Check your knee strength with a leg press

Why do I need to check my knee strength?

Checking knee strength is important if you’ve injured your knee in any way. You’ll want to measure it at the beginning of recovery, which can then be used later to check your progress.

I get a lot of people at my clinic that report they ‘feel’ their knee is strong. This isn’t good enough for me – nor for the patient when I explain it to them. Using an objective measure can help identify any weakness and then used to track progress.

If you’ve ever had pain and/or swelling around the knee, then we know this automatically will reduce muscle strength. The pain stops muscles from working as well as they could do – it’s called muscle inhibition. Swelling also stops muscles from working as well as they could do. We need to get an actual value of strength, so it’s a trip to the gym and trial on the leg press.

Caution

There are different ways to calculate your strength. The way described below is one of them. Make sure you’ve warmed up for at least 5-10 minutes before starting. With each increase, rest for a few minutes before trying. Please don’t do anything that causes any pain or even apprehension – if you’re worried at all, call it a day and document the weight. You can always go back and improve on this score. You’re just wanting a rough idea of how much you can push.

How to check knee strength

Start with your stronger leg and a low-ish weight on the leg press, ensure you’re not too close to the plate (no more than a 90degree knee bend) and that you can straighten your leg. Slowly increase the weight, giving yourself time to rest in between the increases. Stop when you can’t push the leg press anymore, or if you’re apprehensive in any way to continue.

Knee strength
Start with your stronger leg
Knee strength
Start on a low weight…
Knee strength
..and increase until you can’t push anymore

Repeat the above on your injured/affected leg. Stop if you get any pain or apprehension.

What you need to do now…

Write it down!

Write down the date of when you checked strength and the numbers you achieved.  If there’s any difference then single-leg repetitions on the leg press are what you need to work on over the next 4-6 weeks. I treated someone after knee surgery who could push 110kg on the good leg but on 30kg on the ‘bad’ one – BIG difference!

 

Why this is important

‘Feeling’ like something is strong isn’t the same as knowing it. Objective measurements are useful so you’ve got definitive values and you can see your progress. Repeat the measurement after a few weeks of to check your progress.

Seeing that you’ve improved will really help you with motivation and sense of achievement. It’ll also give you confidence in that leg, knowing how strong it is and then you can know it’s strong, rather than just feeling it’s strong!

As always, if in any doubt then contact a health professional to help you out in your individual situation.