Like the pencil marks on a door frame measuring a child's growth, Orlando City coach Adrian Heath calculated his progress recovering from knee surgery with little benchmarks noted on his bed.

It was 1984 and Heath had scored 11 league goals in 17 matches for Everton — his third straight season with double-digit goals — and he looked well on his way to a spot with the England national team. With the 1986 World Cup around the corner, Heath, who was nearing his 24th birthday, had hopes of playing on soccer's ultimate stage.

Instead, a torn ACL wiped out that dream.

Heath spent six weeks in a cast after undergoing knee surgery, and his first task was re-teaching his leg how to extend with the muscles now seized up. Each day he tried to extend past the previous day's mark. Sometimes, there would be no progress for several days.

"Those are the little hurdles you have to overcome," Heath said. "For a week, the line's not moved anywhere. [You] wonder if it's not going to move anymore. These are things you have to overcome."

Heath's recovery is far different than what his star pupil, Orlando City midfielder Kevin Molino, will undergo in the next few weeks and months after tearing his ACL during a friendly against Ponte Preta last Saturday. The medical advances have made ACL surgery far less invasive. The mental part of the recovery has not changed, however.

Like Heath, Molino was in the midst of the biggest season of his career. He had turned down previous MLS offers to stay with Orlando City as it finished its run at the USL-PRO level and was just two months into his first season in the top division. This summer he was expected to lead his country, Trinidad and Tobago, into the CONCACAF Gold Cup.

Now, just two months into that potentially career-altering season, Molino has to shut things down and begin rehabilitation.

Players who have been through similar injuries admit the mental hurdles are the most difficult part — a combination of not feeling a part of the team and being unsure of when exactly they will be able to step out on the field again.

"This will hit home in four weeks time," said Heath, who came back from the injury to score 30 league goals the next three seasons. "He'll be in the gym for a couple weeks and he'll think, '[Oh man,] I've got six, seven months of this.' And then he'll be watching Gold Cup on TV, then he'll be watching his teammates go out every morning. That's the mental part. For you to be patient and to keep the same drive every day to want to physically get yourself better."

For Heath, the hardest moment was watching his team win the European Cup Winners' Cup nearly six months into his recovery. For Orlando City goalkeeper Tally Hall, who tore his ACL last fall, the hardest moment was near the end of his recovery these last few weeks. Hall had just a few more hurdles to overcome, but his progress felt stagnant.

Any player who has had a major injury can rattle off to you those moments when the mental battle becomes as big — or bigger — than the physical one. It was true for a forward straightening his leg in England in the 1980s or a goalkeeper going through the same exercise 30 years later.

There is value that comes in those moments, they said.

"You have exercises that seem extremely menial when you get out of surgery," Hall said. "Straightening your leg is torture. . . . It's little things, and so it's difficult to stay focused and committed. But as you do it over the length of your rehab, which is a long time, it teaches you what sacrifices you have to make to be at your best level."

The hope for Orlando City is that Molino will take something out of that challenge, too, and come back an even better player than before.