Swiss Steffen defended her title in this the second edition of the race in a time of 4 : 12 : 18 .
Swiss Steffen won VNG IRONMAN 70.3 Vietnam 2015 - one of the top 10 most extreme triathlons .
Swiss Steffen , who won VNG IRONMAN 70.3 Vietnam 2015 - one of the top 10 most extreme triathlons , defended her title in this the second edition of the race in a time of 4 : 12 : 18 .