The book is now closed on the 2016 NFL Combine. Despite 40-yard dash times being all over the place, the defensive backs were the fastest group of the week. Several cornerbacks significantly improved their draft stock while others quieted concerns about their athleticism. Here are the risers from the final workout of the Combine.

1. CB Eli Apple, Ohio State - Apple timed 4.40 seconds in the 40 after measuring just over 6-feet and 199 pounds. The time quieted some of the concerns scouts had about his long speed. Apple later looked terrific in drills, displaying a smooth backpedal and the ability to quickly flip his hips in transition. He cemented himself as a top-20 pick.

2. CB William Jackson, Houston - When all is said and done, Jackson helped himself more than any other defensive back on Monday. He timed the 40 in the mid-4.3s, measured over 6-feet tall and looked natural in all the drills. His backpedal, ability to flip his hips and explode to the ball came second nature to Jackson, who moved into the top half of the second round.

3. CB Jonathan Jones, Auburn - Jones was the fastest defensive back of the day, timing in the high 4.2s on a number of watches. He looked equally athletic and fast during drills. Like William Jackson, Jones effortlessly moved throughout all the drills with efficiency and little wasted movement. His terrific Combine performance comes off the heels of a very good Senior Bowl week and Jones' stock is on the rise.

4. DB DeAndre Houston-Carson, William & Mary - The small-school prospect is another who capitalized on a solid Senior Bowl week with a good Combine performance. His 40 time in the low 4.5s was better than expected and Houston-Carson looked good in all the drills. He displayed solid ball skills and was fluid in his hips and backpedal.

5. CB Anthony Brown, Purdue - Brown was not highly rated entering the year, but has been on a tear since January. He followed up a terrific showing at Shrine Game week with an outstanding Combine workout. Brown's times in the 40 clocked in the low-to-mid 4.3s while his vertical jump came in at 35 inches. Brown kept the momentum going and looked sharp in position drills.

6. CB Justin Burris, North Carolina State - Scouts had major questions about the long speed of Burris, but he squashed many of those concerns by timing the 40 in the low 4.5s to high 4.4s Monday. Included was a 10-yard split of 1.59 seconds, just slightly slower than Eli Apple's mark. Burris looked fluid in drills, especially when flipping his hips and transitioning from moving backward to running forward.

7. S Tyvis Powell, Ohio State - Powell had the most complete performance of all the safeties who took the field Monday. His 40 time clocked under 4.5 seconds, giving him one of the fastest marks at the position. His vertical jump was a respectable 34.5 inches and Powell looked terrific in drills. His foot quickness, hip turn and initial burst looked better than many of the cornerbacks who worked out.

8. S Justin Simmons, Boston College - Simmons was a terrific college safety who got a rap for not being a good athlete. He changed that perception on the final day of the Combine. His 40 time clocked in the high 4.5s, much better than expected. His vertical jump of 40 inches bested all other safeties by two inches and his broad jump of 10-6 was a top-five mark. His times in the short shuttle (3.85 seconds), long shuttle (10.84) and 3-cone (6.58) were all outstanding marks bettered by only three defensive backs. !

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