Neuromuscular control of lumbar instability following static work of various loads

Abstract

Neuromuscular control of lumbar stability following exposure to prolonged static work, under low and high loads, was assessed in the in vivo feline model. Six sessions of 10 min work at 20N with 10 min between rest was compared to a group subjected to the same protocol but carrying high loads of 60N. Displacement and tension developed in the spine at the instant the multifidus muscles applied stabilizing contractions, and their amplitudes were obtained from their electromyogram (EMG). Significant (P < 0.001) laxity developed in the various viscoelastic tissues of the lumbar spine that did not recover during and up to 7 h of rest postwork. Simultaneously, there was a significant (P < 0.001) decrease in muscular activity in the 3-4 h immediately postwork under low load but only during the first hour in the high load group. After that period the musculature compensated for the laxity of the viscoelastic tissues by a significant (P < 0.001) increase in activity in the high-load group and a nonsignificant increase in the low group. It was concluded that during 1-3 h immediately poststatic work a significant decrease in the stabilizing function of viscoelastic tissues together with a significant decrease in muscular activity is present, and they render the spine unstable and exposed to high risk of injury. Performance of prolonged static work under low loads, while not harmful during the work, cannot be designated as a "no-risk" condition, as it may result in injury postwork.

The basis for spinal manipulation: Chiropractic perspective of indications and theory

“…Receptors in joint ligaments, capsules, and fascia contribute influential input to critical neural circuitry that control spine stabilizing muscles (Benjamin, 2009;Holm et al, 2002;Kang et al, 2002;Le et al, 2009;Stubbs et al, 1998;Yahia et al, 1992). A team of electrophysiologists have examined these substantial sensory innervations in the spinal and paraspinal tissues (Minaki et al, 1996;Sakamoto et al, 2001;Yamashita, 1990;Yamashita et al, 1993).…”

Acute repetitive lumbar syndrome: A multi-component insight into the disorder

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Load and speed effects on the cervical flexion relaxation phenomenon

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