You can push yourself without being miserable. Here's how

"No pain, no gain." It's a thing people say when you're trying to get in shape, and you're at the gym crying, or dying, or something in between, because your arms are burning and shaking and you've got one more push-up left.

The aphorism is true, in the sense that a leisurely stroll around the block won't do much for your biceps. The problem is that the inverse — fun and comfort mean your mind and body are slowly deteriorating — is not.

This myth is one of several that bestselling author Jon Acuff dismantles in his book "Finish," a breezy but insightful guide to tackling the perfectionistic impulses that keep us from hitting our goals.

Acuff writes: "Perfectionism believes that the harder something is, the more miserable something is, the better." Meaning things only "count" — say, as healthful or educational — if you're having a terrible time. And they definitely do not count if you're enjoying yourself.

This is wrong, Acuff says. So wrong. Not solely because fun stuff counts for something, too, but because we're more likely to achieve our goals when we're having fun.

Case in point: Acuff writes about a photographer named Jeremy Cowart who wanted to "give back" — which is a pretty common, and commonly abandoned, goal. But Cowart asked himself what he already enjoyed doing that he could use to help his community. So he started taking free portraits at events around the world, and has taken upwards of half a million photos.

Acuff himself was determined to read more; but instead of limiting his reading to the likes of "War and Peace," he broadened his horizons to include audiobooks, business books, and even comic books.

Acuff writes: "What invisible standard was my personal goal of reading a hundred books in a year supposed to be measured against? Whose quality level was I judging my goal based on? I made the rules and I decided to make them fun."

"Finish" was partly inspired by a study, led by University of Memphis Ph.D. student Mike Peasley, of 900 participants in Acuff's online goal-reaching video course, "30 Days of Hustle." Based on Peasley's observations, Acuff writes that choosing a goal you believe will be enjoyable increases your likelihood of satisfaction by about 31%. What's more surprising is that you'll also perform about 46% better.

Acuff also cites a paper led by Daniel Chambliss at Hamilton college, which asserts that elite swimmers don't find their rigorous practice sessions and tough competitions excruciating. Instead, they rather enjoy them.

In other words: Pick an activity you enjoy that will help you get stronger, or smarter, or more successful, and you'll have a better shot at becoming stronger, smarter, or more successful than you would if you picked an activity you positively hated.

It's worth noting here that some psychologists — most notably, Anders Ericsson of Florida State University — see sacrifice and struggle as an often important component of success. The kind of practice that will make you an expert at something — if that's what you're going for — isn't supposed to be enjoyable, at least not in the moment. Fun probably doesn't "count" toward your goal of mastery.

That said, Acuff does have a few tricks up his sleeve for making even the dullest or most strenuous of activities more enjoyable.

"Make it fun if you want it done," he writes. It can be as simple as one author's strategy of treating himself to a Friday movie if he finished his work. Acuff upgrades his rental car when he goes on business trips. The important thing is that there's no shame in making it a game.

Acuff uses the phrase "cheating" a few times throughout his book, and says that making things easier for yourself is good, not bad. As in: Hitting up a Zumba class instead of running on the treadmill, assuming they're equally strenuous but you enjoy Zumba more, is good.

No pain, no gain? Sure. But enjoying life is OK, too.