When I was doing clinical work in neurological samples, we would frequently use a simple
hand dynamometer to assess peak grip strength against normative data. You grab the thing and just squeeze as hard as you can. Attached is a table of grip strength means & standard deviations by age and gender.
It's not precisely the same since the grip is different b/w a dynamometer and a disc, but the dynamometer measure is of the transient maximum grip force put on the device. Most people can muster a few more lbs for a brief moment than they can sustain for a few seconds, just like transiently increasing grip tension as a disc enters the hit.
Assuming the peak weight for a high 60's mph ejection is somewhere around 59lbs like in this guy's analysis, you can look across the table and see where grip strength might be a limiting factor in pro-level form/acceleration. For many non-pros' form, grip strength might be less likely to be a limiter. Of course, you might also imagine that the force varies by ejection speed & form/body type (etc.) that influences acceleration curves, which would be interesting.
Of course, I only have this one guy's analysis, these are averages and variances in a randomly sampled population, and grip strength is trainable!