I’m a huge fan of doing and prescribing a few reps of daily deep squats and holding it for a few seconds; just enough to keep the knees healthy. However, a Chinese study showed those who squatted daily for longer that 1-hour, were worse off.
“Prolonged squatting is a strong risk factor for tibiofemoral knee OA among elderly Chinese subjects” – Zhang et al 2004
In a nutshell: A little bit of deep squatting is great, but a few hours a day- not so great!