Please choose the correct ending to complete the given sentence: Work World: [header] How to avoid back soreness or pain at the office [title] Adjust your chair. [step] Sitting for long periods in front of a desk or computer screen puts lots of pressure on your back and on the disks in your spine. A proper chair is key to preventing back pain.

Ending1: Try to get one that can be easily adjusted for height, back position, and tilt. [substeps] Adjust the chair height so that, when standing, the highest point of the seat is just below your kneecaps. Ending2: [substeps] Check your chair's usage requirements to make sure you can wait a minimum of twenty minutes to get a full back massage. You should also see if you can switch seats on your desk. Ending3: Try adjusting your chair position slightly to take a seat closer to the end of the desk where it is not too far forward. This gives you more room to move and provides more room for your neck to move without strain or back injury. Ending4: If you're sitting behind a desk too long, your back may be pulled forward towards the edge of the desk, which can put strain on your back and cause further back problems. [substeps] How much to adjust your chair will depend on your specific days and your workplace.

Answer format: ending1/ending2/ending3/ending4