A junior at Arizona State, Clarke recorded five PRs, including a monster throw of 68 feet, 5 1/4 inches that earned him his second national track championship.
Last spring, Clarke won the shot put at the outdoor national meet to become Alaska's first Division I outdoor track and field champion.
"I've been really close to a big throw, I just haven't put it all together," he said by phone. "I've been very confident the last week with my training but I didn't think I'd throw 68 today.
"I was ready for a PR, but not one that big."