meat, and why do the two kinds of meat taste different? Why is veal pale and delicate, beef red and robust? The key is the muscle fiber There are several different kinds of muscle fiber, each designed for a particular kind of work, and each with its own color and flavor White and Red Fibers Animals move in two basic ways They move suddenly, rapidly, and briefly, for example when a startled pheasant explodes into the air and lands a few hundred yards away And they move deliberately and persistently, for example when the same pheasant supports its body weight on its legs as it stands and walks; or a steer stands and chews its cud There are two basic kinds of muscle fibers that execute these movements, the white fibers of pheasant and chicken breasts, and the red fibers of bird and steer legs The two types differ in many biochemical details, but the most significant difference is the energy supply each uses White Muscle Fibers White muscle fibers specialize in exerting force rapidly and briefly They are fueled by a small store of a carbohydrate called glycogen, which is already in the fibers, and is rapidly converted into energy by enzymes right in the cell fluids White cells use oxygen to burn glycogen, but if necessary they can generate their energy faster than the blood can deliver oxygen When they so, a waste product, lactic acid, accumulates until more oxygen arrives This accumulation of lactic acid limits the cells’ endurance, as does their limited fuel supply This is why white cells work best in short intermittent bursts with long rest periods in between, during which the lactic acid can be removed and glycogen replaced ... force rapidly and briefly They are fueled by a small store of a carbohydrate called glycogen, which is already in the fibers, and is rapidly converted into energy by enzymes right in the cell fluids... necessary they can generate their energy faster than the blood can deliver oxygen When they so, a waste product, lactic acid, accumulates until more oxygen arrives This accumulation of lactic... acid limits the cells’ endurance, as does their limited fuel supply This is why white cells work best in short intermittent bursts with long rest periods in between, during which the lactic acid