Upon release -- without a proper arrow -- unleashed, stored potential-energy will quake about either limb of the bow. This kind of transference is known as a dry fire, & can sometimes rage ..till the arrow-less bow shatters.
This is what can occur when there is no place to send bottled-force. ..It needs room to escape, matching inch for inch the distance covered had an arrow been shot into the sky, fired at the ground, or sent down range. ...That can sometimes be a lot ....of distance.... ..to make up.