Central Sterile Services Department (CSSD) Practice Exam

In the context of endurance training, the correct response is that Type 1 muscle fibers increase. Type 1 muscle fibers, also known as slow-twitch fibers, are specifically designed for endurance activities. They are more efficient at using oxygen to generate energy for prolonged activities, which is why they are predominant in endurance athletes. These fibers increase in size and efficiency through endurance training, allowing for better performance in activities that require sustained effort over a longer duration.

Type 2 muscle fibers, on the other hand, are classified into two subtypes: Type 2a (fast-twitch, oxidative) and Type 2b (fast-twitch, glycolytic). Type 2 fibers are more suited for short bursts of strength and speed. While some adaptations might occur in Type 2 fibers with endurance training, the primary changes are observed in Type 1 fibers, where there is an increase in capillary density, mitochondria, and oxidative enzymes that enhance endurance capacity.

Type 3 muscle fibers do not exist in the standard classification of muscle fibers. This mislabeling could confuse the context of muscle physiology. Moreover, stating that there is no change in muscle fibers contradicts the well-documented adaptations that occur with endurance training, which clearly favor the development