This is episode 29 of the Dunk Talk Podcast and one I’ve wanted to record since the show started. I’m Dylan Haugen, joined by Hunter Castona, and the guest is Isaiah Rivera: 6’1.5” without shoes, two days from turning 27, almost a decade into a pro career, owner of the highest officially tested vertical in the world at 50.5 inches, and co-founder of THP Strength. I’m on THP myself and Hunter has been for two years, so this conversation goes deeper on the training philosophy than most interviews Isaiah gives. The arc runs from bleacher-jumping in Puerto Rico to getting cut from high school basketball three years straight to the phone call with John Evans that produced THP and, eventually, the 50.
Puerto Rico, bleacher jumps, and an N1 Streetball PS2 disc
Isaiah’s earliest athletic memory is climbing the bleachers of a covered court in Puerto Rico in first or second grade and jumping off, chasing that electric feeling in your feet when you drop from too high. His parents put him in basketball at 8 to burn off energy (he’s 90 percent sure he has undiagnosed ADHD), and the hook set in his first game: five minutes of playing time, a made free throw at the end, and the dopamine of the ball going through the net. From then on he was obsessed.
He played everything as a kid: baseball (his most natural sport), football, some wrestling, some volleyball, random track meets. He studied high jumpers and triple jumpers on video purely because he loved jumping. The street-ball creativity came from N1 Streetball on the PS2, whose moves he copied for years. He specialized in basketball around 15 or 16, got cut from his high school team three years in a row, moved from Utah to Florida, and finally made his senior-year team.
The computer-class moment that changed everything
Isaiah’s family didn’t have high-speed internet until he was about 15, so he missed the entire Team Flight Brothers era that raised most pros his age. His introduction to pro dunking happened at 16, in a school computer class, when Jordan Kilganon’s Crown dunk autoplayed on YouTube. His description of the moment is the best I’ve heard anyone give: it shattered his reality. The Crown doesn’t look physically possible even now.
The second reality-shattering moment came minutes later when he scrolled to Kilganon’s oldest videos and saw that Kilganon was rim-grazing at 16. Isaiah was rim-grazing at 16. NBA freaks dunk in games at 12; here was a normal kid who built it. Isaiah, who describes himself as relentlessly logical, ran the math on the spot: no scholarship offers, hadn’t even made a team yet, but this path was provably climbable. He committed that day.
His standing advice for new dunkers came out of what he did next: go to Team Flight Brothers, Dunkademics, and Flying 101 on YouTube, sort oldest to newest, and watch all of it. Learn the history of the sport, then copy the forgotten creative dunks on low rims. There are dunks in those old mixes nobody does anymore.
First dunk to first Eastbay in 11 months
Isaiah’s first dunk came in February 2014 at 16, at 5’9” or 5’10”, before his growth spurt finished. He’s honest that genetics made this part easier than it is for most: a year of consistent trying, no long back-rim purgatory, then boom. The progression after was absurd even by pro standards:
- Spring 2014: consistent one-handers. Then his first-ever depth jump (from the Vertical Jump Bible’s jumper test, with zero plyo background) gave him Achilles tendinopathy and a month off. He didn’t touch depth jumps again for years.
- Summer 2014: found a 9’8”-9’9” court, learned lobs (everything before was off the dribble), hit a 360 Tomahawk Reverse, and started measuring rims.
- Mid-summer: posted a Facebook video asking for windmill tips on 9’6”. Kilganon dropped a wall of text in the comments and four more paragraphs in his DMs. Isaiah read everything and hit the windmill 30 minutes later. That response speed is what put him on Kilganon’s radar; most people never implement the tips at all.
- October 2014: windmill on a legit measured 10’, on asphalt, on his outdoor hoop with a board wedged under the base to keep it honest.
- January 2015: set a New Year’s resolution to Eastbay by year-end. Hit it two days later. Ten or eleven months from first dunk to Eastbay.
Then Willie Rhodes, a one-foot creative legend from the Facebook dunk era, sent him the message that defined the next two years: throw away the realistic goals list and write one made of dunks that feel impossible. Isaiah still has the 2016 list in his phone and read it on the show: head at rim, 360 Eastbay, 540, 360 behind-the-back, 360 Windmill, double Honey Dip, Crown, 720, Underboth, one-foot Eastbay, Windmill Elbow, between-the-legs off vert. Every item is checked.
The stepdad: an Olympic weightlifter and the “best janitor” rule
Isaiah’s stepdad was an Olympic weightlifter and a college athlete of the year in Puerto Rico around 2002. Some of Isaiah’s earliest memories are bumper plates hitting the platform, chalk in the air, and the weightlifting team playing explosive pickup basketball after lifting. He learned barbell technique with a broomstick copying his dad’s VHS lifting tapes.
The mentality came from the same source. The rule in the house was: whatever you do, be the best at it. Be the best janitor in the world if that’s the job. Isaiah applied it to McDonald’s shifts, to out-grading his straight-A friend in seventh grade, and to conditioning drills where he decided he would pass out before he stopped running. He told us he still front-squats 255 for sets of 8 in his garage with the same internal monologue. Whatever you think of the intensity, the results sit on top of it: you can’t fake your way to a 50.5-inch vertical.
Becoming a pro: UCF, the New York charity show, and City Slam at 18
Isaiah’s first contest was an amateur student contest at UCF in October 2015, against CJ Champion and Steven Selby. Chuck from Team Flight Brothers gave him the strategy in one text: do all push-offs. He did, and shut it down. The contest taught him something underrated: performing is a separate skill from dunking, and plenty of elite dunkers never develop it because crowds wreck their nerves.
The Live2Dunk group chat (Isaiah, CJ, Scotty Weaver of Next Chapter, Zeus, and others) produced his first real pro booking: a charity event in New York at 18, where he hit an Eastbay handoff first try on a 10’1” rim, windmilled over people, and pulled out the chair dunk in the contest, which at that point basically only Kilganon and Lipek were doing. He beat a field that included Porter Maybery fresh off Dunk King. Six months later Chuck called with 12 hours notice: Michael Purdie missed his flight to City Slam in Orlando, ESPN cameras, did Isaiah want in? He went, and dunking alongside Guy Dupuy in his prime was the humbling moment where he realized how far “best in the world” actually was.
He’s candid that push-off mastery is what made him competitive in those early years. Without double-ups he couldn’t have hung in elite contests until about 2018, when the 360 Eastbay and Underboth became contest-ready with no props.
Isaiah’s contest preparation doctrine
Hunter asked how he prepares mentally for contests, and the answer is worth printing in full because it’s the opposite of what most people expect. There is no visualization ritual. The preparation is the training. His framework:
- Assume worst conditions. The typical overseas contest: two hours of sleep off a long flight, a true 10’ rim, and a floor that’s sport court, concrete, or slippery. Pick your contest dunks based on what you can hit under those conditions, not what you hit on a flimsy 9’9” with perfect floors.
- Nine out of ten or it doesn’t travel. If you can hit a between-the-legs mid-training-cycle, fatigued, on a true 10’, on a bad floor, then contest adrenaline turns it into a punch.
- First-try punch beats complexity. Traditional judges score a hammered basic dunk over a struggled complex one, and push-offs score disproportionately well. Plan accordingly.
- “Put the hay in the barn.” The THP phrase: by competition day the work is already done or it isn’t. His Michael Jordan paraphrase: I’ve practiced too much to be nervous. The residual nerves that remain only fade with event reps, and even Isaiah felt sick before shows this past year because injuries kept him from practicing beforehand.
The John Evans phone call and the founding of THP
From his first dunk until 2017, Isaiah lived in a knee-pain loop: dunk, flare, rest, repeat. By 2017 it was bad enough that he was close to quitting. His friend Austin (now my coach’s counterpart story, funny enough) insisted he get on a call with the smartest jump-training mind he’d ever met: John Evans. John spent an hour asking what top dunkers’ programs actually looked like, got progressively more horrified, and then asked the question that built everything after: what would happen if a dunker trained the way a track and field athlete trains?
Isaiah’s answer, four or five years later, was the 50-inch vertical. He’s explicit about why he bought in: he changes his mind when the evidence is better, John argued from mechanisms and handed him the books to verify, and the logic held. The knee pain resolved. After a gap (John stepped back from coaching for personal reasons; Isaiah ran knees-over-toes style training for a few months), John returned in 2019, Isaiah asked to be coached again, and that year was his biggest training leap ever.
THP the business came from a deal between them. Isaiah had quit his job for a contest that fell through, started selling 30-minute consultation calls on Instagram, and asked John if he could coach. John’s terms: match my client count and we merge. John had 30-40 clients. Isaiah marketed his own story relentlessly, hit 40, and THP Strength launched as a website a couple of months later. That was almost five years ago.
What makes THP different
I asked the question every THP athlete wants asked: what actually separates John’s training? Isaiah named two things. First, load management built specifically around dunking, because most coaches still don’t grasp how much max-effort dunking costs the body or how to reprogram around a flare-up. Second, variety at a level that sounds fake until you’re on the program: Isaiah says he has never repeated a week of training, ever, and the training keeps escalating as the years stack (he bought a belt squat machine an hour before we recorded). Hunter and I both run THP programming and can confirm the no-repeated-weeks thing is real.
If you want the fuller picture of the ecosystem THP created, the Dom Gonzales episode covers Isaiah DMing a 16-year-old out of nowhere and coaching him free, and the Hyrum Fechser episode covers John giving the Utah crew free access. A lot of the current generation of high-flyers traces back to those two.
What’s next for Isaiah
The stated goal for this year is 51 inches, which would break his own world mark. He came close last year (we watched him jump 50-plus repeatedly at Dunk Camp while chasing 51 on the Vertec without quite catching it). Between that, coaching a growing THP roster, and the contest circuit, he’s in the rare position of still improving at 27 in a sport he helped professionalize.
Isaiah is on Instagram and YouTube as himself, and the THP Strength site is where the coaching lives. Next episode is Dillan McCarthy, the dunker with a 49-inch vertical who jumps seven days a week. Comment with any dunker you want me and Hunter to interview next.