Immediate Effect of Positioning Devices on Infant Leg Movement Characteristics.
Crystal Jiang, Joyce T de Armendi, Beth A Smith
PMID 27341579WHAT IT FOUND
Infants moved their legs less often and with less acceleration in a car seat than on their backs or in a jungle gym.
The speed at which the legs turned did not change. This was immediate, not long-term development.
Key findings
01In the car seat condition, infants made fewer leg movements and had lower average peak acceleration than when on their backs or in the jungle gym.
02Average peak rotation of leg movements did not differ by positioning condition or by infant group.
03The typical development and at-risk groups did not differ in these immediate movement measures.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
Only 26 infants were tested, and the authors did not explore effects of age or Alberta Infant Motor Scale scores because of the small sample. Infants were 2 to 8 months old and had a wide range of motor scores, from 6 to 34, so movement varied greatly between participants. The test lasted only 4 minutes per position, so it cannot show long-term developmental effects. The car seat also placed infants in a semi-upright position and strapped them in, while the other conditions were on their backs, so the device and body position were changed together. Sensors were held on with socks or leg warmers, and it is unknown whether these affected leg movements differently. Home exposure to positioning devices was not controlled, so prior experience with a jungle gym or car seat may have influenced movement. The at-risk group had unknown later neuromotor outcomes, and some infants may have developed typically.
Declared interests
The authors declared no conflict of interest. No funding source is stated in the supplied text.
The easy way to misread this
Do not conclude that car seats cause developmental delay. This study measured immediate leg movement for four minutes in 26 infants, and the car seat condition also placed infants semi-upright and strapped them in, so the long-term effect and the separate effect of the seat are unknown.