Palpitation is an awareness of the abnormal beating of the heart. It may occur in people with or without heart problems. Heart palpitations when lying down is not a common occurrence and can be caused by various factors.
Flat feet occur when the normal foot arches have partially or completely collapsed. When the foot is put to the ground the inner or middle side of the foot comes down to the floor rather than remaining raised. This can cause the whole foot to roll inwards (this is called over-pronation).
As with supination, when pronation is excessive it is referred to as overpronation. Pronation occurs as the foot strikes the ground and rolls in to absorb the impact. Supination occurs as the foot prepares to toe-off to provide a rigid platform for leverage. As the foot rolls out it becomes a rigid lever.