Credit: @YankeesonDemand

On Thursday, the entire Yankees pitching rotation and general manager Brian Cashman donned superhero costumes in a Yankee Stadium club and visited with a group of children with brain cancer.

It was one of the events of this year’s HOPE Week, which the Yankees began in 2009 to concentrate some of their charitable outreach in a contained span of time. Players and staff do a HOPE Week event during the weekday and then generally play a game later that night.

Everyone involved feels good. And the good feelings usually continue during the games. In the nine years of its existence, the Yankees have a 31-12 record during HOPE Week.

Perhaps 43 games over nine years is too small a sample size to draw any conclusions about cause and effect.

Or perhaps it makes perfect sense. Studies show volunteering makes you feel better. When you feel better you are more productive in the workplace, even if your workplace is Yankee Stadium and your job is hitting or throwing a baseball.

After Saturday’s 3-2 win over the A’s, the Yankees have a .721 winning percentage during HOPE Week. In non-HOPE Week games since 2009, their winning percentage is .558.

Hmmmmm . . .

Credit: Yankees on Demand

“I’m not at all surprised, scientifically,” said Dr. Stephen Post, the Director of the Center for Medical Humanities, Compassionate Care, and Bioethics at Stony Brook University and author of many books, including “Why Good Things Happen to Good People” and “The Hidden Gifts of Helping.”

Post cited a 2010 survey of 5,000 people across America who volunteered in 2009 (25 percent of them through their workplace). It in, 89 percent said volunteering improved their sense of well-being.

“Now think about the Yankees,” Post said. “They do a little volunteering, and their sense of well-being — call it happiness — is going to be way up. (The survey asked) did it lower your stress levels? Talk about serenity and tranquillity and focusing on a baseball, right? Seventy-three percent said, ‘Yup, it lowered my stress level.’

“Ninety-two percent said it enriched my sense of purpose in life. So it just gave them a sense of meaning that went beyond the everyday. This is amazing: 68 percent said ‘made me feel physically healthier.’ They feel more energized, they feel physically more robust. Get this: 77 percent said ‘improves emotional health.’ So they’re feeling more upbeat. They’re feeling happier.

Credit: Handout

“Seventy-eight percent — now this is if you’re in a batting slump, like who’s that third baseman, (Chase) Headley? — said ‘helps recovering from loss and disappointment.’ So if you’re in a downspin, one of the best things you can do to break out of it — and I say this seriously — is just go out and do something with people.”

On Thursday, Cashman dressed as Spider-Man and was joined by pitchers CC Sabathia (Superman), Masahiro Tanaka (Teenage Mutant Ninja Turtle), Luis Severino (Ironman), Jordan Montgomery (Captain America) and Michael Pineda (Wolverine).

“It’s cool,” Sabathia said. “It’s fun to be able to experience this, especially with your teammates. To give back and to see the impact that we can have on a community.”

What about the idea that it may help the Yankees perform better on the field, too?

“I hope so,” Sabathia said. “Hopefully we can keep winning this whole week.”

Credit: Yankees on Demand (@YankeesonDemand)

According to Post, even less enthusiastic employees who have to be cajoled into doing volunteer work usually get something out of it that they didn’t expect.

“The bottom line,” he said, “is most people who do this because it’s kind of an expectation, the light turns on and they do have kind of an emotional transformation.”

Of those in the 2010 survey who volunteered through work, Post said: “Seventy-six percent of them felt better about their employer as a result. So when those Yankees are out there in the Bronx, three-quarters of them are going be even prouder than they would normally be just because they’re Yankees.”