I know what you’re thinking. There's something wrong with the picture above -- no one looks that happy when they're exercising. Well, read on and you just might find your next workout a whole lot more fun.

1. Avoid boredom

Let’s face it: Running on the treadmill or using an elliptical gets pretty dull, no matter how many workout playlists you make to entertain yourself. Varying your exercise routine can keep you interested. One study found that people who varied their workouts every two weeks over a two month period were more likely to enjoy exercising and stick to their goals. Try a yoga class, ride a bike or go for a walk with a friend to shake things up.

2. Strengthen new muscle groups

If you’ve done the same workout circuit at the gym for three years, it probably doesn't require the same exertion that it used to. This is because your body gets used to performing the motions and becomes more efficient. By changing the type of exercise you do, you challenge your body by having to use new muscles. According to exercise physiologist Irv Rubenstein, “No one movement gets all the muscle fibers at once. The only way to target all the muscle fibers is by performing multiple exercises.”

3. Prevent injuries

Doing the same exercise can put repetitive stress on joints and ligaments. According to Dr. Arnold Lee, a physician at One Medical Group in San Francisco, this is why many runners suffer from overuse injuries like shin splints, tendinitis and stress fractures. Using the same muscles over and over can lead to strain injuries because the muscles do not have a chance to rest and recover after a strenuous workout.

4. Improve brain health

Exercise plays a major role in maintaining cognitive function and preventing memory deterioration. Research also shows that learning new skills can fend off dementia by strengthening neural connections. So mastering that complicated yoga pose works your brain and your muscles at the same time!

5. Discover new talents

Who knows? You might be a fantastic basketball player. Or a great boxer. Or even the next Michael Phelps. By trying out new activities, you will get fit and learn more about yourself in the process.

6. Make new friends

Even if you make a fool of yourself, you never know who you’ll meet at that tap-dancing class.

If you’ve decided to take the leap and try out a new class or even a different machine at the gym, remember to start slowly. And don’t be afraid to ask for help if you just can’t master the downward dog. (How anyone can get their body in that position remains a mystery to me.)

Most importantly, have fun. The more enjoyable your workouts, the more likely you'll be to stick with them.