Please choose the correct ending to complete the given sentence: Sports and Fitness: [header] How to stretch the upper back [title] Stretch your hands forward in a rounded back stretch. [step] Clasp your hands together, and drop your chin to your chest. Reach your arms straight forward.

Ending1: Drop your head toward your chest, keeping your head straight. [substeps] Hold the stretch for 30 to 60 seconds. Ending2: Your hands should only go so far and touch each other. If you are having trouble reaching your hands into a straight forward stretch, try lowering your hands to your sides slightly. Ending3: Swing your arms to the right, as if to greet a friend, then bring them back to the floor in a rounded position. [substeps] Bend your knees to stretch your hamstrings. Ending4: As you do so, you should be pulling the shoulders forward. Hold the pose for a few breaths before releasing.

Answer format: ending1/ending2/ending3/ending4