Please choose the correct ending to complete the given sentence: Sports and Fitness: [header] How to make a fist [title] Extend all four fingers. [step] Hold your hand out straight and naturally extend all four fingers. Firmly press all four fingers together, leaving the thumb loose.

Ending1: [substeps] Your hand should stick straight out as though you are extending it for a handshake. Squeeze your fingers together with just enough pressure to turn them into a solid mass. Ending2: Gently stretch both fingers, one in front of the other. [substeps] The middle fingers (the injured fingers) should now be held like a fist. Ending3: [substeps] Hold them in this position for 20 seconds or longer. One to two seconds should be sufficient for dominant arm contact with the target. Ending4: Keep your hand at rest with one hand while your thumb rests comfortably behind it. [title] Twist your palms with one hand up, and grip your fist with the other hand.

Answer format: ending1/ending2/ending3/ending4