You know that little voice in your head that whispers annoying things like "you can't do it" and "just give up" when you're uncertain about accomplishing a goal?

When the goal is finishing a 5K or holding a plank for 60 seconds, that voice turns into a screaming champion of doubt, urging you to cut your workout short right before the finish line.

To squash the non-believer in you, we asked fitness experts to give up their most motivating techniques. Here, the Jedi mind tricks that will help you finish your workout strong -- and make healthier choices for the rest of the day.

Sometimes, those fitspiration images of ridiculously ripped women have the opposite of their intended effect: they make you feel bad enough about yourself to consider spending half your salary on a personal trainer. But before you write that check, consider this: Science says that those who use health as their no. 1 fitness motivation reap more benefits than those who focus on physical appearance. That's right, focusing on health benefits like better mood and memory will help you get back into your skinny jeans more than pictures of bikini bridges and thigh gaps will.

At SoulCycle, senior master instructor Janet Fitzgerald asks each student to set an intention for the class -- a dream or goal they are working towards. "I tell them to imagine that with every pedal stroke, they are getting closer to that goal. This pushes riders to keep going -- more than if they were just in class to burn calories or lose weight," says Fitzgerald.

When the alarm goes off at 5:45 a.m., your beckoning spin class feels like anything but a good time. But one study suggests that seeing your workout as fun instead of a chore can have a major impact on your waistline. In the study, those who saw their workout as time to get away, enjoy nature or listen to music ate 200 fewer calories later in the day than those who viewed it as exercise. The exercise group also reported feeling grumpier and more fatigued, even though the mileage and calories burned were practically identical.

To avoid ruining your workout with high-calorie snacks, frame your physical activity as fun -- and do something you really love. Create an awesome playlist that makes you forget to check your progress, or sign up for a fun run -- it's hard to think of a 5K as work when you're wearing a tutu or are covered in colored powder.

From end-of-year bonuses to loyalty programs, we're an incentive-based society. So why not use one at the gym?

Anna Kaiser, founder of AKT in Motion, and trainer of celebs like Shakira and Sarah Jessica Parker, says she makes a deal with clients who are really struggling. "If they finish their workout without stopping, they can put $20 in a cup. When the cup reaches $100, we'll buy them an amazing new workout outfit to rock," says Kaiser. Think of it as making deposits into your fitness bank.

There's one caveat to the reward system approach: Never, ever reward yourself with food for working out. Studies show that we overestimate how many calories we burn. So when we treat ourselves to a slice of pizza or an extra large caramel latte, we end up eating way more than we burned off in the first place.

Instead, use an app like Pact that pays you (with real money!) for going to the gym (and also slaps you with a "lazy tax" if you skip), or Charity Miles, which donates to a charity of your choice for every mile you bike, run or walk.

If you've got a competitive streak, you know the power of adding some friendly rivalry to goad you on.

Dr. Gary Hall, Sr., three-time Olympic medalist and founder of The Race Club, says creating a competitive environment when athletes are struggling at the end of practice helps them to push through pain and fatigue.

Research shows that working out with a super-fit buddy motivates women to work out harder and longer than those who exercise alone. The best part? The women increased their workout without even realizing it.

Your ideal workout buddy is someone who is in just a little bit better shape than you, especially in the areas you want to work on. If you're against the idea of mixing friends and fitness, get a virtual buddy on the app Nexercise.