Why it matters: For wide receivers and running backs, breakaway speed can be the difference between a modest gain and a game-changing play (just check out Jerry Jeudy's film). A measurable combination that NFL evaluators pay close attention to for cornerbacks is length (height and arms) and 40 speed. Safety is another position to keep an eye on, particularly for players who will be asked to cover a lot of ground in the deep middle of the field. The chart below shows the most desirable times, the average combine times over the past five years and the times that should raise a red flag for evaluators.

Past standout: Seahawks WR DK Metcalf. At 6-foot-3, 228 pounds, we knew the Ole Miss stud was a physical freak. But then he broke the internet with a blazing 4.33 40 at last year's combine in one one of the most impressive performances I've seen. Seattle stole Metcalf at the end of Round 2, and he had a great rookie season, catching 58 passes for 900 yards and seven touchdowns.