MIAMI • There's a stranger in the photograph that friends have placed in Ariel Sigler's hospital room.

The muscles in the stranger's shoulders merge with the ones in his neck, and his chest swells through a plain white T-shirt. His eyes are bright, energetic. He looks like a human fighting machine, a man who once was a heavyweight national boxing champion in Cuba.

The man in the hospital bed at Jackson Memorial in Miami has deep inkwells for eye sockets, like a man who hasn't seen the sun for years. His sallow skin stretches tight over the bones in his face like a fist through a plastic bag. And it's impossible to reconcile that these two images — the vibrant boxer and the frail, newly released political prisoner — are the same man.

"He was a tronco, a tree trunk of a man," a new friend and Cuban-American blogger, Valentin Prieto, says later.

Cuba trained Ariel Sigler to fight. He learned discipline, endurance, and how to take a punch. But Sigler also learned to think on his own, and that's when the trouble started.

Sigler, 46, used those lessons to become one of Cuba's most strident dissidents, a decision that earned him a 20-year sentence in the spring of 2003, when more than 75 journalists were jailed in a mass roundup.

Thanks to intervention from the Roman Catholic Church, Sigler was among 52 dissidents Cuba agreed in July to release. He arrived in Miami on a humanitarian visa in late July, the only one of them allowed to enter the United States so far. About 30 others have been exiled to Spain.

Physically, the man who entered prison is not the one who came out. He rolled off the plane in a wheelchair as a paraplegic, his body withering from seven years of malnutrition in prison. But between those emaciated temples remains the mind of a fighter. And that helps explain how a 6-foot, 210 pound boxer, trained under the government, is still chanting "Down with the revolution!" from his hospital bed.

"I wanted to lend a hand to change the way of life in my country," he said between the constant stream of phone calls from media, friends, family and local politicians. "I wanted to be part of the solution."

Paralysis and a wedding in prison

It was this resolve that led him to another dissident's house on the morning of March 18, 2003, to witness the secret inauguration of a private library, a collection of contraband such as the United Nations' Universal Declaration of Human Rights and the complete works of Cuban patriot Jose Marti.

Police arrested Sigler that day. He waited 39 days in jail before he was arraigned, tried and convicted of treason — all in the same day. They gave him 20 years in prison. Labeled a traitor of ideas, he was housed alongside rapists and murderers. His first cell, where he spent a year and a half, was a 7-by-5-foot cage with a hole in the concrete floor for a toilet.

He was awakened at night by rats racing across his lap, roaches tickling his face. For 10 minutes a day, he had running water with which to bathe and drink and rinse the rags he had for clothes. He was fed an unwavering diet of rice and a gruel nicknamed patipanza, which literally means "feet and belly," consisting of leftover animal parts, pig eyes and snouts complete with tough, stray hairs.

"Living in one of Castro's jails is a living hell, befitting something less than a human being," he said.

He interrupts his story as a pair of physical therapists come into the room. They get Sigler out of bed, put him in a wheelchair, and have him push himself around the corridor with trembling arms twice before returning to his room, where lunch is waiting.

Though four friends are in the room, no one speaks to him while he carefully tears the meat off a pair of chicken thighs and eats a couple of spoonfuls of vanilla custard. The man, they all figure, has waited long enough to eat. In prison, he had managed to stay near his fighting weight from a lifetime ago by doing squats, push-ups, sit-ups and dips from the edge of his metal bunk and shadowboxing the way he'd learned as a boy.

But in early December 2008, after five years in prison, his knee buckled going up a step. By Christmas, he was paralyzed from the waist down. He was moved to a military hospital where he continued to serve out his sentence with a pair of guards posted at the door, and no diagnosis on his worsening condition.

Here, another phone call interrupts his story. This time he takes the call.

"... I'm sorry, mi amor. I'm still learning how to make calls on this phone..."

After what sounds like a bittersweet conversation, he hangs up and sighs.

"My wife. She's losing her mind," he says and smiles weakly. This week, she was granted a humanitarian visa to join him, eventually, with her 9-year-old son.

In prison, she was his ray of light. Noelia Pedraza, a girl he had never met, often visited Sigler's mother to check in on her. She liked him from a picture his mother kept on her wall and wanted to meet him. But the prison guards wouldn't let her in unless she was a spouse. So they got married.

Each underwent a three-day hunger strike — he inside prison, she, marching outside the jail — until the government allowed them to wed. He saw her for the first time on the day they were married in a holding cell. He was dressed in a gray prison tank top and matching cutoff shorts, a uniform made for prisoners from the same material used to line coffins.

"I got married inside a prison, dressed like a dead man," Sigler said.

They married with no aspirations. Men who were given 20-year sentences in Cuba serve 20 years, if not more. His wife dressed in all white and silently marched through the streets of Cuba with the wives and mothers of other political prisoners, the Ladies in White, praying for a miracle.

On June 12 of this year, the Catholic Church performed one. Sigler was one of 52 political prisoners Cuba agreed to free. He and Noelia, who spent her days at the hospital, were the last to know.

He was freed that same day, taken to his mother's house by ambulance where the international press was waiting. He said they were not there, however, when he and his wife went to pick up their visas a month later and were beaten outside the government offices before he was given his papers a day later.

The memory still makes his face flush like the 210-pound boxer that burns behind the darkness of his eyes.

From boxer to teacher to dissident

As a boy, he just wanted to box. His mother was afraid his nose and brain would be mangled, but Ariel, one of four brothers, had already learned to stick up for himself and weaker boys in schoolhouse tussles. He was a stylist, not a bruiser, sticking and moving out of the way, compiling a 120-2 record by the time the government determined he was done at 18. He became a trainer and earned a college degree in physical education.

But only when he returned to teach at the sleepover boxing academies did he realize what was being done to mold young men's minds in Cuba. He was in daily meetings where the administration told the staff to lie to the students, telling them that better food and thicker mattresses were on the way to help keep them engaged.

Meanwhile, he argued with the administration about the lowly food, the broken toilets, the rats and the one-sided curriculum until he argued himself out of a job at 31 and was labeled an "untrustworthy citizen."

At night, he would listen to radio broadcasts from circling U.S. C-130s. He began meeting secretly with like-minded men to talk politics, but also about the struggling economy, the failing medical system, the declining education, even sports.

In November 1996, he and the others officially broke their first law: They started a club, the Alternative Option Independent Movement. In Cuba, any group that is not sponsored by the state is considered illegal.

The men lay flowers and read the poetry of Marti by a bronze bust. Other times, they would march silently in a park square on Dec. 10, dubbed International Human Rights Day by the United Nations. They held up signs that read, "Human Rights for All."

But there were hostile consequences for his actions. State police would drag him out of bed and dump him miles away to keep him from a dissident rally the following day. Or, he says, they would beat him and haul him off to detention.

Doctors have told him they expect he will regain feeling in his legs in a few weeks and most likely will walk again with a steady diet and physical therapy.

But none of that will change the drive of a boxer who was never knocked out in 122 fights or in seven years in prison. "I won't stop denouncing those tyrants," Sigler said. "Whether from this hospital bed or a wheelchair, whether I regain my strength or not, you can rest assured that will always be my goal."