What type of muscle fibers are characterized by high fatigability and reliance on glycolysis?

The choice identified as correct refers to fast-glycolytic muscle fibers, which are specifically designed for short bursts of intense activity. These fibers have a high capacity for glycolysis, which is the process of breaking down glucose for energy in the absence of oxygen. As a consequence of this energy production method, fast-glycolytic fibers generate energy rapidly but are also prone to fatigue quickly, as the accumulation of lactic acid during anaerobic metabolism can lead to muscle fatigue.

Fast-glycolytic fibers are particularly important in activities that require strength and power in short durations, such as sprinting or weightlifting. They help athletes perform high-intensity movements but cannot sustain those efforts for long periods due to their quick onset of fatigue.

Other types of muscle fibers, such as slow twitch fibers, are more efficient at using oxygen to generate energy for prolonged activities and are resistant to fatigue. Fast-oxidative fibers utilize both anaerobic and aerobic processes but are generally more endurance-oriented than fast-glycolytic fibers. Intermediate fibers exhibit characteristics of both slow and fast fibers but do not have the same level of fatigue and energy reliance as the fast-glycolytic fibers.