MIAMI -- High-end fashion designers are launching workout lines, Soul Cycle classes are quickly booking up and fitness trainers have become rock stars apart from their celeb clientele.

But with boutique fitness studios popping up everywhere and workout offerings from surfboard workouts to underwater bicycling, it can be a little daunting to find your groove and stick to it past the February chocolate danger zone.

We asked some inspiring, hard-core trainers who have won legions of followers on Instagram for their secrets to staying motivated all year long.

KAYLA ITSINES

An army of 6,000 women showed up to squat and high jump alongside trainer Kayla Itsines in London last summer. Her app is the top health and fitness app on iTunes in several different countries.

The 24-year-old from Adelaide, Australia has spawned a devoted following online as women document their progress following her 12-week Bikini Body Guides. Itsines, who has 4.2 million Instagram followers, is known for getting some serious results thanks to grueling 28-minute high intensity workouts.

Focus on your own progress and don't compare yourself to others, she advises. Find a workout that you love so you can make it a habit and make sure to change it up often.

"Mixing it up can keep you focused and make sure your workout is always interesting."

MASSY ARIAS

This Los Angeles-based trainer is seriously bad in all the right ways.

The sweaty ab photos Massy Arias posts to her 1.9 million Instagram followers might seem untouchable (yes, that's her side lunge jumping up a staircase) but her vulnerable struggles with depression are super motivating and, bonus, she also dishes out all her social media advice in English and Spanish.

"It wasn't until I started being more active and religiously making exercise part of my lifestyle, that I started feeling more alive, alert, confident, happier, and stronger mentally. The motivation to keep moving forward comes from places within myself that I do not want to go back to."

The 27-year-old's MA30DAY Challenge workouts include everything from resistance training and yoga to high intensity interval training and sprinting. She encourages followers to set realistic goals instead of trying to change everything overnight.

"Going in with this mentality usually demotivates people because they start a regimen that is too hard for their fitness level to maintain and keep up with."

RACHEL BRATHEN

Yogi Rachel Brathen's fitness tips are a little unusual, but what do you expect from a woman who spends sizable amounts of time hanging upside down and runs around her house with an adorable baby goat.

The Aruba-based yoga teacher suggests making a gratitude diary as important as daily workouts and green shakes.

"Sometimes we get so caught up in what we want to change that we start seeing flaws instead of focusing on getting inspired to move and feel good. It's important to celebrate the good things. Your body does so much for you every day... It's so much easier to stick to an exercise routine when we appreciate what our bodies can do."

She starts every morning with hot water and lemon to stimulate her digestive system, turns up some music and powers through a 90-minute yoga session, often beachside. And yeah, her arm balances on paddle boards are super cool, but the pics of her rescue puppies have no doubt helped her land 1.7 million followers on Instagram.

JEANETTE JENKINS

She's the celebrity trainer behind Pink and Kelly Rowland's banging post-baby bodies. Los Angeles-based fitness guru Jeanette Jenkins, 42, shares moves from her Hollywood Trainer Club to her 314,000 Instagram followers and is known for double duty moves that target multiple body parts at once.

"A workout is an internal cleaning," says Jenkins who says she feels like she can conquer anything after finishing a workout.

Her daily workout videos (more than 200 of them) combine everything from cardio kickboxing and circuit training to yoga and Pilates so muscles never plateau.

"Schedule your workouts into your smartphone or calendar every week just like any other important meeting and do not cancel on yourself. If it's important to you then you will make it a priority."

SHAUN T

You know you've watched his infomercials in the middle of the night. Shaun T is the original dance cardio king with the street cred to go along with it -- he was a former backup dancer for Mariah Carey.

His 60-day INSANITY workout put high intensity interval training on the map and there's a reason his six-pack ab photos have landed him 436,000 Instagram followers. Last year, the 37-year-old Phoenix-based trainer went back to his dance roots with his new CIZE workout video and his podcasts are all about mastering your mind.

"Only do exercises you love and most importantly find internal motivation."

And remember to build slowly.

"Resolutions can end in failure if you don't leave yourself wanting more, yes, even more exercise, so don't overdue your brand new plan in the first week."

DAVID ALEXANDER

You might not know his name but you definitely know the athletes he's trained. Miami-based trainer David Alexander has rehabbed the Miami Heat's Dwyane Wade and former teammate LeBron James.

This biomechanics expert is old-school as in showing pro athletes and fitness fanatics how to do basic squats, deadlifts and cable pulls so they don't lose range of motion and compromise form further irritating injuries.

Alexander, who travels with Wade for games, opened his DBC Fitness in Miami's trendy design district a year ago, but has been training athletes for nearly two decades. He also posts some cool behind the scenes pics while training your favourite athletes to his nearly 100,000 Instagram followers.

"Try replacing one bad habit with one good habit each week."

During week one, drink three litres of water a day and ditch everything else. Week two, eliminate white flour from your diet to reduce inflammation and get rid of refined sugars in week three. (Healthy sugars like fruits are OK.)