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Endurance training is quite a broad sweeping term. It's often used interchangeably with terms like "aerobic", "anaerobic", "strength" and "speed". This section of the website focuses primarily on aerobic endurance conditioning and the various training methods that have been developed to help athletes reach peak aerobic fitness.

Endurance training is important for many sports - not just the pure distance events like running, swimming and cycling for example. While the type and amount of endurance training will change according to the specific demands of the sport, even some traditional strength and power based games demand a solid aerobic base.

Factors Affecting Endurance Performance

Central to the study of Exercise Physiology is determining the limiting factors in a particular event or activity. In endurance sports those limiting factors are based predominantly around the causes of fatigue. Unfortunately, fatigue is a complex issue and one that is likely to consist of both physical and psychological factors. However, exercise scientists have identified several major causes of exhaustion and research has shown that they can all be manipulated (some to a greater extent than others) with proper training:

VO2 Max
It's difficult to talk about endurance performance and endurance training without mentioning VO2 max or maximal oxygen uptake. Elite endurance athletes typically have a high VO2 max and for the most part it seems to be genetically determined (1). However, in untrained individuals VO2 max can be improved by as much as 20% (2). A goal of any endurance training program is to help the athlete reach thier genetic upper limit for aerobic power. In athletes with the same or similar value for VO2 max, those who perform best tend to have a superior...

Lactate Threshold
If VO2 max can be seen as an upper limit for aerobic exercise, the lacate threshold determines how much of that 'aerobic' upper limit can be used. Numerous terms have been proposed to describe the relationship between blood lactate accumulation and increasing exercise intensity and it's a subject that generates much debate. what is agreed upon is that training can have a favorable effect on lactate accumulation and when it occurs (3,4), which is associated with improved endurance performance.

Exercise Economy
Two athletes may have the same VO2 max expressed in ml/kg/min and they may have the same lactate threshold expressed as a percentage of their VO2 max. Yet what is far more relevant is the speed or workload at which the athlete is exercising when they reach these two markers. Athletes with a high exercise economy expend less energy (consume less oxygen) at any given workload. As such many researchers believe economy of exercise - be it stride length, swimming technique or body position on a bicycle - is an important contributor to endurance performance (5,6,7).

Substrate Utilization
The oxidative energy system can utilize either fat or carbohydrate to produce energy. However, when exercise intensity is higher (>70% VO2 max), there is a greater reliance on carbohydrate than fat for fuel (8). If and when carbohydrate stores are depleted exercise intensity must reduce accordingly. With training, a greater percentage of fat is used as fuel at any given work rate (8,9,10). This has a sparing effect on carbohydrate allowing a higher intensity to be maintained for longer.

Muscle Fiber Characteristics
Elite endurance athletes exhibit a high proportion of type I muscle fibers (11,12). Type I fibers have a high mitochondrial density and oxidative enzyme capacity which allows the majority of energy production to come from aerobic metabolism. While endurance training doesn't seem to change fiber types (i.e. type II fibers to type I), the metabolic characteristics of muscle fibers can be altered so that aerobic energy production becomes more efficient (13,14).

Aside from these changes within skeletal muscle what other adaptations does aerobic endurance training elicit?

Other Adaptations to Endurance Training
Following suitable training, the body becomes better able to produce ATP via aerobic metabolism. The adaptations that occur improve oxygen delivery and oxygen utilization, increase the rate of aerobic energy production and the utilization of fat fuel and reduce disturbances in the acid-base balance (13,15,16,17,18). More specific adaptations are summarized in the table below:

Adaptations to endurance training

Endurance Training Articles

The Different Types of Endurance Training
Interval training, fartlek training, tempo runs... there are several distinct forms of endurance training - here they are with some sample plans...

VO2max - Your Aerobic Potential
Endurance training and VO2 max seem to inextricably linked. While maximal oxygen uptake is certainly not the be all and end all of endurance performance, understanding what it is and how it can be affected by training can help athletes better prepare themselves for competition... 

Lactate Threshold - Tapping Your Aerobic Potential
Perhaps more indicative of success in endurance sports, an perhaps more trainable, is lactate threshold. Often a confusing subject for some coaches and athletes, from a practical point of view, improving lactate threshold is relatively straightforward...

How to Determine Your Anaerobic Threshold
There are several non-invasive tests used to determine the lactate and anaerobic threshold. What are they and which are the most reliable? 

Lactate Threshold Training
Once you have determined your lactate threshold how can you improve it? While the experts debate even its existence, athletes can still benefit from delaying the onset of lactate accumulation... 

Interval Training for Sport-Specific Endurance
Interval training is more demanding than continuous type training and brings about different adaptations. It may also be more suitable for multi-sprint sports such as hockey, rugby and soccer. However, even ultra-endurance athletes are finding that a reduction in volume in favor of some shorter, more intense interval training can improve performance...

How to Design a Fartlek Training Session for Your Sport
Fartlek may sound strange but it's a highly effective form of training. And with so many variations you need to make sure it's specific to your event...

Circuit Training For Endurance
Here are two tried and trusted circuits for long distance athletes...

Heart Rate Training for Endurance Events
Heart rate is a temperamental thing. Yet its practicality continues to make it a popular training aid. Learn how best to use your heart rate to improve your endurance training sessions...

Using Heart Rate Reserve to Calculate Target Heart Rate
How to use the Karvonen formula and the heart rate reserve method for a more accurate target heart rate zone...

Altitude Training
Unquestionably, acclimatization to altitude improves performance at high levels but can altitude training improve an athlete's performance at sea-level?

Lactate Tolerance Training
Lactate tolerance training will help you to recover more quickly from successive bursts of speed and power. It will increase your tolerance to lactic acid and allow you maintain a high work rate for longer...

Advanced 10k Training Program
If you're an experienced runner, this 8-week, 10k training program is designed to improve your times by incorporating more advanced forms of conditioning.


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12) Costill DL, Fink WJ, Pollock ML. Muscle fiber composition and enzyme activities of elite distance runners. Med Sci Sports. 1976 Summer;8(2):96-100

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14) Hoppeler H. Exercise-induced ultrastructural changes in skeletal muscle. Int J Sports Med. 1986 Aug;7(4):187-204

15) Dudley GA, Abraham WM, Terjung RL. Influence of exercise intensity and duration on biochemical adaptations in skeletal muscle. J Appl Physiol. 1982 Oct;53(4):844-50

16) Foster C, Hector LL, Welsh R, Schrager M, Green MA, Snyder AC. Effects of specific versus cross-training on running performance.Eur J Appl Physiol Occup Physiol. 1995;70(4):367-72

17) Klausen K, Andersen LB, Pelle I. Adaptive changes in work capacity, skeletal muscle capillarization and enzyme levels during training and detraining. Acta Physiol Scand. 1981 Sep;113(1):9-16

18) Burke EJ. Physiological effects of similar training programs in males and females. Res Q. 1977 Oct;48(3):510-7