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.

Acute Upper-Body and Lower-Body Neuromuscular Fatigue Effect on Baseball Pitchers' Velocity: A Pilot Study.

ABSTRACT: Tremblay, M, Anderson Sirois, S, Verville, W, Auger, M, Abboud, J, and Descarreaux, M. Acute upper-body and lower-body neuromuscular fatigue effect on baseball pitchers' velocity: A pilot study. J Strength Cond Res XX(X): 000-000, 2024-The purpose of this pilot study was to explore the acute effect of upper-body and lower-body neuromuscular fatigue protocols on baseball pitchers' velocity. Sixteen baseball pitchers were recruited, and a crossover design was used to meet the study purpose. Pitchers were tested twice, 7 days apart, with their upper-body and lower-body explosiveness, pitching velocity, and muscle soreness perception of their throwing arm (forearm flexors, biceps, anterior deltoid, and upper trapezius muscles) assessed before and after an upper-body and lower-body neuromuscular fatigue protocol. Two-way analysis of variances and paired t tests (p < 0.05) were used to identify and compare prescores and postscores. Following both fatigue protocols, results revealed a significant decrease in time for pitching velocity (p = 0.005, ηp2 = 0.462), and increases in muscle soreness perception of the forearm flexors (p = 0.005, ηp2 = 0.470), anterior deltoid (p = 0.045, ηp2 = 0.274), and upper trapezius (p = 0.023, ηp2 = 0.339) muscles. Paired t test results showed a significant decrease in preneuromuscular and postneuromuscular fatigue protocol in the upper-body (p < 0.01) and lower-body (p < 0.01) explosiveness scores. These pilot study results show the impact of different exercise protocols on pitchers' explosiveness, velocity, and muscle soreness perception emphasizing the need for further investigation into the acute effect of exercise targeting the upper or lower-body on pitching performance, specifically at the pitcher's position.

Assessment of exercise-induced hypoalgesia in chronic low back pain and potential associations with psychological factors and central sensitization symptoms: A case-control study.

INTRODUCTION: Exercise is the most recommended treatment for chronic low back pain (CLBP) and is effective in reducing pain, but the mechanisms underlying its effects remain poorly understood. Exercise-induced hypoalgesia (EIH) may play a role and is thought to be driven by central pain modulation mechanisms. However, EIH appears to be disrupted in many chronic pain conditions and its presence in people with CLBP remains unclear. As people suffering from chronic pain often exhibit psychological factors and central sensitization symptoms influencing pain perception, EIH might be associated with these factors. OBJECTIVE: The aim of this study is to compare the level of EIH between participants with and without CLBP following back and wrist exercises and to assess the associations between EIH, psychological factors, and symptoms of central sensitization (using the central sensitization inventory - CSI) in CLBP. METHOD: Twenty-eight participants with CLBP and 23 without pain were recruited. Pressure pain thresholds (PPT) were measured at 4 sites (2 bony sites = capitate, S1|2 muscle sites = wrist flexors, lumbar erector spinae) before and after each of two exercises (wrist flexion and lumbar extension). Exercise-induced hypoalgesia was defined as percent change in PPT from pre- to post-exercise. Participants with CLBP also completed questionnaires to measure psychological factors (e.g., kinesiophobia, catastrophizing, anxiety, and self-efficacy) and symptoms of central sensitization (CSI), and correlations with EIH were calculated. RESULTS: After wrist exercise, EIH measured at the muscle sites was lower in the CLBP group compared with the pain-free group (p = 0.047) but no differences were found at bony sites (p = 0.49). No significant differences for EIH were observed following back exercise at muscle sites (p = 0.14) or at bony sites (p = 0.65). Exercise-induced hypoalgesia was not correlated with any psychological factors or with the CSI score. CONCLUSION: The lower EIH following wrist exercises may represent an alteration in pain modulation control in CLBP. However, psychological factors and central sensitization symptoms may not explain the differences observed.

Conservative interventions and clinical outcome measures used in the perioperative rehabilitation of breast cancer patients undergoing mastectomy: a scoping review.

BACKGROUND: Mastectomy is the first-line treatment approach for more than 90% of breast cancer patients. The numerous physical impairments associated with this surgical procedure negatively impact the patient's quality of life. To date, rehabilitation resources available for breast cancer patients undergoing mastectomy within the institutions affiliated to the Centre intégré universitaire de soins de santé et de services sociaux de la Mauricie-et-du-Centre-du-Québec (CIUSSS-MCQ) are lacking and do not always seem to reflect the particularities of breast cancer care pathways. The purpose of this review was to identify and describe the conservative interventions and the clinical outcome measures used in the perioperative physical rehabilitation of women with breast cancer who are awaiting or have undergone mastectomy. We also aimed to report on the barriers and facilitators to study participation and completion. METHODS: MEDLINE, CINAHL, and the Cochrane Library were searched from inception to January 2021, and we updated the search on July 11, 2022. We included peer-reviewed English and French literature with quantitative designs, describing conservative interventions and clinical outcome measures used within rehabilitation programs designed for women who were awaiting or had undergone mastectomy. Paired reviewers independently reviewed all citations and articles using a two-phase screening process and independently extracted the data. RESULTS: Of the 6080 articles identified, 57 met the inclusion criteria. Most interventions were multimodal, which combined exercise with patient education, manual therapy, and/or lymphatic drainage. The most frequently used objective measures of physical function were shoulder range of motion, muscle strength, and signs of lymphedema. In contrast, the primary patient-reported outcome measures were quality of life, shoulder function, and pain. Undergoing another breast surgery, death, and cancer recurrence were the most reported barriers to study completion. CONCLUSION: This scoping review reports on the heterogeneity and wide range of conservative interventions and clinical outcome measures used in the physical rehabilitation of breast cancer patients who had undergone or were scheduled to undergo mastectomy. Tailoring interventions to breast cancer patients' needs and promoting outpatient rehabilitation interventions appear to be better suited to the particularities of breast cancer care pathways. Further research is needed to better identify barriers and facilitators to study participation and completion.

The effect of low back pain on neuromuscular control in cyclists.

This study was designed to identify neuromuscular adaptations of low back pain (LBP) cyclists , and the impact of a cycling effort on spinal shrinkage. Forty-eight trained cyclists rode their road bike on a smart trainer for 1-hour. Surface electromyography (EMG) recorded muscle activity of the lumbar erector spinae (LES), 3D motion analysis system recorded kinematic of the trunk, and stadiometry measured spinal height. Statistical comparisons were made using repeated measure ANOVAs. The LBP group presented increase in pain levels throughout the effort (p < 0.001). A significant group difference was only observed for the thoracic angle (p = 0.03), which was less flexed for LBP. The one-hour cycling effort (time effect) significantly increased the trunk flexion (p < 0.001) and thoracic flexion (p < 0.001) for both groups. Significant lower LES activation (35% less) was observed at the end of the effort  as well as a decrease in spinal height (p = 0.01) for both groups. Neuromuscular adaptations to cycling effort is identified by a decrease in LES EMG amplitude and an increase flexion of the trunk. Adaptation to pain is seen by an increase in thoracic flexion. Despite these adaptations, LBP cyclists could not ride their bike pain-free.

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.

Variability of Intradiscal Pressure During Cervical Spine Posterior-Anterior Mobilization: A Cadaveric Investigation.

OBJECTIVES: The purpose of this study was to investigate in cadaveric specimens the reliability of measuring cervical intradiscal pressure (CIDP) and if posterior-anterior (PA) mobilizations targeting the cervical spine were associated with CIDP changes. METHODS: Cervical PA mobilizations were performed on the spinous processes of 7 (3 men, 4 women) cadaveric specimens using a servo-controlled linear actuator to provide 25N and 45N forces. CIDP measurements were performed at C4-5, C5-6, C6-7, and C7-T1 intervertebral discs (IVDs) using a fiberoptic catheter system that recorded CIDP for each IVD cervical segment. To assess CIDP measurement reliability, the intraclass correlation coefficient (ICC [3,k]) was calculated. Repeated measures Friedman analysis of variance assessed effect of cervical mobilizations on CIDP for before, during, and immediately after mobilization at 25N and 45N forces for each cervical IVD segment. RESULTS: All CIDP measurements demonstrated excellent reliability (ICC >0.98). During the 25N mobilizations, the median CIDP varied from -0.12 to 0.91 (interquartile range, 5.22-5.36), while for 45N mobilizations the median ranged from -0.94 to 1.21 (interquartile range, -7.74 to 43.49). These changes were not statistically significant (P > .40) during 25N and 45N PA mobilizations, with the exception of C5-6 CIDP at 25N and 45N (P = .05 and .018, respectively). CONCLUSION: There was high CIDP variability between cadavers during and after mobilization. Mobilizations of 1 cervical vertebra resulted in both CIDP increase or decrease at adjacent and remote cervical IVD segments that were not consistent. Cervical PA mobilizations produced variable CIDP changes at adjacent and remote cervical segments in cadavers.

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.

Superficial lumbar muscle recruitment strategies to control the trunk with delayed-onset muscle soreness.

PURPOSE: The lumbar region offers various muscle recruitment strategies to achieve a task goal under varying conditions. For instance, trunk movement control can be reorganized under the influence of low back pain. How such task-modulation is obtained is not fully understood. The objective of this study was to characterize superficial lumbar muscle recruitment strategies under the influence of delayed-onset muscle soreness (DOMS) during unexpected trunk perturbations. METHODS: Healthy participants experienced a series of 15 sudden external perturbations with and without the influence of low back DOMS. During these perturbations, high-density surface electromyography was used to characterize recruitment strategies of superficial lumbar muscles, while kinematics sensors were used to characterize movements of the trunk. Lumbar muscle recruitment strategies, characterized by the amplitude of muscle activity amplitude, the latencies of the reflex activity and the spatial distribution of muscle activity, were compared across perturbations trials and with and without DOMS. RESULTS: An attenuation of lumbar muscle activity amplitude was observed across perturbation trials without DOMS, but not with DOMS. The spatial distribution of muscle activity was similar with and without DOMS. No significant changes in reflex activity latency and trunk flexion movement were observed. CONCLUSIONS: Following an unexpected trunk perturbation under DOMS effects, trunk movement are controlled using two different superficial lumbar muscles control strategies: keeping a constant level of their overall muscle activity and using a variable muscle recruitment pattern.

Association Between Pregnancy-Related Hormones and Lumbopelvic Pain Characteristics in Pregnant Women: A Scoping Review.

OBJECTIVES: The objectives of this scoping review were (1) to document and quantify the potential associations between lumbopelvic pain characteristics and pregnancy-related hormones, and (2) to identify research approaches and assessment tools used to investigate lumbopelvic pain characteristics and pregnancy-related hormones. METHODS: The literature search was conducted in 6 databases (MEDLINE, Academic Search Complete, Cumulative Index to Nursing and Allied Health Literature, SportDiscus, PsycINFO, and Cochrane) from inception up to March 2020 and completed using search terms relevant to pregnant women, pregnancy-related hormones, and lumbopelvic pain. The risk of bias was assessed using the characteristics recommended by Guyatt et al. for observational studies. RESULTS: The search yielded 1015 publications from which 9 met the inclusion criteria. Relaxin was the most studied pregnancy-related hormone. An association between relaxin levels and lumbopelvic pain presence or severity was found in 4 studies, while 5 studies did not report an association between them. One study reported an association between relaxin and lumbopelvic pain presence or severity while 2 studies reported no association and were considered as having a low risk of bias. One study reported measures of estrogen and progesterone levels. It showed that progesterone levels were found to be significantly higher in pregnant women with lumbopelvic pain compared to those without, while estrogen concentrations were similar in both groups. CONCLUSION: The literature showed conflicting evidence regarding the association between pregnancy-related hormones and lumbopelvic pain characteristics in pregnant women. The assessment tools used to investigate lumbopelvic pain characteristics and pregnancy-related hormones are heterogeneous across studies. Based on limited and conflicting evidence, and due to the heterogeneity of assessment tools and overall poor quality of the literature, the association between pregnancy-related hormones and lumbopelvic pain characteristics is unclear.

Regional activation in the human longissimus thoracis pars lumborum muscle.

KEY POINTS: •Longissimus activity in the lumbar region was measured using indwelling electromyography to characterize the territory of its motor units. •The distribution of motor units in the longissimus pars lumborum muscle was mainly grouped into two distinct regions. •Regional activation of the longissimus pars lumborum was also observed during functional tasks involving trunk movements. •The regional activation of the longissimus pars lumborum muscle may play a role in segmental stabilization of the lumbar spine. ABSTRACT: The longissimus pars lumborum contributes to lumbar postural control and movement. While animal studies suggest a segmental control of this muscle, the territory of motor units constituting the human longissimus pars lumborum remains unknown. The aims of this study were to identify the localization of motor unit territories in the longissimus and assess the activation of this muscle during functional tasks. Eight healthy participants were recruited. During isometric back extension contractions, single motor-unit (at L1, L2, L3 and L4) and multi-unit indwelling recordings (at L1, L1-L2, L2, L2-L3, L3, L3-L4 and L4) were used to estimate motor unit territories in the longissimus pars lumborum based on the motor-unit spike-triggered averages from fine-wire electrodes. A series of functional tasks involving trunk and arm movements were also performed. A total of 73 distinct motor units were identified along the length of the longissimus: only two motor units spanned all recording sites. The majority of the recorded motor units had muscle fibres located in two main rostro-caudal territories (32 motor units spanned L1 to L3 and 30 spanned ∼L3 to L4) and 11 had muscle fibres outside these two main territories. We also observed distinct muscle activation between the rostral and caudal regions of the longissimus pars lumborum during a trunk rotation task. Our results show clear rostral and caudal motor unit territories in the longissimus pars lumborum muscle and suggest that the central nervous system can selectively activate regions of the superficial lumbar muscles to provide local stabilization of the spine.

Short-term effect of delayed-onset muscle soreness on trunk proprioception during force reproduction tasks in a healthy adult population: a crossover study.

PURPOSE: The aim of this study was to evaluate the effects of lumbar muscle delayed-onset muscle soreness (DOMS) on the ability of the trunk muscles to reproduce different levels of force. METHODS: Twenty healthy adults (10 males and 10 females) were recruited for this study. Force reproduction in trunk extension and flexion was assessed at 50 and 75% of participants' maximal isometric voluntary contraction in flexion and extension before and after a lumbar muscle DOMS protocol. Trunk proprioception was evaluated and compared between these conditions using different variables such as constant errors (CE), absolute errors (AE), variable errors (VE) and time to peak force (TPF). For each variable, repeated measure ANOVAs were conducted. RESULTS: AE were higher when participants had to reach the target post-DOMS protocol in extension compared to flexion and in the presence of higher demand of force (p = 0.02). For VE, results showed that participants were more variable in extension than in flexion when the required force was higher (p = 0.04). CE variable was higher when participants had to reach the force target in extension compared to flexion under the effect of DOMS (p = 0.02). Results also showed that participants took less time to reach the force target post-DOMS protocol in extension (0.62 ± 0.20 s) and in flexion (0.53 ± 0.19 s) than pre-DOMS protocol in extension (0.55 ± 0.15) and in flexion (0.50 ± 0.20) (p < 0.001). CONCLUSION: Lumbar muscle DOMS affects trunk proprioception during force reproduction tasks especially in trunk extension and at higher force.

Current Evidence on Diagnostic Criteria, Relevant Outcome Measures, and Efficacy of Nonpharmacologic Therapy in the Management of Restless Legs Syndrome (RLS): A Scoping Review.

OBJECTIVE: The aim of this scoping review is to outline the current evidence regarding the management of restless legs syndrome (RLS) with nonpharmacologic approaches. To categorize the efficacy of conservative approaches in reducing symptoms of RLS, we have identified and summarized the current data regarding diagnostic criteria and relevant outcome measures, to inform future research and to guide clinical practice. METHODS: A scoping review was conducted using the National Center for Biotechnology Information; EBSCO; the Manual, Alternative and Natural Therapy Index System; the Cumulative Index to Nursing & Allied Health Literature; and Scopus. All literature related to RLS was extracted, screened, and reviewed based on titles and abstract contents. The authors then extracted data from the 24 admissible studies, that is, the ones about manual therapy, exercises, and alternative treatments for RLS. The Physiotherapy Evidence Database scale was used to rate the methodological quality of the included randomized controlled trials by 2 independent readers. RESULTS: In the 24 articles fulfilling the selection criteria, there was a consistent trend in the findings showing positive results in lowering RLS symptom severity. Most clinical studies based their diagnosis on the International Restless Legs Syndrome Study Group diagnostic criteria; the International Restless Legs Syndrome Study Group rating scale was the most often used outcome measure. The efficacy of exercise, yoga, massage, acupuncture, traction straight leg raise, cryotherapy, pneumatic compression devices, whole-body vibration, transcranial and transcutaneous stimulation, and near-infrared lights showed different effects on RLS symptom severity, and the level of evidence was evaluated. CONCLUSION: Our results showed clinically significant effects for exercises, acupuncture, pneumatic compression devices, and near-infrared light. Short-lasting effects were identified with whole-body cryotherapy, repetitive transcranial stimulation, and transcutaneous stimulation. More studies are necessary to investigate efficacy of yoga, massage, traction straight leg raise, and whole-body vibration. No adverse effects were identified for moderate-intensity exercise, yoga, massage, and pneumatic compression devices.

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.

Association Between Physical Activity, Weight Loss, Anxiety, and Lumbopelvic Pain in Postpartum Women.

OBJECTIVE: Lumbopelvic pain (LBPP) affects 45% to 81% of pregnant women, and 25% to 43% of these women report persistent LBPP beyond 3 months after giving birth. The objective of this study was to investigate the association of physical activity, weight status, anxiety, and evolution of LBPP symptoms in postpartum women. METHODS: This was a prospective observational cohort study with 3 time-point assessments: baseline (T0), 3 months (T3), and 6 months (T6). Women with persistent LBPP 3 to 12 months after delivery were recruited. At each time point, pain disability was assessed with the Pelvic Girdle Questionnaire and the Oswestry Disability Index (ODI), physical activity with Fitbit Flex monitors, and anxiety with the French-Canadian version of the State-Trait Anxiety Inventory. Weight was recorded using a standardized method. Pain intensity (numerical rating scale, 0-100) and frequency were assessed using a standardized text message on a weekly basis throughout the study. RESULTS: Thirty-two women were included (time postpartum: 6.6 ± 2.0 months; maternal age: 28.3 ± 3.8 years; body weight: 72.9 ± 19.1 kg), and 27 completed the T6 follow-up. Disability, pain intensity, and pain frequency improved at T6 (P < .001). Participants lost a mean of 1.9 ± 4.5 kg at T6, and this weight loss was correlated with reduction in LBPP intensity (r = 0.479, P = .011) and LBPP frequency (r = 0.386, P = .047), Pelvic Girdle Questionnaire score (r = 0.554, P = .003), and ODI score (r = 0.494, P = .009). Improvement in ODI score at T6 was correlated with the number of inactive minutes at T3 (r = -0.453, P = .026) and T6 (r = -0.457, P = .019), and with daily steps at T6 (r = 0.512, P = .006). CONCLUSION: Weight loss is associated with positive LBPP symptom evolution beyond 3 months postpartum, and physical activity is associated with reduction in pain disability.

Paraspinal muscle function and pain sensitivity following exercise-induced delayed-onset muscle soreness.

PURPOSE: The aim of this study was to evaluate the effectiveness of an exercise protocol designed to induce delayed-onset muscle soreness (DOMS) in paraspinal muscles and its effects on low back functional capacities. METHODS: Twenty-four healthy participants were asked to perform four series of 25 trunk flexion-extension in a prone position (45° inclined Roman chair). The protocol was performed using loads corresponding to participant's trunk weight plus 10% of their trunk extension maximal voluntary contraction. Perceived soreness and pain were assessed using an 11-point numerical analogue scale three times a day during 5 day post-DOMS protocol. Pressure-pain thresholds (PPT) in paraspinal muscles (L2 and L4 bilaterally) and the vastus medialis (control site), and trunk extension maximal voluntary contraction were assessed 24-36 h post-protocol and compared to baseline (t tests). RESULTS: Muscle soreness (3.8/10) and pain (2.1/10) peak scores were observed 24-36 h post-protocol (mean of 28 h). A significant reduction in trunk extension maximal voluntary contraction was observed post-protocol (p = 0.005). Significant reductions in PPT were observed post-protocol for all trunk extensor sites (ps < 0.01), but not for the control site (p = 0.40). CONCLUSIONS: The exercise protocol efficiently led to low back muscle DOMS, reduced functional capacities, and increased pain sensitivity locally. Such protocol could be used as an efficient and safe experimental low back pain model.

Effects of spinal manipulative therapy biomechanical parameters on clinical and biomechanical outcomes of participants with chronic thoracic pain: a randomized controlled experimental trial.

BACKGROUND: Spinal manipulative therapy (SMT) includes biomechanical parameters that vary between clinicians, but for which the influence on the therapy clinical effects is unknown. This parallel-randomized controlled trial aimed to investigate the effect of SMT biomechanical parameters on the outcomes of participants with chronic thoracic pain (CTP) following three treatment sessions (follow-up at one week). METHODS: Adults reporting CTP (pain within the evaluated region [T6 to T8] for ≥3 months) were asked to participate in a four-session trial. At the first session, participants were randomly assigned to one of three experimental groups (different SMT doses) or the control group (no SMT). During the first three sessions, one SMT was executed at T7 for the experimental groups, while a 5-min rest was provided to the control group. SMT were delivered through an apparatus using a servo-controlled linear actuator motor and doses consisted of peak forces, impulse durations, and rates of force application set at 135 N, 125 ms and 920 N/s (group 1), at 250 N, 125 ms and 1840 N/s (group 2), and at 250 N, 250 ms, 920 N/s (group 3). Disability and pain intensity were evaluated at each session (primary outcomes). Spinal stiffness was assessed before-and-after each SMT/rest and at follow-up. Tenderness and muscle activity were evaluated during each spinal stiffness trial. Improvement was evaluated at follow-up. Differences in outcomes between groups and sessions were evaluated as well as factors associated with clinical improvement. RESULTS: Eighty-one participants were recruited and 17, 20, 20 participants of the three experimental groups and 18 of the control group completed the protocol. In exception of higher pain intensity at baseline in the control group, no between-group differences were found for any of the outcomes. A decrease in pain intensity, disability, spinal stiffness, and tenderness during spinal stiffness were observed (p-values< 0.05). At follow-up, 24% of participants were classified as 'improved'. Predictors of improvement were a greater decrease in pain intensity and in tenderness (p-values< 0.05). CONCLUSIONS: In an experimental setting, the delivery of a SMT does not lead to significantly different outcomes in participants with CTP than a control condition (spinal stiffness assessment). Studies are still required to explore the mechanisms underlying SMT effects. TRIAL REGISTRATION: ClinicalTrials.gov NCT03063177 , registered 24 February 2017).

Effect of Massage on Clinical and Physiological Variables During Muscle Fatigue Task in Participants With Chronic Low Back Pain: A Crossover Study.

OBJECTIVE: The purpose of this study was to determine if a reduction of short-term physiological and clinical effects of muscle fatigue can be seen after a session of massage in nonspecific chronic low back pain (cLBP) individuals and to study the possible association between physiological and clinical changes induced by massage. METHODS: Thirty-six cLBP individuals participated in 2 experimental sessions. In one session, the Sorenson protocol was preceded by a 30-minute massage, but in the other session, only the Sorenson test was performed by participants. Lumbar paraspinal muscle activity was recorded using surface electromyography, and maximal voluntary contraction force was measured using a load cell. Participants rated their lumbar pain intensity before and after massage and after the Sorensen protocol. A 2-way repeated-measures analysis of variance was conducted to test the effect of massage on both variables for both conditions. Pearson correlation analyses were conducted to determine the linear association between physiological and clinical responses to massage. RESULTS: Results showed that pain perception was significantly reduced after massage (P = .004) but did not seem to influence pain score increases occurring after the Sorensen protocol. Individuals with a high score of low back pain-related disability showed lower back muscle endurance time (r = -.35). Massage yielded no significant effect on fatigue-related physiological variables. CONCLUSION: The perception of pain in cLBP individuals was reduced after massage. Although massage yielded some positives clinical effects, they were not explained by a reduction in physiological effect of muscle fatigue.

Motor adaptations to trunk perturbation: effects of experimental back pain and spinal tissue creep.

In complex anatomical systems, such as the trunk, motor control theories suggest that many motor solutions can be implemented to achieve a similar goal. Although reflex mechanisms act as a stabilizer of the spine, how the central nervous system uses trunk redundancy to adapt neuromuscular responses under the influence of external perturbations, such as experimental pain or spinal tissue creep, is still unclear. The aim of this study was to identify and characterize trunk neuromuscular adaptations in response to unexpected trunk perturbations under the influence of spinal tissue creep and experimental back pain. Healthy participants experienced a repetition of sudden external trunk perturbations in two protocols: 1) 15 perturbations before and after a spinal tissue creep protocol and 2) 15 perturbations with and without experimental back pain. Trunk neuromuscular adaptations were measured by using high-density electromyography to record erector spinae muscle activity recruitment patterns and a motion analysis system. Muscle activity reflex attenuation was found across unexpected trunk perturbation trials under the influence of creep and pain. A similar area of muscle activity distribution was observed with or without back pain as well as before and after creep. No change of trunk kinematics was observed. We conclude that although under normal circumstances muscle activity adaptation occurs throughout the same perturbations, a reset of the adaptation process is present when experiencing a new perturbation such as experimental pain or creep. However, participants are still able to attenuate reflex responses under these conditions by using variable recruitment patterns of back muscles. NEW & NOTEWORTHY The present study characterizes, for the first time, trunk motor adaptations with high-density surface electromyography when the spinal system is challenged by a series of unexpected perturbations. We propose that the central nervous system is able to adapt neuromuscular responses by using a variable recruitment pattern of back muscles to maximize the motor performance, even under the influence of pain or when the passive structures of the spine are altered.

Trunk proprioception adaptations to creep deformation.

PURPOSE: This study aimed at identifying the short-term effect of creep deformation on the trunk repositioning sense. METHODS: Twenty healthy participants performed two different trunk-repositioning tasks (20° and 30° trunk extension) before and after a prolonged static full trunk flexion of 20 min in order to induce spinal tissue creep. Trunk repositioning error variables, trunk movement time and erector spinae muscle activity were computed and compared between the pre- and post-creep conditions. RESULTS: During the pre-creep condition, significant increases in trunk repositioning errors, as well as trunk movement time, were observed in 30° trunk extension in comparison to 20°. During the post-creep condition, trunk repositioning errors variables were significantly increased only when performing a 20° trunk extension. Erector spinae muscle activity increased in the post-creep condition, while it remained unchanged between trunk repositioning tasks. CONCLUSIONS: Trunk repositioning sense seems to be altered in the presence of creep deformation, especially in a small range of motion. Reduction of proprioception acuity may increase the risk of spinal instability, which is closely related to the risk of low back pain or injury.