Effects of Short-term Adaptation to Ketogenic Diet on Endurance Trained Athletes

Skeletal muscle glycogen is a major endogenous carbohydrate store and an important substrate for ATP resynthesis during exercise. Its utilization increases with exercise intensity and duration, and low muscle glycogen availability has long been associated with impaired endurance exercise capacity. Beyond its role as a metabolic substrate, glycogen availability may influence excitation-contraction coupling and Ca²⁺ handling, providing multiple mechanisms through which carbohydrate availability can affect contractile function and fatigue. Ketogenic diets (KD), characterized by severe carbohydrate restriction (\

Inclusion Criteria: * Male * Age 18-40 yr, * BMI: 18-25 kg/m\^2, * At least two years of endurance training experience * a cycling volume of at least 150 km·week * habitual consumption of a carbohydrate-based diet (\>50% of total daily energy intake from carbohydrates) Exclusion Criteria: * Chronic diseases * Acute inflammatory states * Psychiatric disorders * Recent (within 3 months) treatment with anabolic steroids or systemic corticosteroids