The Anaerobic (ATP-CP) Energy System

Adenosine Triphosphate (ATP) stores in the muscle last for approximately 2 seconds and the resynthesis of ATP from Creatine/Phosphate (CP) will continue until CP stores are depleted, approximately 4 to 5 seconds. This gives us around 5 to 7 seconds of ATP production.

To develop this energy system, sessions of 4 to 7 seconds of high intensity work at near peak velocity are required. e.g.

• 3 × 10 × 30 metres with recovery of 30 seconds/repetition and 5 minutes/set.
• 15 × 60 metres with 60 seconds recovery
• 20 × 20 metres shuttle runs with 45 seconds recovery

The Anaerobic Lactate (Glycolytic) System

Once the CP stores are depleted the body resorts to stored glucose for ATP. The breakdown of glucose or glycogen in anaerobic conditions results in the production of lactate and hydrogen irons. The accumulation of hydrogen irons is the limiting factor causing fatigue in runs of 300 metres to 800 metres.

Sessions to develop this energy system:

• 5 to 8 × 300 metres fast - 45 seconds recovery - until pace significantly slows
• 150 metre intervals at 400 metre pace - 20 seconds recovery - until pace significantly slows
• 8 × 300 metres - 3 minutes recovery (lactate recovery training)

There are three different working units within this energy system: Speed Endurance, Special Endurance 1 and Special Endurance 2. Each of these units can be developed as follows:

	Speed Endurance	Special Endurance 1	Special Endurance 2
Intensity	95 to 100%	90 to 100%	90 to 100%
Distance	80 to 150 metres	150 to 300 metres	300 to 600 metres
No of Repetitions/Set	2 to 5	1 to 5	1 to 4
No of Sets	2 to 3	1	1
Total distance/session	300 to 1200 metres	300 to 1200 metres	300 to 1200 metres
Example	3 × (60, 80, 100)	2 × 150 metres + 2 × 200 metres	3 × 500 metres

The Aerobic Energy System

The aerobic energy system utilises proteins, fats and carbohydrate (glycogen) for resynthesising ATP. This energy system can be developed with various intensity (Tempo) runs. The types of Tempo runs are:

• Continuous Tempo - long slow runs at 50 to 70% of maximum heart rate. This places demands on muscle and liver glycogen. The normal response by the system is to enhance muscle and liver glycogen storage capacities and glycolytic activity associated with these processes.
• Extensive Tempo - continuous runs at 60 to 80% of maximum heart rate. This places demands on the system to cope with lactate production. Running at this level assists the removal and turnover of lactate and body's ability to tolerate greater levels of lactate.
• Intensive Tempo - continuous runs at 80 to 90% of maximum heart rate. Lactate levels become high as these runs boarder on speed endurance and special endurance. Intensive tempo training lays the base for the development of anaerobic energy systems.

Sessions to develop this energy system:

• 4 to 6 × 2 to 5 minute runs - 2 to 5 minutes recovery
• 20 × 200m - 30 seconds recovery
• 10 × 400m - 60 to 90 seconds recovery
• 5 to 10 kilometre runs

Energy System recruitment

Although all energy systems basically turn on at the same time the recruitment of an alternative system occurs when the current energy system is almost depleted.

The following table provides an approximation of the percentage contribution of the energy pathways in certain sports. (Fox et al 1993)

Sport	ATP-PC and LA	LA-O2	O2
Basketball	60	20	20
Fencing	90	10
Field events	90	10
Golf swing	95	5
Gymnastics	80	15	5
Hockey	50	20	30
Distance running	10	20	70
Rowing	20	30	50
Skiing	33	33	33
Soccer	50	20	30
Sprints	90	10
Swimming 1.5km	10	20	70
Tennis	70	20	10
Volleyball	80	5	15

Table adapted from Fox E. L. et al, The Physiological Basis for Exercise and Sport, 1993