Fitness trends come on strong and often quickly fade into mockery levels of oblivion (remember Shake Weights? How about FitFlops?), but a standout franchise called Orangetheory Fitness is proving that there is still room for innovation and growth in the fitness membership category.

Orangetheory Fitness landed at No. 60 on the Inc. 500 list of fastest-growing companies in America in 2016. With 700-plus locations worldwide, Orangetheory has become the darling of the fitness franchise world. So what's the secret behind this company's success?

Orangetheory Fitness (OTF) is built around the concept of excess post-exercise oxygen consumption, or EPOC. According to OTF, its heart rate monitored training "is designed to maintain a target zone that stimulates metabolism and energy." It claims that members "burn 500 to 1,000 calories in 60 minutes and keep burning calories at an average rate of 15 to 20 percent higher than their standard resting calorie burn" for up to 36 hours post-workout.

In a typical 2,800-square-foot Orangetheory studio, you'll find 12 treadmills, 12 water rowers, and 12 "weight room" floor stations consisting of a step bench, a TRX suspension rig, and light free weights. Monitors in the weight room illustrate the programming and movements. Monitors in the cardio area display a grid showing the members in the class and their current heart rate levels, color-coded by intensity.

Under orange lights, upbeat music, and the direction of an energetic coach, members move through a program that rotates between treadmills, rowers, and free weights with the intent to accumulate 12 to 20 minutes in the "orange zone," which is reached when the chest or wrist monitor registers a heart rate at 84 percent or higher of your maximum heart rate. According to OTF, this is the zone that creates the EPOC calorie burn, and minutes in the orange zone earn members "splat points" (which are tracked and emailed to each member after class purely for fitness tracking purposes).

Interval training is not new, nor is the concept of targeted heart rate training. So why is Orangetheory booming? Because it offers members of all levels immediate gratification through a sense of progress, provided by an instantaneous feedback loop.

Research has shown that the feeling of positive progress is an incredibly powerful performance motivator. Accumulating minutes in the orange zone ("splat points") provides a reward after each workout. Whether we're talking about business or fitness, things that are hard to build because of prolonged effort become more manageable with immediate and consistent pats on the back. It's not exactly gamifying, since there's no strategy or competition -- it's really just a rewards system that feels like recognition. It's like training a seal (an actual seal, not a Navy SEAL): touch the ball; get a fish. Push your heart rate up into the orange zone; get a point.

Success in Orangetheory Fitness is relative to each user's fitness level, making it accessible to a broad audience. It might take months, even years to lose a certain number of pounds or beat your best mile time, but you can feel the recognition of earning splat points for being in orange zone during every session.

This feedback loop encourages members, which keeps them coming in. Whether it feels gimmicky or not, it gets people moving, which creates results. Regular positive reinforcement can be a great motivator if you can find ways to celebrate small but meaningful benchmarks.

While your OTF coach may be careful to remind you that 80 percent of our fitness happens in the kitchen, the positive reinforcement of a few splat points here and there is a welcome encouragement toward living a healthier lifestyle every day.