A lot of people ask me when I'm at the office in my own clinic, "Why does my knee hurt when I'm sitting at my own office? I'm just sitting, getting my work done, but it's really hard to concentrate when my knee is aching and hurting." They're not sure why that is. Usually, it's not just the sitting that causes the problem or the pain, but rather the activity just before or the activities for days before.
The strengthening exercises at the gym that you might be doing. The running that you might be doing, as well. All of these things come together and cause the knee to feel a little warm, a little hot and at that point it's really important to really stretch your exercise, but we often are going to be at the office and just sitting at this point. We haven't stretched yet and there's a little bit of an ache in the knee, because it's very hot from the exercises.
It's 90 degrees and when it's maintained at 90 degrees all day long, the soft tissues inside your knee, namely the meniscus, as well as the capsules of the joint they get a little bit irritated and deformed and this can cause the pain.
The best way to relieve the pain is probably to have your leg out in front underneath your desk and maintaining it there for parts of the day or getting up as frequently as you can during the day, to relieve the tension from that 90 degree position. So these are the main reasons why you're going to have pain at the office. It's not literally the sitting, but it's the combination of the static position, as well as the exercise and activity just prior.