DOMS commonly peaks between 24 and 48 hours (in some reports
up to 72 hours) after exercise and is characterised by muscle
shortening, increased passive stiffness, swelling, decreases in
strength and power, localised soreness and altered proprioception
(Cleak 1992; Proske 2001). DOMS is more likely to occur with
unaccustomed exercise or intense exercise involving eccentricmuscle
activity (i.e. when the muscle is forcibly stretched when active)
(Cheung 2003). Although the physiological mechanism underpinning
DOMS has not been fully elucidated, it may relate
to primary mechanical damage that occurs to muscle cells during
exercise. Microscopic disruption of the small muscle fibre units
(known as sarcomeres) (Proske 2001) is also related to a number of
inflammatory events, and the release of intracellular enzymes such
as creatine kinase (CK) (Chatzinikolaou 2010). This response is
thought to contribute to the characteristic pain, swelling and decreased
muscle function associated with DOMS.