Are straight leg-lifts (with ankle weights) of any real benefit in building quad
muscles?

I've heard that they might not be...

I'm middle-aged and have arthritic knees; my doctor cautions against doing
leg extensions--with weights. He says leg-extensions can harm arthritic knees.

If straight leg-lifts are ineffectual for building quads, what are some other
alternatives for building quad muscles?

No.



Cycling. Squats. Leg press. Check with your orthopedist.

And welcome!

I would not recommend not following your doctors advice, but I will tell you my opinion and you can choose your own poison or medicine as you prefer. Since you have to bend your knees and put a lot of pressure on them to stand and walk in the normal course of your daily activities, I don't see what a couple of sets of leg extensions could do to hurt anything. Given the choice of limiting all daily activity and doing a few leg extensions to try to strengthen the surrounding muscles, which may help stabalize the knee joint and reduce the stress on the joint, I would try a few light leg extensions for a few weeks and see how it feels.

Many years ago after I had knee surgery my doctor advised against ever lifting "heavy" weights again. I followed his advice for a few years and the pain in my knees just kept getting worse. So i figured, what the heck, it can't get any worse. SO I gradually increased the weights until I was doing the whole stack on the leg extension machine and the heavier the weights got the less knee pain I had. So much for my doctors advice!

Yes, it can work quads...i think u end up working a lot of psoas (hip flexor). If that is overtrained it can lead to low back problems.

First to answer your question... no, straight leg lifts do not target your quads in a substantial way. It is a hip flexor/core exercise.

That being said, I would listen to your doctor about leg extensions. I myself am a trainer and I suffer from chondromalacia patella, a condition where my deep knee cartilage is being worn away because of the distinct shape of my knee joint. My physical therapist recommends shallow leg press and shallow squats (shallow as in no more than a 45 degree leg bend at the knee).

The problem with leg extensions is that when the knee is bent at 90 degrees at the start and end of the exercise, your kneecap is as deep in its notch as possible, and this causes extra tension and friction during the exercise.

Start your SHALLOW leg presses or squats at a lower weight and focus on your form, taking 4-5 seconds down, with a 1-2 second pause, followed by a slow count 3-4 returning to the starting position. Do this type of rep 6-10 times over a period of 3 sets with at least 45-90 seconds rest in between sets. You'll find you'll be able to improve your quad strength with lower weights and the shallower rep and you can then gradually increase the resistance.