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.
Causes of Blood in Stool. 1  Anal Fissure. If no diarrhea, most of these children have a small tear in the anus. 2  Strep Skin Infection. A Strep skin infection around the anus can also cause blood-streaked stools. 3  Bacterial Diarrhea. If also has bloody diarrhea, a gut bacterial infection may be the cause.  Red, but not Blood.
You should call your pediatrician if your infant has: Signs of dehydration (a sunken fontanel, few wet diapers, dry eyes when crying, dry mouth, sunken eyes or lethargy) Mucus or foul odor in three or more diarrhea stools (for infants one month of age or younger) Blood in the stool.