Second, the vehicle seat needs to be pushed all the way back to maximize the distance between the child and the airbag. Airbags have saved over 1,700 lives as of November 1996. Doctors and physical therapists warn that these devices can foster bad posture, weaken back and stomach muscles and delay walking. Teenagers, who had visited doctors for back problems, unanimously reported that they had used walkers as infants. Another drawback to exercise saucers is that they inhibit learning.
Babies learn very actively, so inhibiting their activity limits their learning ability.
Newsweek magazine interviewed Peter Gorski, director of developmental research at Massachusetts General Hospital in Boston. Even exersaucer manufacturers recommend that children be placed in them for no more than 20 minutes per day. It's cheap, it's safe and you can get down there with them.