It was a short five-minute window, but still plenty of time for the three red-headed freshmen to get in a little extra work.

Their teammates on the Beverly High girls’ hockey co-op roster, which also includes players from Danvers and Ipswich, had filed off the ice at the Raymond J. Bourque Arena on the Endicott College campus.

So the Foster triplets spread out on the ice, working on their skating, passing, and shooting.

On one side, Brittany, a left wing, fed one-timers to Tiffany, a defenseman. As the shots peppered the net and the glass, Sydney, a center, was over alongside the boards, working on her puck handling skills.

Distinguishing the three 14-year-old sisters from each other was nearly impossible; each girl’s long hair fashioned in a fishtail under their helmets, partially blocking a clear view of their faces.

While the trio worked, Beverly High coach Brian Seabury watched from the bench, grinning as he shook his head.

“This is a frequent thing,’’ Seabury said as the Zamboni rolled into the rink, signalling the official end to practice.

“If the ice was free until 8 they’d take the extra hour. They’re just that competitive.’’

Seabury understands the situation, and better than most.

From 1985-89, Seabury skated on the same line at Stoneham High with his brothers, fellow triplets Craig (now the girls’ coach at Winchester High) and Glenn. Their father, Bill, was the team’s head coach. After leading Stoneham to the Middlesex League title as seniors, the trio made their way to the former University of Lowell. One season later, they transferred together to Salem State.

Twins are competitive. Triplets? On the ice. Ultra competitive.

Seabury and his father, Bill, now an assistant coach for his son, understand the dynamic well.

With a combination of a tight sibling bond and years of playing together, from youth to college hockey programs, the Seabury triplets developed a form of brutal honesty, on and off the ice.

“Because we knew each other and our games so well, we knew when one of us could do better,’’ Brian Seabury said.

“Sometimes [my father] would have to break up fights on the bench or in the car, but it just comes down to being close enough to expect more out of someone and speak frankly to him. Having Craig and Glenn on the team pushing me farther than anyone else made me better than the average player and vice-versa.’’

The verbal sparring often translated to competition on to the ice. At any given practice, one could expect to see the Seabury triplets going at it in drills, attempting to one-up another.

“They weren’t going to let each other leave the rink with the satisfaction that they’d been bested,’’ Bill Seabury said

In his fourth year at Beverly, Brian Seabury has attempted to instill the same sense of communication and aggressiveness.

And the Foster trio? “It’s eerily similar,’’ he said.

“I constantly hear them talking about what they need to be doing in practice in game scenarios. They don’t always like what each other has to say, but at the end of the day, it’s all constructive.’’

Brittany, Sydney and Tiffany Foster learned to skate at age 3. As 5-year-olds, Tiffany and Sydney chose to pursue other sports; Brittany stuck with hockey. Nonetheless, her practices and games were a family affair. They finally reunited on the ice at age 9, after Sydney and Tiffany experienced one of their sister’s tournaments playing for the East Coast Wizards.

“I remember being really involved with Brittany’s team bonding, watching the games and really liking how close everyone was,’’ Tiffany said.

On the ride home, Tiffany and Sydney made a plea to their dad, Jerry, a former trainer/strength coach with hockey programs from the schools (Belmont Hill) to the NHL (Bruins) who is now an assistant athletic director at Northeastern University.

By the end of that season, Tiffany and Sydney were skating for the Lynnfield Ice Caps .

“Brittany has always had more of a teaching role since she has a little more experience, but we still all dish it out,’’ Sydney said.

As high school freshmen, their competitive fire is very apparent, whether it is taking shots in the driveway at home, or in a game setting.

“You get away with being a little tougher,’’ Brittany said.

“Things can still escalate, but for the most part they’ll get that you’re not trying to be mean.’’

Their father added, “They’ve just got higher expectations of their sisters. They voice it not to be contentious but to drive each other and motivate.’’

And in their first season on the varsity, trio made a sizable impact on a 16-5-1 Panther squad that earned the seventh seed in the Division 1 tournament.

Skating on the second line, Brittany tallied 24 points. Sydney submitted seven on an important third-line role And Tiffany has played a hand in Beverly’s plus-50 goal differential.

“I’ve sat down with them and explained that I understand the aggressive talking,’’ Brian Seabury said.

“I’ve seen it from both sides at this point. What’s best is that I know when to step in the middle of things and when to let it keep going, cause it can often lead to teaching moments.’’

Kristen McCarthy, a senior captain at Beverly, said that “it’s funny watching [Fosters] interact sometimes, in between periods, you’ll see them going at it saying ‘you should have done this’ or your should’ve passed it to me,’ but being sisters, you come to understand it’s just them being constructive with each other.

“At first, it seemed a little intense, but coach [Seabury] explained that he knows where they’re coming from and explained the dynamic . . . He said the same thing happened with his brothers.’’

Their shared experiences as triplets (or in Billy Seabury’s case, fathering triplets) provide a mutually beneficial scenario in which the coaches can connect with the triot.

“They’re great at organizing how we can better help each other,’’ Brittany said.

“They understand that we like to do everything together so they run with it. I can tell we remind them of [Brian] and his brothers.’’

But the triplet theme at Beverly is not complete without Isabel Primack, a junior forward from Ipswich. But her sisters do not play hockey.

“She’s probably our best competitor on the team,’’ Brian Seabury said.

“I can only imagine if we had her sisters too.’’

Ethan Schroeder can be reached at ethan.schroeder@globe.com.