IF Simone Biles is feeling the weight of expectation on her shoulders, the reigning world champion certainly doesn't show it.

The 18-year-old star of Team USA has the air of a young woman who is enjoying every minute of life. In a sport where participants can tend to lean towards a more serious demeanour, Biles – who will go for her third consecutive world all-around title in Glasgow – exudes a happy-go-lucky charm.

She can often be spotted giggling with team-mates during training or goofing around snapping selfies for social media. But when she steps up to perform, boy, does Biles know how to deliver.

In podium training at the SSE Hydro earlier this week, she executed an Amanar – one of most difficult vaults – with pinpoint precision.

Such was her missile-like accuracy that USA Gymnastics women's national team coordinator Martha Karolyi let out a loud "wow!" before Biles's feet had even hit the mat.

Biles, who hails from Ohio but is now based in Texas, is notably laidback when asked about her aspirations of making it three-in-a-row at the 2015 World Gymnastics Championships.

"I guess I never think of it that way," she mused. "I just go in and try to do as much as I can for the team. Hopefully once I make all-around finals we can go from there. I think it would be pretty cool."

The seven-strong women's Team USA squad features an interesting mixture of youth and experience. It includes two world renowned gymnasts on the comeback trail: Gabby Douglas and Aly Raisman who were part of the American "Fierce Five" that took gold at London 2012.

Douglas, 19, is the reigning Olympic all-around champion, while Raisman, 21, took the individual title on floor and a bronze on beam three years ago.

Also in Glasgow is national team stalwart Brenna Dowell – who missed out on competing at both the 2013 and 2014 worlds – US all-around silver medallist (and Biles's best friend) Maggie Nichols, asymmetric bars specialist Madison Kocian and MyKayla Skinner, who excels on floor and vault.

Biles described the chemistry with her team-mates as "pretty good" and said they each brought the best in one another. "We are trying to take in as fun as we can as we do our jobs," she said.

The US women will be in action during qualification on Saturday. Only six of the seven-strong squad can compete with the final line-up due to be announced on the eve of competition.

There was a touching photograph posted on social media after podium training showing Raisman and Douglas side-by-side captioned "just like old times".

Raisman admitted to some jangling nerves in the days leading-up to competition, but said she had since harnessed her inner calm.

"The last few days have been a little rough," she said. "I hit my rib on the beam and flew off the bar a couple of times – things I normally don't do but I think we're just so tired and a little bit too hyper.

"You forget what it is like to be out there because it is different from [US national] championships and a bigger stage, so you want to do well but it is important not to get too over excited.

"Simone and I just try to laugh it off – she is so calm. For us, if we fall once on the beam or we wobble, it's a horrible day because we are such perfectionists."

One member of the US team likely to turn heads in Glasgow is Skinner, 18, who has choreographed her floor routine to a bouncy house dance mix of Scotland the Brave.

There was the slight faux pas of having performed said routine in a specially chosen shamrock green leotard at the P&G Gymnastics Championships in August, but it is certainly a crowd pleaser.

Skinner, who was part of the gold-medal winning US team at last year's World Gymnastics Championships, is hopeful her performance will be well received by Scottish fans. "It's exciting," she said. Will the audience get behind her? "I think they might. We will have to wait and see."