Height: It should be equal to the length of the lower leg, when sitting down the calf will sag naturally, the sole of foot can hit the ground. If the seat is too high, the calf hanging and the underside of the thighs will suffer too much pressure; If the seat is too low, the thigh can not be put on the seat surface altogether, and the body weight is all concentrated to the hip, it will be uncomfortable after a long time.
Seat depth: In the chair, the depth of the seat should be equal to the length of the thigh, when sitting down, the bend of knee joint is right to the edge of the chair. If the seat is too deep, the back is not landing; if the seat is too shallow, there is not enough support in the thigh, both are not comfortable.
Back: it is best to play all or part of the supporting role to the waist, back and neck . The longer the chair used, the better the support should be. Because the dining chair is used only at meal time, the neck part can be ignored but for office chair,it is best to take care of all of these. We need to pay special attention to the selection.
The material of seat and back : both should be "An iron hand in a velvet glove." The frame should be strong enough, but the surface should be covered by elastic layer . The outermost material should be breathable, wearable, stain-resistant, and not easy to generate static electricity with the human body or clothing.