Recently i have worked with a powerlifter with a 240kg squat ( @weight 75Kg) who had tendonitis in the lower back.
For the last 6 weeks i subsituted hacksquats for back squats to un-load the lower back & this helped alleviate the tendonitis.
Yesterday was the first day of squating again and no strength loss’s occured.
Thoughts on hacksquats?
Personally, i like to do hack squats. (I am assuming that you mean actual hack squats rather than the machine). I usually do them in the part of the cycle as variety when back squats get old. They appear to work almost everything the same way as back squats (with the exception of it works traps).
Does anyone have any research on this? I assume that because the weight is at the same position (with the exception of height) it would work the same as back squats, but biomechanics can be tricky for me 
I sometimes do hack squats, but i don’t feel it in the hammies as much as a deep or parallel squat. how can we get around this, becuase if I could do them in a way that would get equal Ham stimulas, they would become my favourite exercise.
Note: Sorry to pic hairs but the correct name for the exercise you are describing is: Hack Lifts, (not hack squats).
Hack Squats are something bodybuilders do on those inclined machines that have painfull inclined platforms.
“Hack Lifts” on the other hand, are simmilar to deadlifts but ofcourse with bar behind legs instead of in front.
Hack Lifts I like.
RE: range of motion
To get the same range of motion with a hack lift/squat as a parallel normal squat, i usually do the lift standing on a stable box with the weight touching the ground. The only problem with this is finding a good stable box! It took me awhile to find a good one
Barbell hack squats are primarily a quadricep exercise. They’re best performed with the heels elevated on a small plate.
Hack Squats are something bodybuilders do on those inclined machines that have painfull inclined platforms.
I was refering to those inclined platforms, which is not longer used since the lower back is much better, it was a substitute when back squatting was not possible.
:karate:
Strong man Sven Karlson uses the hack squat machine facing inwards toward the machine. He says it has really strengthened his start and truck pulls.
He recommends doing full squats first with a pause at the bottom, and finshing off on the hack machine.