Hyperextension and Unclarity of its Meaning

Wikipedia lists the word Hyperextension in the context of Back Hyperextension as a misnomer. Which means it is considered a wrong or inaccurate name. Outside of the Back Hyperextension exercise, there is also a lot of confusion as to whether it means overextension (injury) only, the amount of joint range measured in negative (minus) degrees, or both.

This information intends to bring awareness to the lack of clarity when it comes to the word “hyperextension”. You will find a list of definitions, facts, citations, contradictions, and a conclusion, which is a decision reached by reasoning.

Extension

  1. Extension is the act of increasing the angle between two bones at a joint.
  2. Full extension is the position where the joint is straightened as much as possible.
  3. Full extension is generally 0 degrees (different when it comes to the spine).

Flexion

  1. Flexion is the act of decreasing the angle between two bones at a joint
  2. Full flexion is the maximum range in a joint.
  3. Full flexion is a positive number in degrees.

ROM

A normal range of motion in a knee is 150 degrees of flexion [1]. For the hip that is 100 degrees of flexion. For the ankle that is 20 degrees of dorsiflexion.

Zero degrees is the starting point for most joints, which for the hips is standing straight and aligning the pelvis with the femur and spine. For the knees, this is standing straight with the lower leg in line with the upper leg. For the ankles, this is standing straight with the feet planted on the ground.

For the spine, this is different as when standing straight, the thoracic spine has a natural curve (natural kyphosis) between 20 and 45 degrees of extension. [2]

Hyperextension

The word Hyper in Latin means: above or over.

Citation: In Biology, we come across a number of terms that start with the root word “hyper.” It originates from the Greek or Latin word hyper, which literally means ‘above’ or ‘over. [3]

The amount of hyperextension is measured in negative degrees. For example, -20 degrees versus 20 degrees.

Does hyperextension cause injury?

If a movement goes beyond the limit of range, then that is highly likely to lead to an injury. Moving a joint through negative degrees (hyperextension) does not mean injury is certain to happen.

Does hyperflexion cause injury?

The act of hyperflexion is going past the limit of range in flexion. This will likely always result in injury, with the severity of injury depending on how far that hyperflexion goes.

Google AI

AI responded as follows when asked whether the amount of thoracic hyperextension measured in negative degrees: Yes, thoracic hyperextension is measured in negative degrees. Hyperextension, in general, refers to movement beyond the normal range of motion, and in the context of the spine, it means bending backward beyond the neutral (0-degree) position. Since the starting point is zero, any backward bend is considered a negative deviation from that point, according to a doctor specializing in sports medicine. [4] 24th of July 2025

“Hyperextension, in general, refers to movement beyond the normal range of motion”, it says in general, and then confirms that “in the context of the spine, it means bending backward beyond the neutral (0-degree) position”. Hence, hyperextension of the spine is moving past the neutral position and is a safe thing to do when within the limitations of the safe range. There will be a point of limitation, which is the safe end range, and going beyond that can cause injury.

AI responded as follows when asked if back hyperextension is bad: Back hyperextension, or overextension, can be detrimental if not performed correctly or if done excessively, potentially leading to injuries like disc issues, muscle spasms, or ligament damage. However, when done with proper form and controlled movements, back hyperextensions can strengthen the lower back and improve posture.

Note: I am not a fan of taking the word of AI, as it just takes the consensus, which doesn’t mean it is the right answer. If we had asked it whether knees over toes is bad 20 years ago, it would have told us that the answer is yes.

Hypermobility

Citation: Hypermobility means your joints can move beyond the normal range of motion. Hypermobility means your joints can move beyond the normal range of motion. You may also hear the term double-jointed. This means your joints are very flexible. The most commonly affected joints are your elbows, wrists, fingers, and knees. [5] The joints move past the neutral position of 0 degrees, which is hyperextension, and it’s still within a safe range.

Contradictions

Millions of people have been doing Back Hyperextensions, and calling them the best thing for the back. Look up “Are back hyperextensions good or bad?”. This contradicts that hyperextension always means overextension.

Conclusion

The general consensus is that hyperextension is bad and that there has been excessive movement of a joint past its safe end range that leads to injury. When I started researching this topic many years ago, I wanted to find a definite answer backed by credible people or organizations. I was unable to do so. But even Wikipedia (see screenshot below) is unable to find credible citations that make it one way or the other. [6]

Looking at this with common sense, there is hip flexion and maximum hip flexion, the end range, and going past that is hyperflexion, which is the range in which injury occurs, caused by going too far.

Coming out of hip flexion and into full extension is reaching the neutral point of 0 degrees. Going past that, into the negative range, is hip hyperextension. Passing the end range of hip hyperextension is the range in which injury occurs, caused by going too far.

  1. Flexion (positive range of motion)
  2. End range (safe range)
  3. Hyperflexion (unsafe range)
  4. Extension (decreasing the positive range and returning to the starting point)
  5. Neutral (0 degrees for the hips)
  6. Hyperextension (negative range of motion)
  7. End range (safe range)
  8. Past hyperextension (overextension)

I am aware of the doubling up of the word “Past” and “Hyper”, which both mean the same thing. But for clarity’s sake, this felt like the best description to use. In this online course, I will use the word Hyperextension as moving into the negative range and not as overextension.

The uncertainty of the definition can only be overcome if there is going to be a clear explanation based on facts and common sense. The task is then in the hands of the audience to use the terms and definitions as they make the most sense. Which are the words “Hyperflexion” and “Overextension” as the words for the ranges in which injury occurs. Hyperextension means extension past neutral and into negative degrees.

Another way to ask someone to perform hyperextension is to ask them to extend past neutral. Example:

  1. Create maximum flexion at the hips
  2. Create extension at the hips and come into full extension
  3. Create further extension by moving past neutral

My preference goes to using the word Hyperextension.

External References

[1] Range of Joint Motion Evaluation Chart
Washington State Department of Social and Health Services
https://www.dshs.wa.gov/sites/default/files/forms/pdf/13-585a.pdf

[2] Cleveland Clinic
Kyphosis
https://my.clevelandclinic.org/health/diseases/17671-kyphosis

[3] Common Biology Terms Beginning with “Hyper” and Their Significance
https://www.vedantu.com/biology/biology-root-words-starting-with-hyper

[4] Google AI
https://www.google.com/search?q=is+the+amount+of+thoracic+hyperextension+measured+in+negative+degrees

[5] Cleveland Clinic
Joint Hypermobility Syndrome
https://my.clevelandclinic.org/health/diseases/21763-joint-hypermobility-syndrome

[6] Wikipedia
Hyperextension (exercise)
https://en.wikipedia.org/wiki/Hyperextension_(exercise)

Thanks to Philipp Wolf for sparking the debate that led to this information being written and provided in this course.

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