I was never good enough for sevens! - All Black legend McCaw

All Black legend Richie McCaw joked Tuesday he was "never good enough" for rugby sevens, dubbing as "brilliant" the sport's debut at the Olympics.

McCaw, 35, won 148 caps for New Zealand, captaining the team to back-to-back Rugby World Cups in a stellar career.

The fearless flanker, who captained the All Blacks a record 87 times, told AFP in an interview in Rio that the abbreviated form of the game had largely passed him by.

"I never played any sevens, I probably didn't have enough skill for that!" he said.

"You've got to be able to have a step and a bit of speed and I didn't have that, so that's why 15s is a lot better for me."

A potential trip to the Olympics "came at the end of my career where I was too old to be looking at that", he added.

"I never had the chance, but if there was a chance to go to the Olympics, well you'd probably think seriously about it."

McCaw highlighted sevens' Olympic inclusion as a boost for a sport that is becoming increasingly professional and specialised, attracting dedicated players who do not play 15s.

"Sevens was sometimes a way of getting to the 15s. I certainly think that for the rugby players who are a bit younger, now with sevens you can make a career of it and with a pinnacle event like the Olympics it's certainly a big incentive," McCaw told AFP.

"You can see that with guys like (capped All Blacks) Sonny Bill Williams and Liam Messam putting their effort in to having a crack at it."

Turning to the tournament-ending achilles injury that Williams sustained in the Kiwis' shock 14-12 defeat by Japan, McCaw said: "Injuries can happen to any team, you've just got to deal with it.

"The team that will win it will have to deal with some bits and pieces, it's a challenge the lads have got now and we'll see how good they are, won't we."

The defeat was "a bit of a disappointing start for our Kiwi boys", he added.

- Sevens' Olympic inclusion 'brilliant' -

McCaw predicted a bright future for rugby sevens. Its appearance in Rio marks the first time since 1924 that rugby has been played at the Olympics and the debut for sevens, the previous four incarnations featuring men's 15-a-side tournaments.

"It's brilliant!" he enthused. "I've just been talking to (ex-international) Dan Lyle from America, who said the uptake of people watching in America is amazing.

"The recognition and understanding of what rugby's all about -- what better place to show it off?

"Just the hype around here, we're going to see it indefinitely."

McCaw, whose fiance Gemma Flynn plays for the New Zealand women's hockey team, said he had one overriding memory of the Olympics.

"Back in 2008, we were in South Africa preparing for a Test match and Georgina and Caroline Evers-Swindell were rowing for gold in the women's double sculls," he said.

"The whole team sat down in South Africa and watched. That was a pretty cool experience, we had a Test match the next day and it was pretty inspiring."

Away from rugby, a fit-looking McCaw said he had been involved in a 550km-long multi-discipline adventure race.

"It's just nice to not have the pressure of playing," he said.

"I've got involved in a helicopter business, I just finished my commerical licence, so I'll do a bit of flying when I get home. That's keeping me busy."