Age-dependent flexion relaxation phenomenon in chronic low back pain patients.

Background: The flexion relaxation phenomenon (FRP) is characterized by suddenly reduced paraspinal muscle activity during full flexion. Previous studies showed significant differences in FRP and flexion angles in chronic low back pain (cLBP) patients compared to individuals without back pain (no-BP). However, the relationship between FRP and flexion angles remains insufficiently understood in older populations. Thus, this study investigated the relationship between FRP and flexion angles concerning to the age and presence of cLBP. Methods: Forty no-BP subjects (20m/20f; mean age 41.5 years) and thirty-eight cLBP patients (19m/19f; mean age 43.52 years) performed maximum full upper body flexion task. Electromyographic (EMG) measurements were conducted to assess the activity of lumbar erector spinae (ESL), thoracic erector spinae (EST), and multifidus (MF). Lumbar, thoracic, and pelvic angles at the onset (OnsetL/T/P) and offset of the FRP (OffsetL/T/P) and maximum trunk inclination (MaxL/T/P) were calculated. The FRP was evaluated using a flexion relaxation ratio (FRR). Results: cLBP patients showed smaller FRR in MF and right ESL compared to no-BP individuals (p < 0.05), while no differences were found in flexion angles between two groups. Subjects over 40 showed smaller FRR in MF and ESL, and smaller flexion angles on OffsetL and MaxL (p < 0.05). Age-related analysis in the cLBP group revealed that patients over 40, compared to younger ones, had smaller FRR in MF and ESL, and smaller values in all thoracic and lumbar flexion angles (p < 0.05). While in no-BP group, significant larger flexion angles in OnsetL and OffsetT (p < 0.05) were observed in participants over 40. Pain-related analysis in the older group revealed that the cLBP patients, compared to no-BP individuals, had smaller FRR in right MF and right ESL, and smaller values in all lumbar and thoracic flexion angles (p < 0.05), while in younger group, there were no significant pain-related differences in FRR, with larger values in all lumbar flexion angles (p < 0.05). Conclusion: Our findings indicate a reduction or absence of FRP in cLBP patients compared to no-BP individuals, with age being a significant factor as those over 40 showed smaller FRP and flexion angles compared to younger individuals.

Effect of low back pain on the kinetics and kinematics of the lumbar spine - a combined in vivo and in silico investigation.

Lifting is a significant risk factor for low back pain (LBP). Different biomechanical factors including spinal loads, kinematics, and muscle electromyography (EMG) activities have previously been investigated during lifting activities in LBP patients and asymptomatic individuals to identify their association with LBP. However, the findings were contradictory and inconclusive. Accurate and subject-specific prediction of spinal loads is crucial for understanding, diagnosing, planning tailored treatments, and preventing recurrent pain in LBP patients. Therefore, the present study aimed to estimate the L5-S1 compressive and resultant shear loads in 19 healthy and 17 non-specific chronic LBP individuals during various static load-holding tasks (holding a 10 kg box at hip, chest, and head height) using full-body and personalized musculoskeletal models driven by subject-specific in vivo kinematic/kinetic, EMG, and physiological cross-sectional areas (PCSAs) data. These biomechanical characteristics were concurrently analyzed to identify potential differences between the two groups. Statistical analyses showed that LBP had almost no significant effect on the range of motion (trunk, lumbar, pelvis), PCSA, and EMG. There were no significant differences (p > 0.05) in the predicted L5-S1 loads. However, as the task became more demanding, by elevating the hand-load from hip to head, LBP patients experienced significant increases in both compressive (33 %, p = 0.00) and shear (25 %, p = 0.02) loads, while asymptomatic individuals showed significant increases only in compressive loads (30 %, p = 0.01). This suggests that engaging in more challenging activities could potentially magnify the effect of LBP on the biomechanical factors and increase their discrimination capacity between LBP and asymptomatic individuals.

Osteoporosis knowledge and health beliefs among middle-aged men and women in the Southern United States.

CONTEXT: The most common skeletal disease, osteoporosis, causes bone fragility due to decreased bone mass and bone microarchitecture destruction. The health belief model is often applied to asymptomatic, prevention-related diseases such as osteoporosis. Steps to mitigate the insidious nature of osteoporosis, including education, motivation, and monitoring of bone mineral density, must begin at an earlier age. OBJECTIVES: This study evaluates the knowledge and health beliefs surrounding osteoporosis in a population of males and females 35-50 years old to determine sex-based differences in osteoporosis knowledge and beliefs and to assess the correlation between perceptions and health motivation. METHODS: Participants (81 males, 92 females) completed two questionnaires: the Osteoporosis Knowledge Test and the Osteoporosis Health Belief Scale. Descriptive statistics were performed along with Pearson product-moment correlation analysis to determine the relationships between the variables. Sex-based differences were calculated utilizing independent t-tests. RESULTS: We discovered a statistically significant negative correlation between the barriers to exercise and health motivation (-0.434, p < 0.001) and a statistically significant positive correlation between the benefits of exercise and health motivation (0.385, p < 0.001). However, there was not a statistically significant correlation between health motivation with the following: the benefits of calcium, susceptibility, and the seriousness of osteoporosis. Between males and females, there was a statistically significant difference in exercise and calcium knowledge, susceptibility, and the benefits of both exercise and calcium (p < 0.05). CONCLUSIONS: Males and females 35-50 years old perceive themselves to have a low susceptibility to osteoporosis. They do not consider osteoporosis a serious disease and have little motivation to mitigate its inception or progression. Their perceptions show that barriers to exercise impact health motivation more than the perceived benefits of exercise.

Optimal assessment of upper body motion - Which and how many landmarks need to be captured for representing rigid body orientation?

In biomechanical studies, the thorax is often considered rigid. Since it's a well-known simplification, usually more than three markers are used to describe its movement in motion analyses. However, there is uncertainty about how many markers are advisable and which landmarks should be used. The results of the present study describe the expected error depending on the number of markers used. Furthermore, a recommendation is given for the landmarks with the least errors. This recommendation is valid for men and women as well as for different movements. The recommendations roughly reduce the error to about 50% and are beneficial especially in case only a small number of markers were used. For general motion capture, we recommend to use at least six thoracic markers.

Sex-Dependent Estimation of Spinal Loads During Static Manual Material Handling Activities-Combined in vivo and in silico Analyses.

Manual material handling (MMH) is considered as one of the main contributors to low back pain. While males traditionally perform MMH tasks, recently the number of females who undertake these physically-demanding activities is also increasing. To evaluate the risk of mechanical injuries, the majority of previous studies have estimated spinal forces using different modeling approaches that mostly focus on male individuals. Notable sex-dependent differences have, however, been reported in torso muscle strength and anatomy, segmental mass distribution, as well as lifting strategy during MMH. Therefore, this study aimed to use sex-specific models to estimate lumbar spinal and muscle forces during static MHH tasks in 10 healthy males and 10 females. Motion-capture, surface electromyographic from select trunk muscles, and ground reaction force data were simultaneously collected while subjects performed twelve symmetric and asymmetric static lifting (10 kg) tasks. AnyBody Modeling System was used to develop base-models (subject-specific segmental length, muscle architecture, and kinematics data) for both sexes. For females, female-specific models were also developed by taking into account for the female's muscle physiological cross-sectional areas, segmental mass distributions, and body fat percentage. Males showed higher absolute L5-S1 compressive and shear loads as compared to both female base-models (25.3% compressive and 14% shear) and female-specific models (41% compressive and 23.6% shear). When the predicted spine loads were normalized to subjects' body weight, however, female base-models showed larger loads (9% compressive and 16.2% shear on average), and female-specific models showed 2.4% smaller and 9.4% larger loads than males. Females showed larger forces in oblique abdominal muscles during both symmetric and asymmetric lifting tasks, while males had larger back extensor muscle forces during symmetric lifting tasks. A stronger correlation between measured and predicted muscle activities was found in females than males. Results indicate that female-specific characteristics affect the predicted spinal loads and must be considered in musculoskeletal models. Neglecting sex-specific parameters in these models could lead to the overestimation of spinal loads in females.

Spinal and Pelvic Kinematics During Prolonged Rowing on an Ergometer vs. Indoor Tank Rowing.

ABSTRACT: Trompeter, K, Weerts, J, Fett, D, Firouzabadi, A, Heinrich, K, Schmidt, H, Brüggemann, GP, and Platen, P. Spinal and pelvic kinematics during prolonged rowing on an ergometer vs. indoor tank rowing. J Strength Cond Res 35(9): 2622-2628, 2021-This investigation aimed to compare spinopelvic kinematics during rowing on an ergometer vs. in a rowing tank and to evaluate changes with progressing fatigue. Spinal and pelvic kinematics of 8 competitive scull rowers (19.0 ± 2.1 years, 179.9 ± 7.6 cm, and 74.8 ± 8.1 kg) were collected during 1 hour of rowing on an ergometer and in a rowing tank using a routine training protocol. Kinematics of the upper thoracic spine, lower thoracic spine, lumbar spine, and pelvis were determined using an infrared camera system (Vicon, Oxford, United Kingdom). There was a greater lumbar range of motion (ROM) and less posterior pelvic tilt at the catch during rowing on the ergometer compared with in the rowing tank (p = 0.001-0.048), but no differences in pelvic ROM. In the rowing tank, the pelvic ROM increased over time (p = 0.002) and the ROM of the lower thoracic spine decreased (p = 0.002). In addition, there was an extended drive phase (when the rower applies pressure to the oar levering the boat forward) and an abbreviated recovery phase (setting up the rower's body for the next stroke) in the rowing tank (p = 0.032). Different rowing training methods lead to differences in spinopelvic kinematics, which may lead to substantially different spinal loading situations. Greater pelvic rotation and lesser lumbar ROM are considered ideal; therefore, the present results indicate that rowing in the rowing tank might facilitate the maintenance of this targeted spinopelvic posture, which might help protect the lower back. Rowers, coaches, and researchers should consider the differences between rowing training methods, especially when giving training recommendations.

In vivo hip and lumbar spine implant loads during activities in forward bent postures.

Long-term measurements on the lumbar spinal alignment during daily life revealed that humans spent 90% of the day in a forward bent posture. Compared to standing, this posture leads to a substantial increase in spinal loading. The lumbar spine and pelvis, however, contribute differently to the total amount of flexion, which could possibly indicate a different timing of maximum loads in both structures during flexion. This study aimed to evaluate the in vivo implant forces in the hip and lumbar spine during activities in forward bent postures. This work utilized data collected in earlier in vivo measurements on patients either with telemeterized hip endoprostheses (HE) or vertebral body replacements (VBR). The following activities were investigated: standing, upper body flexion with and without weights in the hands using different lifting techniques (straight and bent knees). The maximum resultant forces in VBR were considerably lower than in HE. Increases in flexion inclinations caused direct increases of the resultant forces within VBR, followed by a plateau or even a decrease of the force until maximum inclination. The resultant force in HE displayed an almost continuous increase until the maximum inclination. This general curve behavior resulted in different HE-VBR load ratios, which were affected by lifting additional weights or different lifting techniques. The results emphasize that maximum loads in the spine, in contrast to the hip, do not necessarily occur at maximum upper body flexion as normally expected, rather already at intermediate flexion angles in VBR patients. The results form the basis for more detailed insilico analyzes.

Sex-dependent differences in lumbo-pelvic coordination for different lifting tasks: A study on asymptomatic adults.

During manual material lifting, the sagittal motion is mainly characterized through the lumbo-pelvic coordination, which is quantified by the ratio between the lumbar and hip rotations (L/P ratio). Alteration in the L/P ratio is an important indicator for low back pain (LBP). Previous studies demonstrated sex-dependent differences in LBP prevalence during lifting activities. However, the sex-dependent differences in the L/P ratio during different lifting tasks has to data not been investigated. An optoelectronic system was used to measure the sagittal lumbo-pelvic motion in 10 males and 10 females. Task A was lifting one weight from the ground in front of the body to three target heights with straight knees (A1-3: abdomen, chest and head levels, respectively). Task B was lifting two identical weights from the ground at the sides of the body to three target angles with bended knees (B1-3: arms close and 45° and 90° abducted to the trunk, respectively). Lifts of 10 kg (males and females) and 20 kg (males only) were performed and three phases were investigated: Phase 1 - pure flexion without load, Phase 2 - lifting up weights, Phase 3 - lowering down weights. Females generally displayed a smaller L/P ratio than males. In Phases 2 and 3, the L/P ratio was greater than in Phase 1 for Tasks A and B. The L/P ratio increased with a greater lifting height for Task B, but displayed no difference neither between lifting 10 kg and 20 kg, nor between weight lifting and lowering for both tasks. These results can provide indications for sex-specific recommendations for safer lifting activities.

The Relationship between Anthropometric Indices and Breast Cancer in Central Iran.

Background: Anthropometric indices have a debatable relationship with breast cancer (BC) among different ethnicity. In the current study, we have evaluated the relationship between anthropometric indices and BC in Iranian participants. Methods: Between 2012 and 2014, a total of 7,805 women were enrolled from different mammography centers in Isfahan province, Iran. For each participant, a detailed questionnaire was filled out and anthropometric indices were measured by trained technicians. We used logistic regression models to estimate odds ratios (OR) and 95% confidence interval (CI) for BC risk associated with anthropometry measurements, stratified on menopausal status. Results: In the postmenopausal group, weight ≥68 kg compared to weight <61.75 kg was associated with decreased risk of BC (OR = 0.78; 95% CI: 0.63-0.97). Postmenopausal women with Waist-Hip Ratio (WHR) ≥ 0.85 compared to WHR < 0.77 were at increased risk of BC (OR = 1.36; 95% CI: 1.07-1.73). Both premenopausal and postmenopausal women had a decreased risk of BC with higher Obesity Index (OI) and Relative Weight. Conclusion: Ethnicity appears to play an important role in the discrepancies between results of different studies about the correlation of anthropometric features with BC.

The shape and mobility of the thoracic spine in asymptomatic adults - A systematic review of in vivo studies.

A comprehensive knowledge of the thoracic shape and kinematics is essential for effective risk prevention, diagnose and proper management of thoracic disorders and assessment of treatment or rehabilitation strategies as well as for in silico and in vitro models for realistic applications of boundary conditions. After an extensive search of the existing literature, this study summarizes 45 studies on in vivo thoracic kyphosis and kinematics and creates a systematic and detailed database. The thoracic kyphosis over T1-12 determined using non-radiological devices (34°) was relatively less than measured using radiological devices (40°) during standing. The majority of kinematical measurements are based on non-radiological devices. The thoracic range of motion (RoM) was greatest during axial rotation (40°), followed by lateral bending (26°), and flexion (21°) when determined using non-radiological devices during standing. The smallest RoM was identified during extension (13°). The lower thoracic level (T8-12) contributed more to the RoM than the upper (T1-4) and middle (T4-8) levels during flexion and lateral bending. During axial rotation and extension, the middle level (T4-8) contributed the most. Coupled motion was evident, mostly during lateral bending and axial rotation. With aging, the thoracic kyphosis increased by about 3° per decade, whereas the RoM decreased by about 5° per decade for all load directions. These changes with aging mainly occurred in the lower region (T6-12). The influence of sex on thoracic kyphosis and the RoM has been described as partly contradictory. Obesity was found to decrease the thoracic RoM. Studies comparing standing, sitting and lying reported the effect of posture as significant.

Disparities in HIV Clinical Outcomes among a Cohort of HIV-Infected Persons Receiving Care-Mississippi.

Increasing patients' cluster of differentiation 4 (CD4) count and achieving viral suppression are the ultimate goals of the human immunodeficiency virus (HIV) care and treatment, yet disparities in these HIV clinical outcomes exist among subpopulations of HIV-infected persons. We aimed to assess potential disparities in viral suppression and normal CD4 count among HIV-infected persons receiving care in Mississippi using Mississippi Medical Monitoring Project (MMP) data from 2009 to 2014 (N = 1233) in this study. Outcome variables in this study were suppressed, recent and durable viral load, and normal CD4 count. Patients' characteristics in this study were race, gender, age, annual income, education, insurance, and length of diagnosis. Descriptive statistics, Chi square tests, and logistic regression analyses were conducted using the SAS 9.4 Proc Survey procedure. Our findings indicate that those aged 50 years or older were more likely to have suppressed recent viral load (adjusted Odds Ratio (aOR) = 2.4) and durable viral loads (aOR = 2.9), compared to those aged 18-24 years. In addition, women were more likely to have a normal CD4 count than men (aOR = 1.4). In conclusion, we found that age and gender disparities in HIV clinical outcomes may be used to develop and implement multifaceted interventions to improve health equity among all HIV-infected patients.

Otitis Media with Effusion in Children and the Impact of Risk Factors on Serum Cytokine Levels.

INTRODUCTION: To evaluate the role of allergic-type and infectious-type cytokines in children with chronic otitis media with effusion (OME). MATERIALS AND METHODS: We investigated serum levels of interleukins (IL)-4, IL-5, and IL-13, along with interferon-gamma (IFN-γ) and tumor necrosis factor-alpha (TNF-α), by enzyme-linked immunosorbent assay (ELISA) in 35 children with OME and 28 healthy controls. RESULTS: Children with OME had significantly higher levels of IL-5 in comparison with the control group, ranging from 1 pg/ml in cases to 0.04 pg/ml in controls (P=0.009). However, after adjusting for confounding variables, there was no significant difference in serum levels of IL-13, IL-4, IFN-γ, or TNF-α between the two groups (P=0.287, P=0.627, P=0.793, and P=0.217, respectively). CONCLUSIONS: The findings of this study suggest that in comparison with the control group, serum IL-5 levels were elevated in OME cases.