Do Infant Seats Help Your Baby Sit Up — or Derail Her Progress?
Examining the effectiveness of the Bumbo
Infant seats that hold a baby in a sitting position are popular with parents because they are relatively small, lightweight, inexpensive and marketed as a way for your baby to be able to sit up and remain contained while she plays.
One of the most common of these seats is the Bumbo. Parents may be drawn to it because of its simplicity, price, the idea of having their young infant sit up, or a desire to let him play in a position other than on his back or belly. As physical therapists who work with infants, we have learned that many parents believe this seat will also help their baby learn to sit up by himself.
Unfortunately, when we look at the design of the Bumbo seat, we see features that, in our opinion, make this a less-than-perfect choice for helping your baby learn to sit on her own. To illustrate this observation, it’s important to understand that a baby learns to sit up by using the muscles in her back (extensors) and front (flexors) together.
When a baby is learning to sit up, her bottom (pelvis) should be the farthest thing back, and her shoulders should be in front of her hips. This position places the pelvis in a slight anterior tilt, with the trunk flexed forward over the legs. You can picture this as your baby leaning forward, placing her hands near her feet to provide tripod-like support, or folded over with her chin near her toes. As your baby becomes stronger, she will begin to use her back and hip extensors to move into a more upright position and eventually sit up.
When a child is positioned in the Bumbo seat, the rounded bottom and back of the chair places her pelvis in a posterior tilt, with his bottom tucked under him, limiting the activity of his trunk and hip extensors. Also, the front of the seat is elevated under his legs, causing her position to be tipped back even more. This positioning of the pelvis is a large part of the reason infants look slumped over when sitting in the Bumbo. Without having the space or positioning to lean forward, your baby is not encouraged to activate his extensor muscles or stay in a more upright position. Also, his head moves too far forward over his trunk, leading to additional problems with his posture.
Aside from the major concerns about a baby’s posture in the Bumbo seat, it is also important to think back to your baby’s primary motor goal during his first year: learning to move. If we simply place him in a seat that confines his movement and holds him in a position, it is much more difficult for him to learn to master the skill independently
Like adults, babies need to move and change positions frequently. Once they can sit, infants rarely spend prolonged periods of time sitting still without actively reaching, shifting their weight from side to side, moving to their tummy or back to get a toy, or otherwise wiggling and shimmying around. As they do this, they are learning about their environment and developing the processing of their vestibular system, which tells the brain where a person is in space, and provides information about how the person is moving. Spending long periods of time contained in any device, including the Bumbo, can limit your baby’s opportunities to provide important sensory information to the brain, and help develop this sensory system.
Rebecca Quinones and Rachel Gandy, both of whom have doctorates in physical therapy, are founders of Babies On The MOVE, a Cary-based organization committed to helping children excel in motor development with in-home pediatric physical therapy and community-based infant movement classes for all abilities. Learn more about their services at babiesonthemoverdu.com.