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.
Green: 1  Green stools are always normal, but they can be mistaken for black stools. 2  Bile. 3  Most dark green stools are caused by bile. 4  Green stools are more common in formula fed than breastfed infants. 5  It can be normal with both. 6  Green stools are more common with diarrhea.