Please choose the correct ending to complete the given sentence: Health: [header] How to prevent shoulder dislocation [title] Press inward and outward with your arm to strengthen your rotator cuff. [step] With your elbow at a 90-degree angle, your upper arm against your body, and your other hand directly in front of you, press inward against your other hand. Hold for 5 seconds.

Ending1: That time will create additional tension in the arm. [substeps] To tighten your rotator cuff, you use your elbow. Ending2: With your arm in the same 90-degree angle, press outward against a wall or other solid surface for 5 seconds. Do this 20 times apiece, then repeat with the other arm. Ending3: [substeps] Forearm sprains are more likely to cause shoulder dislocation. If the shoulder dislocations are due to a standing position, squeeze your elbows tightly against your body and press upward (which moves your body into a straddle position) until the forearm becomes non-rigid. Ending4: [substeps] Again, you should feel a lot of impact as you push inward. Your upper arm should be against your body rather than bent at the elbow.

Answer format: ending1/ending2/ending3/ending4