Super Bowl XLIX featured two of the best and hardest-working quarterbacks in the NFL. Tom Brady and Russell Wilson committed thousands of practice hours to reach Glendale, Arizona. Their well-publicized determination to hurdle physical obstacles, real and perceived, underscores their journey.
Yet one rarely discussed aspect of their development is bound to surprise parents of future NFL quarterbacks. Brady and Wilson each played three sports in high school and were drafted by Major League Baseball franchises. Their participation and success reflect one of the starkest findings in ESPN's 2014 Quarterback Survey, one that contradicts the advice of specialization advocates and provides relief to those who promote cross-training even for high school prospects with high potential.
Of the 128 quarterbacks surveyed -- 73 active, 55 retired -- 122 played at least two sports in high school (95 percent). Nearly 70 percent played three or more. Five backups (Matt Flynn, Matt Barkley, Tom Savage, Aaron Murray and Zach Mettenberger) were the only active players to report single-sport participation.
For decades, research has illuminated the benefits of multiple sports for children, but even that advice has suggested specialization after age 16. Malcolm Gladwell's popularization of the 10,000-hour rule -- the number of practice hours required to master a field, per research cited in his book "Outliers" -- has attached an artificial goal to the rat race.
Steve Clarkson, the nation's leading personal trainer of youth quarterbacks, counsels clients of all ages to avoid specialization.
"Even if a kid is dominant at quarterback or in one position or one sport, it's still OK to learn other disciplines," said Clarkson, whose Dream Maker Quarterback Academy has been producing college and NFL quarterbacks for nearly 30 years. "They should never discard their training, even if they're just playing for fun. They don't need to be a master chef. But it's so important to continue developing their skill sets. It'll only enhance their primary sport.
"The biggest mistake is to shut down everything else completely because you want to focus on being a quarterback. These kids think more is better. [Hall of Fame NFL coach] Bill Walsh told me many years ago: Don't mistake activity for productivity. More practice doesn't always mean more success."
Current research and advice
About 1.1 million boys played high school football during the 2013-14 season, according to the National Federation of State High School Associations (NFHS), the governing body of most high school sports in this country. But the NFHS does not differentiate between single-sport and multi-sport participation, a spokesman said, making it impossible to get a full grasp of this trend.
Some per-state evidence is available on an anecdotal basis. A survey of Indiana high school athletic directors a few years ago, for example, found that less than a third of athletes at schools with enrollment of more than 1,200 were playing multiple sports.
Regardless, parents and kids who choose to specialize are chasing a dream that has a high failure rate; 6.5 percent of high school football players go on to play in college and .08 percent make it to the NFL, according to the NCAA.
This trend belies a wide range of research that suggests specialization increases injury probability, accelerates mental burnout and withholds the benefits of cross-training.
In 2012, for instance, a study published in the Journal of Sports Sciences found "a significant association between the number of sports participated in at the ages of 11, 13 and 15 and the standard of competition between 16 and 18 years." Athletes who played in three sports during their early teen years were "significantly more likely to compete at a national, compared with club, standard between the ages of 16 and 18 than those who practiced only one sport," according to authors Matthew W. Bridge and Martin R. Toms.
Specialization is more accepted at age 16 and beyond. But according to researchers Jean Cote and Jessica Fraser-Thomas, teenage athletes should still spend 20 percent of training time in non-specialized sports. That's true even for those playing quarterback, arguably the most specialized and difficult position in major American sports.
"If these kids are hearing they need to specialize in one sport, it's mostly because of business and the ego around these coaches," said Andrew Bark, founder of Student Sports, which runs the annual Elite 11 Quarterback Competition. "You have a lot of untrained or minimally trained adults basically either building their business of club sports, or you have leagues and teams and coaches who only care about their own wins and losses. But the truth is exactly what your [ESPN] numbers say. Playing other sports makes a lot of sense."
Is that true for everyone, though? Planning the athletic development of a child based on the pattern of an elite achiever could be a classic chicken-or-egg dilemma. Did Russell Wilson make it to the NFL because he played multiple sports in high school? Or did his natural ability simply compensate for the time he spent away from football?
"I think what you'll find is that the transcendent guys in football haven't specialized as much," said Brian Stumpf, vice president of football events for Student Sports. "A guy like Matthew Stafford, he played baseball in high school. It didn't affect his path to college. What you see is the push toward specialization in the cases of guys that are more marginal, the guys who are on a path toward a scholarship at San Jose State but want to go to a Michigan State instead."
Still, there is high value for those who can handle the balancing act, Clarkson said. Something has to give, he said, "but a lot of times, it is the social life outside of school." Clarkson's clients train from eight to 11 months per year, though that can come in many forms.
"My argument on the Malcolm Gladwell thing would be you can get some of those 10,000 hours playing other sports and still be productive in the long run toward your main goal," Clarkson said. "Ultimately, if you do it the right way, what you do in another sport can be productive for your primary sport, in this case training to be a college or professional quarterback."
What's the "right way?"
It was natural for former NFL quarterback Oliver Luck, working overseas as part of NFL Europe, to sign his son up for soccer and basketball. Did that cross-training help Andrew Luck's development into a future No. 1 pick in the NFL draft?
"Certainly, for quarterbacks it helps," Oliver Luck said. "Just playing football 12 months a year probably is not going to get you to a point where you can play in college or the pros. I'm a big believer in the value of other sports, certainly playing football and playing basketball, cross-training particularly at a young age, presuming you have talent."
Soccer, basketball and quarterback play share a reliance on "angles and triangles," Luck said. They also, Bark noted, foster a deeper sense of competitive, in-game environments.
"Being in competition, rather than just drills all the time, means something," Bark said. "Think of a basketball player who has to play with his eyes up as he moves down the court, fending defenders away and trying to make a play. That's part of being a quarterback too."
Clarkson, who starred as a high school quarterback in Los Angeles in the 1970s and later at San Jose State, said he isn't a big fan of soccer, but "I love the movement it gives my quarterbacks with their feet."
He added: "It certainly has great benefits. You have to find the common good in the other sports and determine how it relates to how you can succeed in your primary one."
Baseball might be the trickiest sport for quarterbacks, who are naturally drawn to pitching, despite the fundamentally different mechanics. Throwing a spiral is akin to the rarely used screwball motion in baseball, Clarkson said, which puts the two at odds. There have been pitching-quarterback success stories, from Colin Kaepernick to Jameis Winston, but Clarkson said: "Anytime I get a kid who is a baseball pitcher, I'm usually reluctant to take him without a lot of forewarning. Something is going to suffer."
Playing shortstop, Clarkson said, provides "the most compete element" in baseball for quarterback training. The position requires quick hands, natural hip turns and snap throws.
The bottom line, according to those who train and advance quarterback prospects at all levels, is a multi-sport regimen -- even for kids between the ages of 16 and 18 -- is preferable.
"I'm a big believer that participating in other sports is really helpful to anyone who wants to play quarterback," Luck said. "It's a hard position. Learning other movements and reading other defenses helps to play quarterback."
After all, 95 percent of a representative survey, including both of this year's Super Bowl quarterbacks, has spoken.
ESPN.com's Ashley Fox contributed to this story.