Quad sets. 1  Sit with your leg straight and supported on the floor or a firm bed. (If you feel discomfort in the front or back of your knee, place a small towel roll under your knee.) 2  Tighten the muscles on top of your thigh by pressing the back of your knee flat down to the floor.
allergic reaction. allergic reaction in Medicine. allergic reaction n. A local or generalized reaction of an organism to internal or external contact with a specific allergen to which the organism has been previously sensitized. Examples from the Web for allergic reaction.
An allergic response is a hypersensitive immune reaction to a substance that normally is harmless or would not cause an immune response in everyone. An allergic response may cause harmful symptoms such as itching or inflammation or tissue injury. Allergies are an abnormal immune reaction. The human immune system is designed to protect the body from potential harm and in people who have allergies the immune system will react to allergens (substances that trigger an immune response). The immune system will produce immunoglobulin E, IgE, antibodies for each allergen.