Speaking from experience, I can tell you that well prepared bodybuilders do not experience pain when posing in competition. Rather, when done, they typically feel fatigue. And, that's because holding various poses during a competition is a from of isometric contraction. Successful bodybuilders typically practice posing for hours leading up to a competition. Posing helps to add the finishing touches onto a physique.
A typical competition consists of two parts. The “pre-judging” where all competitors of a specific “class” are required to perform and hold various poses while the judges score them on various factors. This allows the judges to make comparisons among each competitor. Each pose is typically held for many seconds. Competitors try to impress the judges by showing their prowess and confidence in each pose (hence, the varied expressions of each competitor). Judges often ask competitors to repeat and hold poses which may very well result in “shaking”.
The second part of the competition is the individual posing. This occurs after a “break” in the “pre-judging”. Once again, competitors are asked to hold poses, but, this time it's individually choreographed to music. And, the competitor decides how long to hold the pose to impress the judges.
Depending upon the competition level, the whole event can last an entire day. Needless to say, after isometrically contracting each major muscle in the body multiple times, it's easy to feel drained, depleted, and fatigued.
