Your economy can have a big impact on triathlon performance, particularly over the longest distance events.
Find out how you can improve yours.
Economy is basically a measure of how efficient you are, measured by the volume of oxygen relative to your body weight that your body needs to be able to run at any given speed. It is therefore a measure of the energy cost of the body’s movement.
The more economical you are, the less oxygen you will use for a given speed. Factors affecting economy include training status, mileage accumulated in training, strength, excess weight and shoe cushioning, running style, tendon stiffness (ability of tendon and muscles to store and release energy).
Economy is closely related to performance in distance events. Traditionally VO2max was thought to be the determining factor in endurance running performance.
However since the 1980s there have been many studies showing that running economy is closely related to running performance.
In fact one study looking at economy and 10km running performance of highly trained athletes with similar VO2maxes found that 65.4% of the variation in race performance could be explained by the variation in running economy.
The graph below demonstrates the effect economy can have on performance. Velocity at VO2max is calculated using running economy and VO2max. This speed can be useful in predicting performance over ~3 – 5km.
Athlete B can match Athlete A’s performance, despite having a VO2max over 10ml/min/kg lower than Athlete A.
As the arrow indicates, if Athlete B had the economy of Athlete A, but still a VO2max of 60.4, their max speed would only be just under 17km/hr.
Therefore an improvement in economy is highly desirable for you as a triathlete, becoming more important the longer the distance you are racing. This is because it allows you to run at a faster speed without an increase in energy expenditure.
There has been many studies looking at economy, differences between individuals and possible factors affecting it, as well as how to improve economy.
There are several factors that affect economy and they can be categorised into internal and external factors.
The main ones are outlined in the table below.
|INTERNAL FACTORS||EXTERNAL FACTORS|
|RUNNING STYLE (can be influenced by several physical/biomechanical factors)||WEATHER|
|MENTAL RUNNING STATE||ALTITUDE|
|FITNESS (training status)||DIFFERENT SURFACES|
|HEALTH / FATIGUE|
In short, to improve economy, you need to reduce the energy cost. There is no real agreement amongst coaches and scientists on the best way to do this, however there are things you can do to help.
Economy tends to be best in more experienced athletes who have accumulated many miles in training. Therefore traditionally long slow distance training was used to improve economy. However there is obviously the risk of injury connected to high mileage, especially for younger athletes.
Explosive Strength Training
When you run, the muscles in your legs that work eccentrically store energy.
Eccentric contractions: When the muscles lengthen whilst working. Muscles working in this way are acting to decelerate or control a movement.
Concentric contractions: when muscles shorten whilst generating force.
This energy is then released during subsequent concentric contractions and so contributes to the energy those muscles require to do their job. Research has shown that there is a large variation between individuals in their ability to store and release elastic energy.
These differences could be related to differences in fibre composition, gender and age. Biomechanics research has shown that the economy of simple movements can be improved by improving the storage and release of elastic energy. This ability can be improved with training.
Many triathletes shy away from strength training, fearing they will gain weight or lose aerobic fitness. However when resistance training is performed in addition to an endurance programme, these potential negative effects have been shown not to occur.
Many studies have shown that VO2max and lactate threshold are not compromised when strength training is combined with endurance training.
Many scientific research studies have shown an improvement in economy and performance following explosive strength training.
Paavolainen et al (1999) found that 9 weeks of explosive resistance training (plyometrics with and without additional weight, high velocity leg press, knee extension, knee flexion) resulted in an improvement in economy of 8.1%.
This in turn led to a 3.1% improvement in 5km run time, with no changes in VO2max or lactate threshold.
Similarly, Spurrs et al (2003) found that male runners who performed 6 weeks of plyometric training in conjunction with their normal running training improved their economy by 4 – 6% across the different test speeds, and as a result their 3km run time improved by 2.7%, whilst VO2max and lactate threshold remained unchanged.
Millet et al (2002) found that performing heavy weight training two times a week in addition to normal training in triathletes led to improved maximal strength, economy and velocity at VO2max, with no effects on VO2 kinetics and as a result recommend strength training to be part of the training programme of all well-trained endurance athletes.
Therefore it seems that there are no negative effects on endurance performance by carrying out resistance training; in contrast there is a positive ‘additive effect’ of strength and endurance training.
Resistance training may improve economy by a number of different mechanisms. An increase in strength could improve mechanical efficiency, muscle co-ordination and motor recruitment patterns. Improvements in the neuromuscular system could enhance economy.
A key component of running economy is the ability to store and use elastic energy produced during eccentric contractions.
It is likely that explosive strength training results in alterations in neural control during stretch-shortening cycle exercises such as running, allowing greater storage and use of the elastic energy, thereby decreasing ground contact time and improving running economy.
Neuromuscular characteristics that could affect economy are regulation of muscle stiffness, motor unit synchronisation and/or motor unit recruitment.
Paavolainen et al (1999) claim that improved neuromuscular characteristics were transferred into improved muscle power (ability of the neuromuscular system to produce power during maximal exercise when glycolytic and/or oxidative energy production are high and muscle contractility may be limited) and economy.
Increased muscle stiffness has been found by several studies to have a positive effect on running economy. Millet et al (2002) conclude that the improvements seen in running economy as a result of strength training were due to an improvement in lower-limb stiffness regulation.
Similarly, Spurrs et al (2002) conclude that the improvements in running economy seen following a period of plyometric training was due to an increase in lower body muscle-tendon stiffness. This led to improved reactive power and hence a decreased energy cost of running.
Our strength training section includes information about how you can incorporate explosive strength training into your training programme.Home › Physiology › Running Economy: Top of page