Microtrauma is any of many possible small
injuries
An injury is any physiological damage to living tissue caused by immediate physical stress. An injury can occur intentionally or unintentionally and may be caused by blunt trauma, penetrating trauma, burning, toxic exposure, asphyxiation, or ...
to the body.
Microtrauma can include the microtearing of muscle fibres, the sheath around the
muscle
Skeletal muscles (commonly referred to as muscles) are Organ (biology), organs of the vertebrate muscular system and typically are attached by tendons to bones of a skeleton. The muscle cells of skeletal muscles are much longer than in the other ...
and the
connective tissue
Connective tissue is one of the four primary types of animal tissue, along with epithelial tissue, muscle tissue, and nervous tissue. It develops from the mesenchyme derived from the mesoderm the middle embryonic germ layer. Connective tissue ...
. It can also include stress to the
tendon
A tendon or sinew is a tough, high-tensile-strength band of dense fibrous connective tissue that connects muscle to bone. It is able to transmit the mechanical forces of muscle contraction to the skeletal system without sacrificing its ability ...
s, and to the
bone
A bone is a rigid organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red and white blood cells, store minerals, provide structure and support for the body, an ...
s (see
Wolff's law
Wolff's law, developed by the German anatomist and surgeon Julius Wolff (1836–1902) in the 19th century, states that bone in a healthy animal will adapt to the loads under which it is placed. If loading on a particular bone increases, the bon ...
). It is unknown whether or not the
ligaments adapt like this. Microtrauma to the skin (compression, impact, abrasion) can also cause increases in a skin's thickness, as seen from the
callus
A callus is an area of thickened and sometimes hardened skin that forms as a response to repeated friction, pressure, or other irritation. Since repeated contact is required, calluses are most often found on the feet and hands, but they may o ...
es formed from running barefoot or the hand calluses that result from rock climbing. This might be due to increased skin cell replication at sites under stress where cells rapidly slough off or undergo compression or abrasion.
Most microtrauma cause a low level of
inflammation
Inflammation (from la, wikt:en:inflammatio#Latin, inflammatio) is part of the complex biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or Irritation, irritants, and is a protective response involving im ...
that cannot be seen or felt. These injuries can arise in muscle, ligament, vertebrae, and discs, either singly or in combination. Repetitive microtrauma which are not allowed time to heal can result in the development of more serious conditions.
Negative effects
Back pain
Back pain is pain
Pain is a distressing feeling often caused by intense or damaging stimuli. The International Association for the Study of Pain defines pain as "an unpleasant sensory and emotional experience associated with, or resembling ...
can develop gradually as a result of microtrauma brought about by repetitive activity over time. Because of the slow and progressive onset of this internal injury, the condition is often ignored until the
symptoms
Signs and symptoms are the observed or detectable signs, and experienced symptoms of an illness, injury, or condition. A sign for example may be a higher or lower temperature than normal, raised or lowered blood pressure or an abnormality showi ...
become
acute, often resulting in disabling
injury
An injury is any physiological damage to living tissue caused by immediate physical stress. An injury can occur intentionally or unintentionally and may be caused by blunt trauma, penetrating trauma, burning, toxic exposure, asphyxiation, or ...
. Acute back injuries can arise from stressful lifting techniques done without adequate recovery, especially when experimenting with more ballistic work, or work where the
extensor spinae
The erector spinae ( ) or spinal erectors is a set of muscles that straighten and rotate the back. The spinal erectors work together with the glutes (gluteus maximus, gluteus medius and gluteus minimus) to maintain stable posture standing or s ...
are stressed during spinal flexion when much of the load is commonly taken up by the slower to heal ligaments which may not adapt progressively to the stress. While the acute injury may seem to be caused by a single well-defined incident, it may have been preventable or lessened if not for the years of injury to the musculoskeletal support mechanism by repetitive microtrauma.
Positive effects
After microtrauma from stress (such as lifting weights) to muscles, they can be rebuilt and overcompensate to reduce the likeliness of re-injury.
References
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Injuries
Musculoskeletal disorders