Thesis (Ph.D.)--Boston University / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / This study grew out of the general problem area concerning the relationship between psychological factors and response to pain. The specific variable focused upon was body image, broadly defined as a constellation of body attitudes and ways of experiencing the body, two of which -- body anxiety and body boundary definiteness -- were studied intensively. Body anxiety, defined as the degree of concern, conflict or anxiety a person experiences about his body, was measured by the Homonym Test, developed by Secord. This is a word association test involving 75 words which can have either a body or a non-body meaning such as "graft" or "colon". Two general measures of anxiety, theTaylor Manifest Anxiety Scale and Holtzman's adaptation of the Elizur Content Anxiety Scale, were also administered. The second body image variable, body boundary definiteness, was defined as an index of a person's sense of differentiation from the world as a separate, intact entity. It was further considered to be an index of the development of differentiated ego boundaries, reflecting highly developed ego-functioning, and consequently, the capacity to modulate response to stress. In order to measure body boundary definiteness, the barrier score of Fisher and Cleveland was used. This score is based on an analysis of inkblot responses emphasizing protective, containing or concealing features. Three aspects of response to pain were studied; these were pain perception, pain tolerance, and adaptation to pain. Operationally, pain perception was measured in terms of the intensity at which an electric shock to the forearm was judged as "uncomfortable" and the level at which it was judged as "painful ". Pain tolerance was likewise measured in two ways. The first, "unmotivated tolerance level", was the point at which subjects first refused to receive higher intensities of shock. The second, "motivated tolerance level", was the point at which subjects refused to go higher following mild urging to go as high as they possibly could. Finally, adaptation to pain was measured in terms of the amount of increase in each of the pain perception and tolerance levels as a result of repeating the level setting procedure following a period of repeated shocks. The specific hypotheses tested in the study were: 1) Definiteness of body boundaries is positively correlated with pain perception threshold. 2) Body anxiety is negatively correlated with pain perception threshold. 3) Definiteness of body boundaries is positively correlated with ability to tolerate pain. 4) Body anxiety is negatively correlated with ability to tolerate pain. 5) Definiteness of body boundaries is positively correlated with adaptation to pain. 6) Body anxiety is negatively correlated with adaptation to pain. The results, based on a sample of 30 subjects, supported only hypotheses one and three, those involving body boundary definiteness. There were significant correlations between the Barrier scores and painful level, unmotivated tolerance level, and motivated tolerance level. The hypothesized relationship between body anxiety and pain perception and pain tolerance were not supported by the experimental results. Neither of the body image variables was correlated with adaptation to pain as stated in hypotheses five and six. This was seen to be the result of the fact that most of the subjects were highly stable in their judgements about pain and in their ability to tolerate pain. Thus, adaptation did not occur. In addition, it was found that the Holtzman Content Anxiety scores were negatively correlated with the two pain tolerance measures. There was a tendency toward an inverted-U shaped relationship between tvlanifest Anxiety and pain perception level and motivated tolerance level. The results of the study were considered to provide partial support for the assumption that body image variables are relevant to response to pain. / 2031-01-01

Shoulder injuries may be associated with proprioceptive deficits, however, it is unknown whether these changes are due to the experience of pain, tissue damage, or a combination of these. The aim of this study was to investigate the effect of experimentally-induced sub-acromial pain on proprioceptive variables. Sub-acromial pain was induced via hypertonic saline injection in 20 healthy participants. Passive joint replication (PJR) and threshold to detection of movement direction (TTDMD) were assessed with a Biodex System 3 Pro isokinetic dynamometer for baseline control, experimental pain and recovery control conditions with a starting position of 60° shoulder abduction. The target angle for PJR was 60° external rotation, starting from 40°. TTDMD was tested from a position of 20° external rotation. Repeated measures ANOVAs were used to determine differences between PJR absolute and variable errors and TTDMD for the control and experimental conditions. Pain was elicited with a median 7 on the Numeric Pain Rating Scale. TTDMD was significantly decreased for the experimental pain condition compared to baseline and recovery conditions (≈30%, P=0.003). No significant differences were found for absolute (P=0.152) and variable (P=0.514) error for PJR. Movement sense was enhanced for the experimental sub-acromial pain condition, which may reflect protective effects of the central nervous system in response to the pain. Where decreased passive proprioception is observed in shoulders with injuries, these may be due to a combination of peripheral tissue injury and neural adaptations that differ from those due to acute pain.

Background: People with chronic shoulder pain have been shown to present with motor adaptations during arm movements. These adaptations may create abnormal physical stress on shoulder tendons and muscles. However, how and why these adaptations develop from the acute stage of pain is still not well-understood. Objective: To investigate motor adaptations following acute experimental shoulder pain during upper limb reaching. Methods: Forty participants were assigned to the Control or Pain group. They completed a task consisting of reaching targets in a virtual reality environment at three time points: (1) baseline (both groups pain-free), (2) experimental phase (Pain group experiencing acute shoulder pain induced by injecting hypertonic saline into subacromial space), and (3) Post experimental phase (both groups pain-free). Electromyographic (EMG) activity, kinematics, and performance data were collected. Results: The Pain group showed altered movement planning and execution as shown by a significant increased delay to reach muscles EMG peak and a loss of accuracy, compared to controls that have decreased their mean delay to reach muscles peak and improved their movement speed through the phases. The Pain group also showed protective kinematic adaptations using less shoulder elevation and elbow flexion, which persisted when they no longer felt the experimental pain. Conclusion: Acute experimental pain altered movement planning and execution, which affected task performance. Kinematic data also suggest that such adaptations may persist over time, which could explain those observed in chronic pain populations.

Shoulder injuries often comprise two separate yet related components, structural tissue damage and pain. The role of each of these components on shoulder function is difficult to ascertain. Experimental pain models allow the assessment of consequences of localized pain when applied to healthy individuals. By understanding the role of pain on shoulder function, clinicians will be able to more efficiently assess and treat shoulder injuries. The objective of the study was to evaluate the role of experimentally-induced sub-acromial pain on shoulder isokinetic rotational strength and throwing accuracy. This was a block counterbalanced, crossover, repeated measures study design utilizing 20 individuals without self-reported shoulder or cervical pathology. Shoulder function was measured with and without experimental pain injection (2 mL of 5% hypertonic saline) in the sub-acromial space. Functional tasks consisted of shoulder rotational strength utilizing isokinetic testing and throwing accuracy via the functional throwing performance index. The hypertonic saline induced moderate pain levels in all participants (4.3-5.1/10). Normalized shoulder internal (t = 3.76, p = 0.001) and external (t = 3.12, p = 0.006) rotation strength were both diminished in the painful condition compared to the pain free condition. Throwing accuracy was also reduced while the participants experienced pain (t = 3.99, p = 0.001). Moderate levels of experimental shoulder pain were sufficient to negatively influence shoulder strength and throwing accuracy in participants without shoulder pathology.

Introdução: dor é um fenômeno complexo que envolve simultaneamente aspectos sensoriais/discriminativos, emocionais/afetivos e avaliativo/cognitivo e está frequentemente associado a desordens musculoesqueléticas e declínio de força muscular. Estudos mostram que na presença de dor a capacidade de gerar força é de 15% a 60% menor se comparada a geração de força em condições normais, sem a presença de dor. Este fenômeno pode afetar negativamente os resultados obtidos durante o treinamento de força. Objetivo: verificar a influência da dor muscular aguda no desempenho de força muscular após a aplicação de um protocolo de treinamento de força no qual dor muscular aguda esteve presente em todas as sessões do treinamento. Métodos: nove indivíduos saudáveis do sexo masculino, destreinados, foram alocados em dois grupos, experimental ou controle. Os grupos realizaram treinamento de força para os músculos flexores da articulação do cotovelo do membro superior dominante com pesos livres ao longo de oito semanas, com frequência de três vezes por semana. O grupo experimental foi submetido à infusão intramuscular de 2,5 ml de solução salina hipertônica (6% de cloreto de sódio) no músculo bíceps braquial previamente ao treinamento e o grupo controle não foi submetido a qualquer tipo de infusão. A partir da terceira semana de treinamento, os voluntários do grupo experimental foram submetidos a uma infusão adicional de solução salina hipertônica após a última repetição da terceira série de treinamento. Previamente ao treinamento, após a quarta e oitava semana os voluntários realizaram testes de uma repetição máxima e contração isométrica e concêntrica voluntária máxima no equipamento de dinamometria isocinética. Durante as avaliações dinamométricas foram adquiridos sinais elétricos dos músculos bíceps e tríceps braquial. Percepção subjetiva de esforço e dor foram mensuradas durante todo o experimento. Depois de identificar que os dados têm distribuição normal, análise de variância ANOVA (3 x 2), considerando-se os fatores tempo (sessão 1, 12 e 24) e condição (controle e dor aguda), para dados pareados, foi aplicada. O teste estatístico post hoc de Tukey foi utilizado para comparações múltiplas. O índice de significância de 0,05 foi adotado. Teste-t de student foi utilizado para se comparar o volume total de treinamento entre os grupos. Resultados: o aumento da capacidade de gerar força dos músculos flexores da articulação do cotovelo, medida pela avaliação de 1 RM, foi de 26% para o grupo controle e 64% para o grupo com dor aguda, entretanto os dados obtidos nas avaliações isocinéticas e eletromiográficas não mostraram alterações significantes. Conclusão: ambos os grupos, experimental e controle, mostraram aumento na capacidade de gerar força máxima dinâmica dos músculos flexores da articulação do cotovelo ao final do estudo, no entanto, este aumento foi considerado maior no grupo submetido a dor aguda. Este estudo sugere que mais investigações sejam realizadas com o objetivo de analisar este fenômeno e quais protocolos podem ser efetivos nestas condições / Introduction: pain is a complex set involving sensory/discriminative, emotional/affective and cognitive/evaluator aspects and is frequently associated with musculoskeletal disorders and declining muscle strength. Studies show that the ability to generate force from 15% to 60% is less than a force generation under normal conditions without a presence of pain. This phenomenon may negatively affect the results obtained during strength training. Objective: to verify the intensity of muscular pain without muscle movement force after applying an unskilled muscle training protocol present in all training sessions. Methods: nine untrained male-based groups were allocated to two groups, experimental or control. The groups performed strength training for flexors of the elbow joint flexion with free weights for weeks, three times a week, the experimental group was submitted to intramuscular infusion of 2.5 ml hypertonic saline solution (6 % sodium) in the brachial muscle prior to training and control group was not submitted to any type of infusion. From the third week of training, volunteers from the experimental group underwent an additional infusion of saline after a last repetition of the third training series. Prev. After training, after one week and eighth week, the volunteers performed maximum isometric and concentric maximal pressure and power tests on isokinetic dynamometry equipment. During the dynamometric evaluations, electrical signals were obtained from the biceps and triceps brachii muscles. Perceived subjective performance and measurement throughout the experiment. After analyzing the data, the normal distribution, analysis of variance ANOVA (3 x 2), considering the time factors (session 1, 12 and 24) and the condition (control and acute pain), for paired data, was applied. Tukey\'s post hoc statistical test was used for multiple comparisons. The significance level of 0.05 was adopted. Student test was used to compare the total volume of training between groups. Results: the increase in the production capacity had strength in the flexors of the elbow joint, by the evaluation of 1 RM, it was 26% for the control group and 64% for the group with sharp, so the results obtained in the isokinetic and electromyographic not significant end changes. Conclusion: both groups, experimental and control, were added in the developmental capacity according to the elbow joint flexion strategy at the end of the study, however, the increase was higher in the group submitted to acute pain. This study was investigated with the objective of investigating and analyzing the issues that can be applied in different conditions

There are numerous indications of possible involvement of the autonomic nervous system in the genesis of chronic pain. The possibility exists that sympathetic activation is related to motor dysfunction and changes in sensory processing, which have otherwise been implicated in musculoskeletal disorders. The primary aim of the thesis has been to investigate autonomic regulation at rest and in response to laboratory tests of autonomic function in subjects suffering from chronic pain in different localisations (lower back, neck-shoulder and neck-jaw), as well as to study the relations between autonomic regulation, proprioceptive acuity and clinical data. Secondary aim has been to assess autonomic regulation in fit, pain-free subjects in response to experimentally induced pain and in occupationally relevant settings. A total of 194 subjects suffering from chronic pain participated [low back pain (LBP) n=93; non-traumatic neck pain (NT) n=40, Whiplash associated disorder (WAD) n=40, Whiplash with temporomandibular dysfunction (WADj) n=21]. Each chronic pain group was subjected to a battery of autonomic function tests combining cognitive (Stroop Colour-Word conflict tests), physical (handgrip), sensory (unpleasant sound) and motor tasks (chewing tests) as well as the activation of reflex pathways (paced breathing and the orthostatic test) and compared to an age- and gender balanced control group. Autonomic regulation was also assessed in exposure to experimentally induced muscle pain in healthy subjects (n=24) in order to describe acute pain reaction. Further assessment was carried out during monotonous repetitive work and dynamic work in healthy subjects (n=10) and in a three-day monitoring of ambulance personnel (n=26) in occupational settings. Autonomic regulation was evaluated using cardiovascular (heart rate and heart rate variability, local blood flow and blood pressure), respiratory (breathing rate) electrodermal (skin conductance), muscular (trapezius and masseter EMG) and biochemical (insulin, cortisol, catecholamines) variables. Proprioceptive acuity was assessed using active-active repositioning tests. Pain levels were assessed using Visual-analogue or Numerical Rating scales. General health was evaluated through the Short-Form SF-36 Health Related Quality of Life questionnaire and Self-Efficacy Score questionnaires, whereas dysfunction was evaluated using the Oswestry Low Back Pain questionnaire, Pain Disability and Neck Disability Index questionnaires, the McKenzie evaluation and primary healthcare diagnoses. Self-reports of pain, stress and exertion were acquired prior to, during and post-testing. Chronic pain subjects were characterised by increased sympathetic and decreased parasympathetic activity as reflected in heart rate (LBP, WAD, WADj), heart rate variability (LBP, WAD, WADj), blood pressure (WADj) and electrodermal activity (LBP). In general, WAD showed more pain and dysfunction than NT, with lower self-efficacy and health-related quality of life. Differential reactivity was observed only in WAD, with increased responsiveness to sensory stimuli (heart rate variability, electrodermal activity), and motor tasks (heart rate) and a decreased response to cognitive challenge (heart rate variability, electrodermal activity). A significant part of WADj subjects showed sensorimotor impairment and low endurance in chewing tests, concomitant with a cardiovascular response that correlated with pain levels. Proprioceptive acuity was not found to be impaired among subjects suffering from chronic pain, and there were no indications of significant individual response specificity. Response to experimentally induced muscle pain in healthy subjects was also characterised by a prominent cardiovascular component. In simulated occupational settings autonomic activation and transient insulin resistance were detected in healthy subjects following monotonous repetitive work, with no similar effects following dynamic exercise. Modest deviations in circadian heart rate variability patterns during workdays were detected in ambulance personnel reporting more pronounced musculoskeletal symptoms, with no such effects on work-free days. Autonomic balance observed in chronic pain subjects was characterised by a trend towards increased sympathetic activity in comparison with pain-free controls. Moderate signs of affected reactivity to autonomic function tests were observed in patients with WAD, however no specific reaction patterns have been observed in any chronic pain group. Correspondence between the intensity of pain and autonomic activity was observed in acute pain and in chronic pain groups characterised by higher pain levels. As indicated by autonomic and neurohormonal changes in the recovery from real and simulated work, further studies with physiological monitoring of the effects of work-related stress are warranted for better understanding of the mechanism of musculoskeletal disorders.

The prevalence of tobacco smoking among persons with recurrent pain is approximately twice that observed in the general population. Smoking has been associated with the development and exacerbation of several chronically painful conditions. Conversely, there is both experimental and cross-sectional evidence that pain is a potent motivator of smoking. A recent study provided the first evidence that laboratory-induced pain could elicit increased craving and produce shorter latencies to smoke (Ditre & Brandon, 2008). To further elucidate interrelations between pain and smoking, and to identify potential targets for intervention, the current study tested whether several constructs derived from social-cognitive theory influence the causal pathway between pain and increased motivation to smoke. Smokers (N = 132) were randomly assigned to one of four conditions in this 2 X 2 between-subjects experimental design. Results indicated that manipulations designed to (a) challenge smoking-related outcome expectancies for pain reduction, and (b) enhance pain-related coping, each produced decreased urge ratings and increased latencies to smoke, relative to controls.

BACKGROUND AND AIMS: Globally, chronic low back pain (CLBP) affects 70-80% of adults at some point in their lives and current treatments are widely unsuccessful in relieving pain. Understanding the underlying neurophysiological (e.g., descending pain inhibition) and biobehavioral (e.g., stress) processes contributing to chronic pain in patients with CLBP is needed for the development of novel treatments. Previous studies have shown that acute stress can impact pain sensitivity and that childhood trauma may predispose a person to CLBP, but the mechanisms underlying this impact are unknown. Conditioned Pain Modulation (CPM) is a psychophysical paradigm used in research to assess descending pain modulatory pathways, which are thought to be impaired in patients with CLBP as well as in those with childhood trauma. The overlap of conditions has not been explored. The current study explored the impact of childhood trauma on the CPM response within a sample of patients with CLBP being treated at a tertiary pain clinic. CLBP patients exposed to an acute stress paradigm were expected to shower higher pain sensitivity, with acute stress significantly interacting with a history of childhood trauma as a factor leading to the higher pain sensitivity. METHODS: 46 Participants with CLBP (n=46, mean age=49 years, 55.3% female) recruited from a pain treatment service completed a Quantitative Sensory Testing (QST) and CPM before and after an acute psychological stressor. Participants were randomized to a control (n=25) or an acute-stress (n=21) condition. The acute-stress condition included the Stroop Color Word Task (SCWT) and a mental arithmetic task prior to completing the QST protocol a second time. The control participants did not undergo any additional stressors and completed the QST protocol a second time after a 20-minute break. Participants’ CPM response was measured by the average change in pressure pain threshold (PPT) from baseline to the conditioning stimulus (non-dominant hand in ice-water bath). A “Good CPM response” was defined as a CPM effect above 100, indicating that the pain threshold increased when exposed to the conditioning stimulus. To examine the impact of childhood trauma on pain sensitivity, participants completed a Childhood Traumatic Events Scale (CTES) to assess the presence and severity of six types of trauma (death, parental upheaval, sexual, violence, illness or injury, other upheaval) during childhood. The CTES was scored as a continuous variable by calculating the sum the trauma severity for all six trauma types. RESULTS: A large majority of the sample (94% of participants) showed an increase in pain threshold during hand immersion in ice water, which was contrary to our hypothesis based on prior research done on other chronic pain conditions and CLBP. Participants exposed to an acute stressor had an impaired CPM effect compared to those that were not exposed to an acute stressor, however there was no difference between groups (p=0.277). A history of childhood traumatic events did not correlate significantly with an impaired baseline CPM or a change in CPM effect when exposed to an acute stressor. CONCLUSION: The current study used novel QST modalities, including CPM, to analyze the interaction between acute and chronic stress on pain sensitivity. Ultimately, this study found that exposure to an acute stressor had a negative effect on CPM, indicating that when under experimental stress participants were more sensitive to pain compared to when they were not under stress, although the findings were not statistically significant. These findings should be further investigated to expand the understanding of the neurophysiological mechanisms underlying CLBP and to potentially provide novel treatment modalities for patients with CLBP.

O objetivo deste trabalho foi analisar a influência da ansiedade e do estresse no limiar de dor à pressão (LDP) de músculos mastigatórios, numa amostra de estudantes universitários em diferentes períodos do ano letivo. Para este propósito, foram selecionados 45 indivíduos, sendo 29 estudantes, que apresentavam DTM de origem miogênica seguindo critérios de inclusão propostos pelo Research Diagnostic Criteria (RDC) e 16 que não apresentavam características de DTM, do gênero feminino, equilibrados em relação à idade. Utilizando um algômetro (KRATOS®) foram realizadas tomadas bilaterais dos limiares de dor à pressão (LDP) dos indivíduos da amostra nos músculos masseter, temporal anterior, médio e posterior. Além disso, os participantes foram solicitados a responder questionários multidimensionais, através do Inventário de Ansiedade de Beck (BAI) e o Inventário de Sintomas de Stress de Lipp (ISSL), para mensurar reações emocionais ou afetivas em situações que causem estresse e/ou ansiedade. Também, o nível de dor foi registrado pela Escala de Análise Visual (EAV). Todos os exames foram realizados em quatro momentos distintos (T1, T2, T3 e T4) tendo como parâmetro o período de avaliações acadêmicas da Faculdade de Odontologia de Bauru. Os dados obtidos foram submetidos à análise estatística (ANOVA, Teste de Tukey, Teste de Friedman e Mann-Whitney), em um nível de significância de 5%. A comparação entre os diferentes tempos do estudo nos 2 grupos mostrou diferença estatisticamente significativa (p<0,05), sendo que o período das avaliações mostrou maiores níveis de estresse e ansiedade e menores valores de LDP. Sob o ponto de vista do músculo nos diferentes grupos e nos diferentes tempos, foram encontradas diferenças estatisticamente significativas (p<0,05). Os resultados da Escala de Análise Visual mostraram diferenças estatisticamente significantes entre o grupo sintomático e o grupo assintomático em T1, T2, T3 e T4. Com relação ao estresse e ansiedade, não houve diferenças estatisticamente significante entre os grupos. Houve, no entanto, uma associação entre o aumento do estresse e da ansiedade e diminuição dos valores de LDP em cada tempo. Concluiu-se que existe relação entre estresse e ansiedade e LDP tanto para indivíduos assintomáticos quanto para sintomáticos com DTM de origem miogênica. / The aim of this research was to evaluate the influence of stress and anxiety on the Pressure Pain Threshold (PPT) of the masticatory muscles and on the subjective pain report of dental students of the Bauru School of Dentistry (University of São Paulo, Brazil) at different situations. Forty-five females, matched for age, were divided into two groups: 29 presenting with myofascial pain, according to the RDC/TMD criteria, and 16 with no TMD signs or symptoms. PPT measurements were taken bilaterally at the masseter, anterior, middle and posterior temporalis muscles in four different occasions throughout the academic year. The Achilles tendon was used as control. In order to quantify emotional or affective reactions under stress/anxiety situations, the sample were requested to fill out multidimensional questionnaires, such as the Beck Anxiety Inventory (BAI) and the Lipp Inventory for Stress Symptoms (LISS). In addition, pain levels were registered with a Visual Analog Scale (VAS). Data obtained were submitted to statistical analysis (ANOVA, Tukey, Friedman, and Mann-Whitney tests), at a 5% significance level. The VAS and PPT had a negative correlation, regardless the period, and group studied (p<.05). Higher levels of stress and anxiety were detected at the time of school examinations for both groups, with a strong association with decreased PPT figures (p<.05). Stress and anxiety, however, were not statistically different between groups. It can be concluded that external stressors as academic examinations have a potential impact on the masticatory muscle tenderness, regardless the presence of a previous condition, such as the masticatory myofascial pain.

La manipulation vertébrale (MV) est l'une des options dans le traitement des douleurs d'origine neuromusculosquelettique. Ses indications ont été identifiées à partir de l'expérience des professionnels qui l'utilisent, ainsi que des études épidémiologiques autour de ses résultats cliniques. Cependant, son mécanisme d'action précis demeure à ce jour inexpliqué.La littérature scientifique sur ce sujet est incomplète, éparse et confuse. Certains auteurs et professionnels proposent des hypothèses des mécanismes d'action neurobiologiques et d'autres biomécaniques. De plus, l'étude de la douleur rend la situation difficile en raison de la complexité des situations cliniques et des traitements associés dont les patients bénéficient. C'est la raison pour laquelle l'objectif de cette thèse est d'étudier si la MV a un effet sur la douleur provoquée de manière expérimentale. Si tel est le cas, il importe de savoir s'il est systémique ou locorégional et dans cette dernière hypothèse, si ce résultat est le produit d'une action directe de la MV sur la douleur ou secondaire à une amélioration du mouvement. N'ayant pas trouvé d'étude englobant la problématique mixte des effets de la MV sur la douleur et le mouvement, nous avons procédé à deux revues systématiques et critiques de la littérature scientifique ; l'une a porté sur son effet sur la douleur et l'autre sur l'amplitude du mouvement des segments vertébraux. Dans la première, nous avons rassemblé 22 articles décrivant 43 essais cliniques montrant un effet hypoalgésique de la MV au niveau locorégional, mais les résultats diffèrent selon la manière dont la douleur a été provoquée. Nous n’avons pas pu tirer de conclusion sur l'action systémique de la MV du fait de la qualité des articles sur ce sujet. Quant à la revue de la littérature réalisée sur l'effet de la MV sur l'amplitude du mouvement, l'étude de 15 articles ne nous a pas permis de prouver l'efficacité de cette technique pour augmenter l'amplitude des mouvements segmentaires, malgré des limitations à prendre en considération, notamment le fait que ces études ont été réalisées sur des volontaires sains et non sur des patients avec une mobilité réduite. A partir de là, nous concluons que l'effet de la MV sur la douleur est plutôt direct, et défendons la thèse que l'hypoalgésie induite par la MV permet l'amélioration et la récupération de la fonction de mouvement, et non l'inverse.Cependant, même si nous répondons à nos questions de recherche, ces réponses demeurent partielles et le sujet reste à approfondir. Nos deux revues indiquent qu’il reste à clarifier : les mécanismes exacts des effets de la MV sur la douleur, la durée des effets, les rapports "dose/effet", l'identification des techniques les plus efficaces, ou encore, sur le ciblage plus fin des patients à traiter. Il en est de même en ce qui concerne l'étude de l'effet de la MV sur l'amplitude du mouvement, où il manque notamment des études réalisées sur des patients et des personnes présentant des mouvements limités. Des améliorations sont également à prévoir dans la coordination des chercheurs les rassemblant autour d'une politique de recherche partagée sur le long/moyen terme, et à partir d'un consensus méthodologique, particulièrement en termes de suivi des essais, d'unités de mesures, de précision des critères de qualité des essais, de promotion de méta-analyses, etc. Au total, si la MV semble avoir un effet direct sur la douleur, il n’en demeure pas moins que la connaissance détaillée de ses mécanismes et des modalités d'application dans la pratique clinique reste à approfondir, ce qui pourrait devenir un véritable enjeu pour la communauté des chercheurs, des enseignants et des cliniciens. / Spinal manipulative therapy (SMT) is one of the treatments used to reduce musculoskeletal pain. Some clinical studies have shown that it really has a pain reducing effect but the indications for when it should be used is mainly based on clinical experience and logic. Further, although SMT is widely used, the precise mechanisms of action that can explain how it works, are unknown.We noticed that the scientific literature on this subject is incomplete, scattered and confused. In relation to the mechanisms, some authors propose a number of neurobiological mechanisms (such as a direct reduction of pain) whereas others are convinced that the mode of action is biomechanical (such as improved range of motion). For this reason, when trying to find out if SMT has a pain reducing effect, a better alternative is to start with healthy people, provoke a pain experimentally, perform the SMT, and measure their pain, to see if it has improved with the “treatment”. If it would be possible to see if SMT does have a pure pain reducing effect, then it would be important to find out if this effect is only regional, in the area of the manipulation, or if this effect is systemic. Also, none of the authors who proposed the biomechanical theory offered any evidence that improved movement results in less pain, but then, the opposite pathway (reduce pain first, better movement after) has not been shown either, by these proponents of theories. For this reason we decided to study the already existing scientific literature in a critical and systematic fashion.Unfortunately, we did not find any study including the mixed problem of the effects of SMT on pain and movement, we therefore performed two systematic reviews of the scientific literature: one focused on its effect on experimental pain and the other on its effect on the range of motion (ROM) of the vertebral segments. In the first one, we collected 22 articles describing 43 trials showing an hypoalgesic effect of the locoregional level. Interestingly, the results differ depending on how the pain was provoked. We were not been able to reach a conclusion on the systemic action of the SMT because of the lack of quality of articles on this topic. Concerning the literature review on the effect of SMT on ROM, the review of 15 research articles did not allow us to « prove » the effectiveness of this technique to increase the range of segmental motion. There were some limitations with these studies, such as the fact that they had been performed in healthy volunteers and not in people with reduced mobility. In sum, we could conclude that the effect of SMT on pain has been clearly shown, which supports the hypothesis that the hypoalgesia induced by SMT allows the improvement and recovery of function of movement, and not the inverse. These results have been reported in our two scientific articles.However, even if we were able to obtain answers to our research questions, these answers are incomplete and the subject remains to be further explored. There are still questions that remain to be clarified, such as: What are the exact effects of SMT on pain mechanisms? How long does the effect remain ? Is there a " dose / effect "? Which are the most effective SMT techniques? and How should patients be best targeted for this treatment ? Does SMT have an effect on ROM on people with limited movement?Finally, a coordination of research is necessary to move forward more effectively. Researchers would need to gather around a shared policy in relation to the medium / long term research, and from a methodological consensus. In conclusion, SMT does seem to have a direct effect on pain. However, we need some more and detailed knowledge of the mechanisms and procedures before we can really apply this knowledge efficiently in clinical practice. No doubt, this could become an important issue for the community of researchers, teachers and clinicians.