Low Back Injury Research Articles

Passive stiffness changes in the lumbar spine following simulated automotive low speed rear-end collisions

BackgroundHistorically, there has been a lack of focus on the lumbar spine during rear impacts because of the perception that the automotive seat back should protect the lumbar spine from injury. As a result, there have been no studies involving human volunteers to address the risk of low back injury in low velocity rear impact collisions. MethodsA custom-built crash sled was used to simulate rear impact collisions. Randomized collisions were completed with and without lumbar support. Measures of passive stiffness were obtained prior to impact (Pre), immediately post impact (Post) and 24 h post impact (Post-24). Low back pain reporting was monitored for 24 h following impact exposure. FindingsNone of the participants developed clinically significant levels of low back pain after impact. Changes in the passive responses persisted after impact for the length of the low stiffness flexion and extension zone. The length of the low stiffness zone was longer in the Post and Post-24 trial for low stiffness flexion and longer in the Post-24 for low stiffness extension. InterpretationFindings from this investigation demonstrate that during a laboratory-simulation of an 8 km/h rear-impact collision, young healthy adults did not develop low back pain. Changes in the low stiffness zone of the passive flexion/extension curves were observed following impact and persisted for 24 h. Changes in passive stiffness may lead to changes in the loads and load distributions during movement within the passive structures such as the ligaments and intervertebral discs following impacts.

Alteration in HDEMG Spatial Parameters of Trunk Muscle Due to Handle Design during Pushing.

Previous research identifies that pushing and pulling is responsible for approximately 9–18% of all low back injuries. Additionally, the handle design of a cart being pushed can dramatically alter a worker’s capacity to push (≅9.5%). Surprisingly little research has examined muscle activation of the low back and its role in muscle function. Therefore, the purpose of this study was to examine the effects of handle design combination of pushing a platform truck cart on trunk muscle activity. Twenty participants (10 males and 10 females, mean age = 24.3 ± 4.3 years) pushed 475 lbs using six different handle combinations involving handle orientation (vertical/horizontal/semi-pronated) and handle height (hip/shoulder). Multichannel high-density EMG (HDsEMG) was recorded for left and right rectus abdominis, erector spinae, and external obliques. Pushing at hip height with a horizontal handle orientation design (HH) resulted in significantly less (p < 0.05) muscle activity compared to the majority of other handle designs, as well as a significantly higher entropy than the shoulder handle height involving either the semi-pronated (p = 0.023) or vertical handle orientation (p = 0.028). The current research suggests that the combination of a hip height and horizontal orientation handle design may require increased muscle demand of the trunk and alter the overall muscle heterogeneity and pattern of the muscle activity.

Lifting Posture Prediction With Generative Models for Improving Occupational Safety

Lifting tasks have been identified to be highly associated with work-related low back pain. Posture prediction can be used for simulating workers’ posture of lifting tasks and thus facilitate the prevention of low back pain (LBP). This study adopts two generative models, conditional variational encoder and conditional generative adversarial network, to predict lifting postures. A regular feed-forward neural network (FNN) developed upon previous studies is also investigated for comparison purposes. Ground-truth lifting posture data collected by a motion capture system is used for training and testing the models. The models are trained with datasets of different size and loss functions, and the results are compared. The conditional variational autoencoder and the regular FNN achieved comparable top performance in lifting posture prediction in terms of accuracy and posture validity. Both generative models are able to partially capture the variability of constrained postures. Overall, the results prove that using a generative model is able to predict postures with reasonable accuracy and validity (RMSE of coordinates = 0.049 m; RMSE of joint angles = 19.58 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^\circ$</tex-math></inline-formula> ). The predicted postures can support biomechanical analysis and ergonomics assessment of a lifting task to reduce the risk of low back injuries.

The Dance Functional Outcome Survey: Cultural Adaptation and Psychometric Validation in Italian (DFOS-IT).

To translate, culturally adapt, and validate the psychometric characteristics of the Italian version of the Dance Functional Outcome Survey (DFOS-IT) in adult dancers. Clinical measurement study. The DFOS-IT was forward translated, reconciled, backward translated, and reviewed by an expert committee to establish optimal correspondence with the original English DFOS. We examined test-retest reliability in 58 dancers within a 10-day period, using intraclass correlation coefficients (ICC2,1). In a sample of 265 healthy and injured dancers, the following were examined: 1) construct validity, comparing the DFOS-IT to SF-36 using Pearson correlations; 2) exploratory factor analysis and internal consistency; and 3) sensitivity, by generating receiver operating characteristic curves and determining area under the curve (AUC). In a subgroup of 44 dancers, we determined internal responsiveness across three time-points using repeated measures ANOVA (p<0.05). Injured dancers' scores were analyzed for floor and ceiling effects. The DFOS-IT demonstrated very high test-retest reliability (ICC≥0.98). Single-factor loading in exploratory factor analysis supported unidimensionality of the scale, with high internal consistency (a=0.93). DFOS-IT total, activities of daily living (ADL), and Dance Technique scores had strong construct validity compared with scores on the SF-36 PCS (r≥0.71). There was excellent sensitivity, with high AUC values (AUC≥0.80). There were significant differences across time for DFOS-IT scores (p<0.001), demonstrating responsiveness to change, and no floor or ceiling effects. The DFOS-IT is a valid, reliable, and responsive tool that can be used as an outcome and screening measure for Italian adult ballet and modern dancers following lower extremity or low back injury.

Inter-individual variability in a repetitive lifting task

Trunk kinematics directly impact the biomechanical loading of the tissues of the low back. Quantifying the variability in trunk kinematics may provide deeper insights into biomechanical loading and low back injury risk. Inter-lifter variability in trunk kinematics was assessed as twenty participants performed a repetitive lifting task at three levels of the NIOSH Lifting Index. Trunk kinematics were captured and Levene’s test of homogeneity of variance was used to test the hypothesis that variance in kinematic parameters increased as a function of level of lifting index. Results showed considerable levels of variability in all kinematics parameters, and for sagittal range of motion, mean sagittal velocity, transverse range of motion, and mean transverse velocity the variance was significantly affected (p&lt;0.05) by level of lifting index. The results of this study demonstrate that variability (both inter- and intra-lifter) should be considered as one considers the relative risk of a lifting task.

A Single-Camera Computer Vision-Based Method for 3D L5/S1 MomentEstimation During Lifting Tasks

Excessive low back joint loading during material handling tasks is considered a critical risk factor of musculoskeletal disorders (MSD). Therefore, it is necessary to understand the low-back joint loading during manual material handling to prevent low-back injuries. Recently, computer vision-based pose reconstruction methods have shown the potential in human kinematics and kinetics analysis. This study performed L5/S1 joint moment estimation by combining VideoPose3D, an open-source pose reconstruction library, and a biomechanical model. Twelve participants lifting a 10 kg plastic crate from the floor to a knuckle-height shelf were captured by a camera and a laboratory-based motion tracking system. The L5/S1 joint moments obtained from the camera video were compared with those obtained from the motion tracking system. The comparison results indicate that estimated total peak L5/S1 moments during lifting tasks were positively correlated to the reference L5/S1 joint moment, and the percentage error is 7.7%.

Hamstring‐and‐lower‐back flexibility is not related to hamstring‐and‐lower‐back injuries in elite female soccer players

Objectives Although muscle flexibility is considered to be a risk factor for hamstring-and-lower back injuries (HLB-injuries) in male soccer players, it is unclear whether this is true for elite female soccer players. Design Prospective observational cohort study. Method One hundred fourteen elite female soccer players were monitored during the 2014-2015 soccer season. Hamstring-and-lower-back flexibility (HLB-flexibility) was assessed using the sit-and-reach test (SRT) and soccer exposure and soccer-related injuries were registered. Poisson regression was used to study the association between HLB-flexibility and HLB-injuries with adjustment for possible confounders. Results Of the 114 players, 46 (40%) reported an HLB-injury (60 hamstring injuries and 20 lower back injuries) during the season, accounting for 22% of all injuries reported. No significant association was found between HLB-flexibility and HLB-injuries (P = .534). Also, after correction for potential confounders (age, weight, height, match exposure, and training exposure), HLB-flexibility was not found to be associated with HLB-injuries ((1.027 (0.989-1.066) (RR 95% CI)), P = .164 unadjusted, and 1.022 (0.987-1.059), P = .217 adjusted). Match exposure was significantly associated with HLB-injuries. When the number of match hours increased by 1, the number of HLB-injuries increased by a factor 1.051. Conclusion HLB-flexibility does not influence the occurrence of HLB-injuries in elite female soccer players.

Lower Back Injury Prevention and Sensitization of Hip Hinge with Neutral Spine Using Wearable Sensors during Lifting Exercises.

The popularization and industrialization of fitness over the past decade, with the rise of big box gyms and group classes, has reduced the quality of the basic formation and assessment of practitioners, which has increased the risk of injury. For most lifting exercises, a universal recommendation is maintaining a neutral spine position. Otherwise, there is a risk of muscle injury or, even worse, of a herniated disc. Maintaining the spine in a neutral position during lifting exercises is difficult, as it requires good core stability, a good hip hinge and, above all, observation of the posture in order to keep it correct. For this reason, in this work the authors propose the prevention of lumbar injuries with two inertial measurement units. The relative rotation between two sensors was measured for 39 voluntary subjects during the performance of two lifting exercises: the American kettlebell swing and the deadlift. The accuracy of the measurements was evaluated, especially in the presence of metals and for fast movements, by comparing the obtained results with those from an optical motion capture system. Finally, in order to develop a tool for improving sport performance and preventing injury, the authors analyzed the recorded motions, seeking to identify the most relevant parameters for good and safe lifting execution.

Stress analysis of intervertebral disc during occupational activities

Background and objectiveManual material handling activities cause large compression of the intervertebral disc of the lumbar spine. Intradiscal pressure (IDP) has generally been employed to predict the risk of low back injury. As an alternative to in vivo measurements, either motion analysis or finite element (FE) analysis has been used to estimate IDP. The purpose of this study is to propose a new biomechanical method that integrates FE analysis with motion analysis, in order to estimate the stresses and deformations of the intervertebral disc of the lumbar spine during occupational activities. MethodsIn the proposed method, motion analysis is performed first by using motion capture data, and the results are employed as input data to FE analysis at specific times of interest during motion. In this method, an in-house interface program is used to scale an initial reference FE model to the subject of experiment, and transformed to the corresponding posture at a specific time during motion. The muscle forces and GRF obtained from motion analysis are applied to FE analysis as boundary and loading conditions. For a total of eighteen occupational activities, the IDP, shear stress, and strain of the L4–L5 segment are estimated. ResultsUnder each in vivo activity, the predicted IDP was in overall agreement with the available in vivo data. For lifting activities according to lift origin position, the maximum IDP occurred in the far-knee position immediately after lifting. As the lift origin position moved away from the spine, the stresses and strains in the disc increased. ConclusionsThis new proposed method is expected to allow the estimation of the stresses and deformations in the intervertebral disc during various occupational activities.

Relationship between Core Strength, Core Endurance and Balance in Folk Dancers – A Pilot Study

Background: Dance performance requires lower extremity muscle strength and endurance, sufficientcore stabilization, dynamic balance during dance movements. Diminished core strength and coreendurance has been shown lead to a higher incidence of lower extremity injuries and to low backinjuries. Greater core muscle strength, increased core endurance and good dynamic balance havebeen reported to be associated with reduced lower extremity injury risk. Still, the exact relationshipsamong these factors remain unclear. Most of studies have examined ballet and modern dancers but folkdance is not studied adequately in the literature as different genres of dance have different physicaldemands, it is important to examine whether the relationships among Core stability, balance, injuries,and performance are similar across the various dance genres.Objectives: Weak core and poor balance are said to be associated with lower limb and low back injuries.Thus the correlation between core stabilization and balance need to be evaluated in details to reducethe risk of injuries.Methods: It is a cross-sectional observational study, with a total of 30 folk dancers. Core endurancewas measured by using plank tests and core strength was measured by the Bent Knee Lowering Test(BKLT).Balance was measured via the Star Excursion Balance Test (SEBT) which was co-related withcore strength and core endurance.Conclusion: There is no correlation between core strength and balance in folk dancers. Core enduranceis weakly correlated with balance.

Ergonomic sofa design to support kangaroo mother care in Indonesia

BackgroundThe chairs used by mothers performing Kangaroo mother care (KMC) in hospitals in Indonesia are not ergonomically designed, so they can cause an awkward posture and musculoskeletal disorders. ObjectiveThe purpose of this study was to create an ergonomic sofa design that would reduce musculoskeletal disorders among mothers who perform KMC in Indonesian hospitals. MethodsThe research method was based on the Nigel Cross concept and involved anthropometric measurement conducted with 69 postpartum mothers from four hospitals in Indonesia as a basis for designing an ergonomic sofa. The sofa design was assessed using virtual human modeling with the Siemens Jack software for posture and lower back analysis. ResultThe Rapid Upper Limb Assessment (RULA) value of 2 and low back analysis (LBA) of 363 N obtained with virtual human modeling showed that a mother who performed KMC with the ergonomic sofa was in a safe position with a low risk of experiencing lower back injuries. The resulting ergonomic sofa design had adjusted to the anthropometry of mothers in Indonesia. The mother's posture with a simulation using the ergonomic sofa design is easily maintained and acceptable and can be categorized as safe to the user. ConclusionThe ergonomic sofa design for KMC potentially improves posture and reduces the risk of musculoskeletal disorders. Further tests are needed, including prototype production and pilot testing, to determine its effectiveness.

Effectiveness of Lumbar Motor Control Exercises in Improving Lumbar Stability among Bharatanatyam Dancers

Background and purpose: Low back injuries among Bharatanatyam dancers are said to be over use relatedand secondary to biomechanical alignment defects. This causes weakness of the deep core muscles resultingin lumbar instability and low back pain. Motor control exercises aim to retrain the optimal control of thedeep spinal muscle and maintain normal control during physical and functional tasks. The study is designedto assess the effectiveness of motor control exercises in improving lumbar stability among Bharatanatyamdancers.Objectives: To find out the strength of the deep abdominal muscle function pre and post intervention. Tofind out the correlation between lumbar spine curvature in standing and the deep abdominal muscle strength.To assess the effectiveness of lumbar motor control exercises in improving lumbar stability.Design: Quasi experimental one group pre and post-test designMethods: A total of 85 subjects (females) aged between 18 to 30 years with Quebec score &gt;20 were recruitedusing purposive sampling method. Subjects were examined for core muscle activity using Stabilizer pressurebiofeedback and were assessed for Lumbar spine curvature using Flexible curve ruler. Pain and disabilitywere scored using Modified Oswestry disability questionnaire (MODQ). The intervention consisted of motorcontrol exercises for 6 weeks. Pre and post-test intervention scores were recorded and analysed. Results:The core muscle activity and Modified Oswestry disability score significantly (p&lt;0.001) improved after theintervention and showed strong significance. The correlation between lumbar lordosis angle and core muscleactivity showed positive relation (r = 0.859) and statistically significant (p&lt;0.001). Conclusion: The resultssuggest that, motor control exercises may be significantly effective in improving lumbar stability amongBharatanatyam dancers.

An analysis of pre-season risk factors for low back injury in high-school baseball pitchers: a prospective study

Pitching motion requires whole-body coordination; therefore, poor control of the lower extremities, pelvis and trunk may cause shoulder and elbow injuries. However, few studies have described the relationship between the shoulder joint function and low back injury in high-school baseball pitchers. A total of 128 healthy high school pitchers underwent pre-season medical checkups, where their shoulder range of motion and shoulder strength were measured. The participants completed a self-recorded daily questionnaire regarding the presence of low back pain. Pitchers were divided into injured and non-injured groups. Low back injury was observed in 13 participants (13.4%). In the injured group, horizontal adduction on the dominant shoulder was significantly less than in the non-injured group. A logistic regression analysis showed that horizontal adduction on the dominant side was a significant independent risk factor for low back injury during the season. It is important to recognize that restriction of the shoulder function not only causes shoulder and elbow injuries but can also risk low back injury.

척추부하 평가를 위한 L4-L5 요추의 유한요소모델 개발

Low back injury (LBI) often occurs during manual materials handling (MMH). Intradiscal pressure (IDP) is used to assess the risk of the LBI and is measured in vivo or by computer simulation. As for computer simulation, motion analysis and finite element (FE) analysis are usually employed. In this study, a FE model has been developed for L4-L5 segment with high risk of injury to predict LBI during manual lifting tasks. The FE model was composed of lumbar vertebrae, discs, and ligaments and a calibration process was performed to set the nonlinear material properties of the intervertebral disc. To validate the developed FE model, IDP and range of motion (ROM) under in vitro loading conditions were compared to the experiments and other FE studies in literature. Within in vitro range, IDP and ROM from the FE model were in agreement with results from previous studies. The FE model developed in this study can be scaled according to the subject used in the analysis integrating FE analysis to motion analysis, and is expected to be used in future work to estimate IDP and stress/strain in joint structures during occupational activities.

Occupational injuries in California's health care and social assistance industry, 2009 to 2018.

Background and AimThe health care and social assistance industry has one of the highest rates of non‐fatal occupational injuries and illnesses, both in California and nationally. In the coming years, the health care industry will face added pressure as both the population and workforce age. The aim of this study is to identify targeted populations that may benefit from interventions to prevent future injuries, keep the workforce healthy, and decrease injury‐related costs.MethodsThis retrospective study analyzed California workers' compensation claims from 2009 to 2018 in the health care and social assistance industry.ResultsAcross the four industry sub‐groups, the highest number of claims came from hospitals (n = 243 605; 38.9%), followed by ambulatory care (n = 187 010; 29.9%), nursing/residential care (n = 133 206; 21.3%), and social assistance (n = 62 211; 9.9%). Nursing/residential care settings reported the highest proportion of both lifting injuries (15.8%) and low back injuries (16.9%) as compared to the other settings. Across all settings within California, nurses had the highest proportion of injuries (22.1%), followed by aides/assistants (20.4%), services staff (13.2%), administrative staff (11.0%), and technicians (10.3%). Thirty‐five of California's counties had an increasing rate of population‐adjusted claims during the study period.ConclusionThis study found that while hospitals have the highest number of injuries, ambulatory care employee injuries are increasing. Employees involved in non‐patient care tasks, such as those working in facility service roles, would likely benefit from additional injury prevention interventions.

Racism in Pain Medicine: We Can and Should Do More

Racism in Pain Medicine: We Can and Should Do More

Musculoskeletal injury symptoms among hired Latinx child farmworkers in North Carolina.

Although children 10-17 years can be hired to work in agriculture, little research has addressed possible musculoskeletal injuries. Children may be at particular risk for these injuries because of the repetitive and load bearing nature of work tasks. Existing research relies on child workers to self-report musculoskeletal injuries. In 2017, 202 Latinx child farmworkers ages 10-17 employed across North Carolina completed survey interviews. In 2018, 145 of these children (94 [64.8%] current farmworkers) completed a physical examination and second interview. The examination obtained findings for upper and lower extremity as well as back injuries. Positive indicators for musculoskeletal symptoms were few in either current or former child farmworkers. The knee was most common site for positive indicators with 15.4% of children having at least one. Combining all anatomical sites, 29.0% of children had at least one positive indicator, with no significant difference between current and former farmworkers. Overall, boys had significantly more indicators of knee injuries than girls (21.3% vs. 4.1%), indicators of ankle injuries were found only in the youngest workers (9.5% of children 11-13 years), and significantly fewer current farmworkers had indicators of lower back injuries than former farmworkers (6.4% vs. 17.7%). Expectations of injuries come from previous studies using child farmworker self-reports, adult farmworker injury rates, and sports medicine pediatric findings. Hired child farmworkers may not perform activities as repetitious and load-bearing as children in sports training or adult farmworkers. Additional research using physical examination is needed to confirm these findings.

Patient Outcomes After Treatment by Athletic Therapy Students.

Patient-reported outcome measures (PROMs) should be used in athletic training and athletic therapy but are rarely incorporated in internships. Student-run clinics are common in other health professions and provide effective treatment and valuable learning environments. To our knowledge, no one has evaluated rehabilitation outcomes in patients treated by athletic therapy students (ATSs). To measure the improvement in function in injured patients seeking treatment at an ATS clinic. Cohort study. An ATS clinic. A total of 59 patients (32 women, age = 33.9 ± 14.7 years; 27 men, age = 38 ± 14.4 years) from the community with a variety of low back, lower extremity, and upper extremity injuries participated. At baseline and 6-week follow-up, all patients completed 1 of 3 scales (depending on their injury location) to assess their injured level of function. Scales were the Oswestry Disability Index for low back injuries; Lower Extremity Functional Scale for lower extremity injuries; and Disabilities of the Arm, Shoulder and Hand for upper extremity injuries. On average, patients received 4.7 ± 1.8 treatments across 48.8 ± 16.1 days. They experienced an increase in function between baseline and follow-up assessments (18.8% ± 20.3%; P < .001, Cohen d = 1.06). Moreover, the amount of functional improvement was clinically meaningful, as it was greater than the minimal clinically important difference for each scale. The efficacy of treatments did not differ according to the internship experiences of the ATSs. Function improved in patients after treatment delivered by an ATS. Patient-reported outcome measures were useful for the students in monitoring patient improvement, but more research is needed regarding effective treatments for patients with chronic pain. Our results suggested that ATS clinics provide effective treatments for patients, service to the community, and a learning opportunity for students.

Lumbopelvic sagittal standing posture associations with anthropometry, physical activity levels and trunk muscle endurance in healthy adults.

Background:Various factors, inherited and acquired, are associated with habitual spinal postures.Objective:The purpose of this study was to identify the relationships between trunk muscle endurance, anthropometry and physical activity/inactivity and the sagittal standing lumbopelvic posture in pain-free young participants.Methods:In this study, 112 healthy young adults (66 females), with median (IQR) age of 20 years (18.2–22 years), without low back pain, injury or trauma were included. Lumbar curve (LC) and sacral slope (SS) angles were measured in standing with a mobile phone application (iHandy level). Anthropometric, physical activity/inactivity levels (leisure-time sport involvement and sitting hours/day) and abdominal (plank prone bridge test) and paraspinal (Sorensen test) isometric muscle endurance measures were collected.Results:LC and SS angles correlated significantly (, ). Statistically significant differences for both LC () and SS () angles were identified between the male and female participants. A significant negative correlation was identified between the abdominal endurance time and LC (, ); however, the power of this result (56%) was not sufficiently high. The correlation between abdominal endurance and SS was non-significant (, ). In addition, no significant associations were identified between either of the sagittal lumbopelvic angles (LC–SS) in standing and the participants’ body mass index (BMI), paraspinal endurance, leisure-time sport involvement or sitting hours/day.Conclusion:The potential role of preventive exercise in controlling lumbar lordosis via enhancement of the abdominal muscle endurance characteristics requires further confirmation. A subsequent study, performed in a larger population of more diverse occupational involvement and leisure-time physical activity levels, is proposed.

Effects of load information on biomechanical characteristics of lifting tasks

The lower back pain caused by manual lifting is one of the most common occupational injuries. This study aims to investigate how biomechanics of lifting tasks is affected by the availability of load information. Twenty-four healthy men with lifting experience were recruited, and they were instructed to perform the lifting tasks under different weights, fragility information and lifting load conditions. The lifting load was set at three levels including light, medium and heavy. The load prompt information has four levels corresponding to "no information" , "prompt mass information" , "prompt material fragility information" and "prompt mass and material fragility information" , respectively. The results show that with the availability of material fragility information, the muscle activity of thigh and back is weakened, meanwhile, the torque of low back and the maximum angular velocity of hip joint are reduced. However, due to the longer duration of lifting, the risk of low back injuries increased instead. The prompt information about load weight has no significant influence on lower back biomechanics. The lifting load effects on lifting biomechanics are more substantial than load prompt information. This suggests that reducing lifting load should be more effective in the control of lower back pain. The experimental results can provide useful guidance for the design of safe manual lifting operation standards.