Revisiting that resolution

Admit it: You could use some help trimming down or tightening up. But the decision to work with a personal trainer can paralyze anyone. Should you team up with a man or a woman? Someone younger or older? A drill-instructor type or a nurturer? I embarked on a two-week tour to test-drive five different trainers and walked away with two things: sore glutes and a feeling that the archetypes I encountered probably exist at a gym near you. So who's right for you?

Darin St. George, 40: The Shaman

Height/weight/body fat percentage: 5-10/183 pounds/"Too busy exercising to test it"

Trivia: Never missed a day of school from fifth grade on, so don't try excuses if you cancel.

How he'll work you out: A high-intensity, 30-minute strength program. "You couldn't do an hour the way I'm going to work you out," he told me. We're talking rapid circuits of two or three exercises that work complementary muscle groups. Cardio is your homework, and, yes, it is required.

You'll like him when: he morphs into whatever kind of motivator you need, from sharing inspirational stories to telling dirty jokes.

You'll dislike him when: you realize you're working out with the Energizer bunny.

You'll do a double take when: he throws out one of his catch phrases: "I teach people to do push-ups at the table -- push the food away."

Perfect fit: St. George straddles the line between Tony Robbins and Charles Atlas, and, as such, he's willing to be involved in his clients' lives. Want to call him with a nutrition question? Need a text message to remind you to do your cardio? No sweat.

Trainer X Fitness, 508-494-5336, trainerx.com; $30 per half-hour

Terry Walsh, 44: The Mother

Height/weight/body fat percentage: 5-3/126 pounds/16 percent

Fastest Ironman: Triathlon 13 hours, 9 minutes

How she'll work you out: Group training classes for cardio, and a mix of resistance bands, free weights, and machines, all under her watchful eye, for strength

You'll like her when: she turns into a cheerleader, sans pompoms, every time you reach a fitness goal.

You'll dislike her when: she asks you what exercises and classes are toughest for you and then prescribes a weekly regimen of them. "The things that you find difficult and hard are the things you need to do," she says. So sweet yet so sadistic.

You'll do a double take when: she starts selling you on triathlons. She had me thinking that an Olympic-length tri (.93-mile swim, 24.8-mile bike, 6.2-mile run) sounded possible. Luckily, like the soreness, that notion faded.

Perfect fit: Walsh pushes you hard but then celebrates with you, too. If it sounds a bit "maternal," she's OK with that.

Boston Athletic Club, 653 Summer Street, Boston, 617-269-4300, bostonathleticclub.com; $725 for 10 sessions

Roberta Norton, 58: The Inspiration

Height/weight/body fat percentage: 5-7/"no comment"/see previous

Weight lost in the last decade: 60 pounds

Motto: "Get up and get moving. It's never too late!"

How she'll work you out: An evenly paced hour that starts with low-impact cardio and then segues into weight machines, abs, and stretching

You'll like her when: she compliments you on everything you do, from bumping up the treadmill incline to eking out an extra rep of chest presses.

You'll dislike her when: Er . . . actually, you won't dislike her at any point unless you're one of those people who can't stand optimism and needs to be abused to feel as if you're making progress.

You'll do a double take when: you see pictures of her before she found fitness at the age of 49.

Perfect fit: She's a solid match for anyone who finds the gym intimidating and has no idea of where to start.

South Shore YMCA, 79 Coddington Street, Quincy, 617-479-8500, ssymca.org; $295 for six sessions

Gregg D'Andrea, 48: The Rock Star

Height/weight/body fat percentage: 5-6/160 pounds/7 percent

Longest spinning class ever taught: Eight hours, for charity

How he'll work you out: Strengthening your core, lifting weights, and definitely one of his signature spinning classes

You'll like him when: he contorts your frame into perfect posture mid-exercise, giving you a glimpse of what your body would look like if you didn't treat it like a garbage scow.

You'll dislike him when: he insists on having you do every exercise on a stability ball, serving to remind you that you're both out of shape and uncoordinated.

You'll do a double take when: he tells you how much water you should be drinking a day to look lean and fit. I started drinking more than a gallon a day on his recommendation, and my kidneys have never had more definition.

Perfect fit: Between his up-to-the-minute jeans and cut physique, D'Andrea is just right for those folks who want some style with their sweat.

gstarfit, 55 Charles Street, 2d floor, Needham, 781-444-7827, gstarfit.com; $1,000 for 10 sessions

Heidi Brown, 26: The Up-and-Comer

Height/weight/body fat percentage: 5-9/149 pounds/17 percent

Fitness background: Three-sport athlete in high school (track, volleyball, and basketball)

Motto: "Know your body, know your goals."

How she'll work you out: She looks for muscular imbalances and weak spots by moving you through a series of planks, squats, lunges, and lifts that will have you bouncing up onto platforms, down on the ground, and up against walls like a sweaty superball.

You'll like her when: she tailors a workout to whatever kinds of exercises you're curious to try. Regardless of whether you're looking for weights, machines, or flexibility, she knows she can make it hurt, um, work.

You'll dislike her when: she makes you focus on your weaknesses before you get to work on your strengths. Didn't I come in here to feel better about myself?

Perfect fit: She's right for those who appreciate balance. But be prepared to swallow more pride than supplements.

Boston Sports Club, 1 Davis Square, Somerville, 617-776-0086, mysportsclubs.com/regions/bsc.htm; $480 for five sessions

Shawn Peters is a writer and creative director in the Boston area. Send comments to magazine@globe.com.