Kiwi single sculls rower Robbie Manson isn't overly concerned about his second place in his heat at the rowing world championships in Florida, instead opting to focus on the little things hindering his performance.

Manson finished second to rival Tom Barras in the sixth heat by five seconds after the British rower clocked in at 6:51.20 for the fastest time of all the heats - Manson's time was second fastest overall at 6:56.97.

The Kiwi rower broke the world record for the event earlier this year with a breathtaking time of 6:30.74 in Poland but has struggled with a niggling injury since the World Rowing Cup III event in Lucerne in July.

"I've been out of the boat for a few weeks," he told TVNZ1's Breakfast this morning.

"I guess I'm not quite as finally tuned as I'd like to be so each race is just learning and building off it."

Manson admitted he overdid it in his race and needed to focus on getting his form right.

"Because I haven't raced for a while - I just went out there and tried to go as hard as I could right from the start and muscled it too much.

"I think it's just fine-tuning it, sort of getting that feel for the boat and getting all the little details right."