3.2.1.1 Diet and nutrition and their effect on physical activity and performance Typeit

The greater competitiveness of modern-day sport has resulted in athletes who strive to seek any competitive edge that will give them an advantage over their competitors. This has led to the development and uptake of  aids in many sports, which describes any method or substance that has a beneficial impact on physical or mental performance. Some of the most commonly used nutritional aids are outlined below.

Dietary supplements

• Creatine as a supplement is most commonly taken in the form of powder used in drinks. It acts by increasing stores of (PC) in the muscle and enhancing its resynthesis. It maximises the use of the  energy system, which can enhance sprint ability and reduce fatigue during short-duration, high-intensity exercise. This enables greater production of power and maximum strength, so is often used by power/strength athletes, e.g. 100 m sprinters and weightlifters. 
• Caffeine as a supplement can come in a range of forms, including coffee, energy drinks and gum. It acts by stimulating the (CNS). This can help lower the perceived effort of activity, allowing the performer to maintain exercise intensity for longer by resisting fatigue. It can also increase  - this would be useful in performing fine skills during gymnastic routines or reacting to stimuli such as the movements of an opponent in rugby.
• Sodium bicarbonate as a supplement is most often taken in powder form with a drink. It helps to buffer by drawing it/them out of the muscle cell and reducing the of blood by dissociating its components. This reduces the sensation of in the muscle so is particularly useful during sporting events that rely on the glycolytic system, such as middle-distance running.

There are also dietary manipulations that a performer could use to maximise their performance. Where a bodybuilder would consume a greater percentage of to increase muscle mass, a marathon runner would consume a greater amount of carbohydrate to boost glycogen stores. Carbohydrate loading aims to trick the body into sparing muscle glycogen during competition. A loading strategy would be to initially deplete the body of glycogen stores around a week before competition, and then consume a low carbohydrate, high diet while keeping training low. In the days prior to the event, intake should be highly increased. This attempts to trick the body into sparing glycogen during the endurance event, promoting a greater fat metabolism at a given intensity.