Elevation gain measurements

So I'm doing Ironman Louisville and im trying to make sure i have enough climbing in my biking. [Here's my ride from today](http://www.mapmyride.com/routes/view/459412136) and here's the newest [ironman louisville course one I could find](http://www.mapmyride.com/us/louisville-ky/ironman-louisville-bike-course-112-miles-route-62525226). According to this I have more then enough to be ready for the race, however the races website has like 5,300 elevation gain. So could someone help clear this up for me is it measured differently or something?