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.
There are likely to be other possible causes, so ask your doctor about your symptoms. 1  Blood in stool - see causes of blood in stool and rectal bleeding for various possible diagnoses. 2  Certain foods Iron supplements. 3  Stomach bleeding - usually causes darker or black blood in the stool. 4  AVM. more causes...Â».