Concentric contractions: A concentric contraction is a type of muscle contraction where the length of the muscles shorten while undergoing tension. For example, when you pick up a curl bar and perform a biceps curl, the length of your biceps muscles shorten.
Blood in Baby's Stool. Babies can sometimes have blood in their stool that is caused by food allergies, a small anal tear or fissure, or even a temporary case of lactose intolerance. It might even be a drop of blood that came from a cracked nipple, which the baby then passed through his system.
You should call your pediatrician if your infant has: Signs of dehydration (a sunken fontanel, few wet diapers, dry eyes when crying, dry mouth, sunken eyes or lethargy) Mucus or foul odor in three or more diarrhea stools (for infants one month of age or younger) Blood in the stool.