How we learn to move: 0-3 months
In the first year of life a typically developing infant learns and practices a large variety of movements which help their nervous system mature and integrate the two sides of their bodies, as well as developing the capacity to lift their body up against the constant forces of gravity. They have a specific set of developmental stages that include grasping, rolling, side sitting, crawling independent sitting, pulling to stand and cruising that precede the ultimate later milestone of walking.
This building on what’s come before creates a rich repertoire of movement, giving the infant more and more independence as they learn more skills. In order to foster this learning, it helps to understand the natural process that unfolds. This article will consider two very significant postures that typically occur by 3-4 months and precede co-ordinated rolling.
The newborn is immature and whether they are lying on their stomach or on their back they are unstable as they have not yet developed balance between the front and back muscles of the spine. Typically, by 3-4 months of age the infants brain has matured to have significantly more coordination between the front and back muscles of the body. They now have two stable postures to interact with the world, a supine posture (lying on their back with their legs held up and the head in the midline) and a prone posture (lying on their tummy with support on the elbows and front of the pelvis).
HOW DO BABIES ACHIEVE THIS?
When an infant under 6 weeks of age is placed on their tummy they often lie with their arms behind or underneath them, making it difficult to hold their head up in a balanced way. The well meaning carer may bring the arms forward for the baby however it is preferable to allow the baby to learn to do this by themselves. Allowing the baby to spend the precious seconds or even minutes to move their own arms develops key muscles about the shoulder and spine. As the baby does this the tummy and lower back muscle are also learning to work together making it possible to be stable and possible to support themselves on the elbows and front of the pelvis. Until this is the case the child is unstable however giving them short regular intervals (even a couple of minutes or less) of tummy time, assisted by you or your children engaging with them at eye level will make this important practice time less arduous.
Awake time spent on the back is another important stimulus for the development of muscle balance between the front and back muscles of the body. It is normal in the first 4-6 weeks of life for the child to have a preferred direction they turn their head, in fact they are still quite unstable and asymmetrical. By 8 weeks the child positions the head in the midline for longer periods. The developing abdominal muscles enable the pelvis and legs to be lifted up against gravity and by 3-4 months the legs are held up for quite long periods, and don’t appear stiff or heavy, and the hands are brought to the midline.
In this early period babies don’t need toys, just your presence, eye contact, and/or vocal interaction is helpful to engage them in these positions. Lying underneath suspended toys can encourage arching of the back rather than lifting of the legs. A bouncer makes it harder for the infant to left the pelvis and legs, and is therefore best avoided in the early stages of development. Lifting your baby up with both head and pelvis support is good practice as is never pulling your baby up by the hands. Waiting to use a carrier until after 3-4 months of age (longer if the infant takes more time to establish the postures described above) limits premature exposure to gravity and compressive forces whilst the head and spine is particularly vulnerable. In these young infants consider using the over the shoulder position as an alternative to sitting for burping.