Anna Keiser is a fitness trainer to celebs such as Shakira, Sofia Vergara, and Kelly Ripa. Founder & CEO of her own studio, AKT In Motion, she practices her own

form of exercise by combining HIIT training with dance to give her clients optimum results. AKT draws on a range of proven methods to expand your limits, strengthen your body, and

improve flexibility and balance with a focused, scaled, and fun approach to movement. 

Check out Anna's 12-minute ab blaster workout to get those rock hard abs.

Justin is a trainer to models Karlie Kloss, Miranda Kerr, Chrissy Teigen, Candice Swanepoel, and several other Victoria's Secret Models. He is all about sculpting lean muscle by way of resistance bands, light weights,

weighted balls, and trampolines. Justin believes in shaping workouts to what your body needs, including your nutrition, health, and generally understanding how your body functions, inside and out.

As for Justin's recommendation for

conditioning, he says to try to take a pilates, yoga, or kickboxing class several times a week. He incorporates all three of these exercise philosophies into his routines. Try to stay away

from heavy exercises — lunges, jumps, heavy weights (anything over 5 pounds), kettle balls — as they add unwanted bulk.

Gunnar is no stranger to fitness, having been in the industry for over 20 years. He works with a variety of celebrities from Khloe Kardashian, Jennifer Lopez, and Ciara to NBA star,

Kevin Love. Even Rocky Balboa visited Gunnar to train for his role in "Rocky VI." Gunnar emphasizes strength training modalities that can be transferred from the gym to daily life, from training

camp to championship game. 

His quick tip: “If you want to enhance the shape of your butt, as well as tone and tighten, the most important exercises are squats and lunges. Be

sure to use weights, weights, weights, and weights… and then some weights!”

Harley has quite the list of celebrities that he has worked with including Ariana Grande, Lady Gaga, Kim Kardashian, Megan Fox, Halle Berry, Orlando Bloom, and more. 

Harley Pasternak is a firm

believer in resistance training. “Pick one exercise a day, a different exercise each day of the week for a different body part,” says Pasternak. “You’re setting yourself up for success because

you don’t need to go to the gym, you don’t need any equipment, you don’t need anything.”

Erica Hood helps her clients sculpt their bodies at the studio, Body By Simone. Erica trains Julianne Hough and model, Rosie Huntington-Whiteley, to get their bodies camera ready. As a dancer, Erica teaches her clients to reach

their fitness goals by leading by example. "My clients mostly tell me that I'm sweet but a killer!" she reveals. "I like the lead-by-example approach by using my own physical strength and

technique while motivating the client with positive encouragement. I will push you to your limit and then tell you how awesome you were once you've succeeded."

Inspired by the Olympics, Julianne Hough asked

Erica to create a workout for her that resembles rowing. In return, Erica created a short and simple workout that works your upper body, back, lats, and core. Luckily, all

you need is a set of resistance bands. Check out the workout and tip here.

David is the man with whom many A-listers train when they need to get in shape fast. He has worked with Heidi Klum and Kate Upton to get their bods

camera-ready at all times. David encourages his clients to visualize the bodies they want to create and pay attention to their form and breathing throughout the training program. 

He states that squats, lunges, and burpees are only

as effective as the soundness of your nutrition, so he suggests steering clear of sugar, artificial sweeteners, processed carbohydrates and alcohol.

Astrid is a sought after personal trainer, fitness model, and athlete. Astrid has worked alongside Julianne Hough, Jessica Alba, and Stacey Keibler. Astrid combines various training techniques and exercises to prevent your body

from reaching the plateau, allowing for better results in less time.  

Astrid's quick tip for those who don't have much time to workout: High-intensity interval training workouts for fifteen to twenty

minutes can get the job done. Use heavy weights and mix in compound moves with cardio bursts.

Ashley Borden is a published author and personal trainer to clients such as Christina Aguilera, Reese Witherspoon, and Ryan Gosling. She has been featured in works such as "InStyle," "Vogue," "Shape,"

"Women's Health," and more.

Ashley's tip for those working on building muscle is to use a foam roller. Spending a little one-on-one time with a foam roller can help improve

your mobility so every exercise is more efficient and effective; putting you closer to your goals, whether you’re looking to build lean muscle or burn fat. Read more on her foam-roller tips at 

href="http://www.self.com/story/why-foam-rolling-is-crucial-for-building-muscle" target="_blank">Self.

Mark is a well-known trainer to celebrities, athletes, and the public. Most recently, he helped "Good Morning America's" host, Ginger Zee lose four inches after having her baby and land a

new gig. 

His favorite way to get his rock hard abs is a little old move that he feels is underrated. Planks, both front and side, are an essential workout

technique as it uses all the vital parts of your body including your legs, core, shoulders, back, and obliques.

Mark is no stranger to training celebrities. He has trained big names such as Diddy, Brandy, L.L. Cool J, Mary J. Blige, and Beyonce.

Mark's biggest tip for fitness success is

to have fun and enjoy it! “Maintain a sense of humor,” Mark suggested. “If you can’t do something the right way at first, learn to laugh about it. Don’t make it unpleasant

or you won’t want to do it. It’s all about how you do it and enjoying the journey.”