French swimming star Leon Marchand still has room to improve before the world championships in Japan next month despite his two titles at his home nationals, his coach Bob Bowman insisted Monday. 

"I'm very happy because he's not fully prepared for this and he has much more that he can do in every event," said Bowman, former coach of US great Michael Phelps, who has guided Marchand for the past two years. 

The 21-year-old, a double world champion last year over the 200m and 400m medley, has still to compete in four races this week at the nationals in Rennes, western France. 

"This is sort of like training for him," continued Bowman. 

"My plan is to just have him on the way to the worlds and he is actually swimming better than I thought he might, which is OK.

"The lactate readings that we have here are indicating that he is not fully peaked which is very good, but he is fit, you can see that."

On Sunday, Marchand made an impressive start with the best time of the year in the 200m breaststroke, less than a second off the world record. 

He continued his fine form on Monday with a title in the 200m freestyle final.

The world swimming championships will take place in Fukuoka, Japan from July 14 to 30.

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