Demarcus Van Dyke is fastest in 2011

Defensive back workouts always produce some of the best 40-yard dash times at the NFL combine, and 2011 is no different.

Miami CB Demarcus Van Dyke blazed the fastest time at this year's combine on Tuesday, posting an official time of 4.28, and LSU CB Patrick Peterson was close behind at 4.34. How do those times compare to recent bests?

RB Chris Johnson (4.24) is the only player since 2005 to run a faster time than Van Dyke, while WR Jacoby Ford ran an identical 4.28 last year. Peterson's time is two-tenths of a second below the average for all cornerbacks (4.54) over the last three years.

Here's a look at the top five official times from this year's defensive back class.

1. Demarcus Van Dyke (4.28)

2. Patrick Peterson (4.34)

T3. Chimdi Chekwa, Ohio State (4.40)

T3. Chris Culliver, South Carolina (4.40)

T5. Prince Amukamara, Nebraska (4.43)

T5. Joe Lefeged, Rutgers (4.43)

• Colorado CB Jimmy Smith posted an impressive 4.46 at 6-foot-2 and 211 pounds, showing good speed to go with his elite size for the position. All three of our top corners -- Amukamara, Peterson, and Smith -- have held up under scrutiny and backed up what we've seen in film.

• Chekwa's 4.40 was also impressive, but Van Dyke and Chekwa are tight in the hips and struggle to make lateral cuts to turn and run in coverage.

• UCLA S Rahim Moore looked good in position drills, showing quick feet and more fluid hips than expected. He was technically sound when turning and running, and just like on film Moore tracked the ball very well.

• West Virginia S Robert Sands is high-cut at 6-4 and struggles to open his hips, something that stood out even more today while he performed alongside smaller, quicker cornerbacks. Sands can play the point effectively but he has limitations in man coverage and will be more of an in-the-box safety at the next level.

• We talked about Chattanooga CB Buster Skrine during the practice week leading up to the NFLPA (Texas vs. Nation) all-star game, and while his technique and anticipation need to be refined Skrine did run a 4.44 40 and confirmed his ability to turn, run and recover when caught in trail position.