If the POH says +4.4g, then it will have had to withstand +6.6g in a static certification test as a minimum before the wing breaks. Pulling +6.6g in a C172 in flight would be a tall order.
I remember an old timer instructor once told me that you could climb a C172 up to it's ceiling, dive it straight at the ground at full power and still never get close to pulling the wings off it! A bit of an exaggerated claim but probably not far off the mark. They are very well built.