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Program Design
Program Design

Intensity

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intensityresistanceloadpercentage-1rmlight-medium-heavy

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DefinitionA short reference note, not a full lesson.
Definition

The amount of weight (resistance) lifted — also shaped by speed, reps, sets, rest interval, and workout duration.

Detail

Intensity is determined by the amount of weight (resistance) used (Fleck & Kraemer, 1997). It is also affected by exercise speed, the number of reps and sets, the rest interval, and the duration of the workout.

Intensity of training is determined primarily by the amount of resistance (load), and is additionally affected by the number of sets and reps, the rest interval, exercise speed, and the duration of the workout.

In strength-training circles (training athletes), intensity can be differentiated by labeling loads as light, medium, or heavy. The following guidelines, based on 1 RM, are used:

  • Heavy: 90 – 100% effort
  • Medium: 80 – 89% effort
  • Light: 70 – 79% effort

For example, if a trainee has a personal best (1 RM) of 400 lb and the workout demands an exercise intensity level of 80% for a predetermined number of repetitions, the trainee uses 320 lb (80% of 400 lb = 320 lb). Note that athletes do not always train to failure. Increasing intensity by increasing the velocity of movement is important when a major goal is to increase the power output of the muscle, not just the ability to lift maximal loads.

The development of a particular feature of muscular performance (e.g. absolute strength) is directly related to the load used; this program variable must be addressed when prescribing exercises.

Key facts

  • Intensity = the amount of weight (resistance).
  • Affected by: exercise speed, number of reps and sets, rest interval, workout duration.
  • Load labels (based on 1 RM): Heavy 90-100%, Medium 80-89%, Light 70-79%.
  • Worked example: 80% of a 400 lb 1 RM = 320 lb.
  • Increasing movement velocity increases intensity for power development.

Connections

Go deeperPrinciple of Progressive Overload

Sources

Historical reference · reference manual (page cited)
p.160p.368p.420p.448
Cited authorities in source: Fleck & Kraemer (1997).

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Atlas Connections

Principle of Progressive Overload
To keep improving, gradually make training harder than your body is used to: more weight, more reps or more sets. You don't need to add weight every week or go to failure. Small, steady increases you can recover from are what work.
Repetition Maximum (RM)
The maximum weight that can be lifted for a specific number of reps to exhaustion — e.g. a 6 RM is the load you can lift for exactly six reps.
Repetition Maximum ContinuumClosely related
Low reps with heavy loads build the most maximal strength, but muscle grows across a broad rep range (about 2–4 to 20–30+ reps) when sets are taken close to failure; the classic strength/size/endurance continuum is a rough guide only.
Volume
How many — not how heavy. Volume is the total amount of exercises, sets, and reps performed, and moves inversely to intensity.
Periodization (Cycle Training)
Planned variation of training volume and intensity across distinct phases to drive optimal long-term gains in strength and power.