The method of delivering chest compressions remains the same, as does the rate (at least 100 per minute). It is hoped that the use of compression-only delivery will increase the chances of the lay public delivering CPR.
Much like when crack your knuckles, loud popping noises from your knees are most likely caused by what is called cavitation. Cavitation results from a change in joint pressure that allows carbon dioxide, which is normally dissolved in your joint fluidâa.k.a.
It's about having your limbs dead straight so that the elbows and knees don't bend when compressed. If you leave just enough of a bend in your legs, when you land from a jump, your knees will fold and your legs will tuck up underneath you which acts like suspension.