What is a Knee Extension Lag?

Have you been taking for granted the fact that you can move and straighten your knee without experiencing any pain or discomfort? You can experience knee extension lag either after undergoing knee surgery, which makes it uncomfortable to straighten and move their knees.

There are so many things that you can’t do when you are experiencing extension lag in your knees, and this can be a frustrating experience, more so if you have been an active person for a significant part of your life.

So read on to understand what happens when you can’t move your knee, causes and how you can treat or prevent this issue.

What Happens When You Can’t Move Your Knee

If you are experiencing difficulties and pain when you try to bend or straighten your knee, you may be experiencing extension lag, and it is measured in degrees. So the doctors describe the degree to which you can straighten your knee. Keep reading to learn if can a tight hamstring cause knee pain.

For a healthy person, when you stand up, the hamstrings and the quadriceps muscles shut off, and thus, you use very little energy to stand. However, when you are experiencing an extension lag when you try to stand, your hamstrings are shortened, and the quadriceps are still working, so you cannot stand straight.

When your quadriceps and hamstrings do this for years, your tendons and muscles start to tear, and eventually, they will be torn fully; thus, your back knee cap will lose cartilage.

Causes of Knee Lag extension

A knee extension lag is both uncomfortable and painful, and it limits your mobility because you cannot straighten your knees. Thus, it is crucial to understand why it happens to change the causative habits and seek help from a physiotherapy expert like Barefoot Physiotherapy.

Here are the most common causes of knee lag extension:

  • Bone spurs
  • When your meniscus tissue is torn or locking unnecessarily
  • Scarred posterior cruciate ligament or if it is too tight
  • Tight meniscus, muscles
  • After orthopedic knee surgery

Unsure if you have a torn meniscus, or looking for exercises to help it recover faster? Learn about the types of meniscus injuries, symptoms and treatment here. Knee extension lag worsens as time goes on because your quadriceps and hamstrings are working to support your body at an unnatural angle. Therefore if you notice any of the symptoms below, you should reach out to your doctor or physiotherapist to recommend an effective treatment plan.

  • Instability in your knee
  • Pain that is localized in the knee joint
  • Swelling and bruising
  • Decreased mobility

Treatment Methods For Knee Lag Extension

Here are methods that physiotherapy can recommend in case of a knee extension lag:


The first thing to do is observe yourself and understand what is causing the lag extension. Once you can keep your feet off the ground for a few days and avoid straining your knee too much.


Compressing the misbehaving knee, such as tying a bandage around your knee, helps the swelling decrease and reduces pain.


A knee extension lag can lead to a sprain or tear, and thus a doctor may recommend surgery as the best treatment option. However, if you schedule physiotherapy in Singapore, the experts will help you prepare for the surgery and bounce back faster.

Parting Words

Don’t wait until it is too late before contacting the experts. Remember that the longer you wait, the worse the extension lag will get.  So call the physiotherapy experts and let them guide you in your recovery journey to recovery! Apart from knee extension lag, back pain in Singapore is also common among athletes and these are problems a physiotherapist can help you with.

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