Rugby Stars Take on the Baltimore Ravens: “The NFL is Almost Impossible”

All Blacks great Dan Carter, former Black Ferns star Portia Woodman-Wickliffe and former All Black Lima Sopoaga have traded rugby balls for footballs, training with the Baltimore Ravens and finding out just how hard the NFL really is.

The visit had a familiar face at its centre. Dr Nic Gill, the long-time head of strength and conditioning for the All Blacks, joined the Ravens this year as vice president of health and performance.

Carter was blown away by the facility. "Man, if I was playing here, I'd still be playing well into my 40s," he said. "From your recovery facilities to your meeting rooms with the technology in terms of the data, the analytics... it's just next level."

WATCH: Find out what happens when the All Blacks and Black Ferns train with the Baltimore Ravens

Then came the ball. NFL footballs must sit between 12.5 and 13.5 PSI, the Ravens explained. The rugby balls the visitors were used to sit closer to 9.5 or 10.

"How do you kick this thing? This is a bloody brick," Sopoaga said. The answer from his hosts: "As hard as you can."

The Ravens walked the group through the three foot positions taught to NFL kickers: soccer style, club and a blend of the two. "I'd say 90% of the league is, we call it three quarter club," they said.

The lessons went both ways. Ravens safety Malakai Starks revealed he had studied the All Blacks at college, during a summer programme run by his sports psychologist. "Nothing but respect for y'all, man," Starks said.

The rugby crew gave the Ravens a crash course in their game: no forward passes, three points for a drop goal, five for a try. With no downs, play stays live "until someone makes a mistake or we score a try or the ball goes out or someone knocks it on".

WATCH: Dr Nic Gill joins Inside the Black Jersey to talk about the differences between rugby and NFL

Then it was out to the field. "Dan Carter's gonna kick. I'm going to retrieve. And Portia's going to try and tackle me," Sopoaga said.

The NFL gear proved the biggest hurdle. "This helmet is, I reckon it's, like, close to three, four kilos maybe. You can do weights with this," Sopoaga said.

Catching a spiralling punt in full gear was another story.

"I think transitioning from rugby to NFL or rugby to gridiron would be extremely, extremely hard."

The Ravens did spot one natural fit. Asked where Woodman-Wickliffe would line up in the NFL, Ravens long snapper Nick Moore did not hesitate. "Probably running back with that damn stiff arm, dude. Her and Derrick Henry get that stiff arm going."

WATCH: An American reacts to Portia Woodman-Wickliffe highlights