The Science of Canoeing By Richard Cox

Table 5.13 General Characteristics of the Energy Systems
ATP – PC (Phosphogen) Latic Acid System Oxygen System
System
Anaerobic Anaerobic Aerobic
Very Rapid Rapid Slow
Chemical Fuel: PC Food Fuel: Glycogen Food Fuels: Glycogen, fats and
protein
Very limited ATP Production Limited ATP Production Unlimited ATP Production
Muscular stores limited By-product, lactic acid, causes
muscular fatigue
No fatiguing by products
Used with Sprintor any high Used with activities of 1 to 3 Used with endurance or long
power short-duration activity minutes duration
duration activities
Different activities and events place different demands on the energy systems described. Explosive events like
the shot-put are over within a few seconds, during which time maximum effort is exerted. Such activities rely
almost entirely on the ATP and ATP/PC or "a lactic" anaerobic system. Events lasting in excess of 15 seconds
but less than 45-50 seconds of maximum effort such as 50 metre swim or 400m dash in athletics rely upon both
the alactic and lactic anaerobic systems of energy metabolisms. Events lasting in excess of 1 minute rely more
heavily on the aerobic system. This is especially true of long distance canoeing events.
It is important to remember that these three systems do not act exclusively and that the tactics adopted in any
race will influence the relative demands placed on any one system. A 1000 metre sprint paddler, for example,
might accelerate off the start line and for the first 100 metres place heavy demands on the ATP-PC and lactic
anaerobic systems. He may then maintain a steady pace for 700 metres or so during which time his muscle cells
have had time to oxidise away the lactic acid build up. During this period he is managing to meet his energy
requirements from the aerobic system of metabolism. It might be necessary, over the last 200 metres, to increase
the pace, in which case he accelerates in an all-out effort sprint to the line. Once he increases his effort to an
intensity that demands more oxygen than his body can supply, the lactic system will function strongly, building
an oxygen debt that will have to be paid off once he has crossed the finishing line.