This story appears in ESPN The Magazine's Sept. 10 NFL Preview issue. Subscribe today!

At 6 a.m., I'm already in trouble. The sun is just beginning to peek through the thick trees that surround Stanford's campus, and I'm shivering in the parking lot behind Bryce Love's dormitory, watching Love pedal away on a black electric bicycle. Even riding shotgun in a Stanford-issue golf cart, I have no prayer of catching up. That's when I realize this assignment -- to shadow the fastest running back in college football from daybreak to lights out -- will reveal Love in exactly the way most Pac-12 defenses see him. Which is to say, I'll have an excellent view of his back. For much of the day, that back is seated on his electric bike -- not that Love, 21, needs any help getting faster; I'm fairly certain the bike actually slows him down. As a 12-year-old in Wake Forest, North Carolina, he ran the 100 meters in 11.64 seconds, the 200 in 23.37 seconds and the 400 in 50.75 seconds. (His times in the 100 and 400 still stand as national age-group records.)

Those legs made him a four-star recruit as a senior at Wake Forest High, even though he stood 5-foot-9 and weighed a smidge under 180. He chose Stanford over most of the SEC, ACC and Big Ten despite never having heard of the school until head coach David Shaw offered him a scholarship in his sophomore year. ("He might not have heard of Stanford, but I can tell you that his parents had definitely heard of Stanford," his mother, Angela, says.) After visiting the Northern California campus, Love fell in love with all those trees and the pink sunsets over the foothills and the nerdy football players who had interests outside of sports, just like he did.

At 6:18, Love locks his bike at the Arrillaga sports complex and descends the steps to the weight room that Stanford football shares with 35 other varsity teams. He walks to the running backs' cubby across from the snack bar and grabs a folder with a record of all the workouts he's ever done in his three years on The Farm. When Love arrived in 2015, the coaching staff didn't quite know what to make of him. Stanford runs a complex, pro-style offense with an enormous, annoying playbook that challenges any teenager during the summer training camp. That complexity -- plus a deep bench and an abject fear that young players will blow assignments that might result in a quarterback's dismemberment more often than 20-something veterans do -- means that Shaw doesn't like to burn a true freshman's redshirt unless absolutely necessary. But in one of Love's first summer scrimmages, he got the ball on a weakside isolation play and casually sprinted 45 yards untouched into the end zone. Shaw looked wide-eyed at his then-offensive coordinator, Mike Bloomgren, saying nothing. He didn't need to. "After that, it was over," Shaw says now. Love would not be redshirting.

A few minutes before 7 a.m., as Love laces his cleats for field drills, I glance around the weight room at his teammates. My eyes stop on a large, shirtless man on the far side of the room who looks familiar ... because it's Andrew Luck. He is doing a set of lunges next to 49ers guard Joshua Garnett, who is joking with Packers offensive tackle Kyle Murphy, while someone wonders aloud when Eagles tight end Zach Ertz will show up. That's when I learn that Stanford football keeps two locker rooms: one for its players and one for its alumni who play in the NFL. The latter has nameplates and everything. The coaching staff motivates its college charges by telling them that the goal is to graduate to the big-boy locker room one day. I think about how Love passed up joining these men in the NFL last season, and I ask whether seeing them every day and knowing they're getting paid a lot of money to lift weights at 7 a.m. might make him regret his decision. But Love insists it really wasn't much of a choice. He rushed for more than 2,000 yards and finished second in Heisman voting, but he was too pissed off about Stanford's disappointing 9-5 season (four of those losses by three points or fewer) to let it be his last year. "It, for lack of a better word, sucked," he says. "I couldn't go out like that."

Love insists that he has no regrets about staying in school after Stanford's 9-5 season last year. "I couldn't go out like that." Ryan Young for ESPN

And so here he is on an early Monday morning in July: sprinting to a practice field with his teammates, crawling on hands and knees like a crab and scooting side to side like a spider on its back -- cashing no paycheck, listening to grown men scream at him. From 7 to 8 a.m., the Stanford football players and their NFL friends jump and lunge and roll and crawl and plank in five-minute bursts, breaking only to do cat and cow yoga poses. The temperature hovers in the 50s, but the marine layer from the peninsula makes it feel even cooler.

By 8:12, they are back in the weight room, huddled for what I think will be hugs goodbye. Then the punter, a surfer dude from Hawaii named Jet Toner, screams for inspiration, "A hero is no braver than an ordinary man, but he is braver five minutes longer!" It sounds random until he follows it up with "Ralph Waldo Emerson!" (yes, really). And then they all yell and begin to exercise again. The running back group is given free time for physical therapy or to retreat to the locker room to check Twitter or text their girlfriends. (No phones are allowed in the weight room.) Love opts for the training room and some routine treatment on his recently healed right ankle.

Love finished as the nation's second-leading rusher last fall with 2,118 yards and set an FBS single-season record with 13 (!) runs of at least 50 yards, but perhaps most impressive is that he gained most of those yards on one leg. He missed just one game after suffering a high ankle sprain in Week 7, but Shaw says that in every game for the rest of the season, Love would finish a ridiculous run, get pummeled and hobble off to the medical tent, only to re-emerge in the huddle for Stanford's next possession. "Bryce is probably one of the toughest guys to ever play in this program," Shaw says. "He would limp off the field and I'd say, 'He's done. Get him out.' And then the training staff would retape him and come find me five minutes later and say, 'Coach, he's able to push off, he's passing all our tests, he says he's fine.' And so I'd put him back in and he'd rip off another 50-yard run." (Love totaled just 29 yards on 18 carries in Week 1 this season, though he and the Cardinal have a big chance to make another statement against USC this week.)

At 9:30, he showers and changes into a Stanford T-shirt and black shorts, ready to head off to class. Love's goal is to graduate after winter quarter so that he can better prepare for the NFL draft next spring -- and completing a demanding premed degree in human biology a quarter early means cramming summer school into his football schedule.

Love wants to be a pediatrician when his football career is over. His mother says he made the decision at 5, after he was hit with a nasty bout of pneumonia. His doctor made it better, became Love's personal superhero, and that was that.

By 10 a.m., on the way to class, Love is back on his bike and looking for an open dining hall. We trail him in our little golf cart at maximum speed, maneuvering past speed bumps, random wood posts and grad students auditioning for the Tour de France. We cannot keep up.

When I ask why only the football players have fancy electric bikes, they laugh and don't seem to know. Somebody at some point got one, and the others thought it was cool. Ryan Young for ESPN

We find him at Gerhard Casper Dining Commons picking up an omelet with vegetables and a side of fruit to go, which he'll eat back at his dorm. By 10:20, he's off to statistics class. He plops down in a third-row seat, next to teammates Trenton Irwin and Curtis Robinson, and takes notes on his MacBook Air.

At 11:24 a.m., he walks out of class with Irwin and Robinson and pedals back to Jimmy V's, a burger-and-smoothie joint attached to the football complex, to grab a burrito bowl and tortilla chips. At 11:40, he returns to his dorm -- temporary digs for the summer, where he rooms with starting safety Ben Edwards -- to begin his statistics homework and to study for a political science midterm. Then he climbs into bed for a quick nap. At 2:40 p.m., Love is back in the weight room for an optional yoga class led by Nanci Conniff, an instructor who works with the school's athletes. When no other football players show up, Conniff and Love take their mats behind a side wall for a private session. It's Love's second time ever doing yoga, and though he's a bit overwhelmed by the up-dog, down-dog of it all, he almost does a standing split straightaway, which would put him in the top 5 percent of yogis in any class I've ever attended.

Love's overwhelmed by his private yoga class, but his flexibility comes through: He almost does a standing split straightaway. Ryan Young for ESPN

Obnoxious rap-rock from the early aughts blares through the gym's speakers, but rather than ask for quiet while the school's football star lies in shavasana at the end of their session, Conniff uses the nuisance as a teaching tool. "Life is never going to be as quiet as you want it to be, Bryce," she says. "Especially in football. People are going to be screaming at you, and it's only going to get worse as you keep getting better. You will have to go inside when the noise is too much. You will have to get quiet." She lightly touches his chest. "It will have to come from in here."

At 4:18, Love leaves yoga and heads back out to the field to catch from the Jugs machine. The temperature on the field nears 80 degrees, but he wears long sleeves and a helmet to make it hotter and more difficult to see the ball. By 4:30, his shirt is stuck to his back, and sweat slicks his hands.

By 5 p.m., he's done, and he sits next to me in the front row of Stanford's empty football auditorium. After shadowing him for 11 hours, I want to know two things, really. The first is how he does all of this exercise -- not to mention class work -- day after day without collapsing from exhaustion. He laughs and says football is life. "I'm never more at peace in my life than when I'm on the field in a game waiting for a hole to open up," he says.

My next question is more serious. As it stands now, he wants to pursue two careers in direct opposition to each other: football, in which he potentially rips bodies apart, and medicine, in which he puts them back together. How does he reconcile the two? We are 60 seconds into our interview, and he is fidgeting and staring straight ahead at a whiteboard, searching for a good answer. "I haven't really thought about that," he says. Then, as if he remembers something important, he sits up straight and turns to look directly at me. "You kind of have to be a little mean to play football at the end of the day. But you can also have a switch. I've always been able to turn that switch on and off."

We have to do our interview quickly, because at 5:30 he has another lifting session, probably using a new set of muscles Stanford scientists just discovered. He changes clothes again and then presses and squats and lunges and lifts and bounces and climbs and laughs with his teammates, none of whom seems grumpy to have been doing voluntary exercise-y stuff for literally half the day.

Weights, yoga, jugs, team tech -- oh, and class, and meals, and homework. Love and his Stanford teammates log hours, even during the summer. Ryan Young for ESPN

This lift is followed by a players-only meeting at 7 p.m., which must have been a hoot, because by 7:15 the young men sprint toward the field as mini speakers blast J. Cole. They scream-sing every word. We have made it to "Team Tech": the best part of the day, when players scrimmage red zone packages and run whatever plays they want. Since coaches are not allowed at summer workouts, the upperclassmen are supposedly in charge, but it looks like controlled chaos. Stanford's defense is good, but the offense is better. It scores on every play. Nobody can outjump star receiver JJ Arcega-Whiteside or body up future NFL tight end Kaden Smith. And nobody can catch Bryce Love. If the season goes the way of the scrimmage, Stanford will be a threat for the Pac-12 crown and possibly a national title.

At 8:15 p.m., Love stretches with teammates. Then they circle up around sports performance director Shannon Turley, who previews what they will work on tomorrow and the next day and the next. Love, who hangs back to talk with one of the new freshmen, is among the last to leave the field. At 8:30, he takes, conservatively, his fourth shower of the day, and by 9 p.m. he is back on his bike in search of supper. From the front seat of the golf cart, I stare at Love's back and wonder again how anyone ever catches him.