In the winter of 1989-90, Gil Reyes was head strength and conditioning coach for the UNLV basketball team. Led by Larry Johnson, Greg Anthony and Stacey Augmon, the Runnin' Rebels capped off a national title with a 30-point win over Duke. Las Vegas had Rebel fever.

But after the season, Reyes walked. He passed on being part of a repeat opportunity at UNLV for another challenge: Training a local tennis phenom named Andre Agassi

"He was so ready to train hard," Reyes recalled in a phone interview. "The kid was so willing to work."

Agassi was 19 when Reyes became as his trainer. Agassi showed promise as a top tier tennis player fundamentally, but physically had restrictions. At 5-11, Agassi's height was inferior to many of his opponents. He also was born with the back condition spondylolisthesis, the displacement of a vertebra, which further limited his abilities.

For Reyes, that meant a few things. First, if Agassi was going to reach the top of the tennis world, he needed to work harder than any of his competitors. Second, he needed equipment designed specifically for his body. Third, Agassi needed all of the equipment to be safe.

The two spent the next two decades constructing safe fitness equipment styled for Agassi's desired workouts. Agassi also put in all the energy his body could give to reap the benefits. The result: Eight grand slam titles, an Olympic gold medal, 101 weeks as the ATP No. 1 ranked player and a Hall of Fame plaque.

And now a fitness equipment line featuring machines modeled after the ones Agassi used in his playing days.

On Sept. 10 in New York, one day after the U.S. Open, BILT by Agassi & Reyes will be put on public display for the first time with 12 pieces of equipment.

"BILT has, no pun intended, literally been built over decades," Agassi said in a phone interview.

In the early 90s, Reyes was a skilled and creative trainer. He was full of strength and conditioning knowledge, but he was also willing to try new things. Agassi was an energetic kid with a focus. He wanted to train in the best way possible to become the best tennis player possible. And he would stop at nothing until he had that.

"I needed Andre to teach me what he needed as an athlete, as a tennis player," Reyes said. "The design certainly had to apply to his needs out there, so you might say it was a perfect collaboration of me wanting to learn what he needed and him being such a good teacher at telling me what he needed."

Agassi remembers the origins a bit differently. When he heard of Gil giving him much of the credit, he chuckled.

"Gil is a very humble man, so he is probably erring on the side that I had more to do with it than he does, which I don't believe to be the case," Agassi said. "I watched him over 20 years care for me so personally that he literally hand built every piece of equipment I trained on. Little did he know at the time, many of these pieces of equipment didn't exist. He knew how important they were. We had to get stronger without risking injury."

When Agassi began training with Reyes, the kind of equipment he wanted was not found in gyms. Machines did not go the right way and were not as kind to his muscles as he would have liked. Weight was not always distributed correctly and muscles were put in vulnerable positions.