How can I ensure I am working the muscles in each leg equally?

Question

I have a problem with my knee where it hurts a lot when my leg takes weight (for example, I can do one-legged squats with one leg but not with the other because my knee hurts too much). This knee hurting when the leg takes weight means that the muscles in that leg are a lot smaller than the muscles in the other leg.

When I went to the physiologist for a solution, I was given a set of exercises, including leaning against a wall with my feet 30cm away from the wall, shoulder-width apart, and slowly skidding down the wall until the angle between my shins and thighs is approximately 90 degrees (squats against a wall). One very important thing I was to ensure was that I applied the same amount of force to each leg.

Upon doing this exercise, I realised it was very easy to allow the strong leg to do all the work and neglect the weak leg. After a few days of doing this exercise, I realised that my weak leg was not benefiting from this.

My weak leg is not strong enough to do exercises of this nature by itself, so I can only do exercises that use both legs. How can I ensure that I am working the muscles in each leg equally? I am not looking for diagnosis for my knee or a set of exercises to strengthen my leg, but a way to make sure that my weak leg benefits from the exercises. Note that the exercises do not hurt my knee at all but do not benefit as my strong leg 'takes over'.

tl;dr summary: how can I ensure that I bear the same amount of weight on each leg when doing leg exercises?

Answer 1

I suggest you build up strength gradually by doing leg presses but pushing with one leg only (of course, alternate legs, although the strongest one will not benefit much until the weakest one catches up).

I mention the Leg Press because it is the closest thing there is to a basic, compound leg exercise like the squat, but with the leg press machine you can easily set the load low enough, so that you can work safely with one single side and gradually build up. There is a description in EXRX of the single-leg version of the leg press so it is probably not a bad idea (invented exercises can be dangerous, you know). One-sided exercises are usually recommended to athletes with lateral imbalances, and the typical example is the bench press and shoulder press with dumbbells, in order to force both sides to work equally and independently.

Take this with a grain of salt because I am neither an experienced athlete, nor a physical therapist. And this answer is likely going to receive a shower of downvotes because I mentioned a gym machine (oh my God!) and the trend now is "either barbell or nothing". But I think machines can be very useful under certain circumstances, and yours seems to be the case. Since you cannot do a single-leg squat without pain, I don't think there is a better alternate than the leg press machine.

Additionally, I guess you have already tried lunges, although they are not a 100% single-leg exercise. If lunges are painful, you may also try a reverse lunges, I have found them somewhat easier on my knees. In any case, I don't think it is a good idea to be messing around with lunges with knee pain. The leg press machine is safer because you can set the load as low as you want and build up from that point. And be sure to have your therapist clearance in order to attempt anything.

Answer 2

Mephisto already alluded to it, but I'll call it out again.

The only way to ensure a weak leg is doing it's job is to exercise each leg independently.

Any single leg work that you can do properly will work, but there are several options. Some examples are:

• Leg press, single leg
• BW and/or dumbbell lunges
• Split squats

One thing has me concerned

Pain like you are describing in a knee is not normal. Make sure there is not an injury before really pushing your knee. I'm wondering whether you have incurred some patellar tendinitis or have an ACL strain. If that's the case, you want to do the proper rehab for that before you work on the left/right strength imbalances. Another real possibility is a pinched nerve causing weakness and/or radiating phantom pain down your leg.

Answer 3

When you are talking about legs, there is only one word that matters: squat. It is the one exercise to rule them all.

Start my simply doing body weight (BW) squats. If you cannot do that, then start by doing mobility stretches to address any areas preventing you from doing a proper BW squat. The focus here should be teaching your body the movement, and practicing good form (e.g. to parallel, straight back, etc.)

After you are able to comfortably do BW squats WITH PROPER FORM, then it is time to start adding weights. You want to start LIGHT and then progressively add small increments each workout. You can add weight by ideally using a barbell and doing back squats where you add 5lb each workout. Less ideal would be doing goblet squats with a dumbbell.

By starting low and then building up slowly, you allow for the muscular imbalances to correct themselves over time without putting strain on the muscle.

With all that being said, it always pays to consult a physical therapist. I am a random stranger on the internet, they are a certified and trained professional who can actually examine your body and pinpoint the issues (whereas the best we can do is guess).