Positive and negative effects of dietary supplements/manipulation on the…

The idea

This section examines how dietary manipulation and supplements affect performers. Glycogen loading maximises muscle glycogen stores for endurance, but can cause water retention and stiffness. Creatine supplements increase phosphocreatine stores for explosive power, yet may lead to weight gain and muscle cramps. Sodium bicarbonate buffers lactic acid to delay fatigue in anaerobic activities, though it often causes gastrointestinal upset. Caffeine acts as a stimulant to increase alertness and mobilise fatty acids, but can result in dehydration and insomnia. While these methods can enhance specific types of performance, their negative effects depend on the dose, timing and the individual performer's tolerance.

What earns the marks

• Glycogen loading increases muscle glycogen for endurance events but can cause water retention and heavy legs.
• Creatine supplementation increases PC stores for short, explosive bursts of energy, though it may cause unwanted weight gain and cramping.
• Sodium bicarbonate acts as a buffering agent to neutralise lactic acid and delay fatigue, but frequently causes gastrointestinal distress.
• Caffeine stimulates the central nervous system to improve concentration and mobilises fats for energy, yet can cause dehydration and insomnia.
• The effectiveness and risks of any dietary manipulation depend on the specific demands of the sport, the dosage, and individual physiological responses.

Common mistakes and how to put them right

• Confusing the energy systems targeted.

  Put it right: For example, thinking creatine benefits marathon runners rather than explosive athletes.

• Ignoring the side effects: assuming supplements like sodium bicarbonate only have positive buffering effects without mentioning gastrointestinal upset.

• Believing glycogen loading is suitable for all sports.

  Put it right: It is specifically beneficial for endurance events lasting over 90 minutes, not short sprints.

Exam tips

• Always link the specific supplement to the correct energy system or type of sport (e.g., creatine for the ATP-PC system).
• Provide both a positive performance effect and a specific negative side effect when evaluating a supplement.
• Use precise terminology, such as 'buffering lactic acid' for sodium bicarbonate or 'mobilising fatty acids' for caffeine.