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.
Common Causes of Blood in the Stool. 1. Hemorrhoids: One of the most common causes of blood in the stool is that it is the result of a hemorrhoid that has started to bleed. Hemorrhoids appear when blood vessels in the rectum or anus become swollen and inflamed. Bleeding from a hemorrhoid is typically bright red in color.