Soreness vs. Injury (Sharp Pain Distinction)

Participants in resistance training commonly experience discomfort, soreness, stiffness, or pain (Alter, 1996). These fall into two general categories: those that occur during and immediately after exercise (which may persist for several hours), and those that usually do not appear until 24 to 48 hours later (delayed-onset muscle soreness, DOMS). Three basic hypotheses attempt to explain muscular soreness: the torn tissue / connective tissue damage hypothesis; the metabolic accumulation hypothesis; and the localized spasm of motor units hypothesis. Some degree of soreness is often experienced by those who have not previously exercised — "the penalty for having been inactive."

By contrast, injury is signaled differently. Among the precautions for stretching, one should not stretch if there is a sharp, acute pain with joint movement or muscle elongation. This sharp/acute pain is the key cue that distinguishes a potential injury from ordinary soreness. The eccentric (lengthening-under-load) phase is the primary instigator of DOMS, and forced repetitions and breakdown training can easily cause muscular soreness — but these are expected soreness, not the same as acute injury pain.

• Soreness/stiffness occurs immediately (lasting hours) or is delayed 24–48 h (DOMS).
• 3 soreness hypotheses: torn/connective tissue damage; metabolic accumulation; localized motor-unit spasm.
• Some soreness in the previously inactive is "the penalty for having been inactive."
• A sharp, acute pain with joint movement or muscle elongation indicates a problem — do not stretch/push through it.

• muscle-soreness — acute vs. delayed soreness.
• doms-three-hypotheses — the three soreness hypotheses.
• stretching-precautions — sharp acute pain as a do-not-stretch condition.
• warm-up-injury-reduction — warming up to reduce soreness/injury.
• static-stretching — the safest stretching method.