Theoretically, the fact that it's summer should mean that you have more motivation to be good to your body. The reality: Your brain is probably in umbrella-drink mode, and your workout routine needs a shakeup. Never fear! It's easier than you think!

1. Jump around.
Aside from weight training and getting enough calcium, the other way to strengthen your bones (super important for all women) is through "plyometrics," or exercise that involves "explosive jumping movements." Awesome. And it's your new excuse to get on a trampoline.

2. Make your fitness functional.
You've got places to be, so now that it's nice out, ride your bike there instead of the usual nowhere in spin class. Even running to pick up your breakfast works -- and no, this does not defeat the purpose of your workout. A survey of people who'd lost 70 lbs. or more and kept it off for a year or more, only 4 percent reported that they never eat breakfast every day.

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3. Think sexy.
Exercise can make you feel like you've got your groove back. Think of it this way: According to a study in the Journal of Sport and Exercise Psychology, just knowing that you work out regularly makes people not only think of you as a harder worker, but as more sexually attractive, too. What more incentive do you need? Or just listen to your favorite make-out music to keep you focused on something other than your wheezing mid-sweat.

4. Say goodbye to monogamy.
Don't just stick to one gym. You probably know that you can do free or low-cost trial weeks at most facilities. But you may not know that your existing membership is good at gyms around the country. If your home location is part of the International Health, Racquet and Sportsclub Association's Passport Program (find out here), you may be able to pop in to one of more than 3,000 fitness centers at little or no cost.

5. Gamble like a sailor.
A study in the Journal of the American Medical Association found that people who had financial incentives to lose weight are much more successful in reaching their goals than those who had no cash to motivate them. What this means for you, regardless of your size: You'll hit the gym regularly if it means not handing over $100 to a smug, super-fit frenemy.