Many people wonder if exercise balls/physioballs/Swiss balls are good for sitting on at the office during the day. My recommendation is to only use them sporadically. Studies have shown that sitting on balls continuously without proper back support places excessive pressure on the musculature of the trunk. Research has also documented increased compression to the spine and intervertebral discs. Use of the trunk muscles during the day can be helpful and for this the ball could be used for 10 minutes every hour. But overusing the trunk muscles leads to fatigue and possible muscle strain so a proper ergonomic office chair should be used for the majority of the time.