If you want to have a go at at real brutal squat program have a look here:
http://www.exrx.net/WeightTraining/RussianSquatProgramGenerator.html

Russian Squat Review 
My total for Russian squat  program was 140kgs. Not quite up to a Double Bodyweight Squat but real damn close.
End at of the Russian Squat Program 140kgs Start at 120kgs. Gain of 20 kgs in around 6 weeks.
And I got through it injury free.
Go here to check out more about the program and how I shaped up using it.
http://www.how-to-bodybuilding.com/russian-squat-program-report.html

Hi All, Over the past 3 months I have made some good gains but body weight has stopped around the same. Strength has gone up and looking far more ripped and lean. I did 4 things all about the same time  started eating more beef mainly at lunch time, started lifting atlas stones gerrr! mixing it with my standard training which includes deep squats, went gluten free, bought a big pile of amino tabs and munched them about every hour. Don’t know if it is any individual factor but together they are working for me.

Stay Well Stay Happy

John