Sur la scène des consultations en chiropraxie : une lecture de la relation de soin.

INTRODUCTION: The caregiver-patient relationship has been the subject of numerous studies in the field of medicine, but has received little attention in the context of chiropractic care, particularly in France. PURPOSE OF THE RESEARCH: This ethnographic and sociological study aims to gain a better understanding of the characteristics of the chiropractic relationship in chiropractic care through the observation of consultations followed by interviews with both patients and caregivers. These observations were carried out in the Franco-European Chiropractic Institute’s two outpatient clinics and in three private practices. RESULTS: The data were collected between October 2022 and March 2023. Most of the patients treated their health as an asset to be preserved or even improved, and had a good knowledge of their body as a tool for work and/or sports performance. They turned to chiropractic care to find relief from their pain and a form of care combining technical and interpersonal skills. Chiropractic care is based on manual therapy, combined with a dimension of self-management by the patient. Follow-up of the exercises and advice given by chiropractors varies greatly from patient to patient, from diligent application to non-application, and with everything in between. CONCLUSION: Trust is the foundation of all care, and even more so in manual therapy, because of the way the hands act on the body. To establish a working alliance with the patient, the chiropractor has to adapt his or her professional ethos and accept compromises regarding the treatment plan envisaged. Cooperation between a patient and a chiropractor is based on trust, the negotiation of objectives, and the division of tasks between the two parties.

Effects of Manual Therapy on Parkinson's Gait: A Systematic Review.

Manual therapy (MT) is commonly used in rehabilitation to deal with motor impairments in Parkinson's disease (PD). However, is MT an efficient method to improve gait in PD? To answer the question, a systematic review of clinical controlled trials was conducted. Estimates of effect sizes (reported as standard mean difference (SMD)) with their respective 95% confidence interval (95% CI) were reported for each outcome when sufficient data were available. If data were lacking, p values were reported. The PEDro scale was used for the quality assessment. Three studies were included in the review. MT improved Dynamic Gait Index (SMD = 1.47; 95% CI: 0.62, 2.32; PEDro score: 5/10, moderate level of evidence). MT also improved gait performances in terms of stride length, velocity of arm movements, linear velocities of the shoulder and the hip (p < 0.05; PEDro score: 2/10, limited level of evidence). There was no significant difference between groups after MT for any joint's range of motion during gait (p > 0.05; PEDro score: 6/10, moderate level of evidence). There is no strong level of evidence supporting the beneficial effect of MT to improve gait in PD. Further randomized controlled trials are needed to understand the impact of MT on gait in PD.

Can self-assessment and augmented feedback improve performance and learning retention in manual therapy: results from an experimental study.

BACKGROUND: The purpose of this study was to investigate how feedback and self-assessment strategies affect performance and retention of manual skills in a group of chiropractic students. METHODS: Seventy-five students participated in two spinal manipulation (SM) learning sessions using a force-sensing table. They were recruited between May and November 2022 during HVLA technical courses. Students were randomly assigned into three different groups: participants in group 1 received visual feedback, those in group 2 received visual feedback after self-assessment, and participants in group 3 (C) received no feedback. During the first session, participants started with one block of 3 familiarization trials, followed by two blocks of 6 SM HVLA (high velocity low amplitude) posterior-to-anterior thoracic SM trials, with 3 trials performed with a target force of 450 N and 3 others at 800 N. They received feedback according to their group during the first block, but no feedback was provided during the second block. All participants were invited to participate in a second session for the retention test and to perform a new set SM without any form of feedback. RESULTS: Results showed that visual feedback and visual feedback in addition to self-assessment did not improve short-term SM performance, nor did it improve performance at the one-week retention test. The group that received visual feedback and submitted to self-assessment increased the difference between the target force and the peak force applied, which can be considered a decrease in performance. CONCLUSION: No learning effects between the three groups of students exposed to different feedback and self-assessment learning strategies were highlighted in the present study. However, future research on innovative motor learning strategies could explore the role of external focus of attention, self-motivation and autonomy in SM performance training.

Headache-related clinical features in teleworkers and their association with coping strategies during the COVID-19 pandemic.

Objectives: The objectives were (1) to describe and compare headache-related clinical features between teleworkers with migraine and those with tension-type headache (TTH) and (2) to determine the association between coping strategies and headache frequency, and intensity in the context of the COVID-19 pandemic. Methods: This cross-sectional online survey was conducted with 284 teleworkers (127 with migraine and 157 with TTH). Sociodemographic data, information related to work factors, headache clinical features, coping strategies used during the COVID-19 pandemic, and headache-related clinical features were compared between headache profiles. Bivariate logistic regression analyses were used to determine the association between coping strategies and headache frequency, and intensity. Results: Results showed that teleworkers with migraine had longer and more painful headache episodes than teleworkers with TTH (ps < 0.001). Higher migraine frequency was associated with the use of the denial coping strategy (p = 0.006) while lower migraine intensity was associated with planning (p = 0.046) and the use of positive reframing (p = 0.025). Higher TTH frequency was associated with the use of venting, self-blame, and behavioral disengagement (ps < 0.007) while higher TTH intensity was associated with substance use and behavioral disengagement (ps < 0.030). All associations remained significant after adjusting for BMI as a covariate. Discussion/conclusion: Teleworkers with migraine had more intense and longer headache episodes than teleworkers with TTH. This could be explained by the fact that a greater proportion of individuals suffering from migraine experienced headaches prior to the beginning of the pandemic compared with teleworkers suffering from TTH. Regarding coping strategies, both primary headache profiles were associated with different types of coping strategies. Most of the coping strategies associated with headache frequency or intensity were maladaptive except for planning and positive reframing that were found to be inversely associated with migraine intensity.

Neuromechanical Responses to Spinal Manipulation and Mobilization: A Crossover Randomized Clinical Trial.

OBJECTIVE: The purpose of this study was to compare the immediate effect of spinal manipulation (SMa) and spinal mobilization (SMo) on muscular responses, spinal stiffness, and segmental spinal pressure evoked pain in a population of participants with chronic middle back pain (MBP). METHODS: In a crossover randomized trial, 2 experienced chiropractors assessed whether volunteers were eligible for the protocol according to a list of specific inclusion and exclusion criteria. Individuals with MBP participated in 2 experimental sessions within 72 hours. During the first session, participants randomly received a SMa or SMo delivered by an apparatus using a servolinear motor. During the second session, the other modality was delivered. Spinal stiffness and pressure-provoked pain intensity outcomes were assessed before and after each therapy, and muscular responses were recorded during the treatment using surface electromyographic sensors. Signed-rank Wilcoxon tests for muscular responses and generalized model for repeated measure for spinal stiffness and pressure-provoked pain were used for statistical analyses. RESULTS: Among the 32 potential participants, 26 (mean age 29.9 [±9.14], 15 women) completed both sessions. Between-group differences were observed for the muscular response amplitude (P < .001), and indeed the normalized RMS muscular response was found to be higher during SMa than SMo. Similar results were observed for pressure-provoked pain intensity at the level of therapeutic modality application (P = .002) as a higher decrease in pain was found after SMa (47.9 [±22.8] to 36.6 [±23.7]) compared with SMo (47.2 [±23.2] to 45.5 [±24.3]). No between-group differences were found for spinal stiffness change, nor for terminal (P = .08) and global spinal stiffness (P = .06). CONCLUSION: In a controlled environment, spinal manipulation and mobilization generated different muscle responses and had different immediate effects on pressure-provoked pain intensity for participants with MBP.

Factors associated with back pain in children aged 6 to 12 years of age, an eight months prospective study.

Associated factors of back pain (BP) development before puberty and its persistence are poorly documented. We investigated the association and possible temporality between prior BP history (PBPH), muscular endurance (ME), aerobic capacity (AC), sport activity variables (SAV) and BP in children aged 6 to 12. We collected baseline characteristics (demographics, PBPH, ME, AC and SAV) of children from three primary schools in Canada. Parents replied to weekly text messages regarding their children BP status over an 8-month period. Logistic regression models were adjusted for potential confounders. Data from 242 children (46% female; 8.6 ± 1.7 years) were included. Over the 8-month survey BP prevalence was 48.1%, while the cumulative incidence was 31.9%. The occurrence of at least one BP event was associated with PBPH [OR (IC 95%) = 6.33 (2.35-17.04)] and high AC [2.89 (1.21-6.90)]. High AC was also associated with the development of a first BP episode [2.78 (1.09-7.07)], but ME and SAV were not. BP appears to be relatively common before puberty. BP history seems to be strongly associated with BP recurrence in children. Aerobic capacity is associated with first BP episode development.

Factors associated with headache and neck pain among telecommuters - a five days follow-up.

BACKGROUND: The current sanitary crisis brought on by the COVID-19 recently forced a large proportion of workers to adopt telecommuting with limited time to plan transition. Given that several work-related risk factors are associated with headache and neck pain, it seems important to determine those associated with headache and neck pain in telecommuters. The main objective of this study was to identify which telecommuting and individual associated factors are related with headache and neck pain occurrence in telecommuters over a five days follow-up. The second objective was to evaluate the impact of wearing a headset on headache and neck pain intensity in telecommuters. METHODS: One hundred and sixty-two participants in telecommuting situation were recruited. Baseline assessment included sociodemographic data, headache and neck pain-related disability (6-item Headache Impact Test (HIT-6) and Neck Bournemouth Questionnaire (NBQ)), headache and neck pain frequency and intensity as well as questions about the wearing of a headset (headset wearing, headset type and headset wearing hours). A prospective data collection of headache, neck pain and headset wearing was conducted using daily e-mail over a 5-day follow-up. A stepwise multivariate regression model was performed to determine associated factors of headache or neck pain occurrence during the follow-up. A t-test was conducted to assess the impact of headset wearing on headache and neck pain intensity during the follow-up. RESULTS: Regarding headache, the stepwise multivariate regression model showed that the HIT-6 score was associated with future headache occurrence in telecommuters (OR (95% CI) = 1.094 (1.042-1.148); R2 = 0.094; p <  0.001). For neck pain, the stepwise multivariate regression showed that the NBQ score was related to future neck pain occurrence in telecommuters (OR (95% CI) = 1.182 (1.102-1.269); R2 = 0.182; p <  0.001). T-test showed no difference between participants that wore a headset and participant that did not wore a headset on mean headache (p = 0.94) and neck pain (p = 0.56) intensity during the five days follow-up. CONCLUSION: Although several work-related risk factors are associated with headache and neck pain in workers, telecommuting did not present the same risks. Working set-up did not have a significant impact on headache and neck pain as headache-related disability was the only associated factor of future headache episodes and neck-pain related disability was the only associated factor of future neck pain episodes. Also, wearing a headset had no impact on headache and neck pain in telecommuters.

Factors Associated With Clinical Responses to Spinal Manipulation in Patients With Non-specific Thoracic Back Pain: A Prospective Cohort Study.

Introduction: The management of musculoskeletal disorders is complex and requires a multidisciplinary approach. Manual therapies, such as spinal manipulative therapy (SMT), are often recommended as an adjunct treatment and appear to have demonstrable effects on pain and short-term disability in several spinal conditions. However, no definitive mechanism that can explain these effects has been identified. Identifying relevant prognostic factors is therefore recommended for people with back pain. Objective: The main purpose of this study was to identify short-term candidate prognostic factors for clinically significant responses in pain, disability and global perceived change (GPC) following a spinal manipulation treatment in patients with non-specific thoracic back pain. Methods: Patients seeking care for thoracic spine pain were invited to participate in the study. Pain levels were recorded at baseline, post-intervention, and 1 week after a single session of SMT. Disability levels were collected at baseline and at 1-week follow-up. GPC was collected post-intervention and at 1-week follow-up. Biomechanical parameters of SMT, expectations for improvement in pain and disability, kinesiophobia, anxiety levels as well as perceived comfort of spinal manipulative therapy were assessed. Analysis: Differences in baseline characteristics were compared between patients categorized as responders or non-responders based on their pain level, disability level, and GPC at each measurement time point. Binary logistic regression was calculated if the statistical significance level of group comparisons (responder vs. non-responders) was equal to, or <0.2 for candidate prognostic factors. Results: 107 patients (62 females and 45 males) were recruited. Mean peak force averaged 450.8 N with a mean thrust duration of 134.9 ms. Post-intervention, comfort was associated with pain responder status (p < 0.05) and GPC responder status (p < 0.05), while expectation of disability improvement was associated with GPC responder status (p < 0.05). At follow-up, comfort and expectation of pain improvement were associated with responder GPC status (p < 0.05). No association was found between responder pain, disability or GPC status and biomechanical parameters of SMT at any time point. Discussion: No specific dosage of SMT was associated with short-term clinical responses to treatment. However, expectations of improvement and patient comfort during SMT were associated with a positive response to treatment.

Learning Spinal Manipulation: Objective and Subjective Assessment of Performance.

OBJECTIVE: The purpose of this study was to investigate associations between objective spinal manipulation therapy (SMT) biomechanical parameters and subjective assessments provided by patients, clinicians, and expert assessors. METHODS: Chiropractic students (N = 137) and expert instructors (N = 14) were recruited. Students were asked to perform a thoracic SMT alternately on each other on a force-sensing table while being observed by an expert instructor. Students who performed (clinicians) and received (patients) SMT, and expert instructors, independently scored each SMT performance using visual analog scales. Correlations between these subjective scores and SMT biomechanical parameters were calculated. The following parameters were evaluated: peak force, preload force, thrust duration, and drop in preload force. Spinal manipulation therapy comfort was also assessed by patients, clinicians, and expert instructors. RESULTS: Results of the study indicate that thrust duration assessed by instructors and patients was the only parameters significantly correlated with the table data (r = .37; P < .001 and r = .26; P = .002). Comfort assessed by clinicians was significantly correlated with their own assessments of thrust duration (r = .37; P < .001) and preload force (r = .23; P = .007), whereas comfort assessed by instructors was significantly correlated with their own assessment of thrust duration (r = .27; P = .002) and drop in preload force (r = -.34; P < .001). Objective biomechanical parameters of performance did not predict perceived comfort. CONCLUSIONS: Overall, the results from the subjective assessments of SMT performance are weakly correlated with objective measures of SMT performance. Only the thrust duration evaluated by expert instructors and patients was associated with scores obtained from the table. Perceived comfort of the procedure seems to be associated mostly with perceived thrust duration and preload characteristics.

Spinal manipulation frequency and dosage effects on clinical and physiological outcomes: a scoping review.

Introduction: The burden of musculoskeletal disorders increases every year, with low back and neck pain being the most frequently reported conditions for seeking manual therapy treatment. In recent years, manual therapy research has begun exploring the dose-response relationship between spinal manipulation treatment characteristics and both clinical and physiological response to treatment. Objective: The purpose of this scoping review was to identify and appraise the current state of scientific knowledge regarding the effects of spinal manipulation frequency and dosage on both clinical and physiological responses. Methods: A scoping review was conducted to identify all available studies pertaining to our research question. Retrieved papers were screened using a 2-phase method, a selective sorting with titles and abstracts. Potentially relevant studies were read, and data was extracted for all included studies. Randomized control trials were assessed using the Cochrane Risk of Bias Tool for quality assessment. Results: The search yielded 4854 publications from which 32 were included for analysis. Results were sorted by dosage or frequency outcomes, and divided into human or animal studies. Animal studies mainly focused on dosage and evaluated physiological outcomes only. Studies investigating spinal manipulation dosage effects involved both human and animal research, and showed that varying thrust forces, or thrust durations can impact vertebral displacement, muscular response amplitude or muscle spindle activity. Risk of bias analysis indicated only two clinical trials assessing frequency effects presented a low risk of bias. Although trends in improvement were observed and indicated that increasing the number of SM visits in a short period of time (few weeks) decreased pain and improve disability, the differences between the studied treatment frequencies, were often not statistically significant and therefore not clinically meaningful. Conclusion: The results of this study showed that SM dosage and frequency effects have been mostly studied over the past two decades. Definitions for these two concepts however differ across studies. Overall, the results showed that treatment frequency does not significantly affect clinical outcomes during and following a SM treatment period. Dosage effects clearly influence short-term physiological responses to SM treatment, but relationships between these responses and clinical outcomes remains to be investigated.

Effects of an 8-week physical exercise program on spinal manipulation biomechanical parameters in a group of 1st-year chiropractic students.

OBJECTIVE: To determine the effects of a physical exercise program on spinal manipulation (SM) performance in 1st-year chiropractic students. METHODS: One hundred and thirteen students from 2 chiropractic schools were assigned to 1 of 2 groups: exercise group (EG) for campus A students or control group (CG) (no training) for campus B students. All participated in 2 1-hour experimental training sessions that were added to the usual technique curriculum. At the beginning and at the end of each session, SM thrust duration and preload force release were recorded as dependent variables in 5 trials performed on a force-sensing table for a total of 10 recorded trials per session. The session consisted of several drills during which augmented feedback was provided to students to improve their skills. The EG performed physical exercises (push-ups, core stabilization, and speeder board exercises) 3 times per week for an 8-week period between the 2 training sessions. RESULTS: The mean thrust duration increased between the 2 sessions [+0.8 ms (±15.6)]. No difference between groups was found using a t test for independent samples (p = .94). The mean preload force release decreased between the 2 sessions (-6.1 N [±17.1]). Differences between groups were found using a t test for independent samples (p = .03); the results showed a reduction of preload force release in the participants in the EG group compared to those in the CG group (-8.1 N [±16.9] vs -0.3 N [±16.5]). CONCLUSION: A physical exercise program seems to be beneficial in the SM learning process; chiropractic students should therefore be encouraged to do home physical exercises to develop their physical capabilities and improve SM delivery.

Pubertal development and growth are prospectively associated with spinal pain in young people (CHAMPS study-DK).

PURPOSE: To examine the prospective associations of pubertal development and linear growth with spinal pain frequency and duration in children. METHODS: We recruited students from 10 public primary schools. Over 42 months, pubertal development was assessed four times and categorized according to Tanner stages 1-5, and height was measured on seven occasions. Occurrences of spinal pain were reported weekly via text messaging. We constructed variables for spinal pain duration (total weeks with pain) and frequency (number of episodes). Potential associations between pubertal development and growth were examined with generalized estimating equations and reported with incident rate ratios (IRRs). All models were adjusted for potential confounders. RESULTS: Data from 1021 children (53% female; mean [SD] age = 9.4 [1.4] years), with median participation duration of 39 months, were included. Advancing pubertal development was associated with increased spinal pain duration (IRR [95% CI] = 1.90 [1.45, 2.49] to 5.78 [4.03, 8.29]) and frequency of pain episodes (IRR [95% CI] = 1.32 [1.07, 1.65] to 2.99 [2.24, 3.98]). Similar associations were observed for each 1-cm change in height in 6 months with spinal pain duration (IRR [95% CI] = 1.19 [1.15, 1.23]) and frequency (IRR [95% CI] = 1.14 [1.11, 1.17]). The relations between pubertal development and spinal pain, as well as growth and spinal pain, were largely independent. CONCLUSIONS: In young people, pubertal development and linear growth are likely to be independent risk factors for the development of spinal pain. Pubertal development demonstrates evidence of dose-response in its relationship with spinal pain. This knowledge may assist healthcare providers with clinical decision-making when caring for pediatric patients. These slides can be retrieved under Electronic Supplementary Material.

Learning spinal manipulation: Gender and expertise differences in biomechanical parameters, accuracy, and variability.

OBJECTIVE:: The purpose of this study was to investigate gender differences and expertise effects on biomechanical parameters as well as force accuracy and variability for students learning spinal manipulation. METHODS:: A total of 137 fourth- and fifth-year students were recruited for the study. Biomechanical parameters (preload, time to peak force, peak force, rate of force), as well as accuracy and variability of thoracic spine manipulation performance, were evaluated during 5 consecutive trials using a force-sensing table and a target force of 450 N. Gender, expertise differences on biomechanical parameters, as well as constant, variable, and absolute error were assessed using 2-way analysis of variance. RESULTS:: Analyses showed significant gender differences for several biomechanical parameters, as well as significant gender differences in accuracy and variability. Although women showed lower time to peak force and rate of force values, they were more precise and showed less variability than men when performing thoracic spine manipulations. Students with clinical expertise (fifth-year students) used less force and were more precise. CONCLUSION:: Our results showed that gender differences in spinal manipulation performance exist and that these differences seem to be mainly explained by alternative motor strategies. To develop gender-specific teaching methods, future studies should explore why men and women approach spinal manipulation tasks differently.

Changes in spinal stiffness with chronic thoracic pain: Correlation with pain and muscle activity.

OBJECTIVE: The objective was to compare thoracic spinal stiffness between healthy participants and participants with chronic thoracic pain and to explore the associations between spinal stiffness, pain and muscle activity. The reliability of spinal stiffness was also evaluated. MATERIAL AND METHODS: Spinal stiffness was assessed from T5 to T8 using a mechanical device in 25 healthy participants and 50 participants with chronic thoracic pain (symptoms had to be reported within the evaluated region of the back). The spinal levels for which spinal stiffness was measured were standardized (i.e. T5 to T8 for all participants) to minimize between-individual variations due to the evaluation of different spinal levels. The device load and displacement data were used to calculate the global and terminal spinal stiffness coefficients at each spinal level. Immediately after each assessment, participants were asked to rate their pain intensity during the trial, while thoracic muscle activity was recorded during the load application using surface electromyography electrodes (sEMG). Within- and between-day reliability were evaluated using intraclass correlation coefficients (ICC), while the effects of chronic thoracic pain and spinal levels on spinal stiffness and sEMG activity were assessed using mixed model ANOVAs. Correlations between pain intensity, muscle activity and spinal stiffness were also computed. RESULTS: ICC values for within- and between-day reliability of spinal stiffness ranged from 0.67 to 0.91 and from 0.60 to 0.94 (except at T5), respectively. A significant decrease in the global (F1,73 = 4.04, p = 0.048) and terminal (F1,73 = 4.93, p = 0.03) spinal stiffness was observed in participants with thoracic pain. sEMG activity was not significantly different between groups and between spinal levels. Pain intensity was only significantly and "moderately" correlated to spinal stiffness coefficients at one spinal level (-0.29≤r≤-0.51), while sEMG activity and spinal stiffness were not significantly correlated. CONCLUSION: The results suggest that spinal stiffness can be reliably assessed using a mechanical device and that this parameter is decreased in participants with chronic thoracic pain. Studies are required to determine the value of instrumented spinal stiffness assessment in the evaluation and management of patients with chronic spine-related pain.

Predictors of disability and absenteeism in workers with non-specific low back pain: A longitudinal 15-month study.

OBJECTIVES: The objective of this study was to identify baseline predictors of disability and absenteeism in workers with a history of non-specific low back pain (LBP). METHODS: One hundred workers with a history of non-specific LBP participated in three evaluations (baseline, 7 and 15 months follow-up). Current and past history of LBP, clinical pain intensity, disability, absenteeism, fear-avoidance beliefs, pain catastrophizing, pain hypervigilance, work satisfaction and patient stratification based on "risk of poor clinical outcome assessment" (RPCO) were evaluated using questionnaires and interviews. In addition, cutaneous heat pain thresholds, cutaneous heat pain tolerance thresholds, conditioned pain modulation (CPM), trunk kinematics and muscle activity were measured during each evaluation. Logistic regression models were used to determine predictors of LBP disability and absenteeism at 15-months. RESULTS: Sixty-eight workers returned for the 15-month follow-up and among this sample, 49% reported disability and 16% reported absenteeism at follow-up. Baseline clinical pain intensity predicted disability (OR = 1.08, 95%CI: 1.03-1.13) at 15-month while work satisfaction (OR = 0.93, 95%CI: 0.87-0.99) and RPCO (OR = 1.51, 95%CI: 1.05-2.16) predicted absenteeism. These results remained significant after adjustments for age, gender as well as type of work and intervention. CONCLUSION: This study highlights the importance of clinical pain and psychological factors in the prediction and potentially the prevention of future disability. Screening tools assessing these risk factors can be useful to evaluate workers with past history of low back pain.

Contribution of Load Expectations to Neuromechanical Adaptations During a Freestyle Lifting Task: A Pilot Study.

OBJECTIVES: The main goal of this study was to determine to what extent load expectations modulate neuromechanical adaptations in individuals with and without chronic low back pain (cLBP) when lifting and lowering various loads. The second goal was to assess the feasibility of a simple lifting protocol during which expectations about loads were manipulated. METHODS: Seventeen participants with cLBP and 18 participants without low back pain were asked to lift and lower boxes of mild to moderate loads. Two kinds of expectations (lighter and heavier) were respectively associated to each experimental block. Self-reported exertion was assessed to control for expectations modulation. Erector spinae and vastus lateralis electromyography (EMG) activity were recorded and kinematics angle calculated. RESULTS: The results showed a main effect of expectations, with loads introduced as heavier being associated to a higher exertion compared with loads introduced as lighter. EMG activity analyses revealed significant interaction involving expectations, movement phase, and loads, as well as significant differences between groups. Kinematic angles did not reveal any significant effect of expectations nor group during the lifting phase. CONCLUSIONS: Psychological factors may contribute to neuromechanical adaptations to low back pain. Our preliminary findings show that expectations about loads may result in neuromechanical differences between individuals with cLBP and those without cLBP. This pilot study showed that testing the manipulation of expectations and EMG records was feasible but highlighted the need to go beyond single infrared markers to assess kinematics.

The Effect of Augmented Feedback and Expertise on Spinal Manipulation Skills: An Experimental Study.

OBJECTIVES: The purpose of this study was to investigate the combined effect of augmented feedback and expertise on the performance and retention of basic motor learning spinal manipulation skills. METHODS: A total of 103 chiropractic students with various training expertise were recruited for the study. Participants were evaluated at baseline, immediately after trials of augmented feedback practice and 1 week later. During all 3 assessments, students were asked to perform several trials of the same spinal manipulation, for which the maximum preload force, onset of thrust, thrust duration, force and peak force, thrust duration, rate of force application, and any drop in preload force were calculated. The constant error, absolute error, and variable error were calculated for the 3 experimental blocks of trials. RESULTS: Results confirmed that augmented feedback training modified several biomechanical parameters such as the rate of force application, the preload force, and the drop in preload force. The study also confirmed that many biomechanical parameters, including thrust duration and rate of force application, are modified with expertise but failed to identify any interaction effect between expertise and augmented feedback training effects. CONCLUSION: The study determined that expertise did not influence how students performed after a session of augmented feedback training. The study also determined that augmented feedback related to the global performance can yield improvements in several basic components of the spinal manipulation task. These results should be interpreted considering basic motor learning principles and specific learning environments.

Effectiveness of preventive and treatment interventions for primary headaches in the workplace: A systematic review of the literature.

Aim The purpose of this systematic literature review is to assess the benefits of workplace-based occupational therapies and interventions, including acute and preventive medication, on headache intensity and frequency, related disability as well as work-related outcomes. Methods A search of the literature was conducted in PubMed, MEDLINE, Cochrane library, CINAHL and Embase using terms related to headache, workplace and occupational health. The Cochrane Collaboration's risk of bias assessment tool was used on individual studies to assess internal validity and the Grading of Recommendations Assessment, Development, and Evaluation system was applied to studies by clinical outcome and used to rate quality of evidence. Results Fifteen articles were included in the systematic review. None of them were classified as low risk of bias according to the Cochrane Collaboration's tool for assessing risk of bias. This systematic review found preliminary low-quality evidence suggesting that exercise and acupuncture can reduce workers' headache pain intensity, frequency and related disability. Conclusion Although this systematic review provided preliminary low evidence in favour of work-based intervention, studies with more rigorous designs and methodologies are needed to provide further evidence of the effectiveness of workplace-based headache management strategies.

Influence of Lumbar Muscle Fatigue on Trunk Adaptations during Sudden External Perturbations.

Introduction: When the spine is subjected to perturbations, neuromuscular responses such as reflex muscle contractions contribute to the overall balance control and spinal stabilization mechanisms. These responses are influenced by muscle fatigue, which has been shown to trigger changes in muscle recruitment patterns. Neuromuscular adaptations, e.g., attenuation of reflex activation and/or postural oscillations following repeated unexpected external perturbations, have also been described. However, the characterization of these adaptations still remains unclear. Using high-density electromyography (EMG) may help understand how the nervous system chooses to deal with an unknown perturbation in different physiological and/or mechanical perturbation environments. Aim: To characterize trunk neuromuscular adaptations following repeated sudden external perturbations after a back muscle fatigue task using high-density EMG. Methods: Twenty-five healthy participants experienced a series of 15 sudden external perturbations before and after back muscle fatigue. Erector spinae muscle activity was recorded using high-density EMG. Trunk kinematics during perturbation trials were collected using a 3-D motion analysis system. A two-way repeated measure ANOVA was conducted to assess: (1) the adaptation effect across trials; (2) the fatigue effect; and (3) the interaction effect (fatigue × adaptation) for the baseline activity, the reflex latency, the reflex peak and trunk kinematic variables (flexion angle, velocity and time to peak velocity). Muscle activity spatial distribution before and following the fatigue task was also compared using t-tests for dependent samples. Results: An attenuation of muscle reflex peak was observed across perturbation trials before the fatigue task, but not after. The spatial distribution of muscle activity was significantly higher before the fatigue task compared to post-fatigue trials. Baseline activity showed a trend to higher values after muscle fatigue, as well as reduction through perturbation trials. Main effects of fatigue and adaptation were found for time to peak velocity. No adaptation nor fatigue effect were identified for reflex latency, flexion angle or trunk velocity. Conclusion: The results show that muscle fatigue leads to reduced spatial distribution of back muscle activity and suggest a limited ability to use across-trial redundancy to adapt EMG reflex peak and optimize spinal stabilization using retroactive control.

Systematic Augmented Feedback and Dependency in Spinal Manipulation Learning: a Randomized Comparative Study.

OBJECTIVE: The purpose of the study was to evaluate if systematic augmented feedback during short sessions of spinal manipulation (SM) training creates a dependency compared with short training session characterized by progressive withdrawal of augmented feedback. METHODS: Forty fourth- and fifth-year chiropractic students enrolled in a 5-year chiropractic program were randomized into 2 groups. The 2 groups performed the same number of SM with a 300-N peak force target on an instrumented device. Baseline assessment consisted of 10 trials without feedback. Three training blocks of 10 SMs were then performed with visual and verbal feedback. For the control group, feedback was always provided. For the experimental group, augmented feedback was provided for each trial of the first training block, 50% of the second block, and 20% of the last training block. A postintervention assessment of 10 trials without feedback was performed, and a retention assessment was conducted 20 minutes later. RESULTS: No group main effect was found on biomechanical parameters and error variables. A main effect of learning for the absolute error was observed, suggesting that short sessions of feedback training improve participants' accuracy. CONCLUSION: The results of the study suggest that feedback scheduling does not influence SM motor performance and learning in clinically experienced students.