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.
Infants might have green stool as a result of: 1  Not finishing nursing entirely on one side, thus missing some of the high-fat content breast milk, which affects the digestion of the milk. 2  Protein hydrolysate formula (for babies with milk or soy allergy). 3  Lack of normal intestinal bacteria in breast-fed infants.