Squats are a great exercise i have already posted on here reference the assistance of squats in healing a very injured and weak back , i had 3 slipped discs 2 ruptured with synovial fluid leakage - end result - end of Muay Thai career, training, fighting, teaching i just gave up and became a drinking, smoking, overworked, stressed out individual for @ 6 years gained over 40 kg and was on my way to an early grave, my previous attempts at getting into shape failed due to the back problem the answer given by my dr's was surgery. i declined that as i had previously experienced guys in wheelchairs as a result of that surgery. i then started weight traing firstly along bodybuilding type routines, then i moved into powerlifting type exercises. 1st 3-4 months avoided squats, deadlifts etc then i gave them a go with very strict form - deep squats which i was always told was going to aggravate my condition. i used a relatively light weight and repped it for 15 x 3 sets that 1st time, the follwoing morning no back pain assocaited with the squats. so i kept at it training legs twice a week amongst other training the end result was that within a month all my pain had gone i had succesfully strengthened my core, back, legs, whole body and healed a serious condition, i then started to notice that my flexibility was improving and i was able to kick and move etc again - the end result was that 2005 i returned to regular instruction, was able to properly demonstrate techniques and 2 weeks ago i was teaching jumping double back spinning kicks. i now love squats and deadlifts (not the leg soreness after lol) and will encourage all of my students to do them. but with proper form and no ego on the bar