Quickness Kills

- WHY THERE'S NO LeBRON JAMES OF THE NFL.

By John Brenkus, special to ESPN

Pretend for a moment that the NFL lifted its eligibility rules, which dictate that three full football seasons must pass after a player's high school graduation date before he can declare for the draft. Would that mean the NFL would suddenly be blessed with its own LeBron James, a teen prodigy who rules the game with his preternatural talent? Not bloody likely.

There are huge, prohibitive differences between even the best young players and their pro counterparts in speed (peak age: around 26), strength (peak age: early 30s) and aerobic capacity (peak age: 25). But the biggest difference is quickness.

For most positions, flat-out speed is less important than quickness. Quickness is that critical first step that allows a lineman to explode off the line and establish the optimal leverage angles on his opponent. That step helps a receiver get separation from the defender. And teenagers simply aren't hardwired to be as quick as veterans.

We've used cutting-edge accelerometers and infrared timing gates to measure the reaction times off the line of scrimmage for numerous college and NFL players. Most recently, we tested receivers Mardy Gilyard, 23, of Cincinnati, and Damian Williams, then 21, of USC, just before they entered the 2010 draft. Each took his first step in .33 of a second, on average.

Compare that with our measured reaction times of 26-year-old Pro Bowler Larry Fitzgerald and Hall of Famer Jerry Rice, who was 44 when we tested him three years ago. They reacted to the trigger, on average, in only .18 of a second - almost twice as fast as the college kids.

The results were no coincidence. Reaction time improves with age, getting shorter until we're in our late 20s, when typically times start to increase. It's all about muscle memory. Our ability to react quickly to a stimuli is dependent upon how efficiently our brain's cerebellum communicates with the primary motor cortex and the motor neurons and neurotransmitters that trigger muscles. Practice and repetition create shortcuts in the neural pathways that transmit messages from brain to body, decreasing reaction times. In other words, practice makes quickness more perfect - and separates the men from the boys.