GLOSSARY

Sprint Performance Enhancement describes better performance in a brief speed task, measured under defined conditions.

A credible supplement claim needs relevant controlled evidence, an appropriate comparison and a meaningful outcome. Randomization, placebo control and blinding reduce different sources of bias but do not guarantee a useful result. Sample size, uncertainty, training status, sex, diet and protocol affect interpretation. A pooled estimate is not a promise to every individual. Mechanistic plausibility, a changed biomarker, exercise capacity and actual competition performance are distinct levels of information that should not be treated as interchangeable.

Apparent individual responses combine biological variation, measurement error, expectations and changes in training or diet. A person classified as a nonresponder after one noisy test may not have a stable absence of benefit. Use repeated, relevant observations under comparable conditions and consider starting nutrient status or habitual intake. Genetic mechanisms can be informative without making a commercial genetic test a validated prescription. Individualization should improve a practical decision, not turn uncertain differences into permanent athlete labels.

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.

For example, compare a claimed performance improvement with the study's actual outcome, participant population and uncertainty. A time-to-exhaustion test differs from a paced race, and a pooled group benefit is not guaranteed for an individual. A useful decision checks relevance, practical magnitude and tolerability before adding the intervention to competition preparation.

A supplement can address a defined nutrient shortfall, provide a convenient sports-food format or target a specific performance mechanism. These purposes require different evidence and assessment. A product is not necessary simply because it is marketed to athletes, and normal training fatigue does not identify a nutrient deficiency. Begin with the athlete's diet, health, training and practical constraints, then define the expected benefit, suitable outcome and stopping or review point before adding a product.

Supplement safety depends on ingredient, dose, duration, health status and other exposures. Natural origin does not guarantee safety, and absence of a reported adverse event in a small trial does not establish long-term safety. Medication interactions, pregnancy, age and kidney or liver disease can change the decision. Distinguish an event occurring during use from a causally established adverse effect. New or severe symptoms require stopping the suspect exposure and appropriate assessment rather than increasing the dose to overcome poor tolerance.

Label accuracy, ingredient identity, potency, contamination control and manufacturing traceability are separate aspects of quality. A proprietary blend may conceal the amount of each ingredient, preventing comparison with research. A certificate of analysis applies to specified tests and samples, not every possible hazard. Verify the exact product and batch in an independent certification program when relevant. Good manufacturing practice and third-party testing can reduce certain risks without proving efficacy or guaranteeing that every batch is free of prohibited substances.