Nebraska's Boyd Epley can still remember the weight-room phone call during a warm August afternoon in 1969. He didn't know the brief talk would forever alter the college football landscape.

For months Epley, a no-name pole-vaulter from a no-name Arizona junior college, had trained -- almost inadvertently -- the Huskers' injured football players. Epley lifted weights to strengthen his injured back -- using techniques he picked up from a body-building friend in high school -- and the Huskers' football players mimicked him.

Tom Osborne, then a first-year offensive coordinator at Nebraska, noticed that those injured players returned to the gridiron even better than before, so he wondered what kind of impact strength training would have on healthy players. Why couldn't Epley work his magic on the entire Huskers team? Why not call down to the weight room and hire him as the nation's first full-time strength and conditioning coach?

"If you're looking for the most impactful change, in terms of progression, Nebraska's coaches coming onto the scene like that -- that was probably the single most important event," said Dr. Peter Weyand, an SMU professor of applied physiology and biomechanics, and one of the nation's foremost experts on human performance.

Progression, or evolution? Either way, there's no denying players are bigger, faster and stronger. According to a 2011 study conducted by Grand Valley State, between 1959 and 2011 the average college lineman gained between 0.74 and 1.98 pounds every year. That means Penn State's largest player in 1959 was senior tackle Charlie Janerette, who weighed in at 234 pounds. And, in 2015, the Nittany Lions' lightest offensive tackle is now 278-pound Paris Palmer, a junior-college transfer.

Speed is more difficult to measure -- the NFL only started electronically timing the 40-yard dash in 1999 -- but, to provide some perspective, take a look at the Pac-12's track champions. In 1976, in the first year of the 100-meter race, USC track-only athlete James Gilkes clocked a conference-best time of 10.5 seconds. In 2015, five Pac-12 football players -- four of them freshmen -- all ran as fast or faster.

There are various reasons for all these changes. Technological advances, such as synthetic tracks and turfs, have artificially increased speeds. There's also a larger pool of athletes today than yesterday, thanks to more people chasing more money in sports. (The average NFL player made $10,000 in 1958 and about $2 million in 2013.) But there's also something else -- something as equally obvious as it is taken for granted.

Strength and conditioning programs -- and, especially, the increased emphasis on the weight room.

In the late 1960s, when the average offensive tackle weighed in the 250s, strength training was mostly seen as an exercise designed solely for the Mr. Universes and Arnold Schwarzeneggers of the world. It was supposed to make you slower, make you worse as a football player, and colleges steered clear of the fad like they did fast food at team meals.

"We thought it was bull----," said Howard Schnellenberger, who played for Kentucky in the 1950s and coached in the NFL and college for 52 years. "We said, 'Why the hell do you want to be a weight lifter? You want to be a football player.'"

Enter Epley, a $2-an-hour hire that reeked of desperation in 1969.

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