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.
Here are just a few reasons why your baby may have blood in his stool: 1  An anal fissure, which is a small anal tear often caused by passing a hard stool. 2  A food allergy. 3  Maternal blood from delivery or from cracked, sore nipples.  An intestinal 1  infection. An intestinal disorder, such as colitis or intussusception.
Red Blood in Baby Poop. While your babyâs poop can turn red because of something he or she ate or drank, such as tomatoes or fruit punch, red baby poop can be a sign of blood in the stool. Red blood found in normal poop could be a sign of a milk protein allergy, while red blood in diarrhea could mean your baby has a bacterial infection.