Bouncing the soles of babies’ feet mainly depends on the strength. If it is only appropriate to play the soles of the feet, there is no effect, but if it is extremely strong, it may have an effect.
The soles of the feet are mainly composed of skin and muscle, and the peripheral nerves of infants are still relatively sensitive, so gently playing the soles of the feet can determine the infant’s reaction and mental state, and generally will not cause damage. But if the force is too large, and may even cause damage to the local, can make the baby local delicate skin redness and bruising.
But generally speaking, with the normal human finger strength to play the heart of the foot, it is difficult to achieve that kind of strength. Therefore, it is possible to judge the child’s reaction by playing the heart of the foot, generally no harm.