How To Do Leg Extensions Without Destroying Your Knees

It's actually pretty simple.

How To Do Leg Extensions Without Destroying Your Knees

Image: The Fitness Maverick

Think you’ve been performing the leg extension correctly? Well, there’s a good chance you’ve been placing unnecessary stress on your knees. Here’s how to perform the leg extension in a safe and effective manner.

The leg extension machine is one you’ll likely find in virtually all gyms. And, while some personal trainers and fitness experts may say using free weights will help build your leg muscles the best – through leg exercises such as squats, lunges and deadlifts – the leg extension machine offers one of the best and safest ways to build up your quad muscles.

However, as with any exercise, it is only safe if you perform it correctly. There are some common mistakes some gym-goers fall foul of when performing the leg extension, but luckily, there are some easy fixes.

Taking to TikTok to explain how to perform the leg extension correctly is @JPGCoaching, who is widely regarded as one of the most trustworthy sources of fitness information on the video-sharing platform. JPGCoaching is the brand name of JP Gallardo, a bodybuilder with a major in exercise science, who perfectly explains how to perform (and how not to perform) pretty much any exercise you can think of.

JPGCoaching has posted several videos revolving around the leg extension and they all touch on a similar subject: positioning when performing.

Line Your Knees Up Properly

Because the leg extension machine is, well, a machine, it is used by anyone who walks into the gym. Different people, naturally, have different heights, and this needs to be factored in when setting up the machine for yourself.

As JPGCoaching says in the video above, you need to make sure you “line your knees up with the axis of rotation.” This is the pivot point on the machine that is clearly identifiable. The leg extension machine at your gym may even have a coloured dot to help identify it more easily. To line your knees up with it, you’ll need to adjust the rear support pad to move your body forward or backwards, depending on your height.

Lining your knees up with the pivot point will allow for the best range of motion and prevent your knees from sustaining an injury.

Maintain Neutral Feet Positioning

JPGCoaching also says you should “maintain a neutral foot position so that your feet extend inline with the knee joint.”

This is another important tip, as some people using the leg extension machine may feel the need to rotate their feet outwards or inwards. Instagram account @charliejohnsonfitness also touches upon this point in his own leg extension tutorial video.

He adds that some people believe that by turning their feet inwards, they will be able to get a better sweeping motion. Even if this is true, it places far too much stress on the knee joints, and will eventually cause knee pain later into the future.

Hold Onto The Handles

Other tips that JPGCoaching suggest are to pull yourself into the seat using the handles down to your sides, “so that you’re not lifting up everytime you extend.” Indeed, by not holding onto the handles, there is a good chance your bum will lift off the seat and move forward slightly when you reach the top of the extension movement.

While this may not necessarily cause any real injury, it removes the tension you’re intending to place upon your quad muscles, rendering the entire exercise pointless.

Lean Foward

It’s not a bad thing to keep your back pressed against the rear pad and pull yourself down into the seat when performing the leg extension. However, JPGCoaching suggests leaning forward slightly from the waist to “maintain hip flexion, which will help with better shortening the rectus fermoris.” JP explains exactly what this does in this video.

Move Slowly

As with most other exercises, if you extend your legs up and down too quickly, you’re not going to reap the full benefit. A slow and controlled motion is going to reward you far greater. Again, Charlie Johnson touches on this point in his video.

Hold At The Top

When you reach full extension, JPGCoaching suggests holding and squeezing the quads for a second or two before returning to the starting position. Doing so will hold the contraction on the muscles

Take all these tips into account next time you’re at the leg extension machine and you’ll soon see your quads grow huge.

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