Olympians are constantly pushing and redefining the physical limits of human potential. They can be disciplined to a fault. Yet when it comes to New Year's resolutions, sometimes even the simplest-seeming missions can trip them up. Below, 11 athletes reveal and reflect upon their hardest resolutions so far.

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Ryan Lochte

Age 31; 11-time Olympic medalist in swimming

I tried to not do soda. I failed at the very end of the year. I was doing so well -- I don't know what happened. I was eating pizza one time. I was dying of thirst, and I just saw soda right next to me and was like, "Alright, I'm doin' it." I did it, and I was just like... FAIL. That's my weakness: all sodas.

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Tamika Catchings

Age 36; three-time Olympic gold medalist in basketball

The hardest one last year was to cook at least three times a week. It could be any meal but it had to be from scratch. I lasted all January, then it kind of went away. Then I got engaged and was like, "OK, I've really got to get back on this. I need to get more domesticated." I did pretty good in April. Then the season started and now it's just kind of an afterthought. I have to try again, because next year is my last year of playing [for the Indiana Fever], then real life hits.

Also in 2016, my goal is to take advantage of every single opportunity. Before, I'd be like, "Oh, I don't see myself doing that," or "No, I think I'll pass." So living life a little bit more, branching out, and really being open to new opportunities.

Claressa Shields celebrates her victory against Marina Volnova of Kazakhstan during the Women's Middle (75kg) Boxing semifinals on Day 12 of the London 2012 Olympic Games at ExCeL on August 8, 2012 in London, England. Scott Heavey/Getty Images)

Claressa Shields

Age 20; Olympic gold medalist in boxing (2012)

The worst resolution I ever made was to stop cursing. It's "the worst" because it's really hard. I was really counting the days, "Wow, my third day without cursing." I made it about two weeks. Then I cursed. I'd be like, OK, let's start over, but you know what? Forget it. It's too hard. For three years, I never accomplished it. I'm going to try again because I feel like it can be done.

For 2016, I want to win all my tournaments again, win the Olympics again, again stop cursing, and get a closer relationship with God which is always one of my resolutions that I accomplish every year. And another one: not letting people get to me, like haters. Instead of responding, I'm going to go ahead and block them.

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Meghan Klingenberg

Age 27; World Cup champion in soccer (2015), Olympic alternate (2012)

I fail at resolutions every year. One was to learn Spanish by the end of the year. I made it two weeks. One was to learn Swedish. I actually went nine months but then I moved back to the U.S., so that fell through [after playing for the Swedish pro team Tyresö from 2012-14]. One was to start investing my money myself, playing around with stocks on E*Trade and trying to become the next Warren Buffett. That didn't happen. That was 2½ months. So I've totally stopped doing resolutions. I'm awful. It's not my thing anymore.

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Jessica Hardy

Age 28; Olympic gold and bronze medalist in swimming

I gave up soda, like three years ago -- just to see if I could. It was definitely the most challenging because, like every American, I loved it. It took a lot of dedication at first. And now, I don't like it any more so it was worth it. I don't really drink it at all, so I'm grateful.

For 2016, I'm definitely open to any suggestions, if any Twitterers out there want to help. But it'll probably be along the lines of getting more sleep and eating less sugar.

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Meb Keflezighi

Age 40; Olympic silver medalist in the marathon (2004), and winner of the 2009 New York City and 2014 Boston marathons

For me, a resolution was to see if I could challenge myself to tie my best high school times in the mile and two mile. I turned 40 in May, so [I wanted to] see if I [could] crank out 4:05 for a full-out mile, or 8:52 for the 3200 meter, which is almost two miles. Those were my best times senior year, ohmygosh, in 1994.

This year, I ran 4:26, 4:27 for the mile -- after like my sixth one though, just [marathon] training in Mammoth Lakes. A couple weeks ago, I did 9:30 for two miles which tied running all-out as a freshman in high school. [That] was pretty solid, but now I'm doing that on my third set of two-mile repeats.

Whenever I train for a marathon and do two-mile repeats, I think about those times. It kind of puts in perspective how far you have come, and how far you can still go. I'm still trying to click on eight cylinders. Trying, at least.

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Carli Lloyd

Age 33; World Cup champion (2015) and two-time Olympic gold medalist in soccer

I do not really ever do a New Year's resolution but I have tried to stop biting my cuticles and it has not worked! I need to have my nails polished so I don't bite them.

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Missy Franklin

Age 20; four-time Olympic gold medalist in swimming

The hardest one last year -- which I didn't accomplish -- was to read a Bible verse every day. I made it to May. I'll try again this year and see if I can get even further, but I think it's important not to be too hard on yourself if something happens and you're not exactly where you want to be. Keep getting after your goal, keep working towards it. It didn't work out one way, so I started trying different ways. Instead of reading the Bible every day I would read a devotional or I would do something with my Bible study group. The overall goal was to increase my faith.

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Taylor Phinney

Age 25; two-time Olympian in cycling

The one I'll always struggle with is to change some dietary thing like, I'm not going to have dessert anymore. You get three days in and you're like, Yeah, I'll have some strawberries. Then it's, "Maybe with some whip cream" and all of a sudden you're just going for the ice cream.

I know myself better than that [now] so I don't really make solid New Year's resolutions. I feel like I'm constantly learning things I can improve on so I like to keep an open practice all year.

I was thinking this year I'd try to constantly learn something from every person I meet. It can be very basic to very complicated, depending on how much you connect with someone.

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Elizabeth Beisel

Age 23; Olympic silver and bronze medalist in swimming

Worst resolution? Giving up chocolate because it's not realistic. I lasted probably two weeks. This year I just want to take care of my body more going into the Olympic year. 2016 is sort of a wake-up call to really lock down and do things that will make you better in the pool while you're outside of the pool, like sleeping more, eating right. It would be awesome to win a gold medal. I have a silver [in the 400-meter individual medley] and a bronze [in the 200-meter backstroke]. It would be cool to have all three.

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Sarah (Groff) True

Age 34; Olympic triathlete (2012)

My toothbrush gets a little crusty, so keeping it clean -- every year that's the goal. I've failed miserably. I lasted I think a few months. One of these years, I'm going to be on top of it. I'll keep trying. It's an ongoing multi-year battle. I'm a very vigorous tooth brusher. I guess I just make a little bit of a mess.