Sylvia Miskoe, in rec.folk-dancing on March 4, 1999 said:

Wrist grip stars became popular after the appearance at New England Folk
Festival (NEFFA) of the Lithuanian Dance Group doing their dances and they all
used wrist grips.  The square dancers thought it was a neat idea and adopted
it.
Cheers,
Sylvia Miskoe, Concord, NH