Deep Squat VS 90 degree Squat - knee health

**original77** · 03-05-2010 04:48 PM

Is it now generally accepted deep Squats are the safest option for healthy knees if you have the flexability to perform them?

I still read a lot of conflicting advice, but hear most conflicting advice in the gym itself - with 80% of personal trainers being very "matter of fact" that parallel 90 degree squats are the safest option.

I like to go ass to the floor but thought i'd get some thoughts on this.

Heres some notes on deep vs 90degree squats >>>

"Note in the drawing that if the thigh is at parallel, the force of gravity pulls 100% in the x direction (i drew from an odd angle so X is up down and Y is left right). That means all of the force is placed over the knee cap directly down... greatest shearing forces. If you go below parallel, then what happens is as you can see, the Fy and Fx change magnitude and direction slightly to lessen the load and pull back on the kneecaps, actually reducing some of the shearing force.
Also, notice how powerlifters mention to push your legs apart? Or how even when you rock bottom when your knees hit about 90 degrees they tend to come in?
Simple reason for that t=rxF or torque=rFsinX. The sine of X is greatest (in our range of motion) at 90 degrees... meaning the MAXIMUM torque (which does the greatest damage to our knees) is done at parallel. Usually people tell you to go a little below parallel for that reason. Changing direction at 90 degrees does the most damage to your knees. Also, because of the direction of r and F, the torque is directed inwards, so your knees tend to buckle in. Hope this clears a few things up."

**Martin Brown** · 03-05-2010 05:34 PM

Thanks for that

I think there are more factors to consider though that affect knee health, not just forces through the knee.

Things like balanced muscle development around the joint are probably more important to knee health than actual force undertaken for the brief period one is squatting.

M

**michael88** · 03-05-2010 05:38 PM

Yeah baby, this is the kind of stuff we like!! Turning common misconception into fact. Ive always squatted as low as possible and never had any problems.

**MoonBoots89** · 03-05-2010 05:57 PM

I loved the needless expansion of F in the final equation, just the sight of it brought me back to my physics A level

Thanks for posting this. Its nice to look at the issue from a different angle.

**tony4100** · 03-05-2010 06:03 PM

I'm sold.

I have also noticed that my young children sit like this instinctively/naturally without any problems - although they have not got an oly bar across their shoulders!

**suj** · 03-05-2010 06:04 PM

i like how i'm not the only person who gets messed up writing "q's" as "g's" then editting them...

and there are loads of factors, like the way muscles cause tension, the way bones slide over blah blah
i tried asking my physics lecturer ages ago

but like you, i like going below parallel, and have no problems

**dope540** · 03-05-2010 06:13 PM

suj likes it deeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeep. lol

**suj** · 03-05-2010 06:27 PM

Quote

Originally Posted by dope540

suj's girlfriends always like it deeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeep. lol

editted it

if they ask...i have to provide

**original77** · 06-05-2010 11:48 AM

I found starting the squat by moving my ass out first instead of knees was the biggest factor which helped me go deep, always a lot sorer next few days on deep squats too!

I still come accross so much confliction about stopping at 90

**Diamond Head** · 06-05-2010 01:47 PM

Quote

Originally Posted by tony4100

I'm sold.

I have also noticed that my young children sit like this instinctively/naturally without any problems - although they have not got an oly bar across their shoulders!

TMUSCLE.com | Third-World Squat

I try and get myself into that position as much as possible. only done it a few times a week so far but defintely improve my flexibility slowly