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.

Boyd Epley changed the way Nebraska approached strength training, and soon after other programs followed their lead. Courtesy of Nebraska athletics

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. Huskers head coach Bob Devaney was on the hot seat after his second straight season without a bowl and a 47-0 end-of-year thrashing against Oklahoma. He was willing to try anything -- even hiring a senior pole vaulter to train his team.

"I can't even tell you what I said because I was shaking so much," Epley said. "They were both looking at me and I must've said something about getting stronger and faster because then Bob says, 'I know this is important to Tom, so we're going to give this a try.'

"Then he pointed his finger in my face and said, 'If anyone gets slower, you're fired.'"

Forty-six years later, Epley still works at Nebraska.

The changes he instilled were incredible for the time. In 1970, according to Epley's records, the average Husker bench-pressed 206 pounds and no one could bench 300. By 1983, the average became 302. But it was the immediate impact that sent tremors through the college football world. In 1969, the Huskers rebounded with a 9-2 record and handed the Sooners what was then their worst loss in the series since 1928, 44-14. In 1970, running back Joe Orduna also bounced back from a knee surgery -- usually a career-ender -- to record career bests in yards (897), yards per carry (4.5) and touchdowns (15). Nebraska went 11-0-1 and won the national title that season.

"I had no idea what the opportunity was back then," Epley said. "It was like, 'Do you want to help me or not?' It wasn't, 'Hey, do you want me to change your life and spark this new thing?' I had no idea."

Suddenly, coaches from around the nation like Woody Hayes, Barry Switzer and Jackie Sherrill inundated the Huskers with phone calls about their quick turnaround. Acceptance didn't come overnight, but Epley got the ball rolling with strength and conditioning -- and the ball never stopped.

"Nebraska was the first team to kind of start opening people's eyes," said Ken Mannie, Michigan State's current strength and conditioning coach and an Akron player/avid weight-lifter in 1971. "We're really indebted to Boyd Epley because he was one of the catalysts. There wasn't a lot of emphasis on strength and conditioning before that."

Epley started out with a 416-square-foot weight room. When Osborne asked for a list of equipment, Epley handed him a list of York Barbell machines the very next day. But when the coach glanced at the list, passed it on to his secretary and said, "Order this," Epley saw his chance for more.

"Uh, Coach? I forgot the second page," Epley said. Osborne just laughed; he knew there was no second page. But he told Epley that was fine, to just bring it in the next day. Epley did, Osborne passed it onto his secretary and once again said: "Order this."

Now the Nebraska weight room is around 20,000 square feet with state-of-the-art equipment. Back in 1971 at Akron, Mannie was forced to haul back scrap steel from the mills so he and his teammates could lift beneath a peeling ceiling and leaky pipes. Mannie now works at Michigan State, which boasts over $1 million just in equipment. (Akron has come a long way, as well, and hosted a strength and conditioning seminar just last year.) The NFL was no different. The Washington Redskins once famously had a disco ball hanging from the weight-room ceiling. Now they again upgraded the weight room in the spring and doubled their number of stations.

The impact of this arms' race of athletic facilities isn't just limited to increasing strength, either. Although strength doesn't matter much for top-end speed, according to Weyand, exercises like squats have had a direct impact on football players' change of direction and quickness, along with acceleration -- at least for about the first five yards. After the first few steps, form and mechanics kick in.

"In my high school days and early college days, I can't remember any out-of-season programs that were geared toward change of direction and agility, movement and quickness," said Kansas State coach Bill Snyder, who was a doctoral student in USC's Physiology department. "Now you have big guys you're training to have some of that athletic ability."

From 1999 to 2002, the median wide receiver time in the 3-cone drill -- which measures agility -- ranged between 6.99 and 7.26 seconds. From 2013 to 2015, that same median lowered to a range of 6.91 to 6.97 seconds.

The next stage, according to Mannie and Weyand, is rooted in sports science. Catapult Technology, a complex player-monitoring system, for example, helps track more than 100 different player metrics and has been utilized by teams such as the Oregon Ducks, New York Giants and Golden State Warriors. (In other words, if you take a play off, there's no longer any hiding it. The technology should also help gauge player progression or lack thereof.)

There's no telling how much further down the rabbit hole that college football can go. But it's already come a long way in a short time -- and some coaches and experts still can't believe it.

"It's not even in the same solar system now," Mannie said. "It's not even in the same galaxy, to be honest with you. It's come a long way to get to this."