A week of full-tackling drills and live mode before a crucial game against Cincinnati left Harris feeling "a little fuzzy" before kickoff, and a huge collision with a Bearcats linebacker dazed him midway through the game. "If you remember what a Pokémon card looked like with the holographic things behind it, that's kind of what the whole surroundings of both my eyes looked like," said Harris. "Everything was fuzzy and really bright."
His suspicions of a third concussion were confirmed. Harris' collegiate playing days were over.
After a season in which 11 Syracuse players -- more than 10 percent of the active roster -- suffered concussions, Marrone and his staff underwent an offseason of study and change. He decided that increasing the size of his players' necks might help reduce the number of incidents; more strength supporting the head could absorb the blow, he reasoned. It a hunch spawned by the daily neck workouts he endured during his playing days at Syracuse under Dick MacPherson in the early 1980s.
"I think a lot of us coaches who have played, we look back and say, 'Gosh, were there this many injuries when we played?'" said Marrone. "So for me, I was thinking of developing [the neck] area to help us."
When he read an article early this summer that linked neck strength to a decrease in concussions -- and after Syracuse made it through spring practice concussion free -- he felt confident his team was making strides in the right direction.
Several experts in the medical and weight training fields agree that Syracuse's new additions to the strength and conditioning program are positive steps, but they note that significant revisions are needed to maximize results. They said the program currently lacks the specific neck-strengthening tests that yield the most telling data, which experts hope could one day be measured at the NFL combine. They want to spur a change in philosophy that utilizes more machine-based workouts and less manual resistance in order to guarantee uniform training among all athletes.
Simply in terms of increasing neck diameter, though, Syracuse's program has been a tremendous success. Each player's neck was measured before the start of spring practice and again in the summer before fall camp. William Hicks, the assistant athletic director for athletic performance, said the average growth rate across the board was roughly eight-tenths of an inch -- with some players gaining as much as an inch-and-a-half in diameter.
"I can't wear regular dress shirts anymore," said Jay Bromley, a 6-foot-3, 280-pound defensive tackle whose neck increased by roughly an inch. "I need custom-fitted now."
The collective enlargement is a result of isometric neck work, weighted neck work and flexion and extension of the neck, all which were a focus of Hicks' workouts. Four times per week, Syracuse players experienced some type of exercise that targeted their neck or trapezius, a triangular-shaped muscle between the spine and the shoulder blade.
Part of the workouts relied on manual techniques in which Hicks used his hands and legs as resistance tools against each player. Other times, players paired up and worked together after Hicks demonstrated techniques. "We'll be on all fours and someone will put their knee out and you push your head up against it, in and out," said Justin Pugh, a junior offensive tackle.
Various other tools supplemented the manual resistance training. Hicks made use of harnesses and neckbands for additional resistance work, four-way neck machines that allow players to work their neck against weight and a HALO, a metal ring with an inflatable bladder. HALO is worn on the head to improve a 360-degree range of motion.
But the backbone of Syracuse's program is the hands-on training, similar to what Marrone experienced during his playing days, which focuses on the circumference of the neck. And it's this approach that experts have called into question.
Dr. Robert Cantu, one of the leading researchers on NFL brain trauma, is conducting a study with research partner Dr. Dawn Comstock that analyzes neck strength and the likelihood of concussions across a variety of high school sports. The study is ongoing, but the data from the first year showed no correlation between the size of one's neck and the likelihood of concussions.
"I thought clearly we would find a correlation between bigger, fatter necks and lesser concussions, but we didn't find it," Cantu said. " ... Some individuals with taller, slender necks surprisingly had greater strength than other individuals with shorter, fatter necks."
What Cantu and Comstock have found to be the crucial measurement is the actual strength of the neck, which they documented using scales that measured the pounds a neck could move. Their data shows that the quartile of athletes with the weakest necks suffered the greatest number of concussions, while the quartile with the strongest necks suffered the fewest.
Hicks, however, opted to keep the measurements for Syracuse's new program simple. He is "not going to test neck strength," only circumference.
His reasoning is that if the circumference of a player's neck is increasing and body fat is decreasing -- he said Syracuse's body fat percentage is down two percent as a team from last year -- then the neck must be getting stronger.
Cantu countered that such logic would present a problem for players attempting to come back from injury. Just like with any part of the body, the muscles in the neck will atrophy during a period of inactivity. And with no base measurements to indicate how strong a player's neck was before the injury, it is impossible to tell when they have returned to 100 percent in Syracuse's system.
"You're ultimately going to have to measure the strength to know what it is when you start and to know what it is when you reach a given level," Cantu said.
Cantu feels the manual techniques that Hicks and Syracuse are using can certainly be valuable and are likely strengthening the neck to a degree. But he also believes they must be combined with some sort of measureble exercise to document changes in strength.
Mike Gittleson, Michigan's former strength and conditioning coach for 30 years, is one of the leading advocates of strengthening the neck to avoid concussions. He speaks on the topic at conferences all across the country, and did so at the second-annual Football Strength Clinic in Cincinnati this summer. He believes Eastern Michigan's neck-strengthening program under coach Ron English is "the one program in American that you can really embrace."
English said the first 20 to 25 minutes of every weight training session are dedicated to neck, head and trapezius work. He has three target neck sizes for his players that vary by position. And in addition to documenting circumference, the players record their weight progression for flexion and extension on the four-way neck machines.
The school invested in six neck machines last year, associate head sports performance coach Gregory Pyszczynski said. They now form the core of the "head, neck and trap shop," as he dubs the program.
Syracuse has two neck machines.
"Ron English doesn't say, 'How much do you bench? How much do you squat? How much can you dead lift?'" said Gittleson, whose weight room at Michigan had 12 neck machines. "He says, 'How strong is your neck? What is its circumference?'
"And that's the first step in trying to address the issue. He's trying to make the field safer for kids."
As a freshman at California in 1987, English suffered a stinger in a tackling drill. He said he is still bothered by the lingering effects of the injury, and that's part of the reason he trains the neck so vigorously. The other reason is to reduce the high number of concussions and neck trauma injuries that Eastern Michigan sustained in his first two seasons at the helm.
The Eagles had 55 occurrences of neck trauma in 2010, according to a document Pyszczynski shared with SI.com. By 2011, that number fell to 35 occurrences, or 23 if you discount two players who Pyszczynski said "had some physiological dispositions that made them more susceptible" to neck trauma.
The team suffered a grand total of only three concussions in 2011.
"I think a lot of coaches, they all want numbers and they don't spend time to develop the neck," English said. "And so they want to spend that time on benching or squatting. But to me it doesn't matter if they're hurt all the time."
It's a fad that both English and Gittleson hope catches on across the country, preferably in the professional ranks. They both cited the trickle down effect that NFL policies have, and they feel that if the combine ever tested neck strength, head musculature or shoulder strength it would force high school and college teams to implement programs that develop those areas.
English said he spoke to one strength and conditioning coach this summer -- he declined to name the coach or the school -- who was removing all of his team's neck machines and claimed that shrugs and other similar exercises were adequate replacements.
"I was like, 'You've got to be kidding me,'" English said. " ... If [testing] ever happened in the NFL, you would see a boatload more people taking neck work seriously in college and high school."
The next step for Syracuse and others is fine-tuning their program to the level of Eastern Michigan's. Through three years, the Eagles' program has shown incredibly positive results that seem to be far ahead of the rest of college football.
Perhaps with spread of this thinking and Cantu's forthcoming study, players like Adam Harris won't have their careers cut short.
"Even if there is a little bit of probability, it's great," Harris said. "Hopefully they keep taking steps forward and protect the guys as best they can."