Exercise Science for Fit Pros: Understanding Muscle Anatomy

Head spin a little bit when thinking about anatomy? Well here is Anatomy 101 made simple!

I’ll be the first to admit, when I was sitting in a huge lecture hall years ago trying to memorize all the different bones in the skull (there are 22 by the way), I hated anatomy. I had trouble remembering all the different bones. Muscle origins and insertions were completely incomprehensible to me. And the concept of the 3 planes of the body was just too much for me to wrap my head around.

To say I couldn’t grasp anatomy was an understatement. However, I knew the importance and pushed through it. Over the years I have taught myself a lot of the concepts and now have a pretty good understanding of how anatomy relates to use fit pros.

I promise you, if I can now totally grasp and get anatomy, you can too! It really isn’t as hard as my insane teacher and horrid lab partner made it out to be.

Anatomy IS Fun!

No really, it is! Since getting my first, and only, C in that god-awful anatomy class, I’ve come to realize that learning anatomy really isn’t that difficult. Nope, it is actually kind of fun. If you approach it from the perspective of movement and make it practical to what we do on a daily basis (and lord knows I’m not going around and observing bull testicles)!

So if you are like me and freak(ed) at the thought of learning anatomy, and all of the muscles stress you out, let me try to break it down in a way that makes sense (at least in my head) and allows it to be practical for your every day teaching.

Without further ado, here is Anatomy 101 (minus a dead kitty and lots of other not so fun things that you won’t need to teach a class)…

Chapter 1: Bones

We’ve got bones in our body. 206 to be exact…

Yup, and they are all really important! The skull has lots of them, the feet and hands have lots of them. Every where else has a few that assist in helping support our body. Without bones we would just fall over and be a big sack of potatoes (that doesn’t sound fun).

There are different types of bones in the body, some having greater importance than others. One of the most important type of bones in your body is your vertebrae. Your vertebrae create your spine and allow the body to stand up right, twist, turn, hinge, and do most movements in life. We want to keep these bones, and the 5 different sections of the spine happy and healthy.

To learn the different sections of the spine, simply think of your spine as Breakfast-Lunch-Dinner (before you think I’m crazy, hear me out).

  • Cervical Spine (7) = Breakfast (who eats around 7am?)
  • Thoracic Spin (12) = Lunch (noon is the most common time for lunch)
  • Lumbar Spin (5) = Dinner (5p is the time all the old folks around us in Florida are finishing up their dinner!)
  • Sacrum & Coccyx (fused 5) = tailbone

There is a ton more cool things to learn about the spine, but that is the basics.

As fit pros and group exercise instructors, we can’t do anything to manipulate or change the bones in a persons body. All the changes we can make in postural alignment come in the form of muscular changes. So if someone shows up to your class with a jacked-up looking finger, send them to the doctor!

Chapter 2: Planes of Motion

Our body moves in three (3) different planes (aka. the body moves in different ways). This can get super complex if you look at the standard Planes of Motion diagrams (check it out on the right) you will see in every college textbook and general discussion on this topic. It’s confusing because it’s trying to make a 3D concept 2D. Stop trying to learn about movement while staring at this picture and instead put it into your body.

You move three (3) different ways:

  • Forward & Backward (Sagital Plane)
  • Side to Side (Frontal or Coronal Plane)
  • By Rotating Side to Side (Transverse Plane)

Without going into my long discussion about having you stand against a wall and think about a piece of glass cutting you up in different ways, simply think the following for each plane:

  • The Sagital Plane cuts your body in to right and left sides. If you didn’t have your entire right side of the body you would still be able to move front and back (although not with much ease).
  • Now don’t get confused about the Frontal Plane, it isn’t about moving forward and back, it is about breaking the body into front and back portions, probably why it’s also refereed to as the Coronal Plane.
  • Your body rotates from the waist, by way of the Transverse Plane, which separates your body into top and bottom parts.

Think about this in practical terms and let’s look at a few examples.

  • To complete a bicep curl your arm is moving in front of your body. Have you seen those guys who try to lift way too much weight and make a bicep curl into a swing forward. While they are going to throw their back out and get little bicep benefit, they are overemphasizing the example that a bicep curl is in the sagital plane.
  • Have you ever side-shuffled up and down a basketball court? If so, then you are moving in that frontal plane.
  • Woodchops are a great example of a total body transverse plane movement. You start with a rotation down, and finish with a high pull. What better movement could you have for training your entire cross-sling?!

Chapter 3: Joints

Try throwing a ball without the ability to rotate your shoulder. Or consider what would happen if your knee could make full circles like your wrist. Not good right?! Nope, we like the fact that we’ve got different types of joints throughout the body that create the best movement for the given action needed in that area.

The joints (where bone meets bone) that allow movement in the body (because as I learned in anatomy class, there are also joints that don’t allow movement, such as in the head) are synovial joints. There are six (6) main types of movable joints.

  1. Ball & Socket Joints = hip and shoulders; allow movement in all directions
  2. Compound Joints = knees; combination of 2 different joint types
  3. Condyloid Joints = wrist; place where two oddly shaped bones join together
  4. Gliding Joints = wrist, shoulder, & vertebrae; can only slide past each other
  5. Hinge Joints = elbow; flexion & extension
  6. Pivot Joints = neck & forearms; one bone rotates around another

Don’t stress yourself out over knowing the names of all of them, instead take a look at your body and see how each of these plays a role in your everyday movement.

Did you just do a full scan of your body and realize that you’ve got a good number of joints that you want to move without troubles?! Good!! You should have realized that the following joints are super important to our movement patterns, and thus vital to exercise technique.

  • Neck
  • Shoulder
  • Elbow
  • Wrist
  • Hip
  • Knee
  • Ankle

When a joint doesn’t work well, then a person’s technique may really suck. Often we think that people don’t understand our technique cues, when in reality their joints are all jacked up by tight muscles and weak stabilizers. Don’t be upset with them when they do their 100th squat that more resembles a person leaning over to drink out of a baby water fountain, than your idea of a squat. Realize that maybe it is time you help improve the mobility in their hips versus just repeating yourself over and over. (I could continue, but that’s a discussion for another article!)

Chapter 4: Muscles Anatomy Basics

Ahh, the real stars of our show. Our musculature system. Without our muscles we would just be a lot of bones stacked on top of each other!

Where to start with muscles, there is so much that we need to understand as fitness professionals about muscles, but as any GOOD 101 class does, let’s start with just the most basic ideas…

You’ve got 640 muscles in the body! But don’t worry, I’m not going to make you remember all of those (I’m much nicer than my anatomy teacher). Nope, instead we’re going to take a look at what these muscles do, and then see if you can label a basic muscle man.

One Big Happy Working Family!

All your muscles get along and like to work together, which is why you can move with control and ease. The ability of your muscles to chat with each other and understand their role in that specific movement is what creates effective and safe technique. It’s when one of these guys doesn’t get the memo and stops communicating with the other muscles that issues start to occur (and don’t we all know the conversations we’ve had with our own bodies to get it to move how we want them to).

It’s like a big superhero universe…

  • Batman is the good guy, and couldn’t be himself without Alfred there as a backbone and support system
  • Robin is always there as a crazy side-kick to help Batman with whatever he needs
  • And it wouldn’t be a real great movie or comic book without the infamous villain (umm, how can you forget the Joker)

Just like that, your body is one big muscle universe.

  • The Agonist (Batman) and Antagonist (Joker) are always there working against each other
  • Synergist muscles (Robin) keep the agonist in check, establishing smooth and coordinated movement
  • Stabilizers (Alfred) are always there to support the agonist in creating full and safe movements; without these guys the agonist wouldn’t be able to maintain control or move well (image Batman trying to get anywhere without the Batmobile – thanks Alfred!)

To put this in practical terms, when doing a bicep curl, who would play each role?

  • Bicep = agonist (Batman)
  • Tricep = antagonist (Joker)
  • Brachioradialis & Brachialis = synergist (Robin)
  • Brachioradialis, Brachialis & Rotator Cuff = stabilizer (Alfred)
Muscle Fibers

Did you know you had two different types of muscles? Type I and Type II. These indicate whether you’re going to be able to be better at power/speed activities or endurance sports.

  • Type I = slow twitch muscle fibers – take a long time to get tired
  • Type II = fast twitch muscle fibers – tire out quickly

People who rock at endurance sports, such as long distance running, cycling, or swimming are more predispositioned to have a higher rate of Type I muscle fibers. Whereas people who are better at short bursts of power likely have a greater supply of Type II fibers.

Is it possible to train and improve in one area? ABSOLUTELY! This is what training is all about. Challenging your athletes to have more power by doing short burst anaerobic activities versus always maintaining steady state cardio training.

Muscle Contractions

To create movement, our muscles have to well, move. This is done through two different phases of contractions:

  • Concentric = shortening
  • Eccentric = lengthening

For example, place your hand on your quad and then straighten your leg. Do you feel that muscle tighten up? That is it contracting, and thus is the concentric phase. As you bend your knee you should feel the muscle do the reverse, lengthen out, thus showcasing the eccentric phase of contraction.

Why do you need to know this you ask!? Well when you are teaching a class you are creating muscle contractions! You want to make sure that people are moving through full ranges of motion to allow the muscle to go through it’s full contraction each time. By constantly causing it to be shorted (ie. in pulsing movements), then you’re not allowing the muscle to work properly, and thus potentially causing injury to that muscle (read Leslee Benders article on how you compromise your feet while doing this in Barre classes).

Isometric work is a form of contraction, it’s just one where the body doesn’t actually move. Planks are a prime example of isometric work. While they are amazing at firing up tons of muscles, they only train the muscle in the ONE position that you happen to be in. Therefore, it’s important to vary how isometric work is done. It can’t be the only type of training done for a specific muscle group.

Chapter 5: Muscle Man!

I know it is super easy to get bogged down in the 640 different muscles of the body. That is a ton to remember, and they are all important for every bit of movement that we make in life. When you are first learning and trying to wrap your head around muscles, get a grasp on the major muscle groups, and understand how many muscles make up each group. Then as you continue your study of the human body, you can continue to learn what each of those different individual muscles actually is.

I don’t have enough space in this article to go into the details of each muscle and their major functions (I’ll save that for another time), but below are some quick facts about the major muscles you’ll use within your classes.

Oh, and before you say anything more, remember that all your muscles work together, and thinking of them as individual muscles is not always the best way to train (but again, that’s a discussion for another article).

Upper Body

Check out the below (awesome) muscle man, and take a moment to see if you can label each of the different muscles of the upper body.

Exercise Science for Fit Pros: Understanding Muscle Anatomy 1

Did you get all of them correct (see the answer key at the end of the article)? If not, no worries, keep studying. They will come to you with time, repetition, and practice.

Starting at the top, and working down, here are key things to know:

  • Trapezius = area where most people hold tension
  • Deltoids = shoulders; 3 muscles
  • Pectoralis Major = chest; the pectoralis major is a smaller muscle above that creates the pectoralis group; tight on most people
  • Biceps = front of arm; 2 muscles
  • Triceps = back of arm; 3 muscles
  • Rhomboids = small muscle between shoulder blades; weak on most people, contributing to poor posture
  • Latissimus Dorsi = large muscles of back; 2 large wings on each side
Lower Body

Muscle man is back, test your skills again on the lower body musculature.

Lower Body Muscle Matching Guide
What are the muscles of the lower body anatomy?

How did you do here? You know the drill, keep practicing if you didn’t master it the first time.

From front to back, here are key things to know about the lower body musculature:

  • Hip Flexors = large group (10) that controls flexion of the hip; tight on most people
  • Quadricps = front of the legs; 4 muscles
  • Abductors* = outside of leg
  • Adductors* = inside of leg
  • Gluteal group = maximus, minimus, medius; often area of weakness
  • Hamstrings = back of leg; 3 muscles
  • Gastrocnemius & Solius = calf

*Have trouble remembering the difference between the ADDuctors and ABDductors?! Then simply remember back to a really horrible date and a really amazing date. (caution, if you are easily offended, maybe don’t read this analogy!)

  • A Dude of a Date (ADD) is one where you want to go crawl out of the bathroom window and escape, allowing no action to happen “down below” that evening. You have shut things off (ie. brought those legs together = ADDuction).
  • Whereas with an amazing date, you want to get through dinner as fast as possible to get back to the house and have some fun. You are saying with your body that you ABsolutely are game for whatever happens and open those legs wide (ie. ABDuction)!
Core Group

The core is tricky because some of the muscles in it are actually part of both the upper and lower body musculature. I chose to seperate it out here becuase too often when someone says CORE they assume one is just talking about the abs, when in reality the core includes many more muscles than that. Check out muscle man and see what you know.

Did you rock that one out? Keep trying if not. These are super important muscles to understand because they really do impact the entire working body.

Some key facts to know about the core musculature:

  • You do NOT have “upper” and “lower” abs. Nope, sorry to burst your bubble. That just isn’t how your body is made. You’ve got the rectus abdominis and the transversus abdominis that sit on TOP of each other. The rectus are those that you can see on the superficial level, whereas the transversus abs are deep and can’t be seen. They are two long muscles that run parallel to each other and make up the abdominals. Just as it sounds crazy to say “upper and lower bicep”, it sounds pretty crazy to talk about the upper and lower abs.
  • Obliques = 2 muscles; rotate the body
  • The Gluteus Minimus and Medius are part of the gluteal group discussed above, but are often discussed with the core as they are super deep hip muscles that are weak on most people
  • Erector Spinae = long muscle group that runs along the spine; keep these muscles strong!

Congrats! You made it through Anatomy 101!!

Okay, well you made it through a portion of anatomy 101. There is a ton more on the other systems of the body, but this is the stuff you need to know and understand to better teach your classes.

I know that it’s a lot of info, but start understanding these little bits and pieces, and eventually you will be able to spew out these facts and information with no problem. Need more help understanding it, and love to color? Then check out the the Anatomy Coloring Book and start making the muscles pretty colors! (It was a life savor to me while trying to learn all those different muscles…or maybe it was just a good stress relief that made me think I was learning?!)

Oh, and please don’t be like the program developer I met once who told me she couldn’t tell someone the difference between a bicep and tricep, but could motivate them…you need to understand the science in order to create safe and well-balanced classes.

Answer Key(s)

Upper Body Answer Key:

  • Deltoids: E
  • Biceps: F
  • Triceps: B
  • Pectoralis Major: A
  • Trapezius: D
  • Rhomboids: G
  • Latissimus Dorsi: C

Lower Body Answer Key:

  • Hamstrings: G
  • Quadriceps: F
  • Gluteus Maximus: C
  • Hip Flexors: B
  • Hip Adductors: A
  • Hip Abductors: H
  • Gastrocnemius: E
  • Soleus: D

Core Musculature Answer Key:

  • Rectus Abdominis: D
  • Obliques: E
  • Gluteus Minimis: B
  • Transversus Abdominis: C
  • Erector Spinae: F
  • Gluteus Medius: A
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