The former Scottish indoor internationalist from Edinburgh has retired from top-level competition, ironically at a time when UK Sport have announced they will continue to support a GB beach volleyball programme but will not back an indoor programme.
The 28-year-old Mullin and her English partner Zara Dampney came close to a place in the last 16 on Horse Guards Parade as beach volleyball proved one of the highlights of the Games.
The London-based player, who played indoors with City of Edinburgh, has decided to split with her regular partner and return to civvy street. Dampney will pursue a place in the team for Rio with a new partner, Lucy Boulton.
"It was just a case of the lifestyle getting too tough; being on the road so much and not really having any control over what I was doing," explained Mullin. "I didn't want to be on the road and travelling 11 months of the year any more and, even though it has changed a bit coming out of the Games – the girls are now training at the indoor facility in Bournemouth – I kind of wanted a change of scene and a new challenge.
"It's a massive commitment and I would have had to commit for another four years with it being an Olympic cycle. That does take a lot and to be able to be committed to that, you have to be motivated. That motivation is getting very difficult these days.
"It's not difficult to get up every day and train but to keep the focus on where you want to get to and the long-term goals is difficult. If it was just a year-by-year thing, it would maybe have been different. There is a sense that we couldn't top London anyway. There was a great atmophere and we were given a tremendous reception and we had a good result, beating Canada."
"It would be difficult to beat that, even though they're bringing the sport to the home of beach volleyball in Rio and the Copa Cabana. We've done a lot of training there and it's going to be an absolutely fantastic event with a superb atmosphere."
Mullin has started working in business development and marketing in London and, along with Dampney, has established a new fitness concept, volleybody (www.volleybody.co.uk), which uses beach volleyball training techniques to get people fit.
Mullin, who will continue to play indoors with London Malory, believes the beach game has won new respect after London 2012 following positive media coverage. "I have two memories that stand out from London 2012. The first is standing in the tunnel before our first match with Canada and just not expecting that many people to make that much noise. We weren't big personalities going into the Games but we had fantastic support from the crowd. Running into that stadium and seeing the crowd erupt will stay with me for the rest of my life."