Editor's note: CoachUp is one of Inc.'s 2015 30 Under 30. This year's readers' choice winner is ThinkLite.  

Jordan Fliegel wasn't a great basketball player as a kid. Poor footwork. An average shot. He rode the bench for his high school freshman basketball team in Cambridge, Massachusetts, only faintly grasping the game's fundamentals and nuances. It wasn't until he met a coach at camp that summer that he began to understand what it took to succeed on the hardwood.

Fliegel and the coach trained one-on-one for months, with the lanky 15-year-old fine-tuning his shot, his footwork, and his on-court instincts. By the opening tipoff of his sophomore season, he was a starter on the varsity team. He went on to play collegiately at Bowdoin, earned all-league, all-state, and all-New England honors, and was named team MVP his senior year.

Fliegel traces it all back to that summer before his sophomore year of high school. "I would not have belonged on the court in any way," Fliegel says, "if it weren't for that coach."

Today, Fliegel, 28, is the founder and president of CoachUp, a company that connects athletes with private coaches. Three years after its launch, CoachUp connects over 13,000 trainers with more than 100,000 clients nationwide. The site vets each coach upon their signing up, then tracks reviews and response rates to ensure they remain up to par--providing athletes with an easy and safe way to improve their skill set.

Finding inspiration

The idea for the business came to Fliegel after a two-year post-college stint playing hoops overseas in the Israeli National League. When he returned home, he felt the itch to give back the way his coach once did for him. But finding clients proved challenging: The personalized coaching industry was fragmented, with athletes and trainers mostly relying on word-of-mouth or general listing sites like Craigslist to find one another. Fliegel recognized the opportunity to streamline this. He envisioned a marketplace where coaches and athletes could connect based on their locations as well as the desired sport and skill level.

Fliegel began pursuing his vision in 2011, seeking out coaches from his personal networks and bringing in Arian Radmand, 29, and Gabe Durazo, 30, as technical co-founders. The following year, CoachUp.com launched to the public with 100 coaches on board. It took off quickly from there, securing investor funding and earning a spot in Boston Techstars.

Today, CoachUp offers specialties in 25 sports, from baseball and football to swimming and yoga. The company takes a small percentage of the coach's fee for each session. In exchange it provides an instant payment tool, a session calendar, and $100,000 in liability insurance--not to mention a self-advertising platform that didn't exist just a few years ago. The majority of CoachUp's athletes range from grade school up through high school--a natural pyramid, as Fliegel points out, with the best athletes most likely to continue through high school graduation.

Coaching is a $6 billion industry according to market researcher IBIS World, and it continues to grow as more weight is placed on physical fitness--and as more parents begin to view sports as way to pay for college. But Fliegel sees it as more than that. "It's not all about getting a scholarship--there are so many positive outcomes," he says. "If you believe in a kid and push them, and they see that they're getting better, suddenly it's, 'Jeez, learning is fun. And mastering something is fun. And I want to apply that.' "

Growth through sports

Fliegel speaks from experience. He says he wasn't a good student--"Cs and D's"--until he started establishing himself on the basketball court. As his game improved, his self-assurance shot up, and so did his grades. Fliegel eventually studied government and legal studies at Bowdoin--and, in his senior year, won the Jefferson Davis Book Award, granted to the top student in the program.

Fliegel doesn't believe any of this is a coincidence. "There are a lot of studies that show that coaches are the most influential people in society when it comes to kids," he says. "It's all about confidence and character development."

Which isn't to say the kids are the only ones benefiting. The hard truth is that only about 2 percent of college athletes go on to play professionally, and even those who do may earn less than the average American. Fliegel sees CoachUp as a great way for former college athletes to make a living or for current athletes to make cash on the side. 

Colleen Connors, a former field hockey player at UPenn, uses the site to connect with athletes for up to four coaching sessions a day. "This has been one of my bigger income drivers lately," says Connors, who used to work a job in finance but left to start her own sports equipment business. "It lets me dictate my own schedule. And there are lots of athletes and parents who wouldn't have found me otherwise."

The site's coach pool currently includes dozens of players on Major League Soccer and Major League Lacrosse rosters, as well as thousands of former college athletes and a slew of retired pros. And in late March, the Golden State Warriors' Stephen Curry invested in the company and became partial owner and company spokesman. Curry, the NBA's leading All-Star vote-getter in 2015, has been an advocate of private coaching, publicly pointing to it as a key to his success as a pro player.

In the end, though, most kids just play for recreation. Yes, extra coaching can help polish top-notch athletes into stars, but the more likely outcome is giving a kid a few more skills and a better understanding of the game.

"Sports are such a pure, beautiful thing," Fliegel says. "I truly believe that's the best way to reach kids.

"And anyway, it's just so much more fun when you know how to play."