To attract and retain top talent, research suggests some employers are spending more dollars on richer benefits in lieu of higher salaries.

A Society of Human Resource Management survey of 450 employers found 35 percent cited having larger benefits packages in 2015, compared to 28 percent the year before.

This year, these enhanced packages include the rise of new benefits such as company-provided fitness trackers as well as more group fitness classes. According to SHRM, 17 percent of employers offer on-site corporate fitness classes, up from 14 percent the year before. Thirteen percent of employers reported offering fitness trackers in 2015.

Keeping group fitness fresh

Specialty group exercise classes can be a great tool to keep fitness fresh and create stickiness with employees to pull them back to the fitness center.

At corporate fitness sites for employers across the U.S., popular group exercise classes evolve over time. Pilates, cycling, yoga and Zumba can be part of a typical rotation used to engage employees in improved personal health, but the roster of group exercise classes rarely ends there.

Many corporate fitness sites also offer unique specialty classes to spark and sustain healthy activity. These classes vary in length—some are 30 minutes; others last 90+ minutes—and some are one-day events, while others last weeks or months.

Finding the right mix

To identify the right mix of corporate fitness classes for an employee population, there are several key initial considerations.

First, it's important to know how to deliver classes in the ways that members need them. For some employers, this means offering a variety of short, 20-minute classes during the lunch hour for time-strapped office workers. Other employers focus heavily on providing before- and after-work classes, as these are high-demand times when many employees participate.

Second, there should be something for everyone, at every level of fitness. For one of our clients, a biotechnology employer client with a 24,000-square-foot fitness center, for example, this means our staff of 25 associates offers 91 different aerobics classes each week, ranging from kettlebells to kickboxing and more. Thanks to these tailored approaches, 73 percent of the 9,200 employees at this site are members and 43 percent of the membership participates six or more times per month.

And third, keep in mind that cost-effective delivery of programs is essential to ensure accessibility. When group exercise classes are offered at employer sites, some could be free while a specialty class could be as low as $12 per session for members or $20 for non-members.

As an additional perk, we find that when a corporate fitness center does offer the right mix of specialty classes, it can pave an inroad with non-members, luring them into the center to experience how great it feels to be fit at the workplace.

Seven Corporate Fitness Trends

While we tailor the specialty classes to each client site, based on employee demographics and interests, below are seven examples of trending specialty classes that employees love right now.

1. Hula hoop

This retro toy has resurfaced as a popular new way to enjoy exercise. Hula hooping combines elements of dance and fitness to improve coordination, balance, rhythm, strength and flexibility. Hula hoops are provided for this six-week class.

2. Kangoo Jumps

Kangoo Jumps use low-impact rebound boots that decrease impact during cardio activities by up to 80 percent. During the six-week class, students wear these boots to bounce, hop, skip and jump, while doing leg lifts, squats and dance moves choreographed to energetic tunes.

3. Thai Yoga BodyWork