Some people have loser ligaments and tendons, its completely normal as long as it doesnt cause pain. As for not creaking during heavy sets, that can be explained with simple concepts, one the hydrostatic pressure is far higher, so the fluid that IS inside your meniscus (Sp) sacs is pushed to the outside and is under pressure, just like you can use less oil in an oil system if the pressure is higher. Also, the velocity is generally lower on heavier sets so there is obviously less contact traversing per second inside the joint. Take a creaky door and experiment
