Most of us have our orgasms in bed…or maybe on the living room floor in front of a fire if we’re feeling frisky. But would you have guessed that the gym is a Big-O hot spot? Well, it’s true—and surprisingly common! And it has nothing to do with the presence of bare-chested, muscle-bound male personal trainers. Rather, it’s because certain types of exercise can trigger orgasms in some women, a new study has found.

The online survey recruited participants via Web sites related to women’s issues, fitness and sexual topics as well as via e-mail. Respondents included 530 women ages 18 to 64, most of whom were married or in a relationship. Exercise-induced orgasms were reported by 124 women (23% of survey respondents)…another 246 (46%) said they experienced exercise-induced sexual pleasure but not orgasm. Do those percentages sound high? The study wasn’t designed to measure prevalence specifically, and researchers estimated that prevalence in the general adult female population is closer to 5% to 15%—but perhaps the phenomenon is more common than people realize because those who experience it keep quiet out of embarrassment. Indeed, the majority of orgasmic exercisers in the survey reported feeling self-conscious…though they also reported feeling happy about the experience.

Climax-producing moves: Among women reporting exercise-induced orgasms within the previous 90 days, 51% said the climaxes occurred while they were doing abdominal exercises. Other common triggers included Pilates (32%)…lifting weights (27%)…yoga (20%)…biking/spinning (16%)…running (13%)…and walking/hiking (10%).

What’s up down there? Orgasm often is associated with fantasizing, but the orgasmic exercisers reported that they weren’t thinking about sex while they were working out. One possible explanation for the phenomenon is that certain exercises work the muscles and stimulate the nerves of the pelvic floor, which in turn can enhance a woman’s arousal. (Some men also climax while working out, a topic the researchers are studying currently.)

Intrigued? If you want, experiment with various abdominal exercises, such as crunches and sit-ups, which the survey showed were most commonly associated with exercise-induced orgasm. Participants also mentioned equipment called a captain’s chair, which consists of a rack with back support and padded armrests that allow the legs to hang free. To use it, stand with your back pressed against the backrest, forearms on the armrests and hands gripping the handles…support your weight on your forearms as you bend both legs and raise your knees to your chest, keeping your legs together…then lower your feet to the floor…repeat 10 to 15 times. At the least, you’ll wind up with fab abs—and maybe you’ll get a secret bonus as well.