ANAEROBIC TRAINING CHANGES

1. Increased Capacity of the Phosphagen (ATP-PC) System. The capacity of the ATP-PC system is enhanced by two biochemical changes:

• Increased muscular stores of ATP and PC - The phosphagens represent the most rapidly available source of energy for muscle, their increased storage correlates well with improvements in performance of activities lasting only a few seconds.
• Increased activities of Key Enzymes of the ATP-PC system. In the ATP-PC system ATP is continually turned over. ATP breakdown is facilitated by ATPase, and its resynthesis is facilitated by Myokinase (MK) and Creatin Kinase (CPK). These enzymes are increased in concentration in the muscle by following sprint type training and resistance work.

2. Increased Glycolytic Capacity. The effect of training, on anaerobic glycolysis (the lactic acid system), brings about an increase in the enzymes controlling glycolysis. When needed Key enzymes speed up the rate and quantity of glycogen broken down into lactic acid and therefore the amount of ATP energy which contributes to the performance. Therefore, activities relying on energy from the lactic acid system are improved as a result of a greater ability to produce lactic acid during exhaustive work, and thus more ATP energy generated through anaerobic pathways.

Changes in Fast and Slow Twitch Fibres

The effects of training do not effect all the fibres in the same way. There are specific responses to fast and slow twitch fibres according to the type of training done. Key points:

• The aerobic potential of all fibres is improved with endurance training but the slow twitch fibres still remain the best aerobically.
• Changes in the glycolytic capacity through anaerobic training are far more specific to fast twitch fibres.
• There is selected hypertrophy of the types of fibres dependant upon the type of training done. For example, sprinting brings about hypertrophy in FT fibres far more than ST.
• There is no conversion of fibre types. ST fibres remain ST and FT remain FT fibres. However, their properties can alter slightly, and relative aerobic or anaerobic properties can alter in a small proportion. FTb fibres (fast glycolytic) can make a gradual conversion to FTa (fast oxidative glycolytic) with aerobic training but overall there are no gross ST-FT ratio changes.