Coach Bobby Kersee may have lost his biggest star when Allyson Felix hung up her spikes but his influence shows no sign of diminishing with another generation of the pack known as "Formula Kersee" stamping out their territory.
No sooner had American Sydney McLaughlin taken a chunk out of her own 400 metres hurdles world record at the World Championships in Eugene last year did she began seeking out new territory, eyeing the 400m flat under Kersee's guidance.
"Bobby's always coming up with new ideas so it's hard to pin down one," she told reporters after scooping up the world title.
At the NYC Grand Prix last month it appeared McLaughlin was succeeding in that experiment, cruising to victory in 49.51 seconds - the year's fourth-fastest time.
She is expected to run the 400m flat at the US nationals, which kick off this week in Eugene, Oregon, with a bye for the 400m hurdles at the worlds as the reigning champion.
Kersee was selected last week to receive USA Track & Field's "Legend Coach Award" in recognition of the past greats he has coached - including his wife, three-time Olympic champion Jackie Joyner-Kersee - as well as the new talent under his guidance.
"The transition's been really easy," 100m hurdles Olympic silver medallist Kendra Harrison was quoted as saying by FloTrack at the LA Grand Prix in May.
The American, who picked up a world silver in 2019 but was disqualified from the final last year, reportedly made the switch to Kersee's group late in 2022.
"Bobby, he's been really welcoming - I'm learning new things. I'm training with some of the best in the world," said Harrison, who has the second-fastest time in the world this year in her signature event and will run at the US trials.
"Just to see their energy and learn from them - I'm glad I made the switch (to Kersee)," she added.
The 21-year-old American wunderkind Athing Mu moved to Los Angeles after underlining her Olympic 800m gold with a world title at the distance in Eugene last year.
Kersee plotted a 2023 agenda that was light on competition for Mu, who delayed her season opener until the NYC Grand Prix in late June where she won in a comfortable 1:58.73.
"I know Bobby knows exactly what he's doing," Mu told reporters in New York.
As the champion, Mu is not obligated to compete at nationals in the 800m and was not listed among the entries in her main event.
"I'm taking this year a lot easier than I did the last three years," she added. "Bobby has definitely been a great person to hold on to."