Extension

A normal range of motion (ROM) at the knee includes flexion, extension and a small amount of hyperextension. When the knee is straight it is said to be extended. 

Full extension of the knee is generally quoted as 0 degrees but may normally be as much as -6 degrees, which is very slightly bent backwards.

• Is it important to regain full knee extension?
• What causes knee extension loss?
• Active extension exercises
• What is passive extension?
• Forum discussions

Is it important to regain full knee extension?

After injury or surgery it is more important to regain full extension of the knee than it is to regain full flexion.

Peer-reviewed papers

• Quote from peer-reviewed paper:

  "....Loss of full ROM at the knee joint can have detrimental effects on the function of the entire lower extremity..[causing] altered gait pattern affecting the ankle and hip, inability to attain the closed packed position of the knee, and difficulty running and jumping..."

  Citation: Shah N. Increasing knee range of motion using a unique sustained method. N Am J Sports Phys Ther. 2008 May;3(2):110-3. PMID: 21509134; PMCID: PMC2953321.

End of papers Quick links

• Quadriceps lag

• Knee extension device

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What causes knee extension loss?

There may be a number of reasons why one struggles to regain knee extension after a knee insult:

• inhibition of the quadriceps muscle
• wasting of the quadriceps muscle
• contracture of the hamstrings muscle
• an obstruction in the joint line
• adhesions in the normally-mobile soft tissues around the front and back of the knee
• adhesions that have turned to scar tissue (arthrofibrosis)

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Active extension exercises

Active extension exercises rely mostly on the quads muscles, but these muscles often become inhibited after knee injury or surgery, and it may take time to get the muscle to start triggering.

Usually an extension exercise regime begins with 'short arc extensions' from a seated position.

Quick links

• Short arc extensions

• Range of motion

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What is passive extension?

Passive extension exercises, such as 'prone hangs' use gravity to help regain extension.

A 'drop-out cast' allows the clinician to gradually improve extension within a plaster-of-Paris erial wedges to be placed under the heel.that has been windowed to allow s

Quick links

• Prone hangs

• Passive extension
• Drop-out cast

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Forum discussions

• The 1% group who never regain full R.O.M.

  Patients compare notes about regaining range of motion.

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