How do diet and legal ergogenic aids support training and performance?
The macronutrients and micronutrients and their roles, dietary strategies such as glycogen loading and hydration, and the benefits and risks of legal ergogenic aids.
A focused answer to OCR A-Level PE on diet, nutrition and ergogenic aids: the roles of carbohydrate, fat and protein and the key micronutrients, glycogen loading and hydration strategies, and the benefits and risks of legal aids such as creatine, caffeine, bicarbonate and nitrates.
Reviewed by: AI editorial process; not yet individually human-reviewed
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What this dot point is asking
OCR wants you to describe the roles of the macronutrients (carbohydrate, fat, protein) and the key micronutrients, explain dietary strategies such as glycogen loading and hydration, and evaluate the benefits and risks of legal ergogenic aids.
Macronutrients and their roles
A games player or sprinter relies heavily on a carbohydrate-rich diet to refill glycogen; an ultra-endurance athlete trains the body to use fat more, sparing glycogen for the finish.
Micronutrients and water
Dietary strategies: glycogen loading and hydration
Around exercise, the timing of intake matters: carbohydrate beforehand tops up glycogen, carbohydrate and fluid during long events maintain blood glucose and hydration, and carbohydrate plus protein soon after exercise speeds glycogen resynthesis and repair (the recovery window). Hydration strategy aims to replace sweat loss, since fluid loss reduces plasma volume and impairs performance.
Legal ergogenic aids
Putting it together: matching strategy to event
The right strategy depends on the energy systems the event uses. A power athlete benefits from creatine for the ATP-PC system; a 400 m or 800 m runner benefits from bicarbonate to buffer the lactic system; an endurance athlete benefits from glycogen loading and nitrates. None of these replaces a sound everyday diet.
Exam-style practice questions
Practice questions written in the style of OCR exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
OCR 20184 marksExplain how glycogen loading could benefit a marathon runner, and identify one drawback of the classic loading protocol.Show worked answer →
A Component 01 Section B application question. Marks for the mechanism, the performance benefit and a drawback.
Award marks for: glycogen loading aims to maximise the muscle and liver glycogen stores before an endurance event. In the classic protocol the athlete depletes glycogen with hard training and a low-carbohydrate diet, then tapers training and eats a high-carbohydrate diet for the final days, which supercompensates the stores above normal. This delays glycogen depletion and the point of fatigue, letting the runner sustain pace later into the marathon. A drawback is the depletion phase, which can cause irritability, fatigue, poor training quality and water retention (each gram of glycogen stores extra water), so many athletes now use a modified loading protocol without the severe depletion phase.
Markers reward linking extra glycogen to a delayed point of fatigue, plus a genuine drawback of the depletion phase.
OCR 20218 marksEvaluate the use of creatine and caffeine as legal ergogenic aids for a games player.Show worked answer →
A Component 01 extended-response (levels of response) question. Markers reward accurate effects (AO1), application to a games player (AO2) and a balanced judgement (AO3).
Award credit for: creatine supplementation increases the muscle stores of phosphocreatine, supporting the ATP-PC system, so it can improve repeated short, explosive efforts such as sprints, jumps and tackles, and may aid recovery between bursts and gains in muscle mass. Drawbacks include water retention and weight gain, possible cramping or gastrointestinal discomfort, and limited benefit for endurance. Caffeine is a stimulant that can increase alertness, reduce perceived effort and promote fat use, sparing glycogen, which can sustain late-game performance; drawbacks include anxiety, raised heart rate, disrupted sleep and a diuretic effect in some people. A reasoned judgement notes that both are legal and can suit the intermittent high-intensity demands of a games player, but the benefit depends on the individual, the dose and timing, so they should be trialled in training first.
A top answer weighs benefits against drawbacks for the named performer and reaches a justified conclusion rather than listing effects.
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Sources & how we know this
- OCR A Level Physical Education (H555) specification — OCR (2016)