Infants are especially vulnerable to the mechanical environments in which they are placed. The biomechanical considerations of infants mean that their body position, movements, and respiratory abilities are greatly affected by product designs or features. Inclined seated products result in head/neck flexion, trunk flexion, and hip flexion—postures which inhibit normal breathing and facilitate some types of rolling. If infants are prone in inclined seated products or on surfaces that are concave or lack firmness, additional suffocation-related hazards are introduced due to the infant’s unique biomechanical characteristics. Infants should sleep on a firm, flat surface to avoid suffocation and asphyxiation-related hazards caused by the interactions of position and biomechanics.