In our week-long on-air series on diet and fitness trends, we took a closer look at workout routines that have become more popular in recent years.

Aerial Yoga, at Kula Kamala in Toms River. (Dianne DeOliveira, Townsquaremedia NJ)

HIIT, or High Intensity Interval Training, is a popular way of working the entire body by doing quick, intense bursts of exercise, with a short recovery to get your heart rate up and burn more fat in less time.

Brian Prendergast, a personal trainer, certified health coach and instructor, teaches the boot-camp style class at Shore Point Fitness in Point Pleasant.

"We set up stations, usually on a timer of some sort. Some classes are designed to be for strength, some are designed to be more cardio, or a combo of both," Prendergast said. "Anybody can do it. We put modifications on any work-out that there is. The modification might be with less weight or a different exercise."

Those taking the class do it for a variety reasons.

"Some of them are training for events, others are looking to lose weight or to get back into some sort of fitness routine, or build muscle," Prendergast said.

Losing baby weight motivates mom Jessica Alongi of Manasquan through the grueling work-out.

"I see the results from all the hard work that you put in," Alongi said. She lost 20 pounds in six weeks.

The gym holds six-week challenges, pitting two teams of Shore Point Fitness members against one another for motivation.

Prendergast and fellow trainer Kim Ciser lead the 5 a.m. team challenge that meets every Monday and Wednesday.

"You help them meet their goals, fitness-wise, nutrition-wise, and whatever else over the course of six weeks. They get weighed and measured in the beginning and at the end," Ciser said.

Ciser said most of them continue coming back to work-out that early, even after the six-week challenge is over.

(Dianne DeOliveira, Townsquaremedia NJ)

Shore Point Fitness also puts teams together for more extreme events like the Tough Mudder obstacle challenges.

Staying fit with boot-camp style classes is appealing to the older generation as well. At Therapeutic Fitness in Point Pleasant, owner Roger Faulkenbury teaches a Fit Club Class three days a week. They also offer yoga and pilates classes and ones specifically for just abs, backside and arms.

Faulkenbury said the philosophy at Therapeutic Fitness is total body, hitting head to toe and keeping people out of pain.

"The best machine you have is your body. That's the only machine you need," Faulkenbury said. "We add some weights, we add some kettle bells to mix it up. We go to the beach to do sand work-outs. So it's a great combination. We try to keep it fresh and unusual and up tempo."

The class attracts all ages, but a number of them are retired couples who enjoy working out together.

"It makes working out easier when you've got a partner and what better partner than your spouse," Faulkenbury said.

Tom and Char Charlton of Bay Head enjoy the combination of working out and socializing with the tight-knit group.

"When you get older you really have to work out every day to keep what you got," Char Charlton said. She recalled first joining Therapeutic Fitness six years ago. "I remember on the beach I could do maybe two push-ups. Today, I did push-ups for 45 seconds, 25 pushups."

Eileen McIntyre of Mantoloking said the senior citizens in the Fit Club Class can "kick everyone's butt."

"We're allowed and encouraged to go at our own pace. But we keep up," McIntyre said, adding she wants to be healthy and strong. "I don't want to be a senior citizen who is losing her balance and falling. I want to be pro-active about my health."

Another exercise trend that continues to evolve is yoga. Hot Yoga classes are offered in heated studios, Ply Yoga combines Plyometric movements with yoga postures, and Aerial Yoga is done inside and outside of silks suspended from a ceiling to enhance mat practice.

Each silk can hold up to 1,000 pounds to allow a student's entire body to fit inside and to be able to wrap it around them, according to instructor Amy Riley of Kula Kamala in Toms River.

"For your average yogi, you're average practitioner, it enables them to take on advance postures that maybe they haven't done yet. Whether it's strength or it's fear, this allows them to come into those postures feeling safe and feeling secure, trusting their bodies and also increasing strength," Riley said.

She said in the silk, you don't realize all the muscles being used.

"They definitely, definitely increase flexibility and strength, and rather quickly," she said.

A group of women who were taking a beginner's Aerial Yoga class, make it a social mission to try different exercise challenges each week. Katie O'Hara said this was "something different, out of the box, adding the fun they have motivates them.

Christine Maritz of Toms River has done Hot Yoga, but joked she hoped to "not fall" during the Aerial Yoga class while Shireen Hatami of Island Heights admitted being "terrified."

Hatami was run over by a car more than two years ago decided to try the class because it is supposed to be good for keeping pressure off of the joints.

Aerial Yoga has been around for a least a decade and according to Riley, it continues to grow because there is a therapeutic side to it.

"If you had an injury, and you wanted to practice but you weren't allowed to put weight on your joints, this could help you," Riley said. "I think that Yoga on a whole is very healing practice. It brings you closer and more connected to yourself. It's a work-out and a work-in. There's everything. There's mind, body and spirit."

Anyone can do yoga from children to the elderly to pregnant women.

Click below to read the previous articles in our "Fitness Trends" series:

In Part 3 of our series on fitness trends, we'll explore how technology plays a role in shaping how we stay healthy and fit.