For choreographer Reggie Wilson, who has dedicated decades to researching and illuminating the spiritual and cultural traditions of the African diaspora, Shakers would seem an unusual source of obsession. But when his investigations led to the discovery of a community of Black Shakers in the middle 1800s, he was all in. He’d always felt there was nothing “any whiter than a New England Shaker,” he admits with a chuckle. “Finding such a thing as a Black Shaker didn’t fit easily into my model of reality. I wanted to understand … how that existed and what that might have looked like.” That curiosity led Wilson to create his latest full-evening dance work, “POWER,” which he and his 31-year-old company Fist and Heel Performance Group present at the Institute of Contemporary Art/Boston this weekend.