There's a totally legit reason you always seem to fall off the workout wagon: the conventional approach to exercise almost forces you to bail out.
We asked experts who specialise in the science of motivation - and real women who fit exercise into their busy lives - to explain how to keep your bum in gear. Turns out, a few simple behavioural tweaks is all it takes to silence the call of the couch.
Research shows that 50 per cent of people who start an exercise program drop out within six months. That's because the most common reasons given for exercising - "My boyfriend says I should lose five kilos"; "My doctor keeps bugging me about it" - have very little to do with you, says Dr Edward Deci, a professor of psychology at the University of Rochester, US, who has studied motivation for decades.
In fact, working out to make others happy is the least successful way to compel you to break a sweat.
Curing the motivation problem is at the crux of a theory developed by Dr Deci and his colleagues called Self Determination Theory (SDT).
It boils down to this: the more you do stuff you like to do, not what you think you should do, the more you'll keep doing it.
The benefits of this "intrinsic motivation" have been proven in studies across the board, from education to healthcare to parenting. In exercise research, intrinsically motivated exercisers were more likely than those who were nagged to continue working out for six months or more.
Experts say these three subtle shifts in your outlook can keep you on track:
STEP 1: TAKE CHARGE
Psychologists call this autonomy, and it's one thing you must develop if you want to harness intrinsic motivation.
"People who feel as if they're making their own decisions report feeling higher levels of self-worth," says Philip Wilson, an associate professor of psychology at Brock University in Canada, who studies SDT and exercise. "And that leaves them feeling more motivated."
Ask yourself why you want to exercise at all. If the answer is that your mate casually dropped the phrase "muffin top" when you were jeans shopping, your efforts are probably doomed. But if you decide to get fit because you want to feel stronger or healthier, you're more likely to succeed, because the end result means something to you.
Next, find a form of exercise you enjoy so much you'd do it even if it weren't good for you. If the mellow vibe of yoga brings you bliss, light up some incense and roll out a mat. If slamming a tennis ball is more your thing, join a club or sign up for lessons.
Perhaps most important: if you truly despise running on the treadmill (or doing crunches or taking spin class), don't! If you're invested in what you're doing, your performance will improve - that will feed your desire to go back for more. If you honestly can't equate exercise with fun, flex your take-charge muscle by setting specific goals. Working your way up to three no-cheating-allowed push-ups? Finishing your first 5km run? Whatever your goal, it can help you stay motivated for the short term (and the long).
"People thrive on feedback, and having goals provides that," says Rachel Cosgrove, co-owner of Results Fitness, a California-based gym. Eighty per cent of the clients there renew their memberships every year - double the industry standard.
Cosgrove helps clients create meaningful goals by getting them to focus on tangible accomplishments: completing an hour-long workout twice a week, doing five pull-ups or 10 push-ups. At the same time, she discourages them from stepping on the scale.
"Goals should be based on feeling good - that's what keeps people coming back to the gym," she says. Dr Deci's research supports Cosgrove's approach. Physical accomplishments give you positive feelings about yourself and increase motivation because they're intrinsic; looking for validation via external motivators, like the scales parked in your bathroom, does not.
STEP 2: GIVE YOURSELF PROPS FOR PROGRESS
The problem: when it comes to working out, women are notorious for seeking a comfort zone. Once we master a new skill (like holding plank position for 60 seconds or running at a 10-minute 2km pace), we stick with it because, hey, we know we can do it. But it also impedes progress and breeds big-time boredom.
"The less interesting something is, the less motivated we are," says Wilson. Some of his earliest SDT studies showed that humans have a basic need to feel engaged - take away the novelty, and motivation vanishes. And Groundhog Day-style monotony isn't just bad for your head; eventually your muscles stop responding and you really hit a wall.
The solutions: mix things up and push yourself. "Changing the intensity and type of exercise trains the muscles differently, and you'll start to see improvements more quickly," says Wilson. For example, increase the weight you're lifting and the number of reps and sets by 10 per cent every week. The same goes for your cardio - increase the amount in 10 per cent increments each week.
Do this for three weeks, and then drop back down to where you started on week four to let your body rest, suggests Cosgrove.
Next, write everything down. A workout log functions not only as an exercise checklist but as a concrete record of how far you've come - a way to motivate yourself if you become frustrated.
In researcher-speak, this is called establishing competence, and it's at the core of the second step in fuelling motivation that lasts. To make it work, keep the focus on what you can do, rather than what you can't, says Wilson.
And don't compare yourself to anyone else. Once you start focusing on you, your confidence will grow and ignite a cycle of positive reinforcement that will keep you hooked.
STEP 3: MAKE IT SOCIAL
Start by finding like-minded workout buddies. A study by Canadian researchers found that a congenial atmosphere, rather than a competitive one, helps people stay motivated by providing a source of encouragement.
In Cosgrove's gym, clients work out in small groups of three to five people with similar fitness goals.
"The group provides built-in support, and it's way more fun than working out alone," Cosgrove says.
Members push each other to reach goals and cheer each other on. And when someone has a bad day, the group is there to lift their spirits and sympathise.
If you go to a gym, get to know a few of the trainers - even if your relationship is limited to their giving you pointers on form. If you don't love gyms, Wilson recommends hooking up with a friend who has a similar fitness level or searching the message boards of local clubs to find people who share your definition of fun. If you're a lone ranger at heart, don't sweat it.
Just focus more on taking charge of your fitness and feeling good about your progress.
The ability to stick to a workout and get the body that makes you happy isn't the sole domain of professional athletes and Type A exercisers. You already have what you need within you: it's just a matter of tweaking your perspective so you can tap into what really gets you going.
3 WAYS TO INJECT SOME FUN INTO YOUR FITNESS ROUTINE
Play gym rat Hold a medicine ball and lie on the floor, arms stretched behind your head, knees bent. Keep arms straight, curl up and toss the ball to a partner in the same position 3 metres away. They catch it, lower themself to the floor, curl back up and toss to you. First to miss gets an R; first to get RAT loses.
Head-to-head high-fives Get into the top of a push-up position. Have your buddy get in the same position facing you. Together, lift your right arms and give each other a high five. Alternate arms as many times as you can. Cheer each other on to do a few more reps each week.
Bet the burn Get on a treadmill or a stationary bike next to a friend. Throw your towels over the display screens. Decide together how long you'll run or ride, then guess how many kilojoules the other will burn during that time. Reveal your displays at the end; the person who comes closest wins.