THURSDAY, Sept. 12 (HealthDay News) -- College football players
may get bigger and stronger during their four-year careers, but
apparently all those grueling drills don't make them run faster or
jump higher, new research finds.
"This longitudinal study shows you can make [players] bigger, leaner and stronger, but speed and power don't change. You have to recruit speed and power," said study author Bert Jacobson, a professor of health and human performance at Oklahoma State University.
"This advice is more geared for wide receivers, running backs, corners and safeties," he noted. The findings appear in the September issue of the Journal of Strength and Conditioning Research.
The researchers followed 156 football players for seven years,
including the four years of their college careers. All were from
NCAA Division I colleges.
Ninety-two players were offensive or defensive lineman. The
offensive lineman's job is to move opposing players out of the way
so that their team can move the ball forward. The defensive
lineman's job is to try block players from moving forward. Size and
strength are crucial for these positions.
The remaining 64 were skill players, defined in the study as
either wide receivers or defensive backs. These are the players who
most need speed and power.
Power is the ability to jump vertically, according to Jacobson,
a skill that comes in handy when a ball is passed too high or if
you need to try to deflect a pass so the opposing team can't catch
it. Strength was measured with various weight-lifting challenges.
Speed was assessed with a 40-yard sprint.
Players' height and weight were also measured each year. At
study's start, linemen's average weight was 283 pounds. Over the
course of the study, they gained an average of roughly 3 percent of
their original weight, with 292 pounds the average ending
During that same time, they dropped their average body fat from
22.5 percent to 20.6 percent, meaning that although they were
getting larger, they were gaining more muscle mass rather than more
The linemen got significantly stronger over their college
careers -- with their ability to bench press increasing by 18
percent, from about 350 to 410 pounds. However, they actually lost
a little bit of speed. Their power was virtually unchanged.
During their college careers, the skill players gained 9 percent
over their original body weight, going from an average of 175
pounds to an average of 191 pounds. At the same time, their body
fat dropped from a lean 8.4 percent to an even leaner 8.1 percent,
according to the study.
As with the lineman, the skill players improved their strength
dramatically. But, they also lost a little speed in the 40-yard
sprint from year one to year four. They gained an average of almost
1.5 inches in their vertical jump from year one to year two, which
was the only year that there was a statistically significant
increase in power, according to the study.
Jacobson said the reason that speed and power don't increase
much over time is that these skills are dependent on the type of
muscle fiber you have. He said people have either fast-twitch or
slow-twitch muscle fibers, and "that's not going to change. You're
born with that speed," he said.
Dr. Victor Khabie, chief of sports medicine and chief of surgery
at Northern Westchester Hospital in Mt. Kisco, N.Y., said he was
surprised by some of the study's findings. "I find it hard to
believe that you can increase strength, but you can't increase
power," he said.
"This study says some things are innate, like speed and power. So, you are who you are, and you can't change natural talent," Khabie said. "But, they didn't measure quickness or reflex. In a play, if you get the first step and get the inside move on a defender, then you're open for a play."
In addition, Khabie said there's more to speed and power than
fast or slow muscle-fiber twitching. "Your hip, knee and ankle
joints hold the muscles together and how those joints are
coordinated in their movement affects your speed," he said. "If
someone has a smooth run, what it means is they have innate
coordination that probably starts in the brain."
Still, he said this was an important study that -- if the
findings are replicated -- "could have ramifications on how we look
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