Muscle Actions: Extension

Extension refers to a movement that increases the angle between two body parts or the straightening of a joint.

Extension Exercise Examples:

Extension of the knee.

Picture a person sitting on a chair. As they flex their leg and straighten it, their heel moves further away from their hip.

Leg Extension

The leg extension machine pictured here is a perfect example of the extension muscle action.

Other examples of extension

  • Shoulder Extension – Arm moves straight behind body.
  • Triceps Kickback – Extension at the elbow occurs via the triceps resulting in an increase in the angle between the ulna and the humerus. Your wrist moves away from your shoulder.
  • Glute Bridge – Hip extension
  • Back Extension – a common core exercise

When it comes to the foot, we don’t use the term extension. Instead the extension and flexion of the foot is referred to as plantar flexion and dorsiflexion. I don’t know why. It’s just the way it is.

The opposite movement of extension is flexion.

Related Terms

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