Also, CJ was 197 at the combine, where I'm sure he was a little light to run a fast time. He could easily play at 205 and be within your "magic range." BMI makes sense, but it's mostly common sense. I'd bet there's a stronger correlation with lower body strength, or Power Clean, Deadlift, Squat, and Leg Press numbers than BMI alone.
The other thing is that BMI only matters if you have skills. BMI in itself doesn't tell you anything. I'm 6'2.5'' and 245 lbs. with a BMI of 31, but I don't think I'd be a very good NFL RB. Vision, instincts, hands, balance, quickness, toughness, burst, etc. are all very important for a RB.
A lot of people misunderstand what I'm saying about BMI. I've never said that every person with an ideal BMI is going to be a great NFL running back. That's a ridiculous argument that I would never make. My basic argument about BMI is as follows:- Most of the elite RBs in the NFL fall within a narrow range of BMIs (roughly 29.5-33.5).
- There are very few RBs outside this range who have achieved sustained success in the modern NFL. Therefore...
- We should probably be wary of RB prospects who don't fall within this range. And...
- When given a choice between a RB prospect with a poor BMI and a RB prospect with an ideal BMI, we should probably favor the RB prospect with the ideal BMI assuming that he has a similar draft pedigree (i.e. favor Mendenhall over Johnson and Rice over Charles).
This year offers a great test of the importance of BMI since there were several ideal guys drafted in the first few rounds and several undersized guys drafted in the same general range. We could split them up into two groups leaving out some of the tweeners:
Ideal BMI
Jonathan Stewart - First Round
Rashard Mendenhall - First Round
Ray Rice - Second Round
Tashard Choice - Fourth Round
Low BMI
Darren McFadden - First Round
Chris Johnson - First Round
Matt Forte - Second Round
Jamaal Charles - Third Round
Anything can happen, but my prediction is that the four backs in the first group will cumulatively outperform the four backs in the second group over the next 6-8 years. Feel free to bookmark this post and bump it in the future. It will be interesting to look back on this.