Yes, RUNNINGS is a Scrabble word!

Letter values in Scrabble US: R 1, U 1, N 1, N 1, I 1, N 1, G 2, S 1.

Is it a valid word?

RUNNINGS is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

(American football) a play in which a player attempts to carry the ball through or past the opposing team
the act of running; traveling on foot at a fast pace
the state of being in operation
the act of administering or being in charge of something
the act of participating in an athletic competition involving running on a track

Also: running play, running game.