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.
Bloody stool is often a sign of gastrointestinal bleeding due to injury or disease. Stools that contain bright red or maroon-colored blood may be referred to as hematochezia, while melena is used to describe black, tarry, and smelly stools.Bloody stool can occur in all age groups and populations. Blood in the stool can appear in a variety of forms.There may be small amounts of bright red blood that is mixed inside the stool or that shows up on toilet paper after wiping the anus.Visible blood clots can also be present.loody stool can occur in all age groups and populations. Blood in the stool can appear in a variety of forms. There may be small amounts of bright red blood that is mixed inside the stool or that shows up on toilet paper after wiping the anus. Visible blood clots can also be present.