Donald Trump shakes hands with former Indiana University basketball coach Bobby Knight during a campaign rally on April 27. (John Sommers II/Getty Images)

They crisscrossed Indiana this week speaking the mishmash language of both politics and sports. In Fort Wayne, the old football coach said, “Coaches know how to get things done. Donald Trump is one of the great coaches in this country.” At a rally in Carmel, the ex-football player said, “He’s not a politician. He’s one of us.” And in Evanston, the iconic ex-Indiana basketball coach stood on the stage sporting his familiar red sweater.

“I’ll tell you one thing: That man that was just up here a moment ago,” Bobby Knight told the crowd of Trump supporters, “I’ll tell ya, that son of a bitch could play for me.”

Leading up to his decisive win in the Indiana primary this week, Trump borrowed from a dog-eared political playbook and did what he does best — turning up the volume a few notches. Other candidates have certainly leaned on figures from the sports world to woo voters in the past but never as early, never as many and, political analysts say, perhaps never as effectively.

“In this particular case, he used athletes that can reinforce a story line or an attribute that is important,” said Kevin Madden, a veteran Republican strategist. “I think it helps send a message to some of those voters who haven’t made up their mind.”

Republican presidential candidate Donald Trump held a campaign event at Trump Tower in Manhattan, after sweeping the Indiana primary. (Victoria Walker/The Washington Post)

Though academics and studies are mixed on the exact impact a celebrity endorsement carries, campaigns still pursue them with vigor, feeling a famous name could boost attendance at events, help with fundraising and generate media interest. Sen. Bernie Sanders (I-Vt.) has the support of Ronda Rousey, the popular mixed martial arts star, and, it seems, colorful ex-NFL wide receiver Chad Johnson, who in February tweeted @BernieSanders, “I love you man . . .” Hillary Clinton, meanwhile, has recently retired soccer player Abby Wambach, tennis great Chris Evert and basketball legends Kareem Abdul-Jabbar and Earvin “Magic” Johnson backing her. Billie Jean King campaigned with Clinton in Iowa, and former figure skating champ Michelle Kwan actually works for the campaign, focusing on outreach efforts.

But no one has leveraged athletic relationships quite like Trump, whose politics, campaign strategy and personality have cut against the grain from Day 1 — traits underscored by the colorful and often controversial sports figures who are backing him.

Personal connections

The polarizing billionaire may not have picked up endorsements from seasoned politicians, party establishment or many media outlets during the primary season, but he’s had no shortage of high-profile athletes eager to take to the stage or social media to sing his praises. Many stemmed from personal friendships forged over the years on golf courses and at charity dinners. Golfer John Daly this week called Trump “one of the greatest human beings I’ve met in my life.”

“I know how many people call him a racist and all that. It just makes me sick because he’s not,” Daly said. “I’ve known him too long. I’ve seen what he does for kids. I know what he does with charities, and the thing I love about Donald is it’s time this country’s run by a businessman and not people with their hands out. Donald doesn’t have his hands out.”

Political analysts say Trump has done a particularly good job of using athletes and coaches who reflect the same attributes he’s trying to project to voters: a winner, a worker, someone who’s willing to challenge the status quo. Just consider some of the names from the cast of outcasts who have pledged their support: boxer Mike Tyson, who served time in prison for rape; Knight, who was fired from Indiana for being “defiant and unacceptable;” Daly, whose career was derailed by alcohol and personal issues; basketball player Latrell Sprewell, who was once suspended for choking his coach; baseball pitcher John Rocker, whose comments about minorities and gays overshadowed his pitching career; and of course, Dennis Rodman, the colorful former basketball player who counts North Korean leader Kim Jong-un as one of his friends.

They’re athletes who stood up to authority, whose words and actions shocked, who toed the line of decency and then often smeared it beyond recognition.

“I think this is one of those areas where Donald Trump is a lot smarter than people give him credit for,” said Anthony Nownes, a political scientist at the University of Tennessee. “The business literature on celebrity endorsements shows that what really helps is a match between the celebrity and the product in question. Donald Trump knows what kind of person he is. He’s done a masterful job of matching himself up with celebrities that would have the biggest impact.”

Retired U.S. soccer star Abby Wambach is among the athletes backing Hillary Clinton in her presidential bid. (Chris Pizzello/AP)

Nownes conducted a study in the last presidential election cycle in which he gauged voter reaction to a celebrity’s hypothetical donation to a political party. He used former quarterback Peyton Manning as an example and found that people tended to view the party positively if they also held favorable feelings about Manning.

In some cases, campaign operatives feel a key endorsement could tip the scales in a tight race. Madden cited President George W. Bush’s reelection efforts in 2004. Trying to lock up New Hampshire, the campaign turned to pitcher Curt Schilling to help sway Boston Red Sox fans in the state. That same year the Bush campaign invited Jack Nicklaus to appear at a rally in the golf legend’s home town, and Nicklaus spoke before 20,000 potential voters in Columbus, Ohio.

“In a race that was so close, it’s better to have Jack Nicklaus than not have Jack Nicklaus,” Madden said. “Just having that association with someone as revered, that’s going help your campaign.”

Similarly, Trump turned to an Indiana legend when he felt his campaign could deliver a knockout blow to Sen. Ted Cruz (R-Tex.). According to Trump’s telling, the businessman and Knight had never met when the former Hoosiers coach called out of the blue last year.

“I said, Coach, I’ll tell you what, give me your number, let me see what I’ll do and I’m gonna call you. . . . One of my political guys said to me two weeks ago, you know we’re going to Indiana. . . . If you could get Bobby Knight, would that be possible?’ I said, ‘Possible? I have his phone number on my desk,’ ” Trump told a campaign rally.

“So I call him up and here’s how smart he is. He said, ‘I’ve been waiting for your call.’ ”

Knight did media interviews and made appearances at Trump events in the days leading up to Tuesday’s primary. He even enlisted his friends. Gene Keady is a retired Purdue basketball coaching legend and said Knight called and asked him to jump on-board, along with Fred Williamson, a Gary, Ind., native who played eight seasons in the National and American football leagues in the 1960s. Keady flew to Indiana and offered an endorsement. So did Digger Phelps, a former Notre Dame basketball coach, and Lou Holtz, who coached the Fighting Irish football team.

“I’ve never been involved in politics before,” Keady said in an interview this week, “but I’ve been so upset with the way our country has been going. We just think he has a lot in common with athletes, with what we do: treating people right and being honest and trying to get the team philosophy back in America.”

Not everyone’s reasoning is quite as nuanced.

“The main reason I’m endorsing him: I’ve played his golf course, [and] I’ve stayed in his hotel,” Holtz said in a video Trump released on Twitter. “He does nothing but go first class in everything. He wants this country to be first class as well.”

Friends till the end

Much of Trump’s recent support from the sports world stems from his personal relationships. Golfer Lexi Thompson and her family are regulars at his club in South Florida, and she has played many rounds with Trump. “He’s a great person,” she reported recently. New England Patriots quarterback Tom Brady has also golfed several times with Trump and even served as a judge at one of Trump’s beauty pageants, but his own endorsement has been somewhat lukewarm: “I support all my friends,” Brady said in December.

Douglas Hartmann, a sociology professor at the University of Minnesota, says political candidates often turn to sports figures but not nearly as overtly as Trump. “We usually see it in subtle ways to establish a candidate’s athleticism, masculinity or regular-guy status,” he said.

Hartmann points out that it’s not accidental that much of Trump’s support comes from coaches and athletes who are no longer active. Present-day competitors tend to avoid political waters, fearful of upsetting bosses, sponsors and fans.

“When you have sponsors and marketing deals, you don’t necessarily want to put yourself in a position where you’re taking yourself out of certain markets,” said Brady Quinn, a former NFL quarterback who supported Sen. John McCain in 2008, Mitt Romney in 2012 and most recently stumped for Florida Gov. Jeb Bush. “Those companies might not want you to be outspoken about your political beliefs.”

Some political observers say Trump trotting out athletes or celebrities is just a small piece of the candidate’s broader strategy: highlighting pomp and circumstance over substance.

“This is substance-free campaign, not one that’s litigated over issues or white papers or detailed policy debates,” said Madden, a strategist for Romney’s failed 2012 bid. “The primary debates were more like ‘American Idol’ or WWE than C-SPAN.”

Evidence is only anecdotal, but support from coaches and athletes certainly didn’t hurt Trump’s efforts in Indiana. In his victory speech Tuesday night, Trump opened by mentioning his family and staff — and then he thanked Knight.

“He was incredible,” the candidate told the crowd assembled at Trump Tower in New York. “I always say about people like that — there aren’t many — it’s called tough, smart and they know how to win. And that’s what our country needs.”