New Brain Tumor Entities Emerge from Molecular Classification of CNS-PNETs.

Primitive neuroectodermal tumors of the central nervous system (CNS-PNETs) are highly aggressive, poorly differentiated embryonal tumors occurring predominantly in young children but also affecting adolescents and adults. Herein, we demonstrate that a significant proportion of institutionally diagnosed CNS-PNETs display molecular profiles indistinguishable from those of various other well-defined CNS tumor entities, facilitating diagnosis and appropriate therapy for patients with these tumors. From the remaining fraction of CNS-PNETs, we identify four new CNS tumor entities, each associated with a recurrent genetic alteration and distinct histopathological and clinical features. These new molecular entities, designated "CNS neuroblastoma with FOXR2 activation (CNS NB-FOXR2)," "CNS Ewing sarcoma family tumor with CIC alteration (CNS EFT-CIC)," "CNS high-grade neuroepithelial tumor with MN1 alteration (CNS HGNET-MN1)," and "CNS high-grade neuroepithelial tumor with BCOR alteration (CNS HGNET-BCOR)," will enable meaningful clinical trials and the development of therapeutic strategies for patients affected by poorly differentiated CNS tumors.

Pathogenic ACVR1R206H activation by Activin A-induced receptor clustering and autophosphorylation.

Fibrodysplasia ossificans progressiva (FOP) and diffuse intrinsic pontine glioma (DIPG) are debilitating diseases that share causal mutations in ACVR1, a TGF-ß family type I receptor. ACVR1R206H is a frequent mutation in both diseases. Pathogenic signaling via the SMAD1/5 pathway is mediated by Activin A, but how the mutation triggers aberrant signaling is not known. We show that ACVR1 is essential for Activin A-mediated SMAD1/5 phosphorylation and is activated by two distinct mechanisms. Wild-type ACVR1 is activated by the Activin type I receptors, ACVR1B/C. In contrast, ACVR1R206H activation does not require upstream kinases, but is predominantly activated via Activin A-dependent receptor clustering, which induces its auto-activation. We use optogenetics and live-imaging approaches to demonstrate Activin A-induced receptor clustering and show it requires the type II receptors ACVR2A/B. Our data provide molecular mechanistic insight into the pathogenesis of FOP and DIPG by linking the causal activating genetic mutation to disrupted signaling.

Young graduates and economic recession: Lessons from the pandemic to prevent the (re)incidence of mental health symptoms.

Economic conditions affect the youth labour market and can leave deep scars. This exploratory study examines the emotional responses and mental health symptoms of young graduates during their transition into the labour market in the pandemic context. It draws on 42 news articles with statements from 86 graduates from a set of European and non-European countries. The graduates had jobs or internships cancelled, numerous applications unanswered or were dismissed from jobs they had recently started. Young people adopt a variety of coping strategies, which are often invisible and cause deep suffering due to anxiety, disappointment, fear, and depression. Their apprehension and uncertainty leave them in a state of limbo. The specific impacts of the pandemic on young people's lives serve as a warning of the need to protect future generations of graduates. More support is required worldwide to manage the mental health issues that affect young graduates, especially during economic recessions.

The Vehicle Seating Intervention Trial: Cross-Over Randomized Controlled Trial to Evaluate the Impact of 2 Car Seat Configurations on Spinal Posture.

Driving posture can lead to musculoskeletal pain. Most work focuses on the lower back; therefore, we know little about automobile seat design and neck posture. This study evaluated an automobile driver seat that individualized upper back support to improve head and neck posture. Specifically, we examined the system's impact on anterior head translation with secondary outcomes of spine posture and perceptions of comfort/well-being compared with a control. Forty participants were block randomized to experience either the activated or deactivated version of the same seating system first. Participants completed two 30-minute simulated driving trials, separated by washout, with continuous measures of anterior head translation, spine posture, and pelvis orientation. Perceptions of comfort/well-being were assessed by survey and open-ended questions immediately following each condition. Small, but statistically significant decreases in anterior head translation and posterior pelvic tilt occurred with the activated seat system. Participants reported lower satisfaction with the activated seat system. Order of the 2 seat conditions affected differences in pelvis orientation and participant perceptions of comfort/well-being. An anthropometric-based seat system targeting upper back support can significantly affect head and pelvic posture but not satisfaction during simulated driving. Future work should examine long-term impacts of these posture changes on health outcomes.

Enhancing comprehensive primary care by integrating chiropractic led musculoskeletal care into interprofessional teams through supporting education, competency attainment, and optimizing integration.

Musculoskeletal (MSK) conditions are the leading cause of disability, resulting in up to 40% of visits to family physicians. Current primary care workforce shortages in Canada require other providers to maximize scopes of practice. Few MSK providers have been trained in team-based primary care settings. Study objectives included: (1) educating participating primary care teams through synchronous education, (2) educating Canadian primary care providers through asynchronous education, and (3) integrating chiropractors into primary care teams, whilst evaluating team MSK care knowledge/attitudes and integration experience. Results indicated improvements in collaborative competency, improved understanding and attitudes to chiropractic, and the importance of providing MSK care within funded primary care. Teams employed unique approaches to integrating chiropractors and indicated high demand for their services by patients and providers. Provision of MSK care without economic barrier is desirable and highly valued by teams. Chiropractors are well suited to participate in funded primary care teams in Canada.

An estimation of the endoscopist's musculoskeletal injury risk for right and left lateral decubitus positions during colonoscopy: a field-based ergonomic study.

BACKGROUND: Colonoscopy exposes endoscopists to awkward postures and prolonged forces, which increases their risk of musculoskeletal injury. Patient positioning has a significant impact on the ergonomics of colonoscopy. Recent trials have found the right lateral decubitus position is associated with quicker insertion, higher adenoma detection rates, and greater patient comfort compared to the left lateral decubitus position. However, this patient position is perceived as more strenuous by endoscopists. METHODS: Nineteen endoscopists were observed performing colonoscopies during a series of four-hour endoscopy clinics. Durations of each patient position (right lateral decubitus, left lateral decubitus, prone, and supine) were recorded for all observed procedures (n = 64). Endoscopist injury risk was estimated by a trained researcher for the first and last colonoscopies of the shifts (n = 34) using Rapid Upper Limb Assessment (RULA), an observational ergonomic tool that estimates risk of musculoskeletal injury by scoring postures of the upper body and factors such as muscle use, force, and load. The total RULA scores were compared with a Wilcoxon Signed-Rank test for patient position (right and left lateral decubitus) and time (first and last procedures) with significance taken at p < 0.05. Endoscopist preferences were also surveyed. RESULTS: The right lateral decubitus position was associated with significantly higher RULA scores than the left lateral decubitus position (median 5 vs. 3, p < 0.001). RULA scores were not significantly different between the first and last procedures of the shifts (median 5 vs. 5, p = 0.816). 89% of endoscopists preferred the left lateral decubitus position, primarily due to superior ergonomics and comfort. CONCLUSION: RULA scores indicate an increased risk of musculoskeletal injury in both patient positions, with greater risk in the right lateral decubitus position.

Effect of a 'spine offloading' chair design on seated height and posture.

A prototype chair with anterior chest and arm supports has been designed to reduce compressive spine loads. The purpose of this study was to compare the effects of this offloading design on seated height compared to a control configuration of the same chair. 20 males sat on each configuration for 1 hour. Seated height, perceived pain, spine angles, seat pressure, and participant experience were measured. Spine height loss was significantly reduced in the offloading (-0.75 ± 3.79 mm) compared to the control configuration (-6.16 ± 4.27 mm, p < 0.001), and participants sat significantly more anterior on the seat pan in the offloading (20.56 ± 1.67 cm) compared to control configuration (18.03 ± 1.92 cm, p < 0.001). There were no differences in spine angles or perceived back and gluteal pain between configurations. This design appears to be a promising approach to protecting the back during sitting when engaging in forward leaning tasks where the offloading effect of a backrest may be minimised. Practitioner summary: A prototype chair with anterior chest and arm supports designed to offload the spine was shown to significantly reduce seated height loss during 1-hour of sitting compared to a control configuration. While participants perceived the offloading design to be more supportive, no differences in perceived pain or posture were found.

Monitoring calf circumference: changes during prolonged constrained sitting.

Prolonged sitting has been associated with negative health effects; however, short-term time-varying exposure and response data is lacking. Twenty-two young and healthy participants were seated for 2 hours with the instruction to avoid the confounding effects of large leg movements while calf circumference, perceived discomfort, and lower limb muscle activity were collected. Calf circumference increased significantly (0.90 ± 0.32 cm) during sitting with no statistical differences between sexes. Perceived discomfort increased significantly over time in the low back and gluteal regions (p = 0.001-0.072, ηp2=0.080-0.360). On average, it took 20.31 ± 10.87 minutes of walking for calf measures to return to pre-sitting baseline. These results suggest that sitting for 2 hours without activity breaks may not be advisable and that recovery may take longer than expected. The exposure/response data from this study may be helpful in the design of future studies, with a larger and more general population, aiming to better define recommended duration/activity ratios for sitting-focused occupations. Practitioner summary: Leg swelling is a concern in prolonged sitting. In this study of young, healthy participants, we found a 2 hour constrained sitting exposure (controlling for large leg movements) induced significant increases in calf circumference that took an average of 20.31 ± 10.87 min of walking to return to baseline.Abbreviations: FMD: flow-mediated dilation, GSC: gastrocnemius; TA: tibialis anterior; EMG: electromyography; VAS: visual analog scale; MVC: maximum voluntary contractions.

Spinal mobility in radiographic axial spondyloarthritis: criterion concurrent validity of classic and novel measurements.

BACKGROUND: Limitations in spinal mobility are a characteristic feature of Axial Spondyloarthritis. Current clinical measurements of spinal mobility have shown low criterion-concurrent validity. This study sought to evaluate criterion-concurrent validity for a clinically feasible measurement method of measuring spine mobility using tri-axial accelerometers. METHODS: Fifteen radiographic-Spondyloarthritis patients were recruited for this study. Two postural reference radiographs, followed by three trials in forward, left and right lateral bending were taken. For all trials, three measurements were collected: tape (Original Schober's, Modified Schober's, Modified-Modified Schober's, Lateral Spinal Flexion Test and Domjan Test), followed immediately by synchronized radiograph and accelerometer measurements at end range of forward and bilateral lateral flexion. The criterion-concurrent validity of all measurement methods was compared to the radiographic measures using Pearson's correlation coefficients. A Bland-Altman analysis was conducted to assess agreement. RESULTS: In forward bending, the accelerometer method (r = 0.590, p = 0.010) had a stronger correlation to the radiographic measures than all tape measures. In lateral bending, the Lateral Spinal Flexion tape measure (r = 0.743, p = 0.001) correlated stronger than the accelerometer method (r = 0.556, p = 0.016). The Domjan test of bilateral bending (r = 0.708, p = 0.002) had a stronger correlation to the radiographic measure than the accelerometer method. CONCLUSIONS: Accelerometer measures demonstrated superior criterion-concurrent validity compared to current tape measures of spinal mobility in forward bending. While a moderate correlation exists between accelerometer and radiographs in lateral bending, the Lateral Spinal Flexion Test and Domjan Test were found to have the best criterion-concurrent validity of all tests examined in this study.

Does Using Multiple Computer Monitors for Office Tasks Affect User Experience? : A Systematic Review.

OBJECTIVE: To compare the impact of multiple computer monitor configurations on health and performance outcomes compared to the use of a single monitor. BACKGROUND: Multiple monitor configurations are used in office settings to promote increased productivity by providing more screen space; however, it is unknown if there are health-related trade-offs to increased productivity. METHOD: A systematic review was conducted according to the PRISMA statement guidelines and adapted the best evidence synthesis. RESULTS: Eighteen studies were included in our review. There was strong evidence that implementing dual monitors is in line with users' preference. There was also moderate evidence for controlled laboratory studies demonstrating that multiple monitors may increase task efficiency with decreased desktop interaction; however, implementing multiple monitors may also result in nonneutral neck postures for users. CONCLUSION: More research needs to be conducted on biomechanical exposures when using larger displays. Longitudinal field studies should be conducted to determine the influence of monitor interventions on health, productivity, and well-being. All studies must consider task complexity and user positioning and should measure health and productivity outcomes together. Researchers must also consider up-to-date purchasing trends when choosing the monitor configurations and sizes for their studies. APPLICATION: Regulatory bodies and practitioners can use the results to develop evidence-based monitor guidelines and inform decision-making in practice, respectively. Researchers can use this information to design future studies on monitor configurations that incorporate current purchasing trends.

Association of Exposures to Seated Postures With Immediate Increases in Back Pain: A Systematic Review of Studies With Objectively Measured Sitting Time.

OBJECTIVE: The purpose of this study was to conduct a systematic review of studies to determine whether sitting time measured objectively (by laboratory controlled time trial, direct observation, or wearable sensor) is associated with the immediate increase in low back pain (LBP) (determined by pain scale rating) in people >18 years of age. METHODS: Four databases (PubMed, EMBASE, SPORTDiscus, and Cumulative Index to Nursing and Allied Health Literature) were searched from inception to September 1, 2018. Randomized controlled trials and cohort and cross-sectional studies, where objectively measured sitting time was temporally matched with a measure of LBP in adults, were included. Studies without a control session conducted on a separate day were excluded. Screening, full-text review, data extraction, and risk of bias assessment (Quality In Prognosis Studies) of included papers were performed independently by 2 reviewers, with a third available to resolve disagreements. RESULTS: In total, 609 articles were identified, 361 titles/abstracts were screened,75 full-text articles were assessed for eligibility, and 10 met the inclusion criteria. All but 1 reported sitting time to be associated with an immediate increase in LBP. Six of these reported clinically relevant pain levels (n = 330). Half of the included studies were rated as having a low risk of bias and the remaining were rated as having a moderate risk of bias. CONCLUSION: Prolonged sitting increases immediate reporting of LBP in adults; however, no conclusion between sitting and clinical episodes of LBP can be made. Based upon these findings, we recommend that future prospective studies should match objectively measured sitting with temporally related pain measurements to determine whether prolonged sitting can trigger a clinical episode of LBP.

Correction to: International experience in the development of patient-derived xenograft models of diffuse intrinsic pontine glioma.

There are two errors and one omission in the original article. Author Gottardo's correct name is Nicholas G. Gottardo, author Hulleman's correct affiliation is no. 3 (VUMC, Amsterdam), and the Acknowledgements should include the following sentence: "We would like to thank Dr Angel Montero Carcaboso (Hospital Sant Joan de Deu, Barcelona, Spain) for generously supplying the HSJD-DIPG007 cells."

International experience in the development of patient-derived xenograft models of diffuse intrinsic pontine glioma.

PURPOSE: Diffuse intrinsic pontine glioma is the most aggressive form of high grade glioma in children with no effective therapies. There have been no improvements in survival in part due poor understanding of underlying biology, and lack of representative in vitro and in vivo models. Recently, it has been found feasible to use both biopsy and autopsy tumors to generate cultures and xenograft models. METHODS: To further model development, we evaluated the collective international experience from 8 collaborating centers to develop DIPG pre-clinical models from patient-derived autopsies and biopsies. Univariate and multivariate analysis was performed to determine key factors associated with the success of in vitro and in vivo PDX development. RESULTS: In vitro cultures were successfully established from 57% of samples (84.2% of biopsies and 38.2% of autopsies). Samples transferred in DMEM media were more likely to establish successful culture than those transported in Hibernate A. In vitro cultures were more successful from biopsies (84.2%) compared with autopsies (38.2%) and as monolayer on laminin-coated plates than as neurospheres. Primary cultures successfully established from autopsy samples were more likely to engraft in animal models than cultures established from biopsies (86.7% vs. 47.4%). Collectively, tumor engraftment was more successful when DIPG samples were directly implanted in mice (68%), rather than after culturing (40.7%). CONCLUSION: This multi-center study provides valuable information on the success rate of establishing patient-derived pre-clinical models of DIPG. The results can lead to further optimization of DIPG model development and ultimately assist in the investigation of new therapies for this aggressive pediatric brain tumor.

Clinicians' Ability to Detect a Palpable Difference in Spinal Stiffness Compared With a Mechanical Device.

OBJECTIVE: The purpose of this study was to quantify the threshold at which clinicians can detect a difference in spinal stiffness of the thoracic and lumbar spine via palpation and then determine if this detection threshold would affect a clinician's ability to identify changes in spinal stiffness as measured by an objective instrument. METHODS: In this study, the threshold at which a change in spinal stiffness was detected was quantified in 12 experienced clinicians (physical therapists and doctors of chiropractic) by changing the differential stiffness in 2 inflatable targets until the clinician could no longer identify which was stiffer. In the second part of the study, clinicians then were asked to palpate pre-identified pairs of vertebrae in an asymptomatic volunteer and to identify the stiffer of the pair (T7 and L3, T7 and L4, L3 and L4), and the biomechanical stiffness of each vertebral pair was quantified objectively by a validated instrument. RESULTS: The mean stiffness detection threshold for the clinicians was 8%. Objective measurement of the stiffness differential between vertebral pairs was 30% for T7* and L3, 20% for T7* and L4, and 10% for L3* and L4 (*denotes the stiffer of the pair). Ten of 12 clinicians correctly identified T7 as stiffer when compared with L3 and T7 as stiffer than L4. Alternatively, when the differential vertebral pair stiffness was similar to the stiffness detection threshold (~8%), clinicians were less successful in identifying the stiffer vertebra of the pair; 4 of 12 clinicians correctly identified L3 as being stiffer compared with L4. CONCLUSION: These results suggest that the physiological limits of human palpation may limit the ability of clinicians to identify small alterations in spine stiffness.

Transient perceived back pain induced by prolonged sitting in a backless office chair: are biomechanical factors involved?

It is not currently known if biomechanical factors contribute to low back pain (LBP) during prolonged sitting. Thus, this study recruited 90 participants (61 with no history of LBP, and 29 with) to sit for 1 hour where back electromyography, spine posture, and perceived pain ratings (PPR) were collected. Participants were classified as Pain Developers (PD) or Non-Pain Developers (NPD) based on their maximum PPR. PDs had significantly higher PPR (p = 0.000) and lower number of spine fidgets (p = 0.004) than NPDs. There was a significant interaction between clinical health history and pain group (p = 0.037) for PPR. Besides fidget frequency, there were no biomechanical differences between pain groups. Therefore, sitting-induced back pain does not appear to be due to posture or muscle activity; however, it may be related to micro-movement strategies. Future work should explore fidgeting further and whether healthy PDs are at risk for clinical LBP in the future. Practitioner summary: We have replicated the differential transient sitting-induced pain response observed in previous studies. Pain developers do not sit differently than non-pain developers, although they do appear to move less. More research is warranted to better understand these groups and the relationship between pain developers and future cases of back pain. Abbreviations: LBP: low back pain; PG: pain group; PD: pain developer; NPD: non-pain developer; +veHx: positive clinical history for low back pain; -veHx: negative clinical history for low back pain; RTS: right thoracic erector spinae; LTS: left thoracic erector spine; RLM: right lumbar multifidus; LLM: left lumbar multifidus; MVC: maximum voluntary contraction; Pelvic N: normalized pelvic angle; ANOVA: analysis of variance; SD: standard deviation.

Correlations Between Individuals' Characteristics and Spinal Stiffness in Individuals With and Without Back Pain: A Combined Analysis of Multiple Data Sets.

OBJECTIVE: The purpose of this study was to describe the correlations between individual characteristics and spinal stiffness as measured with different spinal stiffness measurement devices in individuals with and without back pain. METHODS: A secondary analysis of 3 adult data sets obtained using 3 different devices, in 2 spinal regions, from a total of 5 separate cross-sectional studies was conducted. Differences in spinal stiffness between men and women and in the strength of correlations among spinal stiffness and age and anthropometric characteristics were evaluated using either the t test for independent samples, Pearson's correlation coefficient, or Kendall's τ rank correlation coefficient. RESULTS: As expected, results varied between data sets; however, few factors had consistent correlations. Specifically, spinal stiffness was significantly lower in women than men in all 3 data sets. Height was positively correlated with spinal stiffness across all data sets. Although weight was correlated with thoracic stiffness, its correlation with lumbar stiffness varied. In 2 data sets, body mass index was inversely associated with lumbar spinal stiffness, whereas results from the thoracic spine region revealed a positive correlation. The results for 1 data set suggest that physiological measurement evaluating body weight distribution may also affect spinal stiffness; however, the specific correlation remains unclear. CONCLUSION: Despite data set differences, significant correlations were observed, indicating that participants' characteristics appear to affect spinal stiffness measurement.

The impact of office chair features on lumbar lordosis, intervertebral joint and sacral tilt angles: a radiographic assessment.

BACKGROUND: The purpose of this study was to determine which office chair feature is better at improving spine posture in sitting. METHOD: Participants (n = 28) were radiographed in standing, maximum flexion and seated in four chair conditions: control, lumbar support, seat pan tilt and backrest with scapular relief. Measures of lumbar lordosis, intervertebral joint angles and sacral tilt were compared between conditions and sex. RESULTS: Sitting consisted of approximately 70% of maximum range of spine flexion. No differences in lumbar flexion were found between the chair features or control. Significantly more anterior pelvic rotation was found with the lumbar support (p = 0.0028) and seat pan tilt (p < 0.0001). Males had significantly more anterior pelvic rotation and extended intervertebral joint angles through L1-L3 in all conditions (p < 0.0001). CONCLUSION: No one feature was statistically superior with respect to minimising spine flexion, however, seat pan tilt resulted in significantly improved pelvic posture. Practitioner Summary: Seat pan tilt, and to some extent lumbar supports, appear to improve seated postures. However, sitting, regardless of chair features used, still involves near end range flexion of the spine. This will increase stresses to the spine and could be a potential injury generator during prolonged seated exposures.

Evidence of interventions for the risk of dry eye in critically ill patients: An integrative review.

AIMS: Identify the best scientific evidence available to eye care in order to prevent dry eye. METHOD: Review study conducted according to the three steps of the evidence-based practice, guided by the following question, grounded in the Patient, Intervention, Comparison, and Outcome strategy: "What is the best scientific evidence available to eye care related to preventing dry eye?" Two databases were used, the web portal Medical Literature Analysis and Retrieval System Online and two digital libraries. Data were organized by using three structured forms. RESULTS: Ten studies made up the final sample, in English, with evidence levels between I and III. The results pointed out differences regarding the best or most appropriate occlusion and ocular lubrication methods to prevent dry eye. CONCLUSION: Several care methods showed strong scientific evidence to prevent dry eye, related to occlusion and ocular lubrication. There is a need for further studies to determine the strength of this evidence.

Outcomes of endoscopic management of primary and refractory postcholecystectomy biliary leaks in a multicentre review of 178 patients.

BACKGROUND: Biliary leaks have been treated with endoscopic management using different techniques with conflicting results. Furthermore the appropriate rescue therapy for refractory leaks has not been established. We evaluated the clinical effectiveness of initial endotherapy for postcholecystectomy biliary leaks using an homogenous approach (sphincterotomy + placement of a 10-French plastic stent) in a large series of patients as well as the optimal and efficacy of rescue endotherapy for refractory biliary leaks. METHODS: This was a multicenter, retrospective study of 178 patients who underwent endoscopic management of postcholecystectomy biliary leaks with a combination of biliary sphincterotomy and the placement of a large-bore (10-French) plastic stent. Data were collected to analyze the clinical outcomes and technical success, efficacy of the rescue endotherapy and the need for surgery, adverse events and prognostic factors for clinical success of endotherapy. RESULTS: Following endotherapy, closure of the leak was accomplished in 162/178 patients (91.0%). The multivariate logistic model showed that the type of leak, namely a high-grade biliary leak, was the only independent prognostic factor associated with treatment failure (OR = 26.78; 95% CI = 6.59-108.83; P < 0.01). The remaining 16 patients were treated with multiple plastic stents (MPSs) with a success rate of 62.5% (10 patients). The use of fewer than 3 plastic stents (P = 0.023) and a high-grade biliary leak (P = 0.034) were shown to be significant predictors of treatment failure with MPSs in refractory bile leaks. The 6 patients in whom the placement of MPSs failed were retreated with a fully cover self-expandable metallic stent (FCSEMS), resulting in closure of the leak in all cases. CONCLUSIONS: Endotherapy of biliary leaks with a combination of biliary sphincterotomy and the placement of a large-bore plastic stent is associated with a high rate of success (90%). However in our series there were several failures using MPSs as a strategy for rescue endotherapy suggesting that refractory biliary leaks should be treated with FCSEMS especially in patients with high-grade leaks.

Evaluating Abdominal and Lower-Back Muscle Activity While Performing Core Exercises on a Stability Ball and a Dynamic Office Chair.

OBJECTIVE: The purpose of this study was to evaluate the ability of a dynamic office chair to activate the core muscles while participants performed exercises sitting on the chair compared to a stability ball. BACKGROUND: Prolonged sitting has become an accepted part of the modern office. However, epidemiological evidence suggests that sedentary postures are linked to many adverse effects on health. The concept of dynamic or active sitting is intended to promote movement while sitting to reduce the time spent in prolonged, static postures. METHODS: Sixteen participants performed four pelvic rotation exercises (front-back, side-side, circular, and leg lift) on both a dynamic office chair and a stability ball. Muscle activity from 12 torso muscles were evaluated with surface electromyography. RESULTS: For all exercises, trunk muscle activity on the chair was comparable to that on a stability ball. The right external oblique was the only muscle to produce greater peak activity (p = .019) when using the ball compared to the chair (21.4 ± 14.0 percent maximal voluntary excitations (%MVE) and 14.7 ± 10.8 %MVE for the ball and chair, respectively). The left thoracic erector spinae produced greater average activity (p = .044) on the chair than on the ball. CONCLUSION: These findings suggest that this dynamic sitting approach could be an effective tool for core muscle activation while promoting movement and exercise while sitting at work. APPLICATION: Muscle activations on the dynamic chair are comparable to those on a stability ball, and dynamic office chairs can promote movement and exercise while sitting at work.