Leg extensions

I started doing leg extensions 80kgs/10-15 reps are they any good?

I heard they fuck your knees up.
What do you need them for anyway?

i myself am very conflicted on them. they burn like hell and i get sore when i do them but something in my head just tells me they don't work.

Woah that's why I did feel a little pain in my knees I am doing it too build quads for cycling

when will they learn

This. Leg extensions are very bad for your knees in the long run. I avoid doing them entirely.

i avoided them for years but started doing them not too long ago noticed my quad definition became better

Damn that's pretty shitty thing to go though

I think if you do them with lesser weight like 20-50kg and more reps will it be working? Or it isn't worth it

I definitely noticed the quads were a bit more tight