Motor control of lumbar instability following exposure to various cyclic load magnitudes

Abstract

The motor control system may compensate for lumbar instability following cyclic work with differential response to load magnitude. In vivo felines were exposed to a cumulative 1 h of cyclic work at 0.25 Hz. One group exposed to light whereas the second to heavy load while recording lumbar displacement and multifidus EMG during work and in single test cycles over 7 h rest post-work. Significant laxity and reduced reflexive EMG activity were evident immediately post-work in both groups. EMG and laxity recovered over 7 h rest in the group exposed to light load whereas in the group exposed to heavy load, motor control compensation was triggered within 1-2 h postwork. The compensation was expressed by earlier and stronger muscular activation than in baseline. It is concluded that cyclic work is deleterious to spine stability immediately after work. Work with heavy loads elicits delayed motor control compensation whereas work with light loads leaves the spine unstable and exposed to injury for several hours. Overall, prolonged cyclic or repetitive work elicits a transient instability disorder, regardless of the load handled, exposing the individual to potential injury.

Neuromuscular manifestations of viscoelastic tissue degradation following high and low risk repetitive lumbar flexion

“…The preparation, instrumentation, protocols and data analysis presented below are for the convenience of the reader and a detailed account for each component is given in Hoops et al, 2007;Le et al, 2007;Lu et al, 2004Lu et al, , 2008Navar et al, 2006;Eversull et al, 2001;Solomonow et al, 2001Solomonow et al, , 2008Ben-Masaud et al, 2009;King et al, 2009;D'Ambrosia et al, 2010;Pinski et al, 2010.…”

“…The motor control component of stability was assessed by the Neuromuscular Neutral Zones (NNZ) which was first defined in earlier reports Solomonow et al, 2001Solomonow et al, , 2008Ben-Masaud et al, 2009). Each cycle was analyzed in a 5 s window including 0.5 s before and 0.5 s after the 4-s cycle (0.25 Hz).…”

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

“…The objective of this paper is to provide a systematic integration of the various components active in the hypothesis (creep, neuromuscular control, stability, inflammation/ tissue biology) obtained from a long series of experimental research projects in animal models (Williams et al, 2000;Eversull et al, 2001;Solomonow et al, 2003bSolomonow et al, , 2008Solomonow et al, , 2011Claude et al, 2003;Hoops et al, 2007;Le et al, 2007;Lu et al, 2004Lu et al, , 2008Navar et al, 2006;Youssef et al, 2008;Le et al, 2009;Ben-Masaud et al, 2009;King et al, 2009;D'Ambrosia et al, 2010;Pinski et al, 2010) and healthy humans (Solomonow et al, 2003a;Olson et al, 2004Olson et al, , 2006Olson et al, , 2009Li et al, 2007) in order to provide a comprehensive model of the multi-factorial etiology of RLI, offer validating support for the acute phase of the hypothesis and allow the potential developments of science based methods for its treatment and prevention.…”

Relationship between Handling Heavy Items during Pregnancy and Spontaneous Abortion

“…Most working women in South Korea are employed in service, sales, and elementary (i.e., involving sim-ple, routine tasks mainly requiring the use of handheld tools and, in some cases, considerable physical effort) occupations (Korea Ministry of Labor, 2009). Women in these particular job sectors are often required to lift and move heavy items and thus are susceptible to back pain and musculoskeletal disorders (Ben-Masaud et al, 2009;Holtermann, Blangsted, Christensen, Hansen, & Søgaard, 2009). Handling heavy items poses potentially serious health risks for women of childbearing age because doing so may damage or weaken the pelvic floor muscles (Miedel, Tegerstedt, Maehle-Schmidt, Nyrén, & Hammarström, 2009;Senturia, 1997).…”