Factors related to Successful Endurance Performance
Sports science has conclusively shown that performance in endurance events or sports is due not only to the factors outlined above but to a number of specific physiological characteristics. These are discussed in detail below.
Maximum oxygen uptake (VO2max) or aerobic capacity
VO2max is the greatest rate at which oxygen can be transported by the blood and consumed by an athlete’s working tissues. The units of VO2max are ml/kg/min and values of some outstanding athletes are (were): Said Aouita (5000m runner) – 83.0; John Walker (miler) – 82.0; Sebastian Coe (miler) – 77.0; Greta Waitz (female marathon) – 73.5; Peter Snell (miler) – 72.3; Derek Clayton (marathon) – 69.7. Values in young, elite male runners might be 65-75 ml/kg/min but in 60-plus year-old male runners they are around 50-55 ml/kg/min with females about 10% lower. Swimmers and cyclists usually have a lower aerobic capacity due to the smaller muscle mass involved that can therefore take up less oxygen (see Table 6.1).
Historically, it was thought (and still is by many coaches and athletes!) that VO2max was the most critical factor in endurance performance. Wrong! While it is important facto, it is not the most critical factor when it comes to performance on the track, road, lake, river or pool. A far better predictor of endurance performance is what fraction or percentage of that VO2max can be maintained for the duration of an event – a concept called the anaerobic threshold.
This is the percentage of the athlete’s aerobic capacity that can be used at race pace – what I call the “hurt but hold” intensity. Top marathoners and road cyclists can maintain 80-90% of their VO2max while less elite athletes can only sustain 70-75% of their VO2max for the same distance. Above this pace the muscles start to produce lactic acid that upsets the muscle contraction process and slows the breakdown of carbohydrate so that energy production is compromised.
To highlight the importance of the anaerobic threshold to endurance performance, let’s look at one of the world’s greatest former marathoners – Australian Derek Clayton. Derek held the world marathon record for over a decade in the 60-70′s. Lab tests showed that Derek’s VO2max was lower than most of his competitors. However, his anaerobic threshold was relatively higher than theirs, giving him an edge when it came to racing. History also tells us he was tough – he passed blood in urine and faeces for days after breaking the world record!
This is the ability of an endurance athlete to maintain pace during prolonged endurance exercise. A major adaptation to long duration, low intensity endurance training is fatigue resistance. The long slow distance and “miles in the arms or legs” concept thus allows us to resist fatigue.
Economy of motion
This is the oxygen cost required to maintain a specific speed. By using better technique, the elite endurance athletes use up to 15% less oxygen to maintain a pace than recreational athletes. Technique is critical in improving economy. For example, runners ideally should have a relaxed upper body, swimmers recover the arms in a relaxed manner or not sweep arms across the body under the water, and cyclists should not throw their upper body around and keep relaxed in the upper body. These wasted activities use up valuable fuel and oxygen but don’t produce speed. Longer, slower runs, cycles, swims and rows improve economy as does race-pace training using intervals where technique can be concentrated on while working hard for shorter periods.
At high race speeds there is a greater reliance on carbohydrate than fats as a fuel for energy production. However, well-trained endurance athletes can make greater use of fats as a fuel during racing than less-trained athletes, thereby conserving valuable liver and muscle carbohydrate (glycogen) stores.
Through the correct training techniques, we can adapt our bodies to maximize each of these above factors.