Newborn (0-6 months)

At Newborn, the baby's foot structure is not mature and there is no rigid bone structure. The cartilage tissue is unable to support the body weight.
The foot consists of 22 bones. They are wrapped around by the subcutaneous tissue and fat for protecting the incompletely developed foot bones.
The length of the five toes is similar and the arch has not yet developed in this stage.

Start to Crawling (7-10 months)

The baby needs to raise and rotate the head to the left and right for crawling. It also needs the strength of the shoulders and wrists to support the whole upper body. Therefore, it is beneficial to strengthen their joints of the hands, feet and neck and the muscle of the abdomen, neck and limbs. Exercise on small muscles will promote bone growth, enhance physical strength and lay the foundation for future movements.

The baby will try to stand after the baby get used to crawl as the mind, muscles and nerves mature. Then, they will have the first step of their life. Most babies will know how to walk at age 9-18 month.
由於幼童開始學習走路，下肢開始要適應承受身體重量，膝部在此階段會呈O形狀。
At the beginning of walking, the gait is mostly like a penguin. During walking, they will swing left and right which mean they are not stable.
Appropriate shoes for school should be designed so that the baby's feet can sense the floor during walking. The design should protect the feet while ensure that the shoes do not hinder them from learning to walk.
不建議家長為了讓子女更快學走路而購買學行車。１９９９年一份大學的研究指出，嬰兒經常使用學行車較沒有使用學行車的嬰兒，在體格及智力上較低。家長只要適當地輔助，鼓勵嬰兒自己努力嘗試，他們自然而然地自己走路的。

At this stage, walking will gradually stabilizes and the time for the feet to bear the weight of the body increases accordingly.
Young children have a thick layer of fat covering the arch of the foot, called the "fake flat feet". In addition, there will be more obvious hindfoot valgus and X-legs.
For the choice of footwear, it is recommended that the heel of the shoe should be rigid enough to control the heel. The material of the upper should also be highly breathable (for example, using microfiber, cowhide, etc.) to reduce the chance of fungal infection. Because the forefoot of the young child is more wide, the toe box of the shoe should be wide enough to allow movement between the toes.

At this stage, the fat layer at the bottom of the feet gradually absorbed and disappeared. The arch of the foot began to appear. At the same time, the angle of the hindfoot and the X-legs began to decrease.
此階段家長將察覺到小朋友在跑步時有時會不穩，其中一個原因是X形腿令膝關節內側互相碰撞而導致的。
For the insole, in addition to the appropriate arch curvature, also pay attention to the softness of the insole. In general, the arch support insole used for daily walking should be harder. The material of insole which is for sports is more elastic to provide good cushioning and shocking absorption.
In order to simulate the growth of child's bone structure, parents are advised to choose the shoes with rigid heel cup which will reduce the deviation angle of the hind foot and the X-leg.