SAN CARLOS, Calif. -- It's Wednesday night, and the Undisputed Boxing Gym is closed for business, but owner Brian Schwartz is leaving the lights on as the speakers blare '70s R&B classics for a special client.
"Frank's coming tonight," Schwartz says.
That would be Frank Gore, the San Francisco 49ers' all-time leading rusher, who is spending his third offseason honing his boxing skills to his preferred soundtrack of Al Green, the Isley Brothers and Marvin Gaye.
As for the training regimen, it resembles the one Schwartz and associate Mike Bazzel drew up for current featherweight champion Nonito Donaire, and Gore, coming off his third straight Pro Bowl season, swears by it.
"When I see a guy on the football field huffing and puffing, I know I got an advantage over him," the 31-year-old reveals after punching Schwartz's focus mitts for 30 consecutive minutes without rest. "Since I started boxing, between plays (on the football field), I'm standing straight up."
Keep in mind that this is Gore's second workout of the day; the morning session featured weightlifting at 49ers headquarters in Santa Clara. In a league where running backs on the wrong side of 30 are advised to preserve their bodies, Gore is pushing his to the brink, completing this particular session by performing sit-ups to the point of exhaustion in a high-altitude-simulation dome.
"I'm done when I'm done," a light-headed Gore says matter-of-factly, copious beads of sweat glistening all over his face, neck and arms. "I don't like to have a set number on how many sets or reps (I do). That puts limits on what I can do to be in tip-top shape."
Heading into his ninth season as the top back on the 49ers' depth chart, Gore is an anomaly. But between the team drafting Carlos Hyde last month and Marcus Lattimore receiving medical clearance, along with the presence of Kendall Hunter and LaMichael James, the 10th-year veteran's endeavor to keep his starting job will be more arduous than ever.
Nonetheless, Gore's remarkable journey to the NFL and his subsequent longevity are indicative of an indomitable spirit that makes it tough to bet against him.
"There are so many more doubters saying I can't do this or that anymore, but we'll see," says Gore, who is entering the last season of his current contract. "I've been hearing that my whole life, and I'm still here."
Borne out of his beginnings
Gore attended Coral Gables High School in the Miami area but grew up in nearby Coconut Grove, where the drug epidemic was so rampant his senior year that a police sting operation reportedly revealed some convenience stores were selling "crack kits" to the locals.
"If you want to understand Frank and why he's been on top for so long, you have to know where we came from -- and how tough it is," childhood friend Charles "Chucky" Watson says. "And you definitely have to start with his mom. She did everything to keep Frank and me away from all that."
Lizzie Gore was a general, drill sergeant and nurturer all rolled into one. Such duties are non-negotiable when you have to raise four kids and house countless other relatives and friends in a cramped two-bedroom residence.
"I could've easily gone the other way," Gore says, "but luckily, I had football and the dream to play in the NFL so I could do something positive with my life."
That hope was fostered by former NFL defensive back Neal Colzie, a Coconut Grove native and Coral Gables alumnus who took Gore under his wing before his untimely death in 2001 from a heart attack.
By the time Frank discovered his gift on the gridiron, Lizzie had prevailed in a struggle with drugs only to be afflicted with kidney disease, which left her laboring to get out of bed for dialysis treatment three times per week.
"No matter how much pain she was in, she'd always be coming to my games, though," Frank recalls about his mother, who succumbed to the illness in 2007. "She was everything to me.
"Even with everything going on with her, she put food on the table and clothes on our backs. My goal was always to take care of her and my family one day."
To do that, he would have to become eligible for college. Struggles in the classroom were partially due to an ongoing fight with dyslexia. But rather than seek the path of least resistance and hope for a handout, Gore took matters into his own hands.
After a senior season that saw him shatter the Miami-Dade County record with 419 rushing yards in one contest, the uncommitted back was slated to join teammate Jonathan Vilma in a local all-star game. However, Gore never showed up.
"A lot of people told Frank he wouldn't be able to make it academically, and he's the type of person that loves to be told he can't do it so he can prove you wrong," Trelvin Payne, Gore's position coach at Coral Gables High, remembers. "So instead of going to the game, he actually chose to get tutoring all day so he could work on his grades. It was that important to him."
Eventually, his test scores improved enough for him to earn a diploma, and despite an enticing recruiting visit to Ole Miss hosted by none other than Eli Manning, the University of Miami staff made a successful last-minute plea to keep Gore at home despite an overflow of talent in the Hurricanes' backfield.
"I could've gone somewhere else and started right as a freshman," Gore says. "But you look at the competition I had in Miami: Najeh (Davenport), (Clinton) Portis, (Willis) McGahee, Jarrett Payton. When you go up against the best of the best, you're ready for any type of competition."
Gore's resilience was on trial throughout his collegiate career. After averaging more than 9 yards per carry as a freshman in spot duty, he beat out McGahee for the starting job in 2002 -- only to tear his left ACL in spring practice. The ensuing recovery was seemingly all for naught when he ruptured his right ACL in the fifth game of the 2003 campaign.
At that point, Gore, tired of being college football's version of Sisyphus, contemplated hanging up his cleats for good. But fate intervened in the form of his position coach, Don Soldinger.
"It was really disheartening to him, with the injuries being one right after the other and the rehab the first time being such a bitch," Soldinger says, his signature booming voice permeating the speakerphone. "He was so down in the dumps, but I had to convince him that they haven't even seen what he really could be if he was healthy.
"Now look at him. He's had two flat tires and he's been in the league 10 years."
With a renewed focus, Gore returned to the lineup for his redshirt junior season and recaptured the No. 1 spot, amassing more than 1,000 yards from scrimmage. Still, injury concerns caused him to slip to the third round of the 2005 NFL Draft, where the 49ers selected him 65th overall to spell incumbent starter Kevan Barlow.
"They knew that as long as I'm healthy, the 49ers knew they had a steal."
That was indeed the case for offensive coordinator Norv Turner and head coach/general manager Mike Nolan, who traded Barlow to the New York Jets in the 2006 offseason due to their faith in Gore as a three-down back.
Turner and Nolan have since exited San Francisco -- along with one other head coach and four more offensive coordinators during Gore's time in the Bay Area -- but the running back has never relinquished his starting role, despite a parade of challengers.
Indispensable tools
Oct. 20, 2013. LP Field, Nashville. The Tennessee Titans have forced the 49ers' offense, which is clinging to a 3-0 lead, into a third-and-7 situation midway through the second quarter.
Not to worry. Quarterback Colin Kaepernick takes the snap, fakes the read-option handoff to Gore, finds some daylight and scampers like a gazelle 20 yards into the end zone, untouched.
The broadcast crew credits the signal-caller's speed in the open field as well as fullback Bruce Miller's pancake block of Titans linebacker Colin McCarthy, but in the film room that week, there was no question about the play's true linchpin.
"The quarterback ended up pulling it (in), but we've really tried to emphasize if you don't get the football, sell it up through the middle and then add it on down the field," current running backs coach (and former 49ers fullback) Tom Rathman says. "(Frank) did that because he saw the safety coming down, so he got downfield and blocked him. He got the quarterback in the end zone.
"He adds on in the quarterback-disconnect stuff. Those are things people don't see and take for granted but mean a tremendous amount to the team, and he does all of them."
Even Miller, the purported catalyst of the scoring romp, nods in accord.
"He does it all the time, not just with that play," the fullback says. "We have our assignments on every play, and on the field, not everything is exact.
"But if I don't get the right leverage or miss a block, having a guy like Frank Gore, who knows where everyone's supposed to go, is a relief. He can erase mistakes. I like to say he always makes me right."
Thus, one of the keys to Gore's staying power has been his value as a second coach on the field. Lattimore, who did not see any game action during his "redshirt" rookie season, used the 2013 campaign to observe and learn from the elder statesman.
"He's the smartest football player in the NFL, I think," claims Lattimore, who, like Gore, faced the daunting task of overcoming a gruesome college knee injury. "He not only knows where all 11 players are supposed to line up, but even all the offensive line's blocking assignments.
"He knows the route tree for every receiver, and he can read coverages. He's got the footwork, and he's the best blocking back in the league."
Then there's what Gore does with the ball in his hands. His uncanny ability to consistently squeeze through a modicum of space is the product of his eyes and patience more than it is his speed.
"He comes out of piles or holes like no one I've seen," states the now-retired Soldinger, who was inducted into the University of Miami Sports Hall of Fame last year. "He has what I like to call great lamps -- great natural vision. He's the most natural runner I've ever had."
Dependability and durability go hand in hand, and Gore receives high marks there, too. Since taking the reins from Barlow in 2006, he's notched at least 200 carries per season, with this past campaign's 276 totes ranking as the third-highest total of his career.
Gore also hasn't missed a game since 2010, playing through a multitude of injuries; in January's NFC Championship Game loss to the Seattle Seahawks, neither a broken finger nor a massive headshot sustained at the goal line could keep him out of the contest.
"You never know when you're going to get back to this point," Gore says. "I don't want to look back and say, 'I wish I did this or that.' It was the NFC championship, and I had 53 people who believed in me that would rather see me on the field than on the sidelines."
While the courage was expected against the archrival Seahawks, the production didn't quite match it. Gore's 11 carries for 14 yards raised concerns that he either was being utilized excessively in the regular season or that Father Time had finally begun to gnaw at his ankles.
As a result, Hyde, Lattimore and Hunter likely will get plenty of looks in the preseason -- which will ease Gore's workload but also threaten his viability as the 49ers' unquestionable bell-cow back.
"I'm not ready to stop playing," Gore asserts. "I respect all the guys we got, but I don't care who they bring in. I'm not selfish. I'm willing to help them, but I want to compete."
Crucial juncture coming?
Back in the high-altitude dome at Undisputed, Gore pulls out his phone and attempts to load up a video clip of an ESPN analyst speculating that 2014 could be the running back's final go-around as the 49ers' starter.
"I put this on every time when I work out," he says, pursing his lips and nodding his head in the process.
As Gore enters the last season of a three-year extension, could the talking heads be right? With Kaepernick signing a lucrative pact last week, and several other cogs in the offense (Vernon Davis, Michael Crabtree, Mike Iupati, Alex Boone, et al.) itching for new deals, does Gore hope enough money will be on the table to allow him to finish his career in San Francisco?
"I do, but I just take it one year at a time," Gore says. "The only thing I can do right now is keep getting in shape ... and when the season starts, go play football and try to be the Frank Gore that I've always been. And whenever that comes, if it's here, whatever. Repeat and do the same thing."
Younger and cheaper is the mantra of the salary-cap era. Hyde and Lattimore are both 22 years old. Hunter, 25, has entrenched himself in the rotation, while James, 24, has reportedly been on the trade block.
"It's Frank's spot, but when you get an opportunity, you have to make the most of it," Hunter says. "That's the mentality you have to have, and that's what I've learned from Frank. I have to bring my 'A' game every day."
Veterans truly walk a tightrope, in the sense that they're often tasked with tutoring the very players who are aiming to usurp them in the lineup. Rathman remembers his gold watch moment. After eight seasons and two Super Bowl victories with San Francisco, he spent 1994 with the Raiders -- then called it a career after seeing his skills inevitably deteriorate.
"It's not about what you did last year, or what you've done over the last nine years," Rathman says. "I've seen Joe Montana leave here. I've seen Ronnie Lott leave here. Roger Craig left here. I left here. It's going to happen eventually to everybody, but all you can worry about is the next snap, and I think (Frank) understands that."
Still, you'd be hard-pressed to find anyone at 4949 Centennial Boulevard willing to opine that Gore has reached the end of the line -- his competition included.
"You know what, I think he's got five more good years in him," Lattimore says. "He still can do it all, from what I've seen."
Follow Ryan Maquinana on Twitter @RMaq28.