Clinical tests predictive of temporary low back pain development during the prolonged standing test in physical therapy students.

Low back pain among physical therapists is a common musculoskeletal disorder that first occurs early in their career or as a student. This observational prospective study assessed the ability of hip and lumbopelvic neuromuscular control, endurance and hip range of motion tests to predict the development of transient low back pain development during a standing task. Seventy-two physical therapy students without low back pain completed nine performance tests and a 2-hour standing test on two separate days. Participants were classified as transient pain developers (PD) if they reported a ≥ 10mm increase in low back pain on a visual analog scale. Transient back pain was reported by 37.5% of students during the standing test. A cluster of three positive tests, self-rated active hip abduction (somewhat difficult or more), bilateral total hip internal rotation greater than 81 degrees, and non-dominant limb single-leg squat (moderate deviations), demonstrated an increased probability (94.9%) of identifying PDs. Negative findings on the same three tests decreased the probability to 10.7%. Overall, the classification accuracy for the three-test model was 72.2%. The sensitivity for the model was 63% and the specificity was 77.8%.

A 3-test cluster of poor hip and lumbopelvic neuromuscular control and increased hip internal rotation range of motion is an effective screening tool for identifying physical therapy students who are most likely and least likely to develop transient LBP during 2 hours of standing.

Distinctive characteristics of prolonged standing low back pain developers' and the associated risk factors: systematic review and meta-analysis.

Pain developers (PDs) are considered a pre-clinical low back pain (LBP) population at risk of clinical LBP development and thus exacting great social and economic costs. Therefore, it is necessary to comprehensively investigate their distinctive characteristics and the risk factors of standing-induced LBP based on which appropriate preventive measures can be planned. Scopus, Web of Science, and PubMed databases as well as Google Scholar and ProQuest were systematically searched from inception through 14 July 2022 using a combination of terms relevant to 'standing' and 'LBP'. Studies with low risk of bias in English and Persian using a methodological quality scoring system were deemed eligible for inclusion if they were laboratory studies using prolonged standing duration greater than 42 min to classify adult PDs and non-pain developers (NPDs) without a history of LBP. PDs were compared with NPDs in demographics, biomechanical, and psychological outcomes. Weighted or standardized mean differences, and Hedge's g were generated to determine the pooled effect sizes using STATA software version 17. 52 papers and theses involving 1070 participants (528 PDs and 542 NPDs) were eligible for inclusion in the systematic review 33 of which were used in meta-analyses. Significant differences between PDs and NPDs in terms of movement patterns, muscular, postural, psychological, structural, and anthropometric variables were evidenced. The following factors were found to have a statistically significant association with standing-induced LBP: lumbar fidgets (Hedge's g - 0.72, 95% CI - 1.35 to - 0.08, P = 0.03), lumbar lordosis in participants over 25 years (Hedge's g 2.75, 95% CI 1.89-3.61, P < 0.001), AHAbd test (WMD 0.7, 95% CI 0.36-1.05, P < 0.001), GMed co-activation (Hedge's g 4.24, 95% CI 3.18-5.3, P < 0.001), and Pain Catastrophizing Scale (WMD 2.85, 95% CI 0.51-5.19, P = 0.02). Altered motor control displayed in AHAbd test and higher lumbar lordosis in individuals over 25 years seem to be probable risk factors for standing-induced LBP. In order to detect standing-induced LBP risk factors, future researchers should investigate the association of the reported distinctive characteristics to the standing-induced LBP and that whether they are manipulable through various interventions.

Incidence of Hemodynamic Changes Following Intravenous Acetaminophen Administration in Critically Ill Pediatric Patients.

OBJECTIVE: Acetaminophen is a commonly administered analgesic and antipyretic medication that is generally well-tolerated. Recent studies in critically ill adults and subsets of pediatric patients with underlying cardiac disease identify an association between adverse hemodynamic effects with intravenous (IV) acetaminophen. However, the data may not be generalizable to a broader population of critically ill children. The objective of this study was to determine the incidence of hemodynamic changes associated with IV acetaminophen administration in critically ill pediatric medical-surgical patients. METHODS: This was a retrospective observational study of all patients 18 years of age and younger who received at least 1 dose of IV acetaminophen in a pediatric intensive care unit at a quaternary care medical center, between July and December 2018. The primary outcome was the incidence of hypotension, defined as a decrease in mean arterial pressure (MAP) by at least 15% from baseline. Potential risk factors for IV acetaminophen-associated hypotension were assessed. RESULTS: A total of 212 patients received 492 doses of IV acetaminophen. The primary endpoint of hypotension occurred following 24% of doses. An intervention for hypotension, primarily fluid resuscitation, was required for 11.9% of the dose-associated hypotension events. Patients receiving vasoactive infusions had more frequent dose-associated hypotension events than those not receiving infusions; however, no other potential risk factors were identified. CONCLUSIONS: The incidence of hypotension observed in critically ill pediatric patients after IV acetaminophen administration is clinically relevant. Large placebo-controlled trial and further study of the risk factors and mechanism of this hemodynamic change are warranted.

The impact of living through COVID-19 pandemic on mental health, food insecurity, loneliness and health behaviours in people with obesity.

BACKGROUND: The COVID-19 pandemic has negatively impacted people living with obesity. The aim was to examine the continued impact of the COVID-19 pandemic on the mental health of people living with obesity and associations with food insecurity, loneliness and health-related behaviours. METHODS: The study recruited 1187 UK adults living with obesity who completed an online survey, which examined mental health and associations with food insecurity, loneliness and health-related behaviours from July 2020 (end of the first lockdown in the United Kingdom) to the point they completed the survey in 2021. Regression analyses were used to examine relationships between outcome variables and demographic factors, and hierarchical linear regression models were used to assess levels of loneliness, depression and well-being. RESULTS: Participants reported worse loneliness, depression, well-being and food insecurity compared to pre-COVID. However, participants reported attempting to lose weight, healthier food shopping, diet and increased physical activity. Quality and quantity of sleep deteriorated compared to prior to COVID-19. CONCLUSIONS: Adults living with obesity in the United Kingdom report a continued negative impact of the COVID-19 pandemic upon their mental health together with increased loneliness and food insecurity. However, our findings suggest that UK adults living with obesity have increased their engagement in positive health behaviours and were attempting to lose weight.

Task type, preference, and occupation affect standing desk utilization in office workers.

BACKGROUND: Adjustable height sit-stand desks are becoming the norm in many workplaces. It is not known how task type, worker preference, and occupation impact utilization of the adjustable height feature. OBJECTIVE: This survey-based study aimed to determine how task type, preference and occupation affect office workers' sitting and standing behaviors at work. METHODS: Office workers (n = 123) from different occupations completed surveys about actual and preferred positions (sit, stand, either/both) during 39 common tasks from 4 different categories, as well as barriers to use. Each position was analyzed by task type, behavior, and occupation. RESULTS: There were differences between actual and preferred behavior for each position, with participants sitting more and standing less than preferred across all task categories. There were differences between task categories with participants sitting less for generative and routine, and standing more for communication tasks. The highest rates of either/both responses were for routine tasks. Engineers reported the lowest standing rates, and also indicated standing more than preferred. Information Tech and Engineering had the highest either/both responses. Finance reported the highest sitting rates. Personal, task-based and workplace limitations were cited as barriers to preferred use. CONCLUSION: Office workers would prefer to stand more at work. Occupation-specific needs and preferences, as well as types of tasks should be considered when providing workplace standing options.

N-Oleoyl dopamine induces IL-10 via central nervous system TRPV1 and improves endotoxemia and sepsis outcomes.

BACKGROUND: The transient receptor potential vanilloid 1 (TRPV1) participates in thermosensation and inflammatory pain, but its immunomodulatory mechanisms remain enigmatic. N-Oleoyl dopamine (OLDA), an endovanilloid and endocannabinoid, is a TRPV1 agonist that is produced in the central nervous system and the peripheral nervous system. We studied the anti-inflammatory effects and TRPV1-dependent mechanisms of OLDA in models of inflammation and sepsis. METHODS: Mice were challenged intratracheally or intravenously with LPS, or intratracheally with S. aureus to induce pneumonia and sepsis, and then were treated intravenously with OLDA. Endpoints included plasma cytokines, leukocyte activation marker expression, mouse sepsis scores, lung histopathology, and bacterial counts. The role of TRPV1 in the effects of OLDA was determined using Trpv1-/- mice, and mice with TRPV1 knockdown pan-neuronally, in peripheral nervous system neurons, or in myeloid cells. Circulating monocytes/macrophages were depleted using clodronate to determine their role in the anti-inflammatory effects of OLDA in endotoxemic mice. Levels of exogenous OLDA, and of endovanilloids and endocannabinoids, at baseline and in endotoxemic mice, were determined by LC-MS/MS. RESULTS: OLDA administration caused an early anti-inflammatory response in endotoxemic and septic mice with high serum levels of IL-10 and decreased levels of pro-inflammatory cytokines. OLDA also reduced lung injury and improved mouse sepsis scores. Blood and lung bacterial counts were comparable between OLDA- and carrier-treated mice with S. aureus pneumonia. OLDA's effects were reversed in mice with pan-neuronal TRPV1 knockdown, but not with TRPV1 knockdown in peripheral nervous system neurons or myeloid cells. Depletion of monocytes/macrophages reversed the IL-10 upregulation by OLDA in endotoxemic mice. Brain and blood levels of endovanilloids and endocannabinoids were increased in endotoxemic mice. CONCLUSIONS: OLDA has strong anti-inflammatory actions in mice with endotoxemia or S. aureus pneumonia. Prior studies focused on the role of peripheral nervous system TRPV1 in modulating inflammation and pneumonia. Our results suggest that TRPV1-expressing central nervous system neurons also regulate inflammatory responses to endotoxemia and infection. Our study reveals a neuro-immune reflex that during acute inflammation is engaged proximally by OLDA acting on neuronal TRPV1, and through a multicellular network that requires circulating monocytes/macrophages, leads to the systemic production of IL-10.

Isolation of Primary Mouse Lung Endothelial Cells.

Endothelial cells play critical roles in the regulation of vascular tone, immunity, coagulation, and permeability. Endothelial dysfunction occurs in medical conditions including diabetes, atherosclerosis, sepsis, and acute lung injury. A reliable and reproducible method to isolate pure endothelial cells from mice is needed to investigate the role of endothelial cells in the pathogenesis of these and other conditions. In this protocol, lung microvascular endothelial cells were prepared from 5-7 day old neonatal mouse pups. Lungs are harvested, minced, and enzymatically digested with collagenase I, and released cells are cultured overnight. Endothelial cells are then selected using anti-PECAM1 (CD-31) IgG conjugated to magnetic beads, and cells again are cultured to confluence. A secondary cell selection then occurs with anti-ICAM2 (CD-102) IgG conjugated to magnetic beads to increase the purity of the endothelial cells, and the cells again are cultured to confluence. The entire process takes approximately 7-10 days before the cells can be used for experimentation. This simple protocol yields highly pure (purity >92%) endothelial cells that can be immediately used for in vitro studies, including the studies focused on endothelial cytokine and chemokine production, leukocyte-endothelial interactions, endothelial coagulation pathways, and endothelial permeability. With many knockouts and transgenic mouse lines available, this procedure also lends itself to understanding the function of specific genes expressed by endothelial cells in healthy and pathologic responses to injury, infection, and inflammation.

Office-workers maintain decreased workplace sitting time long-term following participation in a sit-stand desk intervention study.

Previous studies report decreased workplace sitting time when standing desk interventions are provided to office workers. It is unclear whether decreased sedentary behaviours are maintained long-term. This was a follow-up to a previous intervention study to investigate whether observed sitting time decreases of 30-50% were sustained 12-24 months later. A secondary aim was to compare overall physical activity between office workers with and without standing desks. Although sitting time increased over the follow-up period, this did not reach significance and reductions in workplace sitting remained significantly lower (23.5% decrease) from baseline values. There were no differences in the physical activity measures between workers with and without access to standing desks, although this was a small sample size and further research is needed. Individuals who are motivated to try standing desks at work can benefit through decreased sitting time long-term, however this may not extend to increased overall physical activity levels. Practitioner summary: Providing standing desk options to office-based employees can have long-lasting impacts with reducing sitting time at work. Office workers who choose to stand at work do not appear to compensate with overall activity level reduction outside of work.Abbreviations: LBP: low back pain; OSPAQ: occupational sitting and physical activity questionnaire; VAS: visual analog scale; ANOVA: analysis of variance; BMI: body mass index; ICC: intraclass correlation coefficient.

Hip and Trunk Muscle Activity and Mechanics During Walking With and Without Unilateral Weight.

Pelvic drop is caused by decreased hip abductor muscle activity and is associated with lower-extremity injury. Hip abductor strengthening exercises are well established; however, no standard method exists to increase hip abductor activity during functional activities. The purpose of this research was to study the effects of walking with a unilateral weight. A total of 26 healthy adults walked on an instrumented treadmill with and without handheld weight (15%-20% body weight). Muscle activity, kinematic, and kinetic data were collected using surface electromyography, motion capture, and force plates, respectively. Average hip and trunk muscle activity, hip, pelvic, and trunk angles, and peak internal hip moments during stance were compared for each side (contralateral/ipsilateral to the weight) between conditions (unweighted/weighted) using a generalized linear model with generalized estimating equation correction. Interactions between condition and side were observed for muscle activity, frontal plane pelvic and trunk angles, and frontal plane hip moments (P ≤ .003). Compared with the unweighted condition, the weighted condition had higher hip abductor activity contralateral to the weight (P < .001), while no change was found ipsilateral to the weight (P ≥ .790). Similar changes were found for kinematic and kinetic variables. Walking with a unilateral weight may be a therapeutic option to increase functional hip abductor activity.

Catecholaminergic Vasopressors Reduce Toll-Like Receptor Agonist-Induced Microvascular Endothelial Cell Permeability But Not Cytokine Production.

OBJECTIVES: Catecholaminergic vasopressors are the cornerstone of circulatory shock management. Nevertheless, catecholamines have problematic side effects, arousing a growing interest in noncatecholaminergic agents such as vasopressin or angiotensin-II. However, their respective effects on sepsis-associated microvascular endothelial dysfunction such as permeability or inflammation remain elusive. We investigated the role of catecholamines and other vasopressors on Toll-like receptor agonists-induced microvascular endothelial permeability and inflammation. SETTING: University research laboratory/cell research. SUBJECTS: Human pulmonary microvascular endothelial cells from multiple donors. INTERVENTION: Confluent monolayers of human pulmonary microvascular endothelial cells were treated with Toll-like receptor agonists (lipopolysaccharide, Poly[I:C], or tripalmitoyl-S-glyceryl cysteine) in the presence or absence of epinephrine, norepinephrine, vasopressin, and angiotensin-II. Permeability was inferred from transendothelial resistance, measured using electrical cell impedance sensing, where decreased transendothelial resistance is consistent with increased permeability. Cell-cell junction molecule expression was assessed via immunofluorescence microscopy and flow cytometry. We quantified cytokines in supernatants of Toll-like receptor agonist-treated human pulmonary microvascular endothelial cells. MEASUREMENTS AND MAIN RESULTS: Epinephrine and norepinephrine both ameliorate lipopolysaccharide, polyinosinic:polycytidylic acid, or tripalmitoyl-S-glyceryl cysteine-induced reductions in transendothelial resistance, a surrogate for endothelial permeability. In contrast, the noncatecholaminergic agents, vasopressin, and angiotensin-II did not affect Toll-like receptor agonists-induced reductions in transendothelial resistance. ß1- and ß2-adrenergic receptor antagonists reduced the effects of the catecholamines on transendothelial resistance, whereas α-adrenergic receptor antagonists did not. We observed that epinephrine and norepinephrine induced actin cytoskeletal rearrangement and normalized the membrane expression of proteins involved with adherens-junctions (vascular endothelial-cadherin) and tight-junctions (zona occludens-1). Despite having a substantial effect on endothelial permeability, epinephrine and norepinephrine did not affect human pulmonary microvascular endothelial cell survival or production of interleukin-8, interleukin-6, or monocyte chemoattractant protein-1 (CCL-2) induced by Toll-like receptor agonists, suggesting that these functions are regulated separately from permeability. CONCLUSIONS: Our findings demonstrate that treatment with epinephrine or norepinephrine strongly reduces endothelial permeability induced by agonists of multiple Toll-like receptors (Toll-like receptor-2, Toll-like receptor-3, Toll-like receptor-4) in vitro. Our studies suggest that both ß1- and ß2-adrenergic receptors mediate the stabilizing effects of epinephrine and norepinephrine on the endothelial barrier.

ERK1/2 Has Divergent Roles in LPS-Induced Microvascular Endothelial Cell Cytokine Production and Permeability.

ABSTRACT: Endothelial cells play a major role in inflammatory responses to infection and sterile injury. Endothelial cells express Toll-like receptor 4 (TLR4) and are activated by LPS to express inflammatory cytokines/chemokines, and to undergo functional changes, including increased permeability. The extracellular signal-regulated kinase 1/2 (ERK1/2) mediates pro-inflammatory signaling in monocytes and macrophages, but the role of ERK1/2 in LPS-induced activation of microvascular endothelial cells has not been defined. We therefore studied the role of ERK1/2 in LPS-induced inflammatory activation and permeability of primary human lung microvascular endothelial cells (HMVEC). Inhibition of ERK1/2 augmented LPS-induced IL-6 and vascular cell adhesion protein (VCAM-1) production by HMVEC. ERK1/2 siRNA knockdown also augmented IL-6 production by LPS-treated HMVEC. Conversely, ERK1/2 inhibition abrogated permeability and restored cell-cell junctions of LPS-treated HMVEC. Consistent with the previously described pro-inflammatory role for ERK1/2 in leukocytes, inhibition of ERK1/2 reduced LPS-induced cytokine/chemokine production by primary human monocytes. Our study identifies a complex role for ERK1/2 in TLR4-activation of HMVEC, independent of myeloid differentiation primary response gene (MyD88) and TIR domain-containing adaptor inducing IFN-ß (TRIF) signaling pathways. The activation of ERK1/2 limits LPS-induced IL-6 production by HMVEC, while at the same time promoting HMVEC permeability. Conversely, ERK1/2 activation promotes IL-6 production by human monocytes. Our results suggest that ERK1/2 may play an important role in the nuanced regulation of endothelial cell inflammation and vascular permeability in sepsis and injury.

Hip Joint Contact Loading and Muscle Forces During Running With a Transtibial Amputation.

People with unilateral transtibial amputations (TTA) have greater risks of bilateral hip osteoarthritis, related to asymmetric biomechanics compared to people without TTA. Running is beneficial for physical health and is gaining popularity. However, people with TTA may not have access to running-specific prostheses (RSPs), which are designed for running, and may instead run using their daily-use prosthesis (DUP). Differences in joint loading may result from prosthesis choice; thus, it is important to characterize changes in peak and impulsive hip joint contact loading during running. Six people with and without TTA ran at 3.5 m/s while ground reaction forces, kinematics, and electromyography were collected. People with TTA ran using their own RSP and DUP. Musculoskeletal models incorporating prosthesis type of each individual were used to quantify individual muscle forces and hip joint contact forces (HJCFs) during running. People using RSPs had smaller bilateral peak hip joint contact forces compared to when wearing DUPs during stance and swing, and a smaller impulse over the entire gait cycle. Greater amputated leg peak hip joint contact forces for people wearing DUPs compared to RSPs occurred with greater forces from the ipsilateral gluteus maximus during stance. People with TTA also had greater bilateral peak hip joint contact forces during swing compared to people without TTA, which occurred with greater peak gluteus medius forces. Running with more compliant RSPs may be beneficial for long-term joint health by reducing peak and impulsive hip loading compared to DUPs.

Running-specific prostheses reduce lower-limb muscle activity compared to daily-use prostheses in people with unilateral transtibial amputations.

People with unilateral transtibial amputation (TTA) have biomechanical differences between the amputated and intact legs and compared to people without TTA during running. Additional biomechanical differences emerge between running with running-specific (RSPs) and daily-use prostheses (DUPs), but the associated underlying muscle activity is unclear. We collected surface electromyography from the biceps femoris long head, rectus femoris, vastus lateralis, and gastrocnemius as well as body kinematics and ground reaction forces in six people with and six people without TTA. We compared stance phase muscle activity and peak activation timing in people with and without TTA and between people using RSPs compared to DUPs during running at 3.5 m/s. Peak amputated leg hamstring activity occurred 34% (RSP) and 31% (DUP) earlier in stance phase compared to the intact leg. Peak amputated leg rectus femoris activity of people wearing DUPs occurred 8% and 9% later in stance phase than the intact leg of people wearing DUPs and amputated leg of people wearing RSPs, respectively. People with TTA had 45% (DUP) and 61% (RSP) smaller peak amputated leg knee extension moments compared to people without TTA, consistent with observations of quadriceps muscle activity. Using RSPs decreased overall muscle activity compared to DUPs.

A Comparison of Clinical Spinal Mobility Measures to Experimentally Derived Lumbar Spine Passive Stiffness.

Spinal stiffness and mobility assessments vary between clinical and research settings, potentially hindering the understanding and treatment of low back pain. A total of 71 healthy participants were evaluated using 2 clinical assessments (posteroanterior spring and passive intervertebral motion) and 2 quantitative measures: lumped mechanical stiffness of the lumbar spine and local tissue stiffness (lumbar erector spinae and supraspinous ligament) measured via myotonometry. The authors hypothesized that clinical, mechanical, and local tissue measures would be correlated, that clinical tests would not alter mechanical stiffness, and that males would demonstrate greater lumbar stiffness than females. Clinical, lumped mechanical, and tissue stiffness were not correlated; however, gradings from the posteroanterior spring and passive intervertebral motion tests were positively correlated with each other. Clinical assessments had no effect on lumped mechanical stiffness. The males had greater lumped mechanical and lumbar erector spinae stiffness compared with the females. The lack of correlation between clinical, tissue, and lumped mechanical measures of spinal stiffness indicates that the use of the term "stiffness" by clinicians may require reevaluation; clinicians should be confident that they are not altering mechanical stiffness of the spine through segmental mobility assessments; and greater resting lumbar erector stiffness in males suggests that sex should be considered in the assessment and treatment of the low back.

Lumbar Intervertebral Kinematics During an Unstable Sitting Task and Its Association With Standing-Induced Low Back Pain.

People developing transient low back pain during standing have altered control of their spine and hips during standing tasks, but the transfer of these responses to other tasks has not been assessed. This study used video fluoroscopy to assess lumbar spine intervertebral kinematics of people who do and do not develop standing-induced low back pain during a seated chair-tilting task. A total of 9 females and 8 males were categorized as pain developers (5 females and 3 males) or nonpain developers (4 females and 5 males) using a 2-hour standing exposure; pain developers reported transient low back pain and nonpain developers did not. Participants were imaged with sagittal plane fluoroscopy at 25 Hz while cyclically tilting their pelvises anteriorly and posteriorly on an unstable chair. Intervertebral angles, relative contributions, and anterior-posterior translations were measured for the L3/L4, L4/L5, and L5/S1 joints and compared between sexes, pain groups, joints, and tilting directions. Female pain developers experienced more extension in their L5/S1 joints in both tilting directions compared with female nonpain developers, a finding not present in males. The specificity in intervertebral kinematics to sex-pain group combinations suggests that these subgroups of pain developers and nonpain developers may implement different control strategies.

Activation of CB1R Promotes Lipopolysaccharide-Induced IL-10 Secretion by Monocytic Myeloid-Derived Suppressive Cells and Reduces Acute Inflammation and Organ Injury.

Cannabis sativa and its principal components, Δ9-tetrahydrocannabinol (Δ9-THC) and cannabidiol, are increasingly being used to treat a variety of medical problems, including inflammatory conditions. Although studies suggest that the endocannabinoid system has immunomodulatory properties, there remains a paucity of information on the effects of cannabinoids on immunity and on outcomes of infection and injury. We investigated the effects and mechanism(s) of action of cannabinoid receptor agonists, including Δ9-THC, on inflammation and organ injury in endotoxemic mice. Administration of Δ9-THC caused a dramatic early upregulation of plasma IL-10 levels, reduced plasma IL-6 and CCL-2 levels, led to better clinical status, and attenuated organ injury in endotoxemic mice. The anti-inflammatory effects of Δ9-THC in endotoxemic mice were reversed by a cannabinoid receptor type 1 (CB1R) inverse agonist (SR141716), and by clodronate-induced myeloid-cell depletion, but not by genetic invalidation or blockade of other putative Δ9-THC receptors, including cannabinoid receptor type 2, TRPV1, GPR18, GPR55, and GPR119. Although Δ9-THC administration reduced the activation of several spleen immune cell subsets, the anti-inflammatory effects of Δ9-THC were preserved in splenectomized endotoxemic mice. Finally, using IL-10-GFP reporter mice, we showed that blood monocytic myeloid-derived suppressive cells mediate the Δ9-THC-induced early rise in circulating IL-10. These results indicate that Δ9-THC potently induces IL-10, while reducing proinflammatory cytokines, chemokines, and related organ injury in endotoxemic mice via the activation of CB1R. These data have implications for acute and chronic conditions that are driven by dysregulated inflammation, such as sepsis, and raise the possibility that CB1R-signaling may constitute a novel target for inflammatory disorders.

Increasing standing tolerance in office workers with standing-induced back pain.

Sit-stand desks are popular however many people have standing-induced low back pain (LBP). People with LBP have fewer standing weight shifts compared with back-healthy people. Participants were classified as standing-tolerant or intolerant. Participants were provided sit-stand desks for 12 weeks. Participants were assigned to intervention (graded standing exposure and exercise) or control (no instruction) conditions. Participants reported weekly sitting time and average/worst LBP. Standing weight shifts and LBP were re-assessed post-intervention. All groups decreased sitting time (range: 30-50%) over 12 weeks. Sitting time and average LBP were correlated in all standing-intolerant individuals, worst LBP and sitting time were correlated for intervention group only. All standing-intolerant individuals increased standing weight shifts and decreased LBP after 12-weeks. Standing-intolerant individuals benefitted from 12-weeks of sit-stand desk use regardless of intervention. Motivated individuals with standing-induced LBP may increase standing tolerance with sit-stand desk use. Additional benefits may exist when structured guidance is provided. Practitioner summary: Many people are standing-intolerant due to low back pain (LBP). This lab and field-based study showed some benefits from structured approaches to gradually progress standing time when transitioning to standing work. Using a sit-stand desk for 12 weeks resulted in decreased LBP and sitting time in standing-intolerant people. Abbreviations: LBP: low back pain; OSPAQ: Occupational Sitting and Physical Activity Questionnaire; VAS: visual analog scale; GRF: ground reaction force; WeekVASMAX: worst low back pain reported on visual analog scale for prior week; WeekVASAVE: average low back pain reported on visual analog scale for prior week; ICC: intraclass correlation coefficient; LabVASMAX: worst low back pain reported on visual analog scale during lab-based standing; LabVASAVE: average low back pain reported on visual analog scale during lab-based standing; FvR,L: vertical ground reaction force for right and left force plate; BWSSMALL: small (10-29% body weight) body weight shift; BWSLARGE: large (> 30% body weight) body weight shift; ActivPALSED: ActivePAL data for sedentary time; ActivPALSTND: ActivePAL data for standing time; ANOVA: analysis of variance; Standing Intolerant-INT: standing intolerant participants assigned to intervention condition; Standing Intolerant-CON: standing intolerant participants assigned to control condition; Standing Tolerant-INT: standing tolerant participants assigned to intervention condition; Standing Tolerant-CON: standing tolerant participants assigned to control condition; SI: standing intolerant; ST: standing tolerant; INT: intervention; CON: control.

Joint work and ground reaction forces during running with daily-use and running-specific prostheses.

Some individuals with a transtibial amputation (TTA) may not have access to running-specific prostheses and therefore choose to run using their daily-use prosthesis. Unlike running-specific prostheses, daily-use prostheses are not designed for running and may result in biomechanical differences that influence injury risk. To investigate these potential differences, we assessed the effect of amputation, prosthesis type, and running speed on joint work and ground reaction forces. 13 people with and without a unilateral TTA ran at speeds ranging from 2.5 m/s to 5.0 m/s. People with TTA ran using their own daily-use and running-specific prostheses. Body kinematics and ground reaction forces were collected and used to compute joint work. People with TTA had smaller peak braking, propulsive and medial/lateral ground reaction forces from the amputated leg compared to people without TTA. People wearing running-specific prostheses had smaller peak amputated leg vertical ground reaction forces compared to daily-use prostheses at speeds above 3.5 m/s. Medial/lateral forces were also smaller in running-specific prostheses, which may present balance challenges when running on varied terrain. Running-specific prostheses stored and returned more energy and provided greater propulsion, resulting in more similar positive hip work between legs compared to daily-use prostheses. Increases in positive hip work, but not device work, highlight the importance of the hip in increasing running speed. Running-specific devices may be beneficial for joint health at running-speeds above 3.5 m/s and provide advantages in propulsion and energy return at all speeds compared to daily-use prostheses, helping people with TTA achieve faster running speeds.

A comparison of trunk control in people with no history, standing-induced, and recurrent low back pain during trunk extension.

Objectives: This study compares people with recurrent low back pain (rLBP) and people with pre-clinical low back pain (standing-induced low back pain developers; PDs) to each other and back-healthy controls (non-pain developers; NPDs). Movement variability and muscular co-activity related to coordination are important for both rLBP and PDs, and these two groups also have altered static spine extension.Methods: Eleven participants with recurrent low back pain, and twenty-one asymptomatic participants, categorized as PDs (11) and NPDs (10) through an established standing protocol, volunteered for this study. Three phases of standing extension motion (lean, hold, and return to neutral) were analyzed. Root mean square angular jerk was calculated from trunk and pelvis kinematics, co-activation of the trunk and hip musculature were assessed in four-muscle sets.Results: Root-mean-square jerk was greater when returning to neutral than when leaning back during standing extension in all three groups. People with rLBP had reduced co-activity in their trunk extensors, people classified as PD had more co-activity in their hip extensors compared with the other groups, and anterior trunk co-activity was phase-dependent, and similar between groups.Discussion: Movement control alterations with low back pain may start as an over-protective co-activation strategy in those with standing-induced LBP and progress to an under-protective strategy in those with recurrent low back pain. Level of Evidence: 3.

Individuals with low back pain improve in standing tolerance and sagittal plane muscle activation following exercise intervention.

BACKGROUND: Healthy individuals who develop low back pain (LBP) during standing (standing intolerant) respond favorably to stabilization-based exercise interventions. People with clinical LBP meeting clinical prediction rules for stabilization-based exercise share characteristics with standing intolerant individuals. OBJECTIVE: To investigate the impact of stabilization-based exercise on standing tolerance, muscle activation and clinical measures in individuals with LBP meeting clinical prediction rules for stabilization-based exercise. METHODS: Participants with and without LBP completed testing pre- and post-6 weeks of progressive home exercise intervention. Testing included clinical examination and electromyography during sagittal and frontal plane movements. LBP was also assessed by visual analogue scale (VAS) during standing. Outcomes included clinical findings, muscle sequencing, and VAS in standing. RESULTS: The LBP group had non-significant decreases in Oswestry Disability Index (-2.1%, p= 0.22), baseline VAS (-7.1 mm, p= 0.11), lumbopelvic reversal (p= 0.06) and positive active hip abduction test (p= 0.06). Significant improvements were seen in standing VAS (-5.6 mm, p< 0.001). The LBP group had beneficial changes in activation strategies in standing flexion (p< 0.05) following intervention, with no changes during frontal plane movement strategies. CONCLUSIONS: Individuals with LBP meeting clinical prediction rules for stabilization-based exercise demonstrated increased standing tolerance and sagittal plane muscle sequencing following a 6-week intervention.