It should have been a fairy-tale ending to a classic boxing trilogy. Manny Pacquiao had just won his November 2011 fight against Juan Manuel Marquez. Pacquiao won on the scorecards, but there was no postfight euphoria. Against Marquez, the Filipino boxing icon didn’t seem himself. His trademark flurries of punches and tireless work rate in the ring weren’t there. Marquez, the Mexican counterpuncher, seemed to have defused Pacquiao’s explosiveness, and when the victor was announced, thousands of Mexican boxing fans inside the MGM Grand Garden Arena rained boos on Pacquiao. Later, in the press room, Pacquiao’s trainer, Freddie Roach, shook his head and tried to explain what went wrong. Pacquiao’s calf muscles have given him troubles over the years, and once again they seemed to hobble the boxer and slow his attack. “We have to do something about them,” Roach said. But what exactly was he saying? It felt like he was speaking in some sort of pugilistic secret code.

Those powerful, grapefruit-sized calves are an important part of Pacquiao’s success as a boxer, and, by corollary, his political career. Pacquiao is a sitting congressman in the Philippines and he has grand ambitions to someday lead his country. He won’t be old enough to run for president until 2018, and he’s viewed as a potential candidate for the 2022 election. But Pacquiao’s political fate is inevitably linked to the status, fame, and wealth he gains from being one of the world’s best boxers. If his calf problems submarine his campaigns in the ring, then his political campaigns will likely follow.

Pacquiao’s bulbous calf muscles may be the diminutive boxer’s most noticeable physical trait. The knockout power he’s used to drop and bloody far bigger men begins in those legs, as does the speed he’s employed to dance around the larger men’s blows. Those calf muscles are the product of genetics, of course, but they have also been formed over the course of Pacquiao’s life, going back to his childhood. Nearly 30 years ago, when Pacquiao was a boy living in General Santos City, he started carrying water up and down a hill for his family. Back then he was just a poor kid in the southern Philippines, running from place to place to save money on jeepney or pedicab fares. In his youth, Pacquiao ran hundreds of miles, and he fought too, dancing on the balls of his feet for countless hours of sparring and boxing bouts. All of that running and boxing created stamina and those thick, bulging calves.

But sometime in the past five years, Pacquiao’s calves started to bother him. I covered him closely for years and even wrote a biography of him, but Pacquiao rarely communicates his inner feelings and no one in his camp seems to know when Pacquiao’s calves started ailing him. He told associates that they had troubled him in his second fight against Marquez, in March 2008. Later that year, as he prepared to fight David Diaz, he told confidantes (who would later tell me) that it felt like his muscles were being ripped from his shin bone.

Pacquiao proudly insists that he has never visited any specialists to examine his calves. Ryan Capretta, the founder of Proactive Sports Performance, a Los Angeles–area training facility whose clients include Nick Swisher, Dwight Freeney, and Clay Matthews, says modern athletes are usually seeking more, not less, biomechanical information about their bodies to increase their edge and stay injury-free.

Since Pacquiao hasn’t had the problem checked out — or officially admitted he has a problem — no one really knows what’s causing his calf pain. It could be an electrolyte deficiency, a back issue, or even chronic exertional compartment syndrome, a condition that sometimes occurs in endurance athletes and causes their muscles to stop receiving good blood flow. “It’s very easy to work up a diagnosis if he comes in,” says USC sports medicine specialist Dr. James E. Tibone. A typical examination would include an MRI of Pacquiao’s back, a blood test to check electrolyte and calcium levels, and a muscle-pressure measurement in which microscopic wires are inserted in his calf at rest and while he runs on a treadmill. “What does he have to lose by finding out what’s wrong?” Tibone says. “Otherwise, it’s just guessing.”

Of course, Pacquiao’s reluctance to work within the realm of modern medicine is an age-old boxing tradition. Juan Manuel Marquez used to drink his own urine; Archie Moore swore by an “Aboriginal diet” in which he chewed on meat, sucked out the blood, and then spit out the meat; Ray Robinson supposedly drank human blood (an old-timer who was in the Robinson camp swore to me he witnessed it); Evander Holyfield turned to prayer to help a heart condition; Oscar De La Hoya ate deer and kangaroo meat because his trainer told him, “Deer run fast,” and because kangaroos’ “legs are strong and when you get in the fight you’ll be strong like a kangaroo.” Why did he follow such reasoning? “I was in his hands,” De La Hoya explained. “I just trained.”

In 2008, when Pacquiao began preparing to fight bigger opponents, Roach encouraged him to hire fitness trainer Alex Ariza, who instituted exercises to counterbalance Pacquiao’s overdeveloped calves. He put forth a program that brought speed and flexibility drills into Pacquiao’s training. The fighter was reluctant — his idea of training was old-school, based on thousands of miles of cumulative road work and getting his stomach beat by a bamboo stick — but he slowly adopted some of Ariza’s drills. It seemed to work. Pacquiao needed to gain 13 pounds of muscle — and retain his speed — in a nine-month period to compete against a naturally larger fighter like Oscar De La Hoya. Pacquiao was 129 pounds when he fought Marquez. He weighed 134.5 pounds when he overwhelmed David Diaz. And he would weigh 142 before fighting De La Hoya in December 2008. Pacquiao dominated the faded Golden Boy and KO’d Ricky Hatton in spectacular fashion five months later. These were Pacquiao’s glory days. He was plowing through elite fighters, earning multimillion-dollar purses, and his calf cramps seemed to disappear.

After Pacquiao-Marquez II, the calf cramps were nonissues for six fights (Diaz, De La Hoya, Hatton, Miguel Cotto, Joshua Clottey, Antonio Margarito). Pacquiao’s opponents were well chosen, as they say in boxing. Pacquiao looked brilliant against slower, outmatched men, most of whom were fighting at uncomfortably low weight classes or catchweights. Pacquiao was never in trouble. There was never a peep about his calves.

Then, leading up to his fight against Shane Mosley, I started hearing whispers — at the Wild Card Boxing Club, in the Los Angeles hills where he runs, at Pacquiao’s regular dining spot, in his tattoo parlor — that Pacquiao’s calf issues were making a comeback. The calves, however, could have been a code word for the standard list of distractions that make every Pacquiao camp a bit dicey. In the weeks before the Mosley fight, Pacquiao was juggling his camp with his congressional duties, practicing with his band, acting in movies, and leading a messy social life. On top of that, his calves may or may not have been acting up again, but of course, when I asked about them Pacquiao told me his legs felt fine.

Was the pain an excuse to delay another of his tough hill runs? (Pacquiao has hinted at retirement for years, and his associates wondered silently if he still loved fighting.) Were his calves hurting because he had the wrong shoes? (He got new ones.) Did he need to stretch more? (A new regime was introduced but Pacquiao didn’t seem committed to it.) Were his legs just getting old? He was 32 as he trained for the Mosley fight — and at the time Pacquiao had fought 57 professional bouts. Like many fighters, Pacquiao is extremely superstitious. He has always been reluctant to change his training methods, but as he grows older it seems that he should allow his body more recovery time — and yet he couldn’t seem to do it. Several-mile runs straight up a hill followed by sparring later in the day might have been good at age 28, but not in his 30s. Even when he was told not to run, he would sneak out and jog. But if Pacquiao was having an off-day and someone passed him, he would clutch his calves in pain. “Hurt, hurt, tight, tight,” he would say, and beg someone to massage them. No one knew if the pain was related to fatigue or a deeper medical problem. And beyond massage, nothing else was done for one of the greatest boxers in the world. There were no checkups, no diagnostic exams. Pacquiao, his pain, and his inner thoughts were left alone. This is the curse of kings, dictators, and Manny Pacquiao.

In May of last year, Pacquiao fought Mosley and knocked down Sugar Shane with a left in Round 3. Mosley, nearing 40, hadn’t looked good for several fights and there were rumors that he had sustained an Achilles injury in training but wouldn’t drop out because he was guaranteed $5 million for the fight. He was definitely suffering with foot blisters during the fight, and pleaded with his corner to throw in the towel. And yet Pacquiao, considered by many to be the best pound-for-pound boxer in the world, couldn’t finish off Mosley. Why wasn’t he able to cut off the ring, track down Mosley, and end the fight? Word from inside the Pacquiao camp was that his calves slowed him down.

In the run-up to Pacquiao-Marquez III last November, I heard the same rumors about personal distractions, over-training, and calf pain. Pacquiao was expected to stop Marquez, a 6-to-1 underdog, quickly. But without the spring he normally gets from his calves, Pacquiao becomes just another fighter with limited defensive skills. Marquez, whose counterpunching style has always troubled Pacquiao, was able to catch the usually elusive Filipino with a variety of punches. In training camp, Pacquiao, a southpaw, had worked on going to his right to avoid Marquez’s tough left hook. To Freddie Roach’s horror, once the opening bell rang Pacquiao was suddenly incapable of moving to the right. Midway through the fight, as it became apparent that Pacquiao wasn’t on his game and that he might lose, he started complaining about his calves. Was the pain real? Was it an excuse? The cornermen weren’t sure, and even though Pacquiao escaped with a win, there was growing concern among his cornermen and his promoter about the state of his legs — and, to some extent, his desire.

Will he be pain-free for his bout with Timothy Bradley on June 9?

“How are my calves? Bigger!” says Pacquiao, laughing. “They feel fine.”

One Friday morning not long ago, Pacquiao scrambled up the hill to Griffith Observatory. Pacquiao’s usual entourage accompanied him — longtime friend and auxiliary trainer Buboy Fernandez, his voice coach, his watch holder, the man they call the “running monk,” and various others. I heard the usual chorus of calf denial: “They are fine.” “He has someone to massage them.” “He has some sort of exercises for them.”

Pacquiao looked better. More relaxed. Less groggy. Since nearly losing to Marquez, he has started spending his free time in Bible study. His training for the Bradley fight had been relatively distraction-free, except for a brief, unfortunate episode in which an Examiner.com blogger misquoted Pacquiao about his attitudes on gay marriage. The story went national, Pacquiao was lambasted on traditional and social media outlets, and emergency meetings were convened in Beaverton, Oregon (Nike), and Cognac, France (Hennessy), because Pacquiao endorses those products. Floyd Mayweather Jr. even took to Twitter to tweak his rival by saying he supports gay marriage. Before long, Pacquiao’s remarks were revealed to be far less inflammatory than originally reported. The Nike-targeted petition to drop Pacquiao’s line of apparel was stopped and he was more or less forgiven in the press, but the whole episode could still end up costing him millions of dollars in potential sponsorships and thousands of fans.

Less than two weeks away from his fight with Bradley, Pacquiao is back in Griffith Park, shadowboxing by the observatory, looking down on the Los Angeles Basin.

What is the state of Pacquiao’s calves? What story do they tell us this time? Team Pacquiao’s plan is for him to lay off the endurance work in this camp, do more sprints, more boxing-specific leg exercises, and space out intense workouts between more rest days. Who knows if it will work? It’s still unclear if Pacquiao can alter his routine as he grows older, and he proclaims, as usual, that his calves are fine. “I have had no problems with them,” he told me recently. “I have been doing plyometrics and isometrics for the first time in many training camps and I think that has been a big help. Other than that I have not done anything special nor have seen any specialists.”

After the last fight, Roach told me, not for the first time, that “we have to do something” about his star’s calves. It’s unclear how much anyone has actually done — Alex Ariza, the man commissioned with nurturing the mystical calves, has been criticized by Freddie Roach for taking an unscheduled hiatus during training camp to work with another boxer — but those magnificent, mysterious muscles have become a symbol for Pacquiao’s chaotic life. He is a 3-1 favorite over the 28-year-old Bradley, but if Pacquiao’s calves flare up again, his boxing career and his political master plan may be in jeopardy.

But from his perch outside the observatory, the expanse of Los Angeles below him, Pacquiao is in his own world. People surround him. They do not matter. They never really have. Boxing is a sport about an individual — how one person deals with adversity. Pacquiao has come from hard places, and it seems they have helped him survive a hard career in the ring. So there he is, after his long run, dancing with his legs, his calves a blur, performing his beautiful shadowboxing routine, alone, fighting an imaginary opponent, still figuring out how strong his legs are, how far he can push his body, who he is and who he’ll be in the future. For now, however, he’s Manny Pacquiao — world champion, sitting legislator, and Christian true believer — on top of that hill, bouncing on his tender calves and hitting air.

Gary Andrew Poole is the author of PacMan: Behind the Scenes with Manny Pacquiao — The Greatest Pound-for-Pound Fighter in the World and his boxing writing has been published in Time, The Atlantic, and Esquire. This is his first piece for Grantland.