Microtrauma

Abstract: Trigger points are discrete, focal, hyperirritable spots located in a taut band of skeletal muscle. They produce pain locally and in a referred pattern and often accompany chronic musculoskeletal disorders. Acute trauma or repetitive microtrauma may lead to the development of stress on muscle fibers and the formation of trigger points. Patients may have regional, persistent pain resulting in a decreased range of motion in the affected muscles. These include muscles used to maintain body posture, such as those in the neck, shoulders, and pelvic girdle. Trigger points may also manifest as tension headache, tinnitus, temporomandibular joint pain, decreased range of motion in the legs, and low back pain. Palpation of a hypersensitive bundle or nodule of muscle fiber of harder than normal consistency is the physical finding typically associated with a trigger point. Palpation of the trigger point will elicit pain directly over the affected area and/or cause radiation of pain toward a zone of reference and a local twitch response. Various modalities, such as the Spray and Stretch technique, ultrasonography, manipulative therapy and injection, are used to inactivate trigger points. Trigger-point injection has been shown to be one of the most effective treatment modalities to inactivate trigger points and provide prompt relief of symptoms.

Abstract: Clinical reports and research studies have documented the behavior of chronic low back and neck pain patients. A few hypotheses have attempted to explain these varied clinical and research findings. A new hypothesis, based upon the concept that subfailure injuries of ligaments (spinal ligaments, disc annulus and facet capsules) may cause chronic back pain due to muscle control dysfunction, is presented. The hypothesis has the following sequential steps. Single trauma or cumulative microtrauma causes subfailure injuries of the ligaments and embedded mechanoreceptors. The injured mechanoreceptors generate corrupted transducer signals, which lead to corrupted muscle response pattern produced by the neuromuscular control unit. Muscle coordination and individual muscle force characteristics, i.e. onset, magnitude, and shut-off, are disrupted. This results in abnormal stresses and strains in the ligaments, mechanoreceptors and muscles, and excessive loading of the facet joints. Due to inherently poor healing of spinal ligaments, accelerated degeneration of disc and facet joints may occur. The abnormal conditions may persist, and, over time, may lead to chronic back pain via inflammation of neural tissues. The hypothesis explains many of the clinical observations and research findings about the back pain patients. The hypothesis may help in a better understanding of chronic low back and neck pain patients, and in improved clinical management.

Abstract: Low back pain is estimated to occur in 10% to 15% of young athletes,2 but the prevalence may be higher in certain sports.2,4,8,10,18,24 Studies show that back pain occurs frequently in college football players (27%), artistic gymnasts (50%), and rhythmic gymnasts (86%).8,10,18 Patterns of back pain in young athletes are significantly different from those in adults.11,16,23,25 Pars interarticularis injuries are more common, occurring in up to 47% of young athletes.16 Disc-related problems are relatively uncommon in children; only 11% of children have disc-related pathology compared with 48% of adults.16 Idiopathic pain is also less common in young athletes. Physicians who attribute low back pain in young athletes to simple back strains, without investigations, run the risk of delaying the diagnosis and appropriate treatment of more serious injuries, such as spondylolysis or spondylolisthesis.11,25 Injuries to the low back occur from either an acute traumatic event or from repetitive microtrauma (overuse injury), with overuse injuries being more common. Contact sports such as football or rugby tend to produce acute injuries from high-energy impacts, whereas sports involving repetitive flexion, extension, and torsion, such as gymnastics, figure skating, and dance, result in overuse injuries (Figure 1). It is very important to consider other more sinister causes of back pain, such as infection, tumors, or inflammatory conditions. Figure 1. A figure skater hyperextending her spine duringa spin.

Abstract: In sports medicine, a chronic overuse injury is defined as a long-standing or recurring orthopedic problem and pain in the musculoskeletal system, which started during exertion due to repetitive tissue microtrauma (1). Repetitive microtrauma, which is basically repeated exposure of the musculoskeletal tissue to low-magnitude forces, results in injury at the microscopic level, and no single acute trauma is normally involved in the pathogenesis of an overuse injury. In chronic tendon disorders, 'overuse' implies that the tendon has been strained repeatedly to 4-8% strain until unable to endure further tension, whereupon injury occurs (2). The structure of the tendon is disrupted micro- or macroscopically by this repetitive strain, i.e. collagen fibrers begin to slide past one another, causing break-age of their cross-linked structure, and denaturate; inflammation, edema and pain result. Thus, tendinitis, peritendinitis, tenosynovitis, insertion tendinitis, tendinous bursitis or apophysitis is the earliest clinically recognizable manifestation of overuse tendon injury (3).