Used to be the Rule of 370 back when backs got that many carries. If you got 370, you were toast.

But the truth is most backs have short peaks, so anyone getting 370 was probably on the way down anyway. IOW, you don’t get a huge workload unless you’re at peak, and if a peak is only 2-3 years.

But McCaffrey is top-5 all time, many of his touches are receptions which are less taxing (fewer big bodies to tackle you outside the tackles) and those touches were spread out over 20 games instead of 17.

Plus the Niners run block so well, he’s often at the second or third level when he gets tackled.

Still high risk, but also highest reward.