It was a coaching moment that has been repeated time and again over Barber's career.
The 21-year-old won gold at the Pan American Games on Tuesday — the latest highlight in a pole vault partnership between father and son that began when Shawnacy was just four, watching his dad compete.
"It's kind of a role reversal now," George said.
"I was out watching my dad jump all the time," Shawnacy said of his childhood. "I didn't really have anything else to do, so I'd jump on the mats and play on the trampoline. It was just an easy transition into pole vaulting for me."
Barber cleared 5.80 metres to win gold, about an hour after Canada's Elizabeth Gleadle kicked off the track competition with gold in women's javelin, throwing 62.83 on her sixth and final attempt.
Canada added to its medal haul in the evening session with a gold and silver in the men's 3,000-metre steeplechase.
Matt Hughes of Oshawa, Ont., pulled away from the pack with two laps to go en route to gold. Alex Genest claimed the silver.
The Canadians added another silver in the men's shot put. Tim Nedow of Brockville, Ont., threw a 20.53 for second place.
Barber, who lists Toronto as his hometown, grew up on his family's farm in New Mexico, where Shawnacy and his brother Braden would use shortened poles to leap over the irrigation ditches. George, who's originally from Kincardine, Ont., eventually installed a full-size pole vault pit in an old airplane hangar on the farm.
"The first couple of years he was a little bit short so the pit was pretty high for him," George said.
George Barber still competes periodically — he participated in the Canadian championships last month in Edmonton, which Shawnacy won.
The red-headed Canadian got off to a rough start Tuesday, missing badly at 5.40, explaining afterward that he'd just applied sunscreen and his hands were slippery. But one by one his rivals were knocked out, and after guaranteeing the gold at 5.80, Barber took three attempts — all misses — at 5.93, hoping to better his Canadian record of 5.91.
"Anything to one-up myself," Barber said.
"The main thing today was to play, have fun, and to win," George added. "You could kind of tell, once he'd won, the fire was a little bit toned down."
Barber captured both the indoor and outdoor NCAA titles this past season, and breaks his own Canadian record on a regular basis.
His main goal this season is next month's world track and field championships in Beijing, and boasting the fourth-best jump in the world this year, he should be considered one of Canada's top hopes there and at next year's Rio Olympics.
"I'm having a really phenomenal year for me, I'm hitting the marks that I dreamed of," Barber said.
Argentina's German Chiaraviglio took silver at 5.75 and Jake Blankenship of the United States cleared 5.40 to finish third.
The 26-year-old Gleadle, meanwhile, was trailing American Kara Winger when she stepped up to take her final javelin throw, clapping her hands to get the crowd going.
"I was thinking 'Oh no, I'd better get it together,'" Gleadle said. "I was standing there and I thought to myself 'I bet the Canadian anthem would sound a whole lot better from the podium if I was on it,' so that inspired me to throw better."
As the crowd of several thousand at the new stadium at York University clapped in unison, Gleadle was overcome with emotion.
"It's a pretty cool feeling," she said. "When everyone in the crowd is looking at you, and everyone is expecting you to perform, and you know that 95 per cent of the people in the crowd are truly rooting for you to do well. . . It's a pretty electrifying feeling, it's very whole-body, it's like your whole system just lights up like a Christmas tree.
"It's like if you've ever been in love and your heart is about to explode with happiness. It's that exact same feeling, when you realize how overjoyed you are."
The six-foot-one athlete first chucked a javelin in her Grade 8 gym class.
"I was the only kid in my class who didn't hit myself in the back of the head. I'm not kidding. I was OK, it stuck in the ground, it went straight.
"And my teacher was like 'Oh you should throw javelin, you're tall, that might work,'" said Gleadle, who was six feet tall by the time she was 16.
She's six foot one now, and has a large tattoo that winds down her waist over her left hip.
It reads: "Keep your feet on the ground and eyes on the stars."
"I have a tendency to get carried away with stuff, and you say when you're 15 years old, 'I want to win gold at the Olympics,'" she said. "But you've got to remember there's a lot of ground work, there's a lot of years, there's a lot of hard basic work that needs to be done and you've got to keep yourself grounded to get where you want to be."
Winger won silver with a 61.44-metre toss while Brazil's Jucilene De Lima took bronze at 60.42.
Melissa Fraser of Hillsburgh, Ont., finished seventh.