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.
3. Blood in the stool (Hematochezia) - the passage of red, or maroon-colored stools. Red or frank blood in the stool could be caused by hemorrhoids. Bloody stools can also be seen in amebiasis, anal fissures, or colorectal cancer.