They are so competitive they still race each other up the stairs – so it is a good job Katie and Molly Summerhayes are going for gold in different Olympic events in PyeongChang.
The Sheffield sisters were this week confirmed on Team GB’s freestyle skiing squad for next month’s Winter Olympics and head to South Korea with excitement levels off the charts.
Katie, 22, is considered one of Britain’s best medal chances having finished seventh four years ago and won a world silver medal in 2015.
She will compete in the Slopestyle event, which sees skiers judged as they perform a dizzying array of tricks and jumps on a downhill course pitted with obstacles.
And her younger sister will make her first Olympic appearance in the halfpipe, in which she won the world junior title three years ago.
“Having Molly to share the experience with me is great,” Katie said.
“I’ve told her so much about last time and now she gets to share it with me.
“She needs to take as much as possible from the experience and try not to forget anything.”
Making a second Games team has not been easy. Indeed, the older Summerhayes sister has been off the snow since picking up an injury last month, only returning to action this week.
“Four years ago I almost missed out through injury and I feared the same thing was going to happen again,” she said.
“I’ve been working so hard on my rehab to be ready.
“Having six weeks off skis is not ideal but I know what I can do if everything goes right.”
Molly, 20, was part of her sister’s cheering squad in Sochi and admitted the experience only made her more determined to be part of it, with the pair only the fourth British sisters to compete at the Games.
While Katie has toiled with injuries, Molly has struggled on without any funding – indeed just hours after collecting her Olympic kit in Stockport, she was back working the late shift in the McDonalds in Drake House retail park.
“I think I’ve got an idea of the pressure from watching her last time but I also saw how much fun she had and what an experience and privilege it is to compete for your country,” said Molly.
“It’s been difficult and I really couldn’t have done it without McDonalds, who have been so supportive and allowed me time off when I need it.
“I’ve also raised some funds online but the biggest supporter are my Mum and Dad.
“I actually really enjoy work. I’d probably do it even if I got funding, because I love the guys on my team, they’ve all been really excited for me.
“I just really want to go out and have a good time and perform the best I can.
“I’m trying not to set myself any goals but I want to come home with no regrets.”
The Summerhayes sisters are part of a four-strong Sheffield contingent on the team with James Woods and Peter Speight competing in the men’s ski Slopestyle and halfpipe respectively.
You can watch Katie and Molly compete LIVE and on demand across Eurosport channels. Don’t miss a moment of the Olympic Winter Games on Eurosport, the Eurosport App (available on IOS, Android and Windows devices), and online at www.eurosport.co.uk/olympics