“Underhook! Underhook!”

It’s a classic wrestling tactic, used to control an opponent. Over the course of his 50-year career, Coach Rich “Schu” Schumacher has hollered the instruction at his students many times, as they’ve struggled to gain leverage over their fellow combatants.

Now he’s joking with his colleague, coach Cliff Ramos, as Ramos wrestles Schu out of a wheelchair and up onto his feet.

Schumacher, 66, pauses to catch his breath, each hand holding onto the arm of a movie theater chair. He’s taking in an afternoon feature at the AMC Colonial, in Lawrenceville, just a few miles from his home.

It is a short trip, but a tough fight. Lowering himself into the leather theater chair takes all the strength in his 6-foot-2 body, and his breath rattles in his throat.

Then comes the inevitable quip: “Believe it or not, I used to take down 350-pound heavyweights,” he laughs — a defiant gesture in the face of his illness.

In fact, at one time, Schumacher was the best there is.

In his New York high school and at college, Schumacher wrestled at 260 pounds. The heavyweight class usually doesn’t attract the greatest wrestlers. But Schu was great. He was a four-time All-American at East Stroudsburg State College, in Pennsylvania, and in 1970 was national champion.

He went on to further greatness as a coach, at East Stroudsburg and at Bucknell University, where he was the youngest head coach at a Division I school.

Schumacher took an extensive timeout for a career in sales, and as a mortgage broker. He moved to Alabama and Georgia. In the 2000s, he revived his coaching skills as a volunteer at his children’s schools, then as assistant coach at Collins Hill High School in Gwinnett County under Ramos. He became head coach at Meadowcreek High School, another Gwinnett school, starting in 2009.

Meadowcreek once boasted a good team, under the guidance of Ramos, who started the program in 1986. But it slipped after Ramos left. “To simplify, the program was in a shambles,” said Bud Hennebaul, a board member of the National Wrestling Hall of Fame.

Poverty is a problem at the school, where more than 80 percent of students are on free or reduced lunches. “When I got there, there were three kids on the team,” said Schumacher, “and two quit when they found out we had meets on Saturdays.”

Schu brought it back. He started by hitting up his friends around the country for donations so the kids could have uniforms. If you’re going to be great, he reasoned, you have to look great.

“He reached out to us in Pennsylvania,” said Gary Kessel, who became an All-American at East Stroudsburg under Schumacher’s guidance. “He had us sending $500 checks so the kids could have sneakers. When Rich asked me for money, I knew whatever he was doing had to be great.”

Then Schumacher did some driving, picking up kids for meets whose families had no cars, and driving to meet at least one student whose family had no home.

Hennebaul said Schumacher’s impact can’t be measured with trophies. “What he’s done with kids, what he’s done at Meadowcreek is beyond coaching,” Hennebaul said. “He’s saving lives.”

But now it’s Schu whose life is in peril.

The coach was diagnosed with pancreatic cancer earlier this year. Ever since then, he has been hearing from wrestlers he has coached or competed against, starting back in 1965. Lately when they call, Schumacher has been sleeping. His wife, Karen, can’t always put him on the line, and that pains her.

In April, he was admitted in the Rockland County, N.Y., hall of fame. In September, he was inducted into the Georgia chapter of the National Wresting Hall of Fame, for a lifetime of service. “There were a lot of tears shed at that ceremony,” Hennebaul said.

Though Georgia wrestlers are energetically recruited by schools around the country, the sport is eclipsed here by football, baseball and basketball. “A lot of people in Georgia don’t know how accomplished in wrestling he is, and what kind of a person he is,” said Ramos, “and that’s their loss.”

During this time, Schumacher has also checked off a very short bucket list of experiences. (The list is short, he says, because “I’ve done everything.”)

One item on the list was a trip to the beach at Destin, Fla., with Karen. Another was a chance to see the movie “Foxcatcher,” a dramatic retelling of the true story of two brothers, Dave and Mark Schultz, who were legendary Pennsylvania wrestlers and Olympic gold medalists.

The movie has a November release date. Schumacher’s hospice nurse, Jennifer Okuma, decided that November was probably too far away. She contacted Sony Pictures, and a local representative arranged for an advanced screening at a Lawrenceville theater.

“It’s been a little tougher journey to get to this place than I thought,” Schumacher said to the handful of people sharing the theater with him, “but I’m grateful that people think this much of this one person to do this for me.”