GLOSSARY

Endurance Performance is the ability to sustain relevant output in an endurance task. A laboratory capacity measure and a paced race result are related but different outcomes.

A nutritional strategy should be evaluated by the quality and relevance of evidence, the athlete's response and the feasibility of implementation. Molecular signaling, a substrate-oxidation change, a laboratory capacity test and race performance are different outcomes. Association does not establish cause, and a response in one small study need not generalize to all athletes. Define the intended benefit before changing the plan, then evaluate training quality, recovery and performance under comparable circumstances rather than judging success by novelty.

Fatigue is a reduced ability or willingness to sustain the required task and has interacting central and peripheral contributors. Low carbohydrate availability can matter, but heat, hydration, pacing, sleep, muscle damage and illness can also contribute. A late-race slowdown does not prove that all glycogen is exhausted or that blood glucose is low. Persistent or unusual symptoms require appropriate assessment. A useful fueling review investigates plausible causes instead of assigning every performance decline to one missing nutrient.