STATEN ISLAND, N.Y. -- The pep is back in Bronksey's step.

Make that the tail-wagging, four-legged bound of District Attorney Michael E. McMahon's comfort dog, a Black Labrador/Golden Retriever mix who just finished some retraining and shed a few pounds in the process.

"It was like he went to the spa," McMahon said recently, as the 7-year-old canine dashed into his office with the energy of puppy. "It's kind of like he went back for a tune-up. He's refreshed and ready to go."

McMahon said the course is standard after dogs like Bronksey, who are specially trained to comfort crime victims, including children, are in the program for four or five years.

Bronksey was donated to McMahon's predecessor, former District Attorney and current Rep. Daniel Donovan, by the nonprofit Canine Companions for Independence in the spring of 2012.

McMahon said Bronksey had been lethargic before the retraining. He'd trudge into his office and lie down and wasn't motivated to move around.

But the canine boot camp helped him drop some of his excess baggage and made him a new man, er, dog, so to speak.

"It rejuvenated him," the D.A. said.

So, when he isn't busy cheering up kids at Family Court, comforting domestic-violence victims, or making the rounds at borough schools to teach youngsters about animal care and wellness, the lovable pooch keeps in shape by going for walks in the park or picking up his paws and putting them down on an office treadmill.

And the exercise is high-tech. A Fitbit-type device attached to Bronksey's collar tracks and graphs his activity.

Bronksey was at his best on a recent weekday at the D.A.'s office.

Detective investigator Kevin Ivany, one of his handlers - victim advocate Mary Santamorita is the other - knocked on McMahon's door, opened it and Bronksey ran over to the D.A.

At McMahon and Ivany's commands, Bronksey sat, lied down, went to Ivany's side and went "up" - putting his paws and upper body on a chair, a tactic employed to help comfort children.

But it's not all work and sweat for the capable canine.

For as Bronksey knows, yummy treats await those do good deeds.