Most of us think the action of sitting up is a simple, natural act. It becomes much more complex when you think about all the skills involved in the process of learning how to sit. An infant requires core strength to hold the body upright as well as strength in the hips and legs to support the body. Balance is required to keep the body close to midline so as not to topple over. Coordination is required to move the body, legs and arms in a timely manner to stack the body upright. Most infants are able to sit between six and ten months old. Some babies are able to sit earlier than this by leaning on the arms for support, at around five months. By the time a baby is eleven months old he/she is usually sitting on his/her own and is able to turn the body to reach for toys without falling over.