I was born with mismatched legs – my right leg is about 3/4" longer than my left. This sometimes causes me back and hip pain, although my physiotherapist has me doing a stretching program that helps a lot with this. I'm interested in getting stronger and don't want to let me leg mismatch stop me. Should I being doing something like barbell back squats with a set of legs like mine?
Thanks for your question! First off, don't do anything without talking to your doctor first. I'm not a medical professional and don't know the details of your situation. My advice is based on the assumption that you have no deep underlying issues connected with this, but simply have a mismatched pair of legs. Your doctor must be the one to confirm this. If this is the case, I see no reason why you can't start strength training, including the barbell squat. In your case, the first step is to even up your legs as best you can, so that when you do a movement like the squat, you're pushing both feet equally hard against the floor. You can do this in one of two ways. Either get yourself fitted for a good pair of orthotic shoes which correct your mismatch, or place a piece of wood of appropriate thickness beneath the shorter leg while lifting weights. Doing so will correct your natural asymmetry and allow you to get stronger with a barbell safely. Without this correct, either through special shoes or a piece of wood, you'll naturally place more weight and pressure on the longer leg, causing it to become more developed, and possible wear out quicker, while your shorter leg lags behind.
You might wonder why I'm not recommending you swap barbell squats for something easier for you, like single leg leg press or step ups. The reason is simple – barbell squats are the very best way to strengthen your legs and posterior chain. Without them, your leg strength will be sub-optimal. There's no getting around this fact. You can certainly do the other leg exercises listed above if you like, but as an addition, not substitution for the squat.