called the "Biceps" because it has two main bodies (heads). The
triceps on the other side of the arm has three heads.
Some muscles have multiple heads, some do not.

You'll notice that what we consider the "main" part of the muscle is in the middle. The purpose of each muscle is to move a joint like a lever. The biceps, for example, exists to move the distal part of the arm. In order to do this, the muscle must have a starting point and a connecting point. To move a lever, the muscle must become shorter and thicker so that the connecting point can be moved to the starting point. It's all leverage!

So if the muscle contracts and gets shorter, it moves a lever, but how does it contract? How does it get shorter? And what controls how much it contracts? The answer is what we commonly call "Muscle Fibers". Also known scientifically as myofibrils, these are the little strands that are clumped together to form the shape of the muscle.

You don't have to worry about the scientific names of the stuff in the muscle, but this illustration shows how a major muscle is broken down into ever so smaller parts. Basically, it's a strand of muscle fibers wrapped together, then grouped together, then wrapped together again. Much like how rope is made. 

See the resemblance?

To actually cause a muscle contraction, the individual fibers (the smallest piece of the muscle), must be told to shorten. The brain sends a signal down the spinal column, which then goes through the nerves in your body and sends a signal to the muscle. This signal triggers the individual fibers to get shorter. The larger the signal, the more fibers contract.

This is the key point of the entire article: The bigger the signal from the brain, the bigger the contraction in the muscles. This means that we can consciously control how much of those muscles fibers to use every time we move. This process is known as motor unit recruitment.

Motor Unit Recruitment

Okay so we know that a signal is sent to the muscle and it contracts. But it gets just a little more complex than that. Remember how I said the stronger the signal, the stronger the contraction? This is because each group of fibers must be stimulated individually in order to contract. In exercise science, we call each group of fibers (connected to a nerve) a motor unit

If we stimulate a small group of fibers, we move a little bit (think brushing your teeth). If we stimulate a large group of fibers, we move a lot (think of starting the lawn mower). We recruit more muscles to do harder jobs. Like a switch we can turn on and off, we can control how much or how little muscle to use.

This is so that we don't brush our teeth with the same force as starting the mower!

I tried to find a funny picture to illustrate, but I'll settle for a cat.

Now, like with any skill, a little practice goes a long way. We control how much force to produce for a given skill. When we do a weightlifting exercise (especially if it's a new movement), we don't quite know how to recruit the motor units properly. The exercise may be a little wobbly, a little uncoordinated, and you might feel weak.

However, with enough repetitions, your brain will send more and more signals to the muscles so that you can contract with more and more force each time. 

This is how you get stronger without getting bigger! You're literally "learning" a new skill.

Unfortunately, he never learned how to recruit his legs.

Weightlifting and Muscular Size

Okay, so you do enough weightlifting repetitions and you can get stronger because you're brain and muscles are learning how to move properly. But doesn't weightlifting make your muscles bigger?

Yes and No.

There are currently two schools of thought for how muscles get bigger.

1) The muscle fibers themselves get thicker (most likely)
2) The muscle grows more fibers (unlikely, less research to support)

Body building takes years of hard, dedicated work. There is a common phrase: "In order to gain one inch of size in your biceps, you must gain 15-20lbs of muscle throughout your entire body." If everyone who lifted a weight suddenly got big, bulky muscles, we would all be bodybuilders. 

In order for muscles to grow bigger they need two things:
1) Stimulus to grow
2) Nutrient resources to grow bigger.

So while weightlifting can make your muscles bigger, you must be providing each muscle with enough stimulus (lots and lots of reps with heavy weight) to grow and you must be eating enough calories to make them grow (lots and lots of protein and carbohydrates).

Short and sweet: If you're dieting (below maintenance calories), you can get stronger, but you won't build muscle.

Now there is one final thing to add. The question is then brought up: "Wouldn't bigger muscles make me stronger?" And it totally makes sense. If you have MORE muscle, then you should be stronger, right?

Yes. That is theoretically the case.

However, strength comes first, then with enough repetitions and stimulus, the muscle can grow to get bigger.

Wrapping It All Up

So the take-home points are as follows:
  • Muscles contract, get shorter, and move a lever
  • A stimulus from the brain tells the muscles to contract
  • The stronger the stimulus, the stronger the contraction
  • We can learn to contract harder with practice
  • The muscles can get stronger (more contraction) without getting bigger
  • Bigger muscles can potentially create stronger contractions

I hope this helps clarify how strength and muscular size are separate, yet related. We can train specifically for strength, and in addition train for size. However, they do not necessarily happen at the same time.

As always, feel free to contact me with questions, or "like" and discuss this article on my facebook page:

All the best,
Jeremy Bushong

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