Thus a typical high endurance fibre is relatively small to allow for diffusion of oxygen and nutrients, has a rich blood supply, an intrinsic nutrient supply that must be burnt aerobically (triglyceride), a high density of mitochondria, a high activity of enzymes of the tricarboxylic acid cycle (Fig. 6.7) and a high density of oxygen carrying pigment (cytochromes and myoglobin). Because of this last property, high endurance fibres provide the colouring of red muscles, and are sometimes called red fibres. | Thus a typical high endurance fibre is relatively small to allow for diffusion of oxygen and nutrients, has a rich blood supply, an intrinsic nutrient supply that must be burnt aerobically (triglyceride), a high density of mitochondria, a high activity of enzymes of the tricarboxylic acid cycle (Fig. 6.7) and a high density of oxygen carrying pigment (cytochromes and myoglobin). Because of this last property, high endurance fibres provide the colouring of red muscles, and are sometimes called red fibres. |