I'll admit that I haven't done a great job at sticking to my New Year's fitness resolution -- even though I had high hopes of getting arms like First Lady Michelle Obama by summer. A commute into work that spans three states, hours spent on my laptop and forfeiting my running shoes for the couch and latest episode of "Scandal," has made me a slacker. So when I learned that I was going to be working out with Serena Williams, I thought this was the kick in the well-toned butt I needed.

Packed into a studio with about 30 other would-be gym rats, I delved into a "moderate" version of Serena's workout: 15 reps of push-ups, crunches, squats and burpees without any breaks. As I looked over my sweaty shoulder, I could see the tennis champ breezing through the exercises in spite of saying she would take it easy after just returning from the red clays in Europe. Twenty minutes later and my mass of curls ready to break through the ponytail holder, I could feel the burn that produces a bodacious body like Serena's.

And even though she has a killer shape that gives any outfit sex appeal, Serena revealed that her biggest style dilemma actually has nothing to do with her muscles.

"My problem comes in the bust area," said Williams. "[Blazers and tops] will fit my shoulders, but they won't fit my bust. You can belt and get things tailored, but who wants to go through the trouble of that."

Her fashion fix? If she can't get it off the rack, design something for her figure and then share it with the masses via her HSN collection, of course. Lucky girl.

Click through the slideshow below for more on Serena's shopping strategy, her go-to workout hairstyle and the exercises she recommends for non-athletes (uh...like myself) to get in shape for bikini season. And keep clicking for a look back at some of her most memorable style moments, both on and off the tennis court.

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On Dressing Her Body Type...
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I look for things that are really great for curves. I have a really small waist, so I like high-waisted pieces. And I love tank tops. Photo: Getty Images