Detroit Lions draft preview: Combine 40 vs. the Pro day 40

Pro day season is heating up and headlines of players performance are blowing up. Lets take a look on why the pro day 40 is almost always better than the combine 40.

Ways to time speed:

1. Slowest and most accurate fully automated time (FAT). Used in major track competitions like the State meet in Michigan. It is estimated to be about .20 to .24 slower that hand timed. Almost no one uses this method at football workouts.

2. The combine: 2 hand times plus an one with a hand timed start and electronic finish. This estimated about .1 slower than hand timed.

3. Hand timed. Most prodays are hand timed.

Other factors:

1. Fast track. Some surfaces are faster than others. A track is faster than turf. Some turf field are faster than others. Turf is faster than grass.

2. Amount of testing. Some athletes just test the 40 on their pro day. The combine usually takes thru a menu of tests and interviews.

3. Comfort: No place like home.

Here are some examples:

Calhoun runs 4.6 for the Lions

Wisconsin is a very fast track. In 2006 Lions 3rd round bust RB Brian Calhoun ran a 4.59 and 4.62 at the combine. At his pro day less than two weeks later, Gil Brandt reported Calhoun ran a 4.38. After watching him fail in the NFL, it is safe to say he probably was closer to the 4.6 timed at the combine.

Running back Montee Ball ran a 4.66 40 at the combine. In less than two weeks he ran 4.49 at his pro day. I will grade Ball as a 4.66.

Penn State:

Derrick Williams and his 4.65 speed

Lions third round bust WR Derrick Williams in 2009 ran a 4.65 at the combine claiming he had the flu. At his pro day, he ran 4.47. On NFL game days for three years he ran a 4.65.

Purdue:

CB Josh Johnson ran 4.65 at the combine less tha a week later he ran 4.55 at Purdue.

Bottom line: Add about .1 to any 40 hand timed at a pro day and you will get the players combine time. You can then compare apples to apples.