A Beginner's Guide to Your Muscles, What They Do, and How to Work Them

The fitness world can be confusing. When you first dive into fitness, you'll hear a lot about the different muscles in your body, what they do, and how to exercise them. If you're not a fitness professional, all the technical jargon that your personal trainer throws around might give you a headache. More knowledge is always better, but not all of us have time and interest in learning about the intimate details all the complex muscles in our bodies. 

Fortunately, you don't need to have an exhaustive, complete understanding of your anatomy to learn how to use your body well. This is a list of the biggest muscles and muscle groups that you need to know about. Learn these, and you'll be able to understand and make decisions about your body way better than most people.

Lower body




The four big muscles on the front of your thigh are the rectus femoris, vastus lateralis,vastus medialis, and vastus intermedius. Collectively they are called the quadriceps femoris or quads.

  • Primary Function: straighten the knee and flex the hip
  • Targeting exercises: squat, lunge
From top to bottom: Glutes, Hamstrings, and Calves

From top to bottom: Glutes, Hamstrings, and Calves


The hamstrings are muscles on the back of your thighs: the Biceps Femoris, the Semitendinosus, and the Semimembranosus. 

  • Primary function: bend the knee and extend the thigh
  • Targeting exercises: deadlift, cable pull-through, good morning


The calves are composed of the gastrocnemius, the soleus, and the tibialis anterior. 

  • Primary function: move your foot
  • Exercises: calf raises


Your butt is made up of the gluteus maximus, gluteus medius, and gluteus minimus. 

  • Primary Function: move your hip and thigh
  • Targeted exercises: glute bridge, hip thrust, hip extension





The major muscles in the chest are the pectoralis major and pectoralis minor. 

  • Primary function: move and stabilize arm and shoulder movements
  • Targeted exercises: bench press, fly, push-up
A Trapezius B Teres Major C Teres Minor D Latissimus Dorsi E Sternocleomastoid F Rhomboid Major

A Trapezius B Teres Major C Teres Minor D Latissimus Dorsi E Sternocleomastoid F Rhomboid Major


The back is a huge major muscle group. The primary muscles you'll hear about here are the trapezius and latissimus dorsi, or "traps and lats."

  • Primary function: pull the arm down or bring the body up towards the arm, stabilize the torso, control the shoulder blades
  • Targeted exercises: row, pull-up




Abdominals are comprised of obliques, the rectus abdominis, and the transverse abdomonis. 

  • Primary function: assist in the breathing process, protect the inner organs, provide postural support 
  • Targeted exercises: crunch, reverse crunch, leg raise, ab roller



The the biggest muscle group in your shoulder are the deltoids: anterior, posterior, and lateral.

  • Primary function: move the arm
  • Targeted exercises: shoulder press, row, lateral raise

Upper Arms

The two biggest muscles in the part of your arm above your elbow are the biceps and triceps.

  • Primary function: bending and straightening your forearm
  • Targeted exercises: triceps kickback, barbell curl


For the purposes of this basic introduction to muscle groups, I don't think you need to know the names of all the little muscles in your forearms.  It is most important to learn about what they do and how you can exercise them.

  • Primary function: flex and extend your fingers, flex the elbow, and turn the hand to face down or upwards.
  • Targeted exercises: wrist curl, farmer carry

So, now you know the most important muscles. Knowledge is power, so your workouts should become even more powerful!

photo credit: Romain via photopin (license)