Nicole Nichols, front, chose backup exercisers with strong but realistic physiques to make the program less intimidating.

If you’ve seen a Nicole Nichols workout before, chances are it was on YouTube. The fitness expert, known as just Coach Nicole to the millions of members of SparkPeople.com, has filmed dozens of routines for the free health website. The popular videos showcasing her girl-next-door style, gentle encouragement and clear cueing have built such a devoted following that the American Council on Exercise and Life Fitness just named her “America’s top personal trainer to watch.”

But “SparkPeople: 28 Day Boot Camp” ($17, Acacia) is her first slickly produced DVD and a chance to bring her fans something beyond the quick hits she’s been able to offer online. “We put it all together so you get more done in less time. There’s upper body, lower body and cardio intervals throughout to elevate the heart rate more,” she says.

Viewers can choose from four segments, ranging from 12 to 30 minutes. (The longest one, which is packed with kettlebell-inspired swings and lifts, is Nichols’ favorite.) The DVD includes a calendar with a suggested plan for how to mix up the workouts, so you’re rarely repeating moves. And when you are, Nichols hopes you get comfortable challenging yourself with the more difficult modifications — which might mean balancing on one leg while you perform that lateral raise or turning a step into a jump. “Whatever your level, there is something for you,” she says. “But I wanted to give people something to progress to.”

One unusual feature of the program is the countdown clock on the screen during each of the segments, reminding you of exactly how much longer you need to sweat it out. “I like to know I’m making progress. I find that motivating,” Nichols says.

At the end of the 28 days, which is how long research has shown it takes people to establish a habit, Nichols is certain you’ll see some progress of your own.

Stick With It

Nichols’ tips for keeping your New Year’s resolution

1. Be Realistic. “It’s important that expectations aren’t over the moon,” she says. “That’s what sets you up for failure.”

2. Set your alarm clock earlier. “Morning workouts work for people for a reason. Nothing else will get in the way, and being tired is your only excuse,” she says. Later in the day, you’ll find many more reasons you don’t have time.

3. Prioritize. When people say they can’t fit exercise in their schedule, Nichols always asks, “How much TV do you watch?” Use your shows as a reward for your workout instead of the replacement, she suggests.