Lifting Definitions 1

The 3 Muscle Fibre Types

White Muscle Fibres are Type 2b muscle fibres. They are fast-twitch fibres generally recruited when powerful bursts of force are required. These muscles can double in size, the most increase in size of any other muscle fibre. Type 2a muscle fibres (Pink) are the 'teachable' fibres - they take on the characteristics of either White fibres or Red fibres, depending on the training stimulation most practiced. These muscles can increase in size by 30%. Type 1 fibres are known as Red - the endurance muscles - and are used for long endurance exercise as they do not exhaust quickly due to their high blood capillary density. Although they can increase blood capillary density, they cannot increase in size.


In Order to increase muscle size and shape we must focus our training on Type 2a and Type 2b muscle fibres (Pink and White), with a priority on White fibres for maximum growth.

Sets and Reps

'Set' refers to the group of repetitions you perform on a single exercise. 'Rep' is the abbreviation of 'Repetition' and refers to one full range movement associated with an exercise. For example; 4 sets of 12 repetitions means that the exercise was approached 4 times and the movement performed 12 times each - for a total of 48 Repetitions.


When constructing a program we use these increments of measurement to describe and determine the amount of work we wish to perform during a workout.


'Intensity' refers to the 'challenge factor' of your Training Approach on both your muscles and nervous system. Some exercises are more challenging than others by nature but there are many things you can manipulate to increase or decrease Intensity. Here are some examples; Rest Periods, Forced Reps, Weight, Tempo, Range, Repetitions, Time under Tension, Set Variations, Machine vs Free Weight, Volume, Frequency, Lactic Acid Build Up etc. To continue to change our bodies, there must always be an increase in Intensity from week to week, in order to induce the change.


Intensity is a vitally important factor when inducing change in our bodies. Increasing Intensity means constantly challenging our muscles and nervous system from week to week. Training without Intensity will fail to change your body long term.

Concentric, Eccentric + Isometric

These words represent the different portions of a Rep. 'Concentric' is the 'raising' of the weight/ resistance - also described as the 'Positive' portion of the Rep. 'Eccentric' is the 'lowering' of the weight/ resistance - also described as the 'Negative' portion of the Rep. 'Isometric' is the stationary 'holding' of the weight in one position - also described as the 'Static' portion of the Rep (usually at the bottom or top of the Rep, although there can be Isometric holds at various points of the Rep). All three elements of a Repetition can be changed/ manipulated in order to induce more muscular adaptions.


All three elements of a Rep are important to an exercise and can be altered in different ways to induce muscular adaptions. Understanding these three terms will allow you to get the most from your training program.

Muscular Failure

All three elements of a Rep; Positive, Negative and Static - must be fully exhausted to reach Full Muscular Failure. The first to fail is the Positive portion (no more raising of the resistance can occur unassisted), then the Static (becomes too hard to hold resistance steadily in one place), then the Negative (resistance cannot be lowered in a slow controlled manner). It is paramount that failure happens in this order (although Static holds may not be actively being performed), if not then it is a sign that the exercise is being performed incorrectly, e.g. different muscles performing different portions of the Rep.


All three portions of a Rep must fail to achieve true Muscular Failure. Different failure order can help you identify poor form in one or more of the portions.

Forced Reps/ Negatives

'Forced Negative Reps' are performed when Positive Failure has been reached and a Training Partner or Coach enables you to continue performing the Set by assisting you with the Positive portion of the Rep. Forced Reps are then continued until Negative Failure has been reached. These types of Reps can only be performed with the assistance of someone else, as when training alone the Set stops when Positive Failure is reached, as the weight/ resistance can no longer be raised up. Exercises like Bicep curls, Upright rows and Lateral Raises can allow for self directed Forced Reps with a slight hip pivot or knee bend + extension motion to assist with the Positive portion of the Rep, but must be performed with great care and responsibility.


Positive Failure must be reached before Forced Reps can be performed. Forced Reps are needed to achieve Negative Failure and for most exercises can only be performed with the assistance of a training partner or coach.

Rest Periods

'Rest Period' is the length of time waited in-between each Set. Its length is manipulated according to particular training approaches and which specific body part is being worked. Generally, 'Straight Sets' are performed mostly with 30-45 seconds rest in-between each set for Upper Body, and 60-90 seconds for lower body. See here for definitions of 'set variations'.


Rest Periods are integral to an effective workout program. They are as much a part of the workout as the set itself, due to manipulation of the Rest Period either increasing or decreasing Intensity.


'Volume' refers to the amount of total Repetitions, Sets and Weight moved in a training program. Getting the amount of Volume correct is vital for steady continued growth and improvement. Generally, 4 sets of 8-12 Reps will be performed per exercise in a bodybuilding program. 4-6 Exercises will be performed per workout, resulting in a total amount of 16-24 Sets and 128-288 Reps. Volume by Weight Formula: Amount of Reps x Weight x Amount of Sets e.g. 12 reps of 50kg means = 600kg, x 4 sets means a total of 2400kg in Volume for that exercise. This is important because a higher or lower amount of reps on a higher or lower weight may actually equal the same Volume, e.g. 20 Reps of 30kg = 600kg OR 8 Reps of 75kg = 600kg. The Volume appropriate for continued muscular adaption can and should change throughout an effective program.


Volume is a form of measurement to determine the amount of work performed in a workout. As one of the ways of improving Intensity, increasing Volume slowly over time can be a factor for continued growth. This can be done by either increasing the Repetitions and Sets, Frequency of Training or increasing the Weight.


Workout 'Density' is the Volume performed in a given time frame, and can illustrate how Intense a workout can be. If you performed a total of 4 Sets of 12 Reps on 200kg on the Leg Press in 10mins, with a Volume of 9,600kg (see 'Volume' above for formula) your workout Density would be 16kg per/sec. If the following week you did the same Volume but it only took you 8 minutes, your Density would be 20kg per/sec - a higher Density of work and thus a more Intense workout. What this essentially means is that you either reduced your rest periods OR increased the weight, thus needing less reps and sets to complete the same volume. Increasing tempo (faster reps) might also account for a quicker time as it would almost certainly result in shorter sets, however there would be less 'TUT' (time under tension). In general, higher Density workouts are more Intense than longer extended sessions.


Density is yet another unit of measurement you can apply to training Intensity. The higher the Density the shorter the Rest Periods/ higher the weight and/ or faster the Rep 'Tempo' (see below for definition of 'Tempo').


'Frequency' refers to how often you workout a body part. It is important to acknowledge this as part of determining the effectiveness of your program. How often you train plays a role in how much you progress. This does not mean training more will give you more progress, it may mean the exact opposite. There is no universal Frequency that fits everyone, it must be discovered and determined by your Individual Recovery speed of different body parts, e.g. Your Chest may recover quickly while legs take longer. It may mean Training body parts with different Frequencies, i.e. Legs once per week, Chest twice every 8-9 Days. Make notes about your Recovery to determine your correct Frequency (it may change over time).


Frequency of training is very relevant and is Individually determined by Recovery speed of each Body Part. Frequency can either be increased or decreased to enhance/ speed up growth.

Time Under Tension (TUT)

'Time Under Tension' is a phrase that has become synonymous with Bodybuilding. As opposed to any form of Strength Training, Bodybuilding is focused purely on training muscles for growth, not performance. To do that the muscle must be under Tension for a given time period. What this means is that the target muscles (e.g. Biceps during Bicep Curls) continually contract without relaxing; during the Rep there are no points where Tension is significantly lost. Losing Tension may enable that muscle to Rest momentarily (much like in strength and power movements) and therefore reduce Intensity. The Time Under Tension refers specifically to how long the Set of constant muscular tension lasts. In a typical set of 8-12 Reps with a Tempo of 4 seconds per Rep the 'TUT' would be between 32-48 seconds.


TUT is vital for Bodybuilding training. By nature there should be no resting points throughout the Set. TUT is a protocol synonymous with Bodybuilding because long periods of Tension are beneficial for muscle growth.


'Tempo' with regards to Bodybuilding/ Weight Lifting refers to the length of time of each of the Positive, Static and Negative portions of one Repetition. Most of the time there are no Static portions of a Rep, meaning that the weight/ resistance and joints involved in the exercise will be in constant motion (no holding still at the top or bottom). However, sometimes a Static hold or 'squeeze' may be employed at the bottom or top of the movement to increase Intensity. Tempo times can be displayed in a sequence of 4 numbers, the first being the first portion of the rep (raising or lowering depending on start point), then the static at the bottom or Top of the movement, then the third portion (raising or lowering), then the static at the other end. A Rep with no static holds with a total of 4 seconds per Rep might be displayed like this; 2-0-2-0. A Rep with a 1 second hold after the first portion of the Rep; 2-1-2-0. And a Rep with a slow first portion and a fast third portion may look like this; 4-0-1-0. Rep Tempo is a powerful variable when manipulating the Intensity of a movement and should not be ignored.


Tempo describes the speed of various portions of the Repetition. Manipulating Tempo can increase or decrease Intensity of an exercise. Tempo is displayed in a sequence of 4 numbers.

Lactic Acid

During prolonged strenuous exercises more Energy is needed than is produced (energy deficit), so the molecule 'Pyruvate' that is normally converted to Glucose by Oxygen is temporarily converted to Lactate (+ Hydrogen Ions = Lactic Acid). The Energy deficit is due to the muscular demand of Oxygen not being met, resulting in a Lactic Acid build up which causes an ever increasing burning sensation in the working muscle. Producing Lactate in your muscles during strenuous exercise is a pre-requisite for higher Growth Hormone release in the body. Hence the reason Lactic Acid training is common amongst Bodybuilders looking to grow larger and burn more Fat (Growth Hormone mobilises Body Fat to be used as energy). Generally speaking, although not always true - Lactic Acid build up normally only happens if the TUT (Time Under Tension) is quite long.


Lactate and Hydrogen Ions form in the muscle to create Lactic Acid when Oxygen Levels are not high enough to cope with the increased Energy demand of working muscles. Lactic Acid build up is vital for higher HGH (Human Growth Hormone) release, enhancing muscle growth and Fat Burn.

Click here for definitions of different Set Variations!

Happy Lifting!

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