England's Manu Tuilagi believes his run of injuries is behind him as he zeros in on next month's Rugby World Cup and Saturday's warm-up against Ireland.
The 28-year-old went without an international start for more than four-and-a-half years but has played in all seven of England's Tests in 2019.
"I'm feeling good. Having injuries, you get to know your body and what it needs," he told BBC Sport.
Tuilagi is considering losing weight to suit the game he expects at Japan 2019.
"Condition-wise I am the same as in the autumn and the Six Nations which is 111-112kg," he added.
"But maybe as we get closer to Japan I will probably want to be a bit lighter. The games are going to be quick and fast out there.
"When you are lighter you are using less energy and you can repeatedly do the things that you want for the whole game."
A series of chest, knee and hip problems checked Tuilagi's progress since he made his debut as a 20-year-old, directly before the 2011 Rugby World Cup.
He made only two replacement appearances for England between June 2014 and the start of 2019.
However he scored six tries in 17 appearances for Leicester this season as well as starting all five of England's Six Nations fixtures.
"As you get older you know exactly what you need; what you have worked on with the Tigers medics and here with England," he added.
"We have a tight relationship and you have to be honest with them and they will be honest with you."
Tuilagi played at 12, inside Exeter's Henry Slade, for all but one of England's Six Nations matches, but says he is adaptable enough to play in either midfield role.
"There is not that much difference really," he said.
"It is good to know both so if, for whatever reason, something happened we are ready."
Along with Tuilagi and Slade, Jonathan Joseph and Piers Francis are the other specialist centres in Eddie Jones' 31-man Rugby World Cup squad.
Fly-half Owen Farrell could also be deployed in midfield, with wing Jack Nowell, who played outside centre in the autumn win over Japan, a possible, if unlikely, option.