The bumper plates are the obvious problem. I guess it's time for him to invest in his training.
I have a unique situation that I have no experience fixing. I have a lifter I work with online who is a massively strong individual. His last Squat workout was 5x5 at 505lbs, watching his technique video he was getting loose in the bottom and had some knee slide. His response was that the bar whip at the bottom and top of the squat was throwing him off a bit. He said there are no stiffer bars available at his gym. My advice was to use iron plates if possible (he was using bumpers) to get the center of mass closer to the middle, OR purchase his own bar and store/bring it with him.
I have absolutely zero experience on an issue like this as I don't think I'll ever squat a weight so heavy that the whip causes issues. Are there any other pieces of advice from more experienced coaches?
Also, I did not include a video as I have not asked him permission to share it with you.
The bumper plates are the obvious problem. I guess it's time for him to invest in his training.
He bought an Ohio Power Bar today, investment has been made.
The plates are the problem, not the bar.
I recently went to a small local meet. They did have an Ohio Power Bar, but used bumper plates on all lifts. Even with that bar it was the whippiest squat of my life. It was awful to have to manage that shit.
I train with an Ohio Power Bar and iron plates. No whip issues at all squatting the same weights I did in that meet.
Deflection of a bar is generally governed by the following equation:
Deflection = (FL^3)/("Some Constant"*E*I) where I is the second area moment of inertia. In the case of a rod, I = Pi*(r^4)/4, so we can see that the equation becomes
Deflection = (FL^3)/("Some Constant"*E*r^4).
E (elastic modulus or Young's modulus) is essentially the same for all steels.
Therefore, the only factors you can controls are:
1) F, Force - which we are not going to modify for the sake of reduced deflection
2) L, Length - which is the distance from the center of mass of the plates (sort of) to the center of the bar.
3) r, Bar radius
Let's examine the Ohio Power Bar.
You can buy the Ohio Power Bar at 29 mm bar instead of a 28.5mm bar which is a 1.8% difference. A 7ft bar with collar to collar length of about 54 inches will have a length from collar-to-center of 26". If you can go from 5 rubber plates to 5 cast iron plates, you reduce the distance between the plate center of mass and center of bar from about 34.1in to 29.3 (a 4.8in difference or 14% change).
When we account for the power factors, it is shown that increasing the radius will decrease the deflection by 6.7% and going from rubber plates to cast iron plates will decrease the defection by 57.6%.
The conclusion being that the biggest realistic factor in affecting the whip of the bar is going to be the distance from center of bar to center of mass of plates.
Starting Strength Indianapolis is up and running. Sign up for a free 30-minute coaching session.
I answer all my emails: ALewis@StartingStrengthGyms.com
Understood, I'll talk to him more about what is available in terms of plates. In the end this guy needs a new place to lift.
This lifter is not using ALL Bumper plates to get 505 on the bar, as I don't think that is possible. I had to double check after I posted this as I realized that it's not possible. He has 2 red 50lb bumpers and sandwiches iron plates in between. At his level of experience under the bar I would imagine he wouldn't use the bumpers if he didn't have to. He is planning on starting a home gym this summer when he moves out of his apartment, that in my opinion is the best route.
Andrew your post made my brain hurt, but you summed it up nicely at the end. If you're lifting that much you need cast iron or calibrated plates.