NASSAU, Bahamas, May 4, 2024 (BSS/AFP) - Marcell Jacobs took the radical decision to dump his coach, up sticks and move from Italy to the United States in his bid to arrive in Paris this summer ready to defend his Olympic 100m title.

That split from Paolo Camossi saw the 29-year-old Italian team up with Rana Reider, whose Florida training group also includes American Trayvon Bromell, Olympic 200m champion Andre De Grasse and Japanese sprinter Abdul Hakim Sani Brown.

"There's been a lot of change from last year," Jacobs said with no little understatement ahead of competing in this weekend's World Athletics Relays in Nassau.

Jacobs, born in the US to an Italian mother and American father but raised by the former since infancy in Italy, stunned the athletics world with two golds in the Covid-delayed Tokyo Olympics.

He went on to be crowned world 60m world champion and 100m European champion in 2022.

However he then struggled with a series of muscular problems and flopped at last year's worlds in Budapest where he was eliminated in the semi-finals.

"There was a lot of injury so I decided to change everything," he said.

"This year is Olympic year and I'm Olympic champion so I tried to do all to come back stronger than before."

Jacobs insisted, however, that heading to Paris as the defending title holder was not a bad thing.

"No, I don't think it's pressure, it's a lot of motivation to arrive there and win again," he said.

"I know it's not easy, I'll do my best to arrive there to win the gold medal again in the 100m and the 4x100m for sure.

"The first month was a little bit difficult because during my training in Italy, I would have an hour or an hour-and-a-half to warm-up, now after 30 minutes you have to go, go, go, go.

"There's a lot of difference. But I guess I like it. I see a lot of difference in my body."

Life in the United States was "very quiet", Jacobs added.

"I'm there with my family. I do training, home, home, training, nothing else. I'm really happy, the work is really good."

Jacobs enjoyed an opening run-out in his home town of Jacksonville last weekend, coming in second over 100m to Bromell, the two-time world bronze medallist.

"That was just training. Now I'm here with my team, we are world relays champion, Olympic champions. We are really focused on these races (this weekend) and then I'll start my season."

Up for grabs in Nassau will be Olympic qualification, World Athletics president Sebastian Coe hailing the "injected jeopardy" as raising the profile of the two-day event at the Thomas A. Robinson National Stadium featuring 893 athletes from 54 countries.

"They call it 'Paradise to Paris' and a good tagline it genuinely is," the two-time 1500m gold medallist for Britain said.

"There's an absolutely star-studded cast. In terms of a relay event, it's something for the ages."