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Flexion and Extension: Definition and Examples for Coaches

What are Flexion and Extension?

Flexion and extension are movements that affect joint angle. Flexion is the bending of a joint that decreases the angle between two segments of the body. Extension is the opposite of flexion; it’s the straightening of a joint that increases the angle between two body parts. Both are essential in athletic activities and gym training for muscle and strength gains.

Examples of Flexion

  • Bicep curls – flexion at the elbow
  • Deadlift – it involves flexion at the hips, knees, and ankles during the descent
  • Leg raises – flexion occurs at the hips
  • Hamstring curl – knee flexion occurs during the concentric portion

Examples of Extension

  • Push-ups – extension at the elbow
  • Squat – extension at the ankles, knees, and hips while moving up
  • Leg extension – extension at the knee
  • Hyperextensions – extension at the hips


1. What is hyperextension, and how does it differ from extension?

Hyperextension occurs when the joint extends beyond its natural range of motion, whereas extension refers to the straightening of a joint within its normal range. Pushing a joint beyond its natural ability to move can lead to discomfort and injuries. An example would be when someone leans far back and hyperextends their spine at the top of a deadlift.

2. What muscles cause joint flexion?

Muscles that shorten (contract concentrically) to bend joints and reduce the angle between two parts of the body cause flexion. Examples include the biceps of the upper arms and the hamstrings of the thighs.

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