A kneeling chair is a type of chair for sitting in a position with the thighs dropped to an angle of about 60° to 70° from vertical (as opposed to 90° when sitting in a normal chair), with some of the body's weight supported by the shins. The kneeling chair is meant to reduce lower back strain by dividing the burden of one's weight between the knees and the buttocks.
Pro Varying leg positions can help restlessness when you need to keep sitting
You can use the chair with your shins on the shin pad, as intended, or use the shin pad as a foot rest for one or both feet. Being able to switch it up can be very helpful if you get restless sitting still very easily, but don't have the option to get up and move around.
Con Research on health benefits is mixed
While some studies have shown these style chairs to be good for maintaining posture, other studies have suggested they may be no better and possibly worse than a well-designed traditional chair. Prolonged usage of the shin pad with both knees (sitting as intended) may lead to decreased circulation to the lower legs.