How Muscles Work: Key Functions & Movements

How Muscles Work: The Real MVPs of Your Body

Before I knew what I wanted to do with my life, I was just a student going about my day when I saw someone doing pull-ups. Curious, I asked them why they were doing it, and with a smug grin, they replied, "I'm training my biceps brachii."

At that moment, I thought, Wow, this guy is so intelligent. I want to be like him.

Fast forward to today, and I’ve realized... I definitely don’t want to be like him. Why? Because the main muscle at work during a pull-up isn’t the biceps brachii—it’s the latissimus dorsi.

But that moment sparked something in me. It made me curious about how muscles actually work—what moves what, which muscles are truly engaged during different exercises, and why understanding biomechanics matters. That curiosity is what ultimately led me to study physiotherapy.

And that’s exactly what I’ll be diving into in this blog: How muscles work. Let’s break it down. 💪

Muscle 101: The Three Types of Muscles

Not all muscles are created equal. Some are voluntary (you control them), while others do their own thing.

1. Skeletal Muscles (The Gym Bros of the Body)

  • These are the ones you flex in the mirror when nobody’s watching.

  • Attached to bones and responsible for movement.

  • Require conscious effort.

2. Smooth Muscles (The Overachievers You Never Notice)

  • Found in your intestines, blood vessels, and organs.

  • Work involuntarily (thankfully, because who wants to think about digesting every meal?).

  • Essential for things like blood circulation.

3. Cardiac Muscle (The One That Keeps You Alive)

  • Exclusive to your heart (VIP status).

  • Pumps blood 24/7 without a break—because unlike you, it doesn’t take rest days.

  • If this muscle stops, well... let’s not go there.


How Muscles Actually Move

Ever wondered how your biceps know to curl that dumbbell? It’s all about teamwork between your brain, nerves, and muscle fibers.

  • Step 1: Your brain sends an electrical signal to your muscles

  • Step 2: Your nerves pass the message, telling your muscles to contract.

  • Step 3: The sliding filament theory (could write a whole blog on this) kicks in—actin and myosin (tiny protein filaments) slide together, shortening the muscle.

  • Step 4: Your muscle contracts, and you (hopefully) complete your rep without dropping the weight on your foot.

💡 Fun Fact: Your strongest muscle (by force) is the masseter (jaw muscle). That’s right—your ability to chew through an entire pizza is a legitimate show of strength.


The Main Functions of Muscles (AKA Why You Should Care)

Muscles do more than just make you look good in a tank top. Here’s why they matter:

💪 Movement: Walking, running, jumping, flexing in the mirror—it’s all muscle power.

🛡 Posture & Stability: Sitting upright in a chair without looking like a melted candle? Thank your core muscles.

❤️ Blood Circulation: Your heart is pumping around 2,000 gallons of blood daily—that’s like refilling your bathtub 50 times.

🔥 Heat Production: Ever shivered when it’s cold? That’s your muscles trying to keep you warm, basically doing tiny, involuntary workouts.


Muscle Movements: The Greatest Hits

Muscles don’t just contract randomly (unless you have a cramp—then they do what they want). They move in specific ways:

  • Flexion & Extension – Bending and straightening (e.g., bicep curl).

  • Abduction & Adduction – Moving away/toward the body (e.g., leg lifts).

  • Rotation – Twisting

  • Circumduction – Circular movement (e.g., windmill arm exercises that make you look ridiculous but work).

📌 Pro Tip: Want to move like an athlete? Focus on functional exercises that mimic everyday movements—because nobody actually isolates their biceps in real life.


Final Thoughts: Respect the Muscles

Muscles are the real MVPs of your body. They let you move, lift, jump, and survive leg day (barely). Take care of them, and they’ll take care of you—whether you're lifting in the gym, running for the bus, or just trying to hold in a sneeze at the worst possible moment.

Call to Action: Now that you know how your muscles work, go do something with them—maybe a workout, maybe just flexing in the mirror. Either way, they deserve some appreciation.

🚀 Share this blog with someone who needs to stop skipping leg day!

Email me to request blogs: student2physio@gmail.com

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