( CNN ) -- Before I applied for the CNN Fit Nation program , I thought I knew quite a bit about the sport of triathlon . I had volunteered at a few races , helping athletes navigate the courses , and I even witnessed newly crowned world champions crossing the finish line . But what I knew , or thought I knew , was from the perspective of an outsider and very superficial . I really had no idea about the training that these athletes had gone through to prepare for their races . As with most things in life , seeing and doing are two very different things . I 've already written about my struggles with running , so you know that worried me from the beginning . But I 've changed as an athlete . The aches and pains are mostly gone now , and as long as I beat the heat and fuel my body , my running workouts are amazing . I 've learned to listen to my body throughout the day -- especially during and after a workout -- and my successes have surprised me . Follow the CNN `` 6-Pack '' with this interactive . Information is a powerful thing , and what I 've learned from my coaches and what I 've learned about myself has turned even me into a runner . I think many of my past problems resulted from trying to go too fast , too soon . In the past , when I started to see success , I wanted more , and that usually led to injury derailing my progress . I 've learned how to build my base endurance slowly and teach my body how to train with a slow and steady progression . I 've learned that you should never increase your distance more than 10 % per week so that your body has time to adjust to the increased workload . I 've been cycling for a few years , and I thought that would be my strongest discipline . However , I learned more about cycling at our May training camp in Florida than I thought possible . I learned the basics of riding in a `` paceline '' with my teammates and coaches , how to better control my bike and about the importance of keeping the pedals turning even when coasting ( the `` soft pedal '' ) . Who knew that central Florida was such a hilly place ? I learned quickly . After climbing some of those never-ending hills , I 'm a better climber and a better cyclist . Behind the scenes : Training for a triathlon . And that leads me to the pool . Swimming has become my nemesis -- and my biggest area of opportunity . Before starting this journey , I thought I could swim . I was wrong ! My first attempts at swimming in a lap pool looked like I was `` fighting the water , '' to paraphrase my coach . It 's much harder to swim when you 're trying to keep your head out of the water the entire time . The freestyle stroke , the breathing and everything else about swimming was completely foreign to me . As with the other disciplines , I 've learned to swim with the guidance of my coach and through lots of trial and error . Constantly practicing the exhale under water while only putting my face in the water or `` bobbing '' at the deep end of the pool has taught me how to control my breathing better . For me , the key to swimming was learning to relax . Now that I can better control my breathing , my workouts have finally become aerobic activities . To make my personal journey even more exciting , my girlfriend and a few of my closest friends have committed to taking a similar journey with me . They have started training and will be there in Malibu , California , not just cheering me on but racing their first triathlons as well . Now I 'm able to share what I 've learned with those closest to me . I often pass on simple tips , such as `` slow down and focus on your form . '' There 's no hurry when you 're training ; I 've learned that once my form is good , I 'm much more efficient when I pick up the pace . 10 ways to act like a champion . When I look back at the guy who first submitted an iReport to CNN , I thought I knew a bit about triathlons . But really I had no idea . The training once foreign to me is now a major part of my daily life , and I 'm excited to say it 's become a part of the lives of many people around me as well . I 've grown as an athlete and as a person , and I 'm learning how to train my mind as well as my body . When I cross the finish line in Malibu , I 'll cross with my teammates , my family and my friends . We will have all shared a similar journey , and we will all become triathletes together . Follow Mantooth on Twitter @ TriHardStacy and Facebook .
Stacy Mantooth was an avid fan of the sport of triathlon before joining CNN 's Fit Nation . She is now a fitness instructor and has been featured on CNN's The Biggest Loser, Dr. Oz, Good Morning America, Today Show with Kathie Lee Gifford and more. Mantooth is sharing his knowledge with family and friends who are training with him .