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Journal ArticleDOI

Postural sway and integration of proprioceptive signals in subjects with LBP

01 Feb 2015-Human Movement Science (Hum Mov Sci)-Vol. 39, Iss: 39, pp 109-120
TL;DR: A model for control of postural sway is proposed that suggests that subjects with LBP use more co-contraction and less cognitive control, to maintain a standing balance when compared to subjects without LBP.
About: This article is published in Human Movement Science.The article was published on 2015-02-01 and is currently open access. It has received 38 citations till now. The article focuses on the topics: Balance (ability).

Summary (4 min read)

Introduction

  • A partir da década de 1980, o mundo vem enfrentando rápidas e significativas mudanças de ordem econômica, social, tecnológica e ambiental.
  • Assim, o conhecimento e a informação são considerados produtos econômicos mais valiosos que o aço, automóveis, equipamentos ou qualquer outro produto da Era Industrial.
  • E nestas ações, o conhecimento se faz presente como o maior recurso gerador de vantagem competitiva.
  • A quinta seção aborda a análise dos dados, seguida das considerações finais e referências.

2 DADO, INFORMAÇÃO E CONHECIMENTO

  • Para abordar o processo de criação de conhecimento, é oportuno, primeiramente, fazer uma distinção entre o significado de dado, informação e conhecimento, pois de acordo com alguns autores, dentre os quais Davenport e Prusak (2003) e Santos (2005), há certa tendência de se utilizar os termos dados, informação e conhecimento como sinônimos.
  • Os dados descrevem apenas uma parcela dos acontecimentos; não fornecem julgamento, interpretação e nem base para a tomada de decisão sustentável.
  • Informações são dados constituídos de significados, pois são tratados e analisados, o que implica dizer que exige mediação humana.
  • Já o conhecimento explícito pode ser formalizado, sistematizado e facilmente comunicável.
  • Assim, quando o conhecimento tácito não é transformado em conhecimento explícito e disseminado na organização, este fica restrito a um membro ou pequeno grupo de pessoas, “o que, em determinado momento, pode fazer com que a organização despenda esforços para saber algo, ou recuperar um conhecimento que já sabe” (FRANCISCO, 2003, p.20).

2.1 Gestão do conhecimento: conceitos e objetivos

  • O processo de criação do conhecimento é um processo explorado pela Gestão do Conhecimento.
  • Neste sentido, antes de abordar a teoria de criação do conhecimento organizacional de Nonaka e Takeuchi faz-se necessário apresentar um recorte conceitual da referida temática.
  • Sobre isto, Martensson (2000) afirma que a literatura sobre Gestão do Conhecimento está dirigida principalmente à questão do capital intelectual, da inovação e da geração de competências, que, em suma, voltam-se à ideia de conhecimento como geração de valor.
  • De acordo com Davenport e Prusak (2003, p.61), a gestão do conhecimento é “o conjunto de atividades relacionadas à geração, codificação e transferência do conhecimento”, baseia-se em aperfeiçoar os recursos disponíveis na organização de forma orientada para o conhecimento.
  • Bukowitz e Williams (2002) apontam as tecnologias de informação e comunicação, como uma das principais forças que levaram a gestão do conhecimento para o primeiro plano e para o centro das organizações.

2.2 A teoria de criação de conhecimento de Nonaka e Takeuchi - a espiral do conhecimento

  • Para compor a base da teoria da criação do conhecimento organizacional, Nonaka e Takeuchi (1997) resgatam a tipologia de conhecimento de Polanyi (1966).
  • Para estes autores, o conhecimento é criado através da interação entre o conhecimento tácito e o conhecimento explícito, por meio de 4 modos de conversão do conhecimento, a saber: socialização, externalização, combinação e internalização.
  • Através da documentação serão relatadas as experiências dos indivíduos para que sejam incorporadas à sua base de conhecimento.
  • Assim, entende-se que a criação do conhecimento é um processo em espiral, que começa com a socialização.
  • Para proporcionar a criação do conhecimento organizacional, o conhecimento tácito acumulado precisa ser socializado com os outros membros da organização, aumentando assim o campo do conhecimento e iniciando uma nova espiral de criação do conhecimento.

2.3 Condições e fatores que fomentam a criação do conhecimento organizacional

  • O grande desafio das organizações concentra-se em oferecer um contexto apropriado para a criação e compartilhamento de conhecimento organizacional.
  • A autonomia permite um maior grau de flexibilidade ao adquirir, interpretar e relacionar informações, tornando os funcionários automotivados.
  • Baseia-se no princípio de que a diversidade interna deve ser condizente à variedade e complexidade do ambiente externo de modo que ela supere os desafios deste ambiente, also known as Requisito variedade.
  • Com base neste modelo, Nonaka e Takeuchi (2008) alegam que o processo de criação do conhecimento organizacional inicia-se com o compartilhamento do conhecimento tácito .
  • O conceito criado, precisa ser justificado na terceira fase, na qual a organização reflete sobre a sua importância.

3 SERVIÇO DE REFERÊNCIA EM UMA BIBLIOTECA UNIVERSITÁRIA

  • As bibliotecas universitárias são espaços que adquirem, armazenam, organizam, disponibilizam e disseminam informação científica e tecnológica, atendendo às necessidades informacionais da comunidade acadêmica e da sociedade na qual está inserida.
  • Para atender às demandas informacionais de seus usuários, os profissionais destas bibliotecas, em especial os bibliotecários, desenvolvem atividades de administração , seleção, aquisição e processamento técnico de materiais, implantação e gestão de repositórios institucionais, restauração dos materiais bibliográficos e atendimento ao usuário, no qual este último abarca o serviço de referência.
  • A partir dessa análise, fará uso dos produtos documentários, de estratégias de busca e de ferramentas de recuperação para levar o usuário até o documento que poderá satisfazer sua necessidade informacional (ALMEIDA JÚNIOR, 2003, p.60).
  • O bibliotecário de referência precisa ter a arte de pesquisar através dos seus conhecimentos, experiências, habilidades e criatividade.
  • Este processo inicia a identificação do problema, ou seja, a identificação das necessidades do usuário, gerando a oportunidade do ensino/aprendizagem no serviço de referência.

4 METODOLOGIA

  • Esta pesquisa caracteriza-se, do ponto de vista da abordagem do problema, do objetivo, e dos procedimentos técnicos, respectivamente, como: pesquisa qualitativa, descritiva e estudo de caso.
  • E também por fazer uso de técnica padronizada de coleta de dados, o questionário.
  • E estudo de caso, por envolver um estudo profundo do processo o processo de criação de conhecimento durante a atividade de serviço de referência de uma dada biblioteca.
  • Sabe- se que, nesta etapa, o pesquisador organiza e tabula os dados para posterior interpretação e correlação do material coletado com o propósito da pesquisa.
  • Para facilitar a tabulação dos dados, criou-se um arquivo de dados eletrônicos no aplicativo Excel da Microsoft.

5.1 Caracterização da biblioteca e dos profissionais que atuam na atividade de serviço de referência

  • A Biblioteca Universitária, doravante denominada de Biblioteca Central Zila Mamede (BCZM), da Universidade Federal do Rio Grande do Norte (UFRN) foi fundada em 1959.
  • Já os assistentes administrativos possuem formação em gestão pública e em arquitetura e urbanismo.
  • Com isso, pode-se inferir que tal formação diferenciada agrega valor aos produtos e serviços oferecido pelo setor estudado.
  • De acordo com o tempo de atuação de cada membro do setor, é de se esperar que a equipe estudada possua um certo conhecimento organizacional e que tenham construído conhecimentos tácitos acerca das atividades preestabelecidas, processos internos, normas e valores que regem o sistema de bibliotecas.
  • É oportuno pontuar também que, a interação dessa equipe heterogênea gera, em alguns momentos, conflitos, em função da visão e percepção diferenciada.

5.2 Fontes de informação internas e externas (formais e informais) utilizadas pela equipe que atuam no serviço de referência para responder as questões apontadas pelos usuários

  • As fontes de informação são canais onde são extraídas informações importantes para a formulação de ideias e obtenção de conhecimentos.
  • Em se tratando das fontes externas informais, a pesquisa aponta que durante a atividade supracitada, a equipe faz uso de: Redes sociais com profissionais de outras instituições (42,85%); grupos de discussão na WhatsApp com profissionais de outras instituições (42,85%) e dos conhecimentos obtidos por meio de Palestras, Seminários/Congressos/Encontros profissionais (28,57%).
  • 3 Conhecimentos e habilidades necessárias para a atuação plena no serviço de referência.
  • No tocante às habilidades é preciso ter o domínio das tecnologias da informação; técnicas de entrevista; aptidão para elaborar estratégias de busca, proatividade, dinamismo, flexibilidade e tato com as pessoas.

5.4 Conversão do conhecimento tácito para explícito apoiado nos 4 modos de conversão

  • A pesquisa apontou, com (100%) das respostas dos respondentes, que o conhecimento individual criado durante a atividade de serviço de referência é difundido entre eles, fazendo parte da memória da organização.
  • Quanto aos meios utilizados pelo setor estudado para disponibilizar conhecimentos criados durante a atividade de serviço de referência, a pesquisa revelou que as reuniões presenciais com a equipe (conhecimento tácito e explícito), treinamentos (conhecimento tácito e explícito), interação individual ou conversas (conhecimento tácito), intranet/internet e emails (conhecimento explícito) são os meios utilizados pela equipe.
  • Para que o conhecimento seja criado, depende de algumas ações, entre as quais se destacam: registro (ou armazenamento) e o acesso .
  • Quando o conhecimento explícito é internalizado (transformado em tácito) sob a forma de modelos mentais ou conhecimento técnico compartilhado, as experiências através da socialização, externalização e combinação tornam-se ativos valiosos (NONAKA; TAKEUCHI, 1997; 2008).
  • Após a incorporação do conhecimento, o conhecimento tácito recém-criado é socializado com os outros membros do setor, dando início assim a uma nova espiral de criação do conhecimento organizacional.

5.5 Condições e fatores que interferem no processo de criação de conhecimento, durante a atividade de serviço de referência

  • A pesquisa apontou que as cinco condições favoráveis para a criação do conhecimento organizacional apresentadas por Nonaka e Takeuchi, perpassam o ambiente organizacional da divisão de processos técnicos, conforme segue: Intenção: esta condição atingiu (100%) das respostas, sinalizando que as metas e os objetivos da divisão estudada são comunicados a todos os membros, que ali atuam.
  • Para findar este tópico é importante ressaltar que a TI não é tudo no processo de criação de conhecimento.
  • Este estudo revelou que o processo de criação de conhecimento depende de dados, informações e conhecimentos oriundos do meio interno e externo da biblioteca.
  • DAVENPORT, T. H.; PRUSAK, L. Conhecimento empresarial: como as organizações gerenciam o seu capital intelectual.

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Citations
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Journal ArticleDOI
TL;DR: The findings indicate that CLBP affects the balance of both younger and older adults, and that the age-related changes also affect balance and modify the magnitude of CLBP effects on balance.
Abstract: Background and Purpose The prevalence of chronic low back pain (CLBP) is higher in older than in younger adults and is associated with poor postural control and falls. The objective of this study was to compare the postural control of younger and older subjects with and without CLBP during a one-leg stance.

41 citations


Cites background or result from "Postural sway and integration of pr..."

  • ...A limitation of the present study was that there was no comparison with neuromuscular activation and/or with the influence of vibration [28] to help explain the possible proprioceptive mechanisms for maintaining balance during a one-leg stance with CLBP....

    [...]

  • ...[28] showed no significant differences in COP oscillation between those with low back pain (n = 33) as compared to those without pain (n = 182)....

    [...]

Journal ArticleDOI
TL;DR: While the results show that none of the parameters alone lead to significant effects, the combination of neuromuscular and biomechanical parameters was associated with the impairment of postural control in individuals with LBP during standing.
Abstract: Background: There is a great number of people who require treatment for non-specific low back pain (LBP) yet the causes are still unclear. One proposed cause for LBP is impaired motor control and more specific an impaired postural control. Objective: The purpose of this review is to provide an overview of postural control parameter differences in persons with and without non-specific LBP during quite standing. Methods: A literature search in five databases from January 2000 until January 2018 was performed and was followed by a hand search. Twenty-one articles comparing healthy adults and adults with non-specific LBP in neuromuscular and/or biomechanical parameters during bipedal stance without external perturbation in lab studies were examined. Data extraction and quality assessment were independently performed by two persons. Factors such as study population, outcome measures, and results were extracted from the articles and included in this analysis. Results: The results show that persons with and without non-specific LBP differed in several parameters of postural control such as the center of pressure displacement, postural control strategy, and muscle activation patterns. Conclusion: While the results show that none of the parameters alone lead to significant effects, the combination of neuromuscular and biomechanical parameters was associated with the impairment of postural control in individuals with LBP during standing. Since the studies included in this analysis used different methodological procedures a replication of these studies with standardized procedures is imperative for the acquisition of more conclusive evidence on the differences in postural control during standing.

38 citations


Cites result from "Postural sway and integration of pr..."

  • ...The results of recent studies in which the amount of joints involved in balance control was examined suggest that models with up to seven degrees of freedom had the highest shared variance with CoP (Kilby et al., 2015)....

    [...]

Journal ArticleDOI
TL;DR: Increased postural sway in children and seniors seems to be counteracted with higher TA/SO co-activity and SO modulation, however, TA modulation is higher inChildren and adults, whereas seniors’ TA modulation capacity is diminished.
Abstract: Incomplete maturation and aging-induced declines of the neuromuscular system affect postural control both in children and older adults and lead to high fall rates. Age-specific comparisons of the modulation of ankle muscle activation and behavioral center of pressure (COP) indices during upright stance have been rarely conducted. The objective of the present study was to quantify aging effects on a neuromuscular level. Thus, surface electromyography (SEMG) modulation and co-activity of ankle muscles during single-leg standing was compared in healthy children, young adults and seniors. Postural steadiness (velocity and mean sway frequency of COP), relative muscle activation (SEMG modulation) and co-activation of two ankle muscles (tibialis anterior, TA; soleus, SO) were examined during single-leg stance in 19 children [age, 9.7 (SD 0.5) years], 30 adults [23.3 (1.5) years] and 29 seniors [62.7 (6.1) years]. Velocity of COP in medio-lateral and anterior–posterior directions, mean sway frequency in anterior–posterior direction, relative muscle activation (TA and SO) and co-activation revealed large age effects (P < 0.003, η p 2 > 0.14). Post-hoc comparisons indicated higher COP velocities, anterior–posterior frequencies, relative SO activation and co-activation in children and seniors when compared with adults. Relative TA activation was higher in children and adults compared with seniors (P < 0.001). Increased postural sway in children and seniors seems to be counteracted with higher TA/SO co-activity and SO modulation. However, TA modulation is higher in children and adults, whereas seniors’ TA modulation capacity is diminished. An aging-induced decline of TA motor units might account for deteriorations of TA modulation in seniors.

28 citations


Cites background from "Postural sway and integration of pr..."

  • ...2014), postural control mechanisms (Kiers et al. 2015) or even brain function (Tabara et al....

    [...]

Journal ArticleDOI
TL;DR: Elders with LBP have greater risk for falls than those without LBP, and fall-risk screening may be sensible in elders with L BP, the results suggest.
Abstract: Background Low back pain (LBP) is a common musculoskeletal condition among elders and is associated with falls. However, the underlying biological risk factors for falling among elders with LBP has been poorly investigated. The Physiological Profile Assessment (PPA) is a validated fall-risk assessment tool that involves the direct assessment of sensorimotor abilities and may contribute to the understanding of risk factors for falls among elders with LBP. Objective To assess fall risk using the PPA in elders with and without LBP. Method This is an observational, comparative, cross-sectional study with elders aged ≥65 years. The present study was conducted with a subsample of participants from the Back Complaints in the Elders (BACE) - Brazil study. Fall risk was assessed using the PPA, which contains five tests: visual contrast sensitivity, hand reaction time, quadriceps strength, lower limb proprioception, and postural sway. Results Study participants included 104 individuals with average age of 72.3 (SD=4.0) years, divided into two groups: GI) 52 participants with LBP; GII) 52 participants without LBP. The participants with LBP had a significantly higher fall risk (1.10 95% CI 0.72 to 1.48), greater postural sway (49.78 95% CI 13.54 to 86.01), longer reaction time (58.95 95% CI 33.24 to 84.65), and lower quadriceps strength (–4.42 95% CI –8.24 to –0.59) compared to asymptomatic participants. There was no significant difference for vision and proprioception tests between LBP and non-LBP participants. Conclusion Elders with LBP have greater risk for falls than those without LBP. Our results suggest fall-risk screening may be sensible in elders with LBP.

26 citations

01 Jan 2009
TL;DR: In this paper, the authors used the analysis of center of pressure (COP) excursions as an index of postural stability in standing and provided recommendations for maximizing the reliability of COP data.
Abstract: Summary of background data: The analysis of centre of pressure (COP) excursions is used as an index of postural stability in standing. Conflicting data have been reported over the past 20 years regarding the reliability of COP measures and no standard procedure for COP measure use in study design has been established. Search methods: Six online databases (January 1980 to February 2009) were systematically searched followed by a manual search of retrieved papers. Results: Thirty-two papers met the inclusion criteria. The majority of the papers (26/32, 81.3%) demonstrated acceptable reliability. While COP mean velocity (mVel) demonstrated variable but generally good reliability throughout the different studies (r= 0.32-0.94), no single measurement of COP appeared significantly more reliable than the others. Regarding data acquisition duration, a minimum of 90 s is required to reach acceptable reliability for most COP parameters. This review further suggests that while eyes closed readings may show slightly higher reliability coefficients, both eyes open and closed setups allow acceptable readings under the described conditions (r≥0.75). Also averaging the results of three to five repetitions on firm surface is necessary to obtain acceptable reliability. A sampling frequency of 100. Hz with a cut-off frequency of 10. Hz is also recommended. No final conclusion regarding the feet position could be reached. Conclusions: The studies reviewed show that bipedal static COP measures may be used as a reliable tool for investigating general postural stability and balance performance under specific conditions. Recommendations for maximizing the reliability of COP data are provided.

22 citations

References
More filters
Journal ArticleDOI
TL;DR: This chapter discusses anticipatory postural adjustments associated with equilibrium maintenance in the context of dual-modular approach to posture versus global approach to equilibrium.

1,510 citations


"Postural sway and integration of pr..." refers background in this paper

  • ...Postural control, the part of motor control involved in maintaining an upright position (Massion, 1992), is often studied by analyzing postural sway....

    [...]

Journal ArticleDOI
TL;DR: A relatively simple control scheme for regulation of upright posture that provides almost instantaneous corrective response and reduces the operating demands on the CNS is proposed.
Abstract: Winter, David A., Aftab E. Patla, Francois Prince, Milad Ishac, and Krystyna Gielo-Perczak. Stiffness control of balance in quiet standing. J. Neurophysiol. 80: 1211–1221, 1998. Our goal was to pro...

1,389 citations


"Postural sway and integration of pr..." refers background in this paper

  • ...Increasing stiffness through co-contraction reduces dependence on feedback and will cause higher sway frequencies (Winter et al., 1998)....

    [...]

Journal ArticleDOI
TL;DR: Proprioceptive senses, particularly of limb position and movement, deteriorate with age and are associated with an increased risk of falls in the elderly and the more recent information available on proprioception has given a better understanding of the mechanisms underlying these senses.
Abstract: This is a review of the proprioceptive senses generated as a result of our own actions. They include the senses of position and movement of our limbs and trunk, the sense of effort, the sense of force, and the sense of heaviness. Receptors involved in proprioception are located in skin, muscles, and joints. Information about limb position and movement is not generated by individual receptors, but by populations of afferents. Afferent signals generated during a movement are processed to code for endpoint position of a limb. The afferent input is referred to a central body map to determine the location of the limbs in space. Experimental phantom limbs, produced by blocking peripheral nerves, have shown that motor areas in the brain are able to generate conscious sensations of limb displacement and movement in the absence of any sensory input. In the normal limb tendon organs and possibly also muscle spindles contribute to the senses of force and heaviness. Exercise can disturb proprioception, and this has implications for musculoskeletal injuries. Proprioceptive senses, particularly of limb position and movement, deteriorate with age and are associated with an increased risk of falls in the elderly. The more recent information available on proprioception has given a better understanding of the mechanisms underlying these senses as well as providing new insight into a range of clinical conditions.

1,280 citations


"Postural sway and integration of pr..." refers background in this paper

  • ...Muscle vibration is a potent stimulus for muscle spindles (Burke, Hagbarth, Lofstedt, & Wallin, 1976; Roll, Vedel, & Ribot, 1989) and muscle spindles play the major role in the detection of movement (Proske & Gandevia, 2012)....

    [...]

Journal ArticleDOI
TL;DR: These data confirm that vibration is able to preferentially activate the Ia afferent channel, even when the vibration amplitude is low, and show that the physiological messages triggered by ongoing motor activities undergo a series of changes during the exposure of muscles to vibration.
Abstract: The activities of single proprioceptive fibres were recorded from the lateral peroneal nerve using transcutaneously implanted tungsten microelectrodes. Unitary discharges originating from muscle spindle primary and secondary endings and Golgi tendon organs were identified by means of various physiological tests. The sensitivity of proprioceptors to mechanical vibrations with a constant low amplitude (0.2–0.5 mm) applied at various frequencies to the tendon of the receptor-bearing muscle was studied. Muscle spindle primary endings (Ia fibres) were found to be the most sensitive to this mechanical stimulus. In some cases their discharge could be driven in a one-to-one manner up to 180 Hz. Most of them also fired harmonically with the vibration up to 80 Hz and then discharged in a subharmonic manner (1/2–1/3) with increasing vibration frequencies. Muscle spindle secondary endings (II fibres) and Golgi tendon organs (Ib fibres) were found to be either insensitive or only slightly sensitive to tendon vibration in relaxed muscles. The effects of tendon vibration on muscle spindle sensory endings response to muscle lengthening and shortening induced by imposed constant velocity or sinusoidal movements of the ankle joint were studied. Modulation of the proprioceptive discharge frequency coding the various joint movement parameters was either completely or partly masked by the receptor response to vibration, depending on the vibration frequency. Moreover, vibrations combined with sinusoidal joint movements elicited quantitatively erroneous proprioceptive messages concerning the movement parameters (amplitude, velocity). The sensitivity of the Golgi tendon organs to vibration increased greatly when the receptor-bearing muscle was tonically contracted. These data confirm that vibration is able to preferentially activate the Ia afferent channel, even when the vibration amplitude is low. They define the frequency sensitivity of the muscle spindle primary and secondary endings and the Golgi tendon organs. They also show that the physiological messages triggered by ongoing motor activities undergo a series of changes during the exposure of muscles to vibration.

804 citations

Journal ArticleDOI
TL;DR: The characteristics of the vibration-induced illusory movements and the muscle spindle responses to tendon vibration and to active and passive joint movements strengthened the possibility of the contribution of primary endings to kinaesthesia, as suggested by several previous works.
Abstract: The characteristics of vibration-induced illusory joint movements were studied in healthy human subjects. Unseen by the subject, constant frequency vibration trains applied to the distal tendon of the Triceps or Biceps induced an almost constant velocity illusory movement of the elbow whose direction corresponded to that of a joint rotation stretching the vibrated muscle. Vibration trains of the same duration and frequency applied alternatively to the Biceps and Triceps evoked alternating flexion-extension illusory movements. During successive application of vibration trains at frequencies from 10 to 120 Hz, the perceived velocity of the illustory movements increased progressively from 10 to 70-80 Hz, then decreased from 80 to 120 Hz. The maximal perceived velocity was three times higher during alternating vibration of the Biceps and Triceps than during single muscle stimulation. Unit activity from 15 muscle spindle primary endings and five secondary endings located in Tibialis anterior and Extensor digitorum longus muscles were recorded using microneurography in order to study their responses to tendon vibration and passive and active movements of the ankle. Primary endings were all activated by low amplitude tendon vibration (0.2-0.5 mm) previously used to induce illusory movements of the elbow. The discharge of some was phase-locked with the vibration cycle up to 120 Hz, while others responded one-to-one to the vibration cycle up to 30-50 Hz, then fired in a sub-harmonic manner at higher frequencies. Secondary endings were much less sensitive to low amplitude tendon vibration. Primary and secondary ending responses to ramp and sinusoidal movements of the ankle joint were compared. During the movement, the primary ending discharge frequency was almost constant, while the secondary ending activity progressively increased. During ankle movements the primary ending discharge appeared mainly related to velocity, while some secondary activities seemed related to both movement velocity and joint angle position. Muscle spindle sensory ending responses to active and passive ankle movements stretching the receptor-bearing muscle (plantar flexion) were qualitatively and quantitatively similar. During passive reverse movements (dorsiflexion) most of the sensory endings stopped firing when their muscle shortened. Active muscle shortening (isotonic contraction) modulated differently the muscle spindle sensory ending discharge, which could stop completely, decrease or some times increase during active ankle dorsiflexion. During isometric contraction most of the muscle spindle sensory endings were activated. The characteristics of the vibration-induced illusory movements and the muscle spindle responses to tendon vibration and to active and passive joint movements strengthened the possibility of the contribution of primary endings to kinesthesia, as suggested by several previous works...

770 citations


"Postural sway and integration of pr..." refers background in this paper

  • ...Under vibration, the muscle is usually perceived to be longer than it actually is (Cordo, Gurfinkel, Brumagne, & Flores-Vieira, 2005; Goodwin, McCloskey, & Matthews, 1972; Roll & Vedel, 1982), and consequently a corrective movement is made....

    [...]

Frequently Asked Questions (13)
Q1. What contributions have the authors mentioned in the paper "Postural sway and integration of proprioceptive signals in subjects with lbp" ?

In the following 6 trials, vision was occluded and subjects stood under various conditions of vibration/no vibration of the lumbar spine or m. The authors performed a factor analysis to reduce the large amount of variables that are available to quantify all effects. This model suggests that subjects with LBP use more co-contraction and less cognitive control, to maintain a standing balance when compared to subjects without LBP. 

Nonlinear variables, that give insight into the dynamic structure of the sway pattern, have been used much less frequently in LBP research. 

Muscle vibration is a potent stimulus for muscle spindles (Burke, Hagbarth, Lofstedt, & Wallin, 1976; Roll, Vedel, & Ribot, 1989) and muscle spindles play the major role in the detection of movement (Proske & Gandevia, 2012). 

The authors hypothesized that, compared to subjects without LBP, subjects with LBP would show a more regular sway pattern, a decrease in response to lumbar paraspinal musculature (LPM) vibration and an increase to TSM vibration, that these differences would increase when standing on foam, and that recovery after cessation of vibration would take more time in subjects with LBP. 

Subjects with LBP have been suggested to use stiffening strategy to increase robustness of the trunk to mechanical perturbations (Hodges & Tucker, 2011; van Dieen, Selen, & Cholewicki, 2003). 

There is evidence that conscious control over a task increases postural sway (Andersson, Hagman, Talianzadeh, Svedberg, & Larsen, 2002; Nafati & Vuillerme, 2011) and that withdrawing attention from the postural task leads to a decrease in postural sway (Andersson et al., 2002; Nafati & Vuillerme, 2011; Riley, Baker, & Schmit, 2003). 

For the vibration trials, proprioceptive parameters were included based on the findings in a previous study, and with at least a fair reliability in intra- and inter-day reliability (ICC > 0.4) (Kiers, Brumagne, van Dieën, & Vanhees, 2014). 

In summary, the authors suggest that attentional reserves are used less to control balance on foam in subjects with LBP, due to pain interference. 

Four factors were identified for CoP sway, with a combination of variables that mainly represented velocity and range, and frequency and regularity both on rigid surface and on foam (Table 3). 

The authors suggest that the competing effect of fear of pain on sway is achieved by means of increased use of co-contraction, specifically in the more challenging condition on foam. 

In addition, a54 0608.reduced weighting of proprioceptive signals in subjects with LBP is suggested as an explanation for the findings in this study. 

Subjects with LBP showed the same amount of sway as subjects without LBP, but the structure of their sway pattern was less regular with higher frequency content. 

The subjects in these other studies had pathologies that contain larger threats to postural balance than LBP does, such as CVA and Parkinson disease.