The lexicon of muscle-building, and training - Part 27

Exercise intensifiers are methods of intensifying a set beyond the point at which a trainee has completed the maximum number of reps under his or her own efforts, with a constant weight. The intensifiers include drop sets, forced reps, and negative-only reps. They have no place in a beginner's program. Other trainees may find intensifiers helpful, but only if they are used sparingly. They are commonly misused, with negative consequences.


In this book, intensity is the relative degree of effort put into training. High-intensity exercise is hard training, whereas low-intensity exercise involves a much reduced effort level. Sufficient intensity of effort is required to stimulate muscular growth, although the precise degree of effort required is unknown.

Many coaches and organizations, however, define intensity in terms of a given percentage of one's single-rep maximum (1RM) for a specific exercise. For example, six reps at 75% of 1RM involves a higher intensity level than six reps at 65% of one's 1RM. Although this interpretation of intensity can be applied to all trainees, it requires knowledge of individual 1RMs. Testing for a 1RM in any given exercise is fraught with a high chance of injury, and should be avoided by all beginners. It's not even necessary for non-beginners to test for 1RMs, unless they are competitive lifters. It's possible, however, using conversion tables, to calculate 1RMs based on multiple-rep achievements. This is a much safer way to discover 1RMs.

Intervertebral disk

A cartilaginous disk that lies between vertebrae.


The part of the digestive tract that extends from the stomach to the anus, consisting of the small and large intestines.

Involuntary muscle

Muscle that's not subject to voluntary control, such as in the digestive tract.

Iron Game

Umbrella term to include all forms of activities that focus on strength training, weight training, or weight lifting in some form. The principle activities are bodybuilding, Olympic weightlifting, and powerlifting.

Isokinetic exercise

Isokinetic exercise is an attempt at providing accommodating resistance, that is, resistance that, in theory, changes over the course of an individual rep of an exercise in line with the strength curve of the exercise — more resistance is provided where the muscle is strongest. In isokinetic exercise the accommodating resistance aims to keep the speed of movement constant for a given machine. The bar will move only at a certain speed regardless of how hard it's pushed or pulled.

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