Riley Masters 2019 running season didn t get off to a great start thanks to a back injury that sidelined him early this spring.

But with the USA Track & Field Championships set to start Thursday in Des Moines, Iowa, the 2008 Bangor High School graduate is poised to stake his claim as one of the nation s top competitors at 5,000 meters.

There s a lot at stake for the former University of Maine and Oklahoma University distance standout, who now competes professionally for Nike and lives in Boulder, Colorado.

The U.S. championships offer the opportunity to qualify for this year s IAAF World Championships, scheduled Sept. 28-Oct. 6 in Doha, Qatar, which may serve as a preview for the 2020 Summer Olympics in Tokyo.

Masters needs a top-three finish in Sunday s USATF 5,000-meter final and must achieve the qualifying time of 13 minutes, 22.50 seconds to advance to the world championships.

While he hasn t yet achieved that standard in limited opportunities within the IAAF-mandated window that began last Sept. 7 and ends this weekend, Masters ranked as the third-fastest American at 5,000 meters in 2018 with a personal-best time of 13:16.97 in a May race in Palo Alto, California.

This year and next year are the two years that all these years and all these miles have been geared toward,” the 29-year-old Masters said. Right now I m in the prime of my career and I think my results are showing that. I m being really competitive in all my races so I think I ve got either that time in me or maybe a little faster, and if I do that I should end up running in Doha in October.”

Masters had a big 2018, winning the USATF 1-mile road race championship and placing fourth in the 5,000 at the U.S. championships last June in 13:30.23.

After recuperating from a back injury he suffered earlier this year, Masters returned to competition last month with a victory in the 5,000 at the Portland (Oregon) Track Festival and has raced again once since then in Los Angeles, California.

I like to think that I have a little more running in my legs this year right now as this will only be my third race of the outdoor season,” said Masters, who has been buoyed further by his recent track workouts.

You never want to be injured and the consistency of training is what will really benefit you over time, but I feel well rested and the (U.S. championships) are a month later than they usually are so it was a bit of a blessing in disguise that I got banged up in late March and early April. I m full of energy right now.”

Masters also hopes to benefit from training at altitude in Boulder, where he trains under Colorado University coach Mark Wetmore and also serves as a volunteer assistant coach for the Buffaloes cross country and track teams.

It s nice because up here you re able to build a lot more red blood cells so when you get down to sea level you re just more efficient in using that oxygen,” Masters said.

Masters will be among 24 runners in the 5K field, a contingent led by reigning Olympic silver medalist Paul Chelimo. Chelimo is one of seven entrants who already have achieved the world-championship standard, a group that also includes North Yarmouth native Ben True, who finished fifth in the 5,000 at the 2016 U.S. Olympic Trials.

I feel comfortable saying this as one of those people who used to just be happy to be at the U.S. championships,” Masters said. When you look at a field that has 24 entrants, usually 12 will be competitive or fairly competitive and the other 12 are happy to be there … you just have to make sure you find yourself in that top 12 so you can be competitive at the end of the race.”

Masters said the quality of the field and the chance for as many as three runners to qualify for the world championships will dictate the pace of the race.

I believe the race will go fast, which should weed out quite a few people,” Masters said. I think you ll see eight or 10 of us that are really competitive in the last mile of the race.”

Masters and True are among five Mainers who will compete at the U.S. Track & Field Championships.

Isaiah Harris of Lewiston, the 2018 NCAA Division I 800-meter champion at Penn State University, will compete Thursday in the 800 prelims.

Kate Hall of Casco, a former indoor and outdoor NCAA Division I long jump champion at the University of Georgia and the reigning USATF indoor long jump champion, will compete Saturday in the long jump.

Sanford native Rachel Schneider will run in Sunday s 5,000-meter final.