Straight Leg Raise

If you have had knee surgery or suffered a significant knee injury you know what it is like to have quads that do not work properly. It can feel as though they have been disconnected from your brain and no matter how hard you try your quads feel like jello. Fear not! Follow these instructions and you will be well on your way to a more functional knee.

Why do my Quads shut down after surgery/injury?

When your knee is swollen the fluid collects in the knee capsule just under the quads tendon. Because of this, your brain feels the need to protect the area from increased stress. One way to protect the knee is to prevent the quads from acting on the joint. Certainly, if you have a very serious knee injury resulting in instability or fractures, this would be important. But in most cases, it is advisable to work toward getting the knee working properly again. If you are unable to bear any weight or if you have ongoing pain at rest or when bearing weight, be sure to get your injury assessed by your physiotherapist before trying any rehabilitation exercises.

What do my Quadriceps Do?

The quadriceps are a key muscle group in the function of your knee. They forcefully extend the knee and help to prevent your knee from rapidly bending when loaded. You need functioning quadriceps to prevent falls, walk normally and be able to safely navigate stairs. Athletes need very strong quadriceps to aid in power generation for running, jumping and cycling. The sooner your quads are back, the quicker your rehab process will be.

Should I be on crutches when my Quads are Weak?

If you have had surgery, always follow your surgeons post-op protocol for the use of crutches. Even if your leg feels strong, there are sometimes good reasons to limit weight-bearing (such as a delicate cartilage repair). Assuming your surgeon is ok with it, the decision for when to drop the crutches is left to you. As a general rule, once you can straighten your leg and perform a straight leg raise without the knee bending at all, and your walking pattern looks normal, you can drop the crutch.

My Quads are Weak, What Should I do First?

A common place to start is an exercise called “quad sets”. The purpose of this exercise is simply to regain your ability to voluntarily contract the quad muscle with little or no resistance. Once you have mastered this exercise you can move on to “quads over a roll” and “straight leg raises”. See the video below where each of these exercises is shown and explained in detail.

Physiotherapy After Knee Surgery: Activating Quadriceps

When you are able to comfortably perform several straight injured leg raises you will be ready to walk without crutches and you will be safer to ascend and descend stairs.

How Often Should I do my Quadricep Exercises?

You will benefit from doing these exercises as shown for four sets of 10-15 reps twice daily. Once this becomes easy and you are comfortable walking, ascending and descending stairs it will be time to move on to more difficult exercises aimed at improving strength and range of motion. This would be a good time to check in with your favourite Physiotherapist to update your home program.

Final thoughts on quadriceps activation

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