At the Free Family Field Day, on September 17, Teresa Gisburne showed passing guests a trick that might just save their lives.

The assistant instructor of the University of Massachusetts Dartmouth’s Karate Club showed off a simple self-defense trick: escaping from a grab to the wrist. Taking advantage of a grip weakness between the thumb and fingers, one can simply slip away by pulling towards that weakness point.

“We wanted to give people a simple self-defense move to walk away with,” explained Head Instructor Tony Benevides.

The university’s karate club was one of dozens of health and fitness-centric organizations offering activities and demos during the event, sponsored by the Bristol County District Attorney’s Office.

“This is an opportunity to have some healthy family fun,” explained District Attorney Tom Quinn.

It was the seventh annual event, and the third time the event was held at Cressy Field at UMass Dartmouth. The goal, Quinn said, is to introduce families to resources and activities to stay in shape.

Ryan Dwelly from the Track + Channel rowing and running gym in New Bedford brought a rowing machine for people to try out and hopefully find a new affinity with the sport.

“When we talk about rowing people don’t know what to expect,” Dwelly explained. “We brought our machine here to show people that it’s not intimidating.”

Other organizations in attendance included youth sports leagues, gyms, public safety groups, Dartmouth Fire District No. 3, and staff from the District Attorney’s Office.