"The most significant advance in running training since the original interval training."

jar•gon noun [jahr-guhn, -gon] 1) a strange, incoherent, unintelligible language
2) the language, especially the vocabulary, peculiar to a particular trade, profession, or group
3) any talk or writing that one does not understand.

Jargon Busters

Many of you know words you consider to be ‘jargon’ and you may dismiss considering these words or phrases because, “they are just jargon”. Jargon can be defined as a strange, incoherent, unintelligible language but it is also defined as being related to the technical terminology, vocabulary or language of a special activity. Running, exercise physiology and the other sport sciences are all heavily populated with necessary jargon. This page seeks to explain and clarify some of the ‘jargon’ used on this website - hopefully, to take it from a strange, incoherent, unintelligible language to something with meaning.


When lactic acid is formed it immediately dissociates, it splits up, into Lactate and the ‘acidic bit’, formed of Hydrogen ions. Lactate and hydrogen ions are therefore formed in a one-to-one relationship. If hydrogen ion production exceeds buffering (neutralising) and clearance, the accumulation and increase in hydrogen ions and subsequent acidity of the internal environment is called ‘acidosis’.

Acidosis Tolerance Training

When intense training is performed to deliberately learn how to physically and psychologically tolerate the accumulation of high amounts of Hydrogen ions this is called Acidosis Tolerance Training, also known as Lactic Acidosis Tolerance Training. In the past this was incorrectly called ‘Lactate Tolerance Training’ due to the misunderstanding of the role and function of lactate.


Aerobic Energy System

The energy system that uses and requires oxygen to provide the energy for ATP resynthesis is called the Aerobic system, with the process occurring in the mitochondria.

Anaerobic Threshold

The term ‘anaerobic threshold’ is not now commonly used. The idea that the skeletal muscle cell suddenly switches over from aerobic to anaerobic metabolism is simplistic and misleading, since this does not reflect accurately what is taking place in the muscle.


ATP stands for Adenosine Triphosphate, which is a high-energy phosphate compound from which the body derives energy. Every living cell has the capacity to synthesise and use ATP within itself. There is a small amount of ATP present in a resting muscle and energy is not stored as ATP but it can be produced metabolically, as needed. For the coach and athlete, what ATP stands for is not so important as what it is capable of doing. ATP can be used to drive any energy-requiring process in the cell.

Date Pace

The term ‘Date pace’ is attributed to the legendary US coach, Bill Bowerman. It’s a simple concept that reflects the fact that you cannot run your personal best pace every day because of variations in fitness, fatigue levels, environmental conditions, absence of competition, etc. It represents your current race pace for a specific distance. If a repetition called for a ‘5k pace’ or ‘3k pace’ this would be run at what the athlete perceive they would feel in the middle of a 5,000m race or 3,000m race, if run that day. Athletes train at ‘date pace’ for most of their cycle before transitioning to ‘goal pace’ in the pre-competition and competition phases, if using a periodised programme and terminology.

Fartlek Training

The word ‘Fartlek’ comes from the Swedish for 'Speed Play' and reflects that this training provides for a variety of speeds or paces combining continuous aerobic emphasis training with faster than race pace efforts. True Fartlek allows the athlete to run whatever distances and speeds they wish and to ‘play’ with varying the intensity, occasionally running at high intensity levels, occasionally at lower intensities. Fartlek is a classic form of Lactate Dynamics Training and trains the lactate shuttle in an environment away from the track.

Four-seconds Rule

The Four-seconds Rule is a guide that was introduced by the British coach Frank Horwill to relate the pace for different distances. It states that an athlete who can run, for example, a 1500m in 4:00 (64 seconds/400m) should also be able to run 2:00 for 800m (60 seconds/400m), 3000m in 8:30 (68 seconds/400m), 5000m in 15:00 (72 seconds/400m) and 10,000m in 31:40 (76 seconds/400m). Using the ‘Horwill 4-seconds Rule’ we know that 800m, 1500m, 3000m, 5000m, 10000m paces, and even half-marathon and marathon paces, should all potentially vary by 4 seconds per 400m, or by 1 second per 100m. These small differences are the order of variation we should observe in training paces. Note: if the athlete’s performance is much slower than the example given, then the difference per 400m may be 5-seconds or greater.

Goal Pace

The term ‘Goal pace’ is attributed to the legendary US coach, Bill Bowerman and is simply the pace required for your goal time for any distance. It is generally introduced into repetition training to replace ‘date pace’ as the selected competition approaches.

Interval Training

A specific type of repetition training where the training effect takes place during the recovery intervals between the faster paced runs or repetitions.

Kenyan Intervals

A form of repetition training that Peter Thompson developed in the mid-1970s to mimic the fluctuating rhythms of the internationally emerging Kenyan athletes. As an example, repetitions of 400m might be run with straights at 66 seconds pace and the bends at 70 seconds pace, rather than running 400s at a steady 68 seconds pace. Originally, the ‘Kenyan Intervals’ were actually ‘Kenyan Repetitions’. But at that time Thompson, like many coaches, incorrectly used the term ‘Interval Training’ interchangeably with ‘Repetition Training’. Now the ‘Kenyan Intervals’ have become a type of New Interval Training and are true ‘Intervals’.


Lactic acid dissociates into Lactate and Hydrogen ions as soon as it is formed in the body. Lactate is a positive and central player in our metabolism and in how we produce energy. It is an important intermediary in numerous metabolic processes and a particularly mobile fuel for aerobic metabolism.

"Lactate is now recognised for its important metabolic functions and is a key substance used to provide energy, produce blood glucose and liver glycogen and promote survival in stressful situations. Oxidation of lactate is one of our most important energy sources. In highly oxidative muscle fibres, lactate is the preferred fuel source."

Brooks GA, 1988

Lactate Dynamics Training

This term was introduced by Peter Thompson in 1994 to specifically classify the training for the dynamic utilisation and clearance of lactate so that lactate is optimally used around the body. It refers to any form of training where lactate production is deliberately increased by the intensity of exercise and then alternated with periods of less intense activity. In this way the muscle cells learn how to both use and clear the produced lactate during the less intense recoveries

Lactate Energy System

We now understand that the Lactate energy system works synergistically with the aerobic system and permits activity at greater intensity and duration than would be supported solely by ‘aerobic processes’. The lactate system works all the time and is active in the presence of oxygen even though it does not require oxygen.

The Lactate Shuttle

The hypothesis introduced by Dr G.A. Brooks in 1986 to describe the dynamic action of lactate as a metabolite moving about within muscles and the systemic circulation to provide metabolic energy.

Lactate Threshold

There is a point, in increasing intensity of exercise, where individuals may show a rapid increase in the levels of blood lactate. This turning point is referred to as the Onset of Blood Lactate Accumulation, or OBLA. The OBLA is considered to correspond with the Lactate Threshold and is the point when the dynamic equilibrium, which can exist between lactate addition to and removal from the blood, has been upset.

Lactate Tolerance Training

In the past Acidosis Tolerance Training was incorrectly called ‘Lactate Tolerance Training’ due to the misunderstanding of the role and function of lactate. Lactate has a useful and positive presence in the body and does not have to be ‘tolerated’.

Lactic Acid

Lactic acid, as such, just does not exist in the body. As soon as it’s formed it dissociates, it splits up, into a ‘lactate bit’ and an ‘acidic bit’.


Monocarboxylate transporters, or MCTs, constitute a family of proton-linked plasma membrane transporters that have been identified in the past 15 years and can carry molecules having one carboxylate group (monocarboxylates), such as lactate and pyruvate, across biological membranes. There are at least 14 MCTs that have been identified, although MCT1 and MCT4 seem to be most relevant to lactate and pyruvate transportation within cardiac and skeletal muscle.

Metabolic Energy Systems

There is general agreement that three metabolic energy systems can be identified: the ATP-CP system, the Lactate system and the Aerobic system. Of these, the Aerobic system is probably best known by the person-in-the-street because of the questionable use of the term ‘Aerobics’ to describe a form of exercising.We now understand that the Aerobic and Lactate systems function synergistically and that the Lactate energy system works all the time. In fact, all the three energy systems work all of the time with the duration and intensity of activity determining which energy system is emphasised.


The mitochondria, singular mitochondrion, are considered to be the aerobic ‘energy powerhouses’ of the cell.

Multi-paced Training

A system of training introduced by the British coach Frank Horwill in 1970 that advocates the use of sessions at 5 different paces over a ten to fourteen day period. It is also referred to as ‘5-pace Training’ and ‘Multi-tier Training’.

New Interval Training

This term was introduced by Peter Thompson in 1995 to describe a form of repetition training where what the athlete does during the ‘recovery intervals’ is crucial and actually has a profound effect on the training of the metabolic energy systems. The method is characterised by the very active roll-on recovery intervals during which the cells ‘learn’ to use and clear lactate, developing the synergistic relationship between the lactate and aerobic energy systems.


There is a point, in increasing intensity of exercise, where individuals may show a rapid increase in the levels of blood lactate. This turning point is referred to as the Onset of Blood Lactate Accumulation, or OBLA. The OBLA implies that the dynamic equilibrium which can exist between lactate addition to, and removal from, the blood has been upset. It is not clear at this time what processes have been disturbed or may have reached ‘critical’ levels to cause the OBLA.

Original or Gerschler Interval Training

Devised by Woldemar Gerschler and Herbert Reindel in the late 1930s. The name of the system, interval training, was because the rest or recovery period between the faster runs was considered the most important and vital part of the training. It is during the interval that the heart adapts, growing larger and stronger.


Pace has been used throughout this website to be equivalent with Bill Bowerman’s concept of ‘Date pace’. Using ‘pace’ means that each athlete trains at their individual rhythm and level of performance, developing the fitness that they need. It is thought that, in practice, pace judgement and the Rating of Perceived Exertion, RPE, are in close correlation.

Rating of Perceived Exertion, RPE

Introduced by the Swedish psychologist Dr Gunnar Borg in 1970, the RPE scale represents an individual’s subjective rating of the exertion, or effort, required to do any physical activity. It is a psychophysical function of the perception of effort and is more closely correlated to blood lactate levels than is heart rate or some arbitrary target time. If athletes are to exercise relative to their lactate threshold, it would be more accurate to do this from perception of effort than with a heart rate monitor.

Repetition Training

The breaking of training distances into smaller, more manageable, parts. The parts are repeated, hence ‘Repetition Training’. A typical, simple traditional repetition session might be 15 repetitions of 400m, which would be referred to as a ‘400m rep session’, or doing ‘400m reps’.


This is a common abbreviation of the term ‘repetitions’, which are the faster runs or sections which comprise Repetition Training and Interval Training.

Roll-on Recoveries

The activity that is done in the interval between faster repetitions is called a ‘roll-on recovery’ and this is what defines the New Interval Training. It is where the metabolic training effect takes place. Roll-on recoveries are at a pace controlled by the athlete and become more active as the athlete’s lactate utilisation and clearance abilities develop. The goal, whether it’s an experienced or inexperienced athlete, would be not to slow down suddenly at the end of the faster repetition and then speed up as the next repetition approaches but to transition smoothly and quickly from the pace of the faster repetition to the pace of the active roll-on recovery interval.

Running Economy

Running economy is a measure of how efficiently, or economically, a person uses oxygen while running at a given velocity that is below vVO2max. It is expressed as the rate of oxygen consumption per distance covered in ml/kg/km. A runner who consumes less oxygen than another at a given velocity has a better running economy.


The tlimvVO2max is the length of time you can exercise at vVO2max.


The oxygen uptake by the tissues of the body increases with physical exercise to a maximum value. This value is known as the maximal oxygen uptake, or VO2max. The maximal oxygen uptake is defined as: “the highest oxygen uptake an individual can attain during physical work and breathing air at sea level”. The maximal oxygen uptake is a measure of the aerobic capacity of an individual and has traditionally been used as one of the critical indicators of endurance performance. On its own, however, VO2max is a relatively poor predictor of performance.


The term vVO2max stands for the running velocity at VO2max and is simply the minimal running velocity which produces the VO2max i.e. causes your muscular system to utilise oxygen at its highest possible rate. It is a useful variable that combines VO2max and running economy into a single factor that can identify performance differences between runners who may possess similar VO2max values. The vVO2max explains individual differences in performance that VO2max or running economy alone do not. Using the velocity (vVO2max) and duration (tlimvVO2max) that an athlete can operate at their VO2max will provide a better indication of future performance than other measures. More importantly, it can guide in the structuring of sessions specifically to target the development of vVO2max.