Need a little extra encouragement to shape up in time for that wedding, class reunion or vacation? 

Boutique fitness studios are keeping track of clients' progress with methods ranging from videotaping their workouts to measuring their fat, to posting a friendly nudge on their Facebook pages.

Gregory Chertok, a sports psychology consultant with the American College of Sports Medicine, said research has shown that even small amounts of social support can produce large and lasting gains in physical activity.

In a 2007 study by Stanford University in California, researchers showed that even a simple, computer-generated phone call could be effective in motivating the sedentary to exercise.

“These exercisers are being held accountable by their fitness studios to a degree,” he said.

AKT InMotion, a New York/Connecticut chain of dance and circuit-based interval training studios, offers a $2,000, personalized, eight-week exercise and nutrition program. It includes periodic body measurements and is supervised by a fitness concierge.

Anna Kaiser, founder of AKT, said photographs and measurements are taken every two weeks to track progress.

“A client will say ‘I still feel fat’ because you don’t actually see that you’re changing, so it helps,” said Kaiser, who added that measurements were private and optional.

Accountability, she explained, is a two-way street. Clients must show up as well as work on nutrition, and if aspects of the program are not producing results, AKT will change it.

Videotaping is popular for tracking progress. At Refine Method studio in New York City, which features full-body circuit training and small classes, it is used to give clients a concrete measure to gauge progress.

Clients do a few key assessment moves, such as a squat, and the videotape will show how they have improved over time.

Founder Brynn Putnam, a former New York City Ballet dancer, said unlike professional athletes, who can count their wins, most people don’t get clear indications of progress.

Regularity is also an important factor for improvement. Barry’s Bootcamp, a national chain of interval cardiovascular treadmill and strength-training studios, clients can sign up for a program called 'Academy,' in which they commit to the same classes at the same-time Monday to Friday for four weeks.

Trainer Joey Gonzalez said he has used Facebook to reach out to no-shows.

“Social media gives us a short cut for clients who have signed up for accountability-based programs,” he said.