Desk workers develop tight chests and weak backs from sitting all day. Trying to sit up straight feels like a workout because your back isn't strong enough to hold it. One client got sore just from attempting good posture for a day.
One of the biggest muscular imbalances that I see comes from people who sit at a desk all day. You have tight chest, your back's hurt, and that's a muscular imbalance because your back is not strong enough to hold you up. I told a client many years ago, I said, the hardest exercise I could ever have you do is getting you to sit up straight with your shoulders back all day long. I said, if you do that, you will feel like you had the hardest workout you've ever done. She came back to me 2 days later and said, my back is so sore from sitting up straight all day. And I said, yep, I know.
