Supposedly it also hurts your knees like all getout if you already have such problems. I don't know if it actually causes knee problems, but removing the strain totally and then retensioning the knees is baaaad news for us arthritic types!
My orthopaedic doc lifts at my club and went ape when she saw me get up off an incline bench holding a loaded bar. It was less than 250, but she says that the strain is too concentrated for me when my knee is flexed more than about 60 degees. Seeing as my knees always hurt worse and swell slightly the few days following legs and glutes, I believe her.
I still squat, but not to 90 degrees. LOL, I would probably fall on the floor if I went that low now days, even with a bench to stop me.
Of course, you youngsters can still parallel squat all that iron without too much problem....For now anyway....
BE