It came a week after he ran another sub-4m mile at the Prefontaine Classic in Eugene, Oregon.
In March, aged 15, the Tauranga Boys’ High School student became the youngest person in history to run a four-minute mile (about 1.6km) with a time of 3m 58.35s.
“I went out pretty hard,” Ruthe told Athletics New Zealand after the Los Angeles race.
“With one lap to go, the pace lights were right beside me, and I thought ‘ooh, feeling quite good’. The last lap it felt like the pace light sped up.”
On running against senior men, he said, “they obviously race a bit smarter, having a field this deep is obviously handy, there won’t be as many breaks in the line”.
Competing in the top section of the men’s 1500m, Ruthe was right in the race from the gun.
Aside from a strong kick from Ben Allen of Empire Elite Track Club to take out the race, the second- through fifth-place finishers were only separated by less than half a second.
Athletics New Zealand said Ruthe had made a rapid turnaround in his season, flipping from the cross-country season in winter to the international track and field circuit in just three weeks.
He went from finishing second at the 2025 New Zealand Secondary Schools Cross Country Championships in Whangārei in June to setting national records over the 1500m in Los Angeles.
He finished the cross country race behind Caleb Wagener, who since has the world U19 duathlon title in Pontevedra, Spain.