Pec bounce is by far the most popular muscle control performance and not without reason, as they are the easiest ones one can develop impressive control over.

Physiologically, pec bounce is  probably the repetitive attempt of the pectoralis major to extend the humerus back to the anatomical position. Exactly because the humerus already is in anatomical position (provided relaxed, hanging arms), the pectoralis major is moving itself, causing the bounce effect. However, there are very few performances of pec bounces with extended arms which may mean that the pec bounce is a repetitive attempt of humerus adduction.

Pec bounce can be performed in four variations:

• mono (only one of the pecs bounce),

• double (both the pecs bounce simultaneously),

• linear (the pecs bounce one after the other) and

• synchronized with music / song (pec dance) which, depending on the musical beat, often requires excellent pec control.

After mastering the pectoral control skill, the perfomer can easily bounce his pecs at all aforementioned variations, switching between them abruptly and with ease, perform at all speeds and all that without flinching the rest of his body.

Since pec bounce is the most common muscle control, we may break it down to levels as the activated pec major sections and speed varies from performer to performer. 

The first pec bounce performances go as far back as the 1890s (see American Hunks: The Muscular Male Body in Popular Culture, 1860-1970) but it wasn't popular until the 1960s, the golden age of bodybuilding. 

During that period, muscle control was routinely performed both off and on stage by bodybuilders, most of them being able to control multiple muscle groups. Gradually, its popularity decreased, with the bodybuilding community focusing solely on symmetry, size and definition and neglecting the mind-muscle neurological connection despite the fact that a bodybuilder with muscle control on most of his muscle groups can pose better and train more efficiently.

Those who are new to developing muscle control over their pectorals tend to use a slight downward movement of their hands to perform the pec bounce. They also have limitations to the various forms of pec bounce. They can either bounce one of their pecs (mono pec bounce) or both their pecs at the same time (double pec bounce) but they usually can NOT bounce one of their pecs and then immediately the other (linear pec bounce).

As the performer gains control over his pectorals, he ends up to feel them just the way he feels and therefore controls other obvious muscle groups.

Despite what one would expect, most performances of pec bounce mastery come from either teen or non-pro bodybuilders with slightly above-average or even just average muscle mass.