In order to perform a task to the best of your ability you first need to understand how it works.

Today’s lesson? A basic dissection of the arm and a quick study of human anatomy.

The arm is a fascinating part of the body and it has the ability to move in flexion, extension, abduction, and adduction. A very simplified definition of these terms can be found below – for more in-depth definitions, visit here.

What is flexion?

Simply put, think of flexion as bringing your joint closer to the center of your body. Fingers bending upwards would be a good example, or your arm bending towards your shoulder.

What is extension?

Extension is extending a limb away from the body.

What is abduction?

Think of abduction as moving away from your body, like your limbs are being abducted. Abduction = abducted or being taken away from your body.

What is adduction?

Think of adduction as adding to your body, bringing your limbs closer. “Add”-uction = “adding” to body.

Due to the arms being high-performing muscles, it’s important to build this part of your body to prevent pain and injury. Not to mention, extra muscle leads to more calories burned, so let’s learn about the four muscle groups to target on your next arm-day.

The Four Main Muscle Groups


  1. The biceps, also known as the biceps brachii, is made up of the brachioradialis and brachialis.
    1. Sample exercises to help tone/build the biceps include:
      1. Barbell curl, incline dumbbell curl, standing bicep cable curl, reverse-grip bent-over row, concentration curl, overhead cable curl, and hammer curl (to name a few).


  1. The tricep is made up of three heads, the medial, lateral and long head. The triceps brachii is the muscle that runs down the back arm of the humerus, which is the lone bone of the forearm.
    1. Sample exercises to help tone/build the triceps include:
      1. Decline triceps extension, triceps pushdown, dip, suspension trainer triceps extension, and closed grip pushup (to name a few).


  1. The shoulder is made up of about eight muscles that attach to the scapula, humerus and clavicle bones. The largest muscle in the shoulder is the deltoid.
    1. Sample exercises to help tone/build shoulders include:
      1. Overhead press, dumbbell fly, band lateral raise, pike press, dip, and dumbbell bent-over lateral raise (to name a few).

Rotator Cuffs

  1. The rotator cuff is made up of the supraspinatus, infraspinatus, teres minor, and subscapularis.
    1. Some exercises/stretches to help build and prevent injury of the rotator cuff include:
      1. Reverse fly, doorway stretch, external rotation at neutral, and external rotation at 90-degree abduction, and the Turkish get up with kettlebell (to name a few).

If this quick lesson still leaves you feeling lost, book a complimentary fitness assessment with a City Sports Club trained and certified personal trainer today. They can help you better understand how to train and target your muscles, so you have the best chance at building muscle while helping to prevent injury.