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.
Other conditions and situations that can cause blood in the stools include: 1  colon cancer. 2  non-cancerous growths, such as polyps. 3  intestinal infections (bacterial enterocolitis) that can be caused by foodborne pathogens, such as salmonella and E. coli.  inflammatory bowel disease (Crohn's disease, ulcerative colitis)