Senior defenseman Bray Malphrus: “It’s been my goal ever since I came to Virginia, to change the whole ‘laxer’ image.” (Matt Riley/VIRGINIA ATHLETICS MEDIA RELATIONS OFFICE)

Bray Malphrus, a senior defenseman for the Virginia men’s lacrosse team, said he knew exactly how he wanted to spend the time between the end of the regular season on April 30 and the start of the NCAA tournament on May 14.

“The two weeks off, guys were mentally and physically ready for a break; they had been going crazy,” said Malphrus, one of the Cavaliers’ four captains. “But I thought we should be running, practicing, lifting.”

The seventh-seeded Cavaliers (10-5) hope that hard work pays off Saturday, when they face No. 2 Cornell (14-2) in an NCAA tournament quarterfinal in Hempstead, N.Y.

Malphrus’s teammates must have known what they were getting into. Not for nothing did his mother, when asked to describe him, use the phrase “very restless.”

When Malphrus made the U.S. under-19 boys’ lacrosse team in 2008, he received a questionnaire that included the staple, “Who is your favorite athlete?” His answer: Dean Karnazes, who once ran 50 marathons in 50 days.

His work on the field has included ups and downs, sometimes within seconds of each other.

Late in the fourth quarter of a first-round game against Bucknell last Sunday, Virginia trailed by a goal and the Bison had possession. Malphrus tried to force a turnover, but slipped and fell instead. The Bucknell player raced past Malphrus and toward an open he goal.

Malphrus’s mother said she turned her head and looked away from the game. Virginia senior midfielder John Haldy, Malphrus’s roommate the past three years, was asked if he thought the team was in trouble at that point. “I think the whole stadium thought we were in trouble,” he said.

But Malphrus scrambled to his feet, lunged at the player and landed a check that caused a loose ball. The Cavaliers recovered. Nine seconds later, they scored the tying goal.

“I went out and pressured hard, but he did a great job protecting his stick,” Malphrus said. “Then I slipped, but I said to myself: ‘This isn’t ending here. This isn’t ending now. I’m not going to let down the 40 other kids [on the team]. I’m going to get up make something happen.’ ”

Off the field, Malphrus and the Virginia’s three other captains — Haldy, senior goalie Adam Ghitelman and junior attackman Steele Stanwick — instituted strict behavioral rules for the team. In part, Malphrus said, the rules came about after the death of Yeardley Love, the Virginia women’s lacrosse player who was killed last May. Former Cavaliers men’s player George Huguely is facing first-degree murder charges in connection with Love’s death.

“If we didn’t change the way we conduct ourselves on and off field, it would have been blatantly disrespectful to the Love family,” Malphrus said. “It would have been pretty much spitting on her grave if we didn’t take a sober look at the program.

“It’s been my goal ever since I came to Virginia, to change the whole ‘laxer’ image. . . . The events last spring sort of accelerated things.”

Malphrus’s unrelenting attitude has carried over to his leadership of the team off the field. He said he went to the library a couple of weeks ago, soon after the regular season ended, to study for a cell biology exam. He wound up involved in an e-mail exchange with the team.

“We had been pushing the kids pretty hard for three months, and some of the older guys thought we should let them relax,” Malphrus said. “I started to sense some complacency and I have a very, very low tolerance for complacency and a lack of effort.”

Malphrus said he spent the next three hours exchanging e-mails with his teammates.

“I had a three-hour window to study and I spent it furiously writing e-mails responding to kids,” he said. “I got into it with them.

“Finally, Haldy got me and said, ‘Listen, I love you, but you’re scaring the troops a little.’ And I was a little too into it. I was profusely sweating. I said to myself, ‘I’ve got to relax here.’ But I’m always looking for ways to get better as a team.”