The photo below reveals a puzzling revelation. When squatting, President Putin does it in a regular European fashion. As a matter of fact, there’s no photos except photoshopped fan memes where our President does a Slav squat.
Since Putin spends hours working out and in the swimming hall, almost certainly in the company of competent PTs, flexibility in the joints and muscles shouldn’t be a problem. Neither has he the kind of pouch that pushes him too far back out of balance.
At the much-profiled bare-chested photo-op, Putin also does a regular squat. His weight is all on his right leg, which blocks blood circulation below the knee. This means he can’t sit this way longer than a few minutes, which is unacceptable for a Slav squat.
In the photo below, Putin seems to have what it takes of the stretch in his hams and gluteus.
This leaves a hip/knee/foot joint injury, which is understandable for an old practitioner of martial arts and downhill skiing. However, the most likely cause is the back condition that often impacts his gait.