There are many things that can make you have a bad posture, so instead of making your posture bad lets make it great. Many chairs have a 90 degree angle back rest. That makes the seat uncomfortable for some people. Some people may like the back rest more than 90 degrees because its more comfortable and they wont have to lean forward.
Some chairs that claim or prove to have a positive effect on posture is allowing the person on the chair to lean back and forward. That causes people to get distracted and be off task. Another effect on positive posture is to relieve back pressure. Many people like to lean forward and backwards because sometimes they get tired. That’s why chairs have to have the ability to tilt forward and backwards.
Chairs that claim or prove to have a negative posture is it can prevent blood pressure when you are sitting a long time on a 90 degree chair. Also you have to be careful where you sit because you can get very easily injured. Another reason is your muscles can weaken after sometime. It depends on how old you are, on which chair your sitting and how your sitting.
In conclusion, their are some positive and negative things about the different types of chairs. For example sometimes it’s better to have a back rest because it’s more comfortable. This is why my mythbusters group is testing which chair helps you concentrate more while doing a test. We are testing four students with different chairs and the same test.