If you are a student of the NBA you are aware of the gravity-defying abilities of Michael Jordan, Clyde Drexler, Julius Erving, Connie Hawkins and Elgin Baylor. You have witnessed the explosive power of Charles Barkley outjumping and outrebounding players half a foot taller. Wilt Chamberlain exhibited feats of strength that former players speak of with great reverence. Bob Cousy, Larry Bird and Magic Johnson exhibited a "feel" for the game that enabled them to make the impossible look routine. Jerry West, Moses Malone and Kareem Abdul-Jabbar possessed toughness, resiliency and stamina rarely seen in athletes. These are examples of players with "special" qualities who played at a level rarely seen, a level I refer to as "freak" status.

Today, the NBA is full of world-class athletes who possess a unique combination of size, speed, quickness, agility and stamina. A select group of current players exhibit physical attributes that raise the bar even further, however. They aren't circus performers or sideshow attractions, but their physical abilities should be gawked over.

Here are five current players who possess physical qualities that elevate them to "freak" status.

Allen Iverson -- Speed and Quickness
When I selected Allen Iverson with the No. 1 pick in the 1996 NBA Draft, I knew he was the quickest player in that draft and that he was the most difficult rookie-to-be to defend one-on-one. Studying college tapes and watching him play over the last four NBA seasons lead me to wonder if there has ever been a quicker and more difficult player to contain.

Isiah Thomas comes to mind and the "Answer" is often compared to the former Pistons Bad Boy and current Pacers coach. Aside from the speed and quickness, it is his physical toughness that separates Allen from normal world-class athletes. How else do you explain scoring 46 points, grabbing nine rebounds and adding nine assists while playing with a separated shoulder as he did against the Kings on Dec. 30? After Iverson scored a career-high 54 against the Cleveland Cavaliers on Jan. 6, Cavs coach Randy Wittman said, "Believe it or not, we tried doubling him. But he got the ball so far out and was shooting before the double team got there. Plus his jump shot was falling. What could we really do any way?"

Iverson is so quick that it appears as if his would-be defenders are running in the sand. His dazzling speed leaves his peers, coaches and fans awestruck. He beats defenders so often and so decisively that they are often left with no alternative but to grab at him in an effort to contain (Iverson averages about 10 free throw attempts a game). His quickness is also evident at the defensive end, where he currently holds the NBA single-game playoff steals mark of 10 set in May 1999 against the Orlando Magic.

Shaquille O' Neal -- Power
I often hear people voice criticism of Shaquille O'Neal for supposedly not having a lot of moves or range at the offensive end of the floor. Personally, I think it's pretty good to be able to dunk the ball 10 times a game. In a day and age where style points are sometimes admired more than production, he epitomizes high percentage basketball with a career field-goal percentage that approaches 58 percent.

O'Neal is so strong that opponents hurt their arms trying to foul him. Maybe he is the reason there is a dwindling pool of competitive centers. Would you want to match up and fight for position with this 7-1, 330-pound opponent to make a living? And the scariest thing is that he is still evolving as a player.

Tim Duncan -- Head and Hands
While I was the vice president of player personnel for the Portland Trail Blazers, I visited Wake Forest to watch a practice early in Tim Duncan's sophomore season. Duncan was on the cusp of establishing himself as a "special" frontcourt prospect. His Velcro hands caught everything thrown near him and his defensive rebounding range was exceptional. But I witnessed something in that practice that has forever stood out to me as an example of his mental excellence, which surpasses even his physical attributes.

Wake Forest coach Dave Odom called Duncan and a freshman guard over for some instruction. When the freshman guard had his head down while listening to his coach, Duncan gently placed a finger under his teammate's chin and lifted his head to emphasize the importance of eye contact and respect. Without seeing another play I knew that this was not only a special basketball prospect with great hands, but also a uniquely mature young man with a special "touch" and the mental awareness to be a professional star. Even as a sophomore, Duncan was aware of the importance of respect for one's coach, as well as the obligation of a star player to serve as a mentor to younger players.

Vince Carter -- Body Control
With all due respect to Dr. J, Elgin Baylor and Connie Hawkins, Vince Carter does things on a basketball court that are being seen for the first time. No lob pass is too high, and no defender can stay up long enough or cover enough real estate in Carter's "fly zone" to contest his drives to the rack. What Michael Jordan showed us about making plays in the air during the '80s and '90s, Vince Carter is doing in the new millennium.

Still evolving as a player, Carter utilizes "freakish" physical attributes that make him nearly impossible to cover with or without the ball. In two-plus seasons he has scored at a 0.63 point-per-minute clip. If he continues on that pace he will be a 20,000-point scorer in his early 30s. If Dominique Wilkins was the "Human Highlight Film," then Vince Carter could appropriately be labeled the "Human Highlight Library."

Karl Malone -- Stamina and Durability
Karl Malone is the most productive power forward of all time. He is also the most durable power forward of all time. Malone has played in more than 1,200 regular-season games, 158 playoff games, and has only missed six games in his entire career.

Are you kidding me?

We are talking about playing more than 45,000 minutes as the prime-time, go-to player on a perennial contender. He now holds the NBA record for most seasons with 2,000 or more points. Have you ever seen a Utah Jazz game where Karl Malone didn't beat his man down the court for at least two fast-break layups? He has been named to the All-NBA first team 11 times and the second team twice. In 1997 he was named NBA MVP at the age of 34, and two years later at 36 he repeated the feat. This combination of durability and productivity may never again be duplicated in the NBA. Karl Malone is a "FREAK!"

Brad Greenberg brings 22 years of successful NBA and NCAA management and coaching experience to NBA.com as our player personnel expert.