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.
While blood in stool can signal a serious problem, it doesn't always. Here's what you need to know about the possible causes of bloody stools and what you -- and your doctor -- should do if you discover a problem. Causes of Blood in Stool. Blood in the stool means there is bleeding