Back Injury Research Articles

Cardiorespiratory fitness is a risk factor for lower-limb and back injury in law enforcement officers commencing their basic training: a prospective cohort study

ABSTRACT We aimed to report the epidemiology of lower-limb and lumbosacral injuries in Police Force recruits. We performed a cohort study of Police Force recruits undergoing a six-month training program with prospective injury data collected between 2018 and 2021. Cardiorespiratory fitness was quantified by the beep-test and police-specific-functional-capacity was quantified using a specifically designed physical performance evaluation (PPE) tool. Injury frequency and prevalence were reported. Fifteen percent (n = 180) of study Police Force recruits (n = 1,181) sustained a lower-limb or lumbosacral injury. The six-month training program significantly improved cardiorespiratory fitness (p < 0.001) and functional capacity (p < 0.001). Increased cardiorespiratory fitness at baseline decreased injury risk (OR = 0.8, 95%CI: 0.66–0.97, p = 0.019). Injury rates decreased over time and females were injured significantly earlier than males (HR = 0.70, 95%CI: 0.52 to 0.95, p = 0.021). Interventions that can pre-condition Police Force recruits prior to the commencement of their basic physical training may reduce the number of lower-limb and lumbosacral injuries.

A Fermatean fuzzy Fine–Kinney for occupational risk evaluation using extensible MARCOS with prospect theory

The extant Fine–Kinney frameworks are insufficient to tackle the risk evaluation problem with Fermatean fuzzy information, in which the prioritization degrees and psychological characteristics of decision-makers are considered. Hence, this study develops a hybrid Fine–Kinney-based occupational risk evaluation framework with an extended Fermatean fuzzy MARCOS method (measurement of alternatives and ranking to Compromise solution). Such a MARCOS method improves conventional MARCOS by integrating Fermatean fuzzy prioritized weighted average operator and prospect theory. This improved method has the capability to handle the occupational risk analysis problem with Fermatean fuzzy data in the risk ranking procedure considering the prioritization degrees and bounded rational behavior of decision-makers. In addition, the Fermatean fuzzy numbers-based risk rating scales are established to transform the linguistic risk scores from decision-makers, it allows for handling uncertain risk rating information from decision-makers more effectively. Further, the improved MARCOS method is incorporated into the occupational risk ranking procedure, as it considers the decision-maker’s prioritization relationships among decision-makers and their reference point effect in occupational risk priority calculation. After that, an occupational risk analysis case for construction operations is selected to test the applicability and validity of the proposed framework. The result indicates that the occupational risk OR6 (Back injury) is the most serious risk with the lowest utility function value (-0.324), and OR7 (Tendinitis) is the least severe risk with the highest utility function value (0.682). Finally, sensitivity exploration and comparative study are implemented to further test the advantages of the developed framework.

Study of the influence of adaptation-changing exercises for the back muscles of fencers in the training process

The article describes the generally accepted direction of physical training of fencers and its importance in the training process. During the study of scientific and methodical literature, it was found that in the training of fencers, little attention is paid to the prevention of back injuries and diseases, which is the main problem of the musculoskeletal system for this sport. An experiment was conducted to introduce adaptation-strengthening exercises into the training process of fencers at the stage of preliminary basic training (children aged 12-13). Two groups of fencing athletes took part in our experiment at the stage of preliminary basic training, which corresponds to the age stage of advanced training. The experiment took place on the basis of the "Harmony" Fencing Center. The control group consisted of 11 athletes aged 12–13 years. There were 12 fencers of the same age in the experimental group. The study took place from September 2021 to May 2022. At the beginning of the study (September 2021), the control and experimental groups were tested according to the standards of general and special physical training provided for in the program for fencing sports schools. Both groups (experimental and control) trained 5 times a week: 4 times specialized training and 1 time general physical training. With the help of testing, it is shown that such an innovation does not affect the general and special preparedness of fencing athletes during the annual training cycle. This shows that adaptive strengthening exercises for the back can be actively used in the training process of young fencers, without harming the basic physical qualities necessary for this sport. In the training process of fencers of training groups, insufficient attention is paid to strengthening and relaxing the muscles of the muscular corset, which is a necessary prevention of injuries and diseases of the back, which is the biggest problem area of the musculoskeletal system of fencers.

Biomechanical effects of a mechanical lift on the risk of low back injury during transfers from bed to wheelchair

Biomechanical effects of a mechanical lift on the risk of low back injury during transfers from bed to wheelchair

Factorial and Construct Validity of Sit-Up Test of Different Durations to Assess Muscular Endurance of Police Students

Background: The number of completed sit-ups in a given period of time is a commonly used assessment to measure trunk endurance in tactical populations. This study investigated factorial and construct validity of three different durations of a sit-up test—30 s, 60 s, and 120 s; Methods: Anthropometric characteristics and sit-ups performed for 30, 60, and 120 s by101 (♂: n = 62 and ♀: n = 39) police students were assessed. A factorial analysis was used to determine if three test durations group together in one factor, correlation analysis determined whether the sit-up tests were associated with anthropometric measures and whether the three variations in the test duration correlated between each other, and the Fisher’s transformation determined whether these correlations differed significantly; Results: All three sit-up variations loaded together into one factor in both sexes, providing factorial validity for all three test durations. Anthropometrics were associated with sit-up tests lasting 30 s in males and 120 s in females. A sit-up test lasting 60 s correlated significantly stronger to 120 s than to the 30 s sit-up test; Conclusions: The 60 s sit-up test seems to have the highest construct validity, as it was not affected by anthropometrics, and it may be an optimal choice for its lower risk of lower back injuries. By applying the results of this study, agencies could reduce the bias that may occur during the sit-up test and reduce the risk of injury during physical fitness assessment.

Workplace hazards and health among informally employed domestic workers in 14 cities, United States, 2011-2012: Using four approaches to characterize workers' patterns of exposures.

We characterized informally employed US domestic workers' (DWers) exposure to patterns of workplace hazards, as well as to single hazards, and examined associations with DWers' work-related and general health. We analyzed cross-sectional data from the sole nationwide survey of informally employed US DWers with work-related hazards data, conducted in 14 cities (2011-2012; N = 2086). We characterized DWers' exposures using four approaches: single exposures (n = 19 hazards), composite exposure to hazards selected a priori, classification trees, and latent class analysis. We used city fixed effects regression to estimate the risk ratio (RR) of work-related back injury, work-related illness, and fair-to-poor self-rated health associated with exposure as defined by each approach. Across all four approaches-net of individual, household, and occupational characteristics, and city fixed effects-exposure to workplace hazards was associated with increased risk of the three health outcomes. For work-related back injury, the estimated RR associated with heavy lifting (the single hazard with the largest RR), exposure to all three hazards selected a priori (worker did heavy lifting, climbed to clean, and worked long hours) versus none, exposure to the two hazards identified by classification trees (heavy lifting, verbally abused) versus "no heavy lifting," and membership in the most- versus least-exposed latent class were, respectively, 3.4 (95% confidence interval [CI] 2.7-4.1); 6.5 (95% CI 4.8-8.7); 4.4 (95% CI 3.6-5.3), and 6.6 (95% CI 4.6-9.4). Measures of joint work-related exposures were more strongly associated than single exposures with informally employed US DWers' health profiles.

In vivo intervertebral disc mechanical deformation following a treadmill walking “stress test” is inversely related to T1rho relaxation time

To assess the in vivo relationship between the mechanical response of intervertebral discs (IVDs) to dynamic activity and IVD biochemical composition assessed via T1rho relaxation imaging. Eighteen asymptomatic participants with no history of low back pain (LBP), injury, or surgery underwent magnetic resonance (MR) imaging of their lumbar spine prior to and immediately following a treadmill walking "stress test." Anatomic (SPACE, FLASH) MR images were obtained pre- and post-exercise and utilized to measure IVD mechanical deformation. Quantitative (T1rho) imaging was performed pre-exercise to reflect IVD composition. Pre-exercise anatomic images were also utilized to assess IVD degenerative status based on the modified Pfirrmann scale. To quantify mechanical response, 3D surface models of the L1-L2-L5-S1 IVDs were created from manual segmentations of pre- and post-exercise anatomic images and utilized to assess changes in IVD height. IVD strain (%) was defined as change in IVD height normalized to pre-activity height. Linear mixed models were used to assess the relationships between IVD mechanical deformation (strain), composition (T1rho relaxation time), and degenerative status (Pfirrmann grade). Increased compressive IVD strain was associated with lower T1rho relaxation times in the nucleus pulposus (NP) of the disc (βT1rho=5.07,CI:[1.52,7.77],Rmarg2=0.52,p=0.005). Thus, an inverse relationship between IVD strain and NP T1rho relaxation time was observed. The in vivo mechanical response of the IVD to the "stress test" was sensitive to differences in NP composition. The results of this study suggest that quantification of in vivo IVD mechanical function and composition may provide insight into IVD health.

Functional versus conventional strength and conditioning programs for back injury prevention in emergency responders.

Back pain and back-related injuries are common complaints among emergency responders. The purpose of this study was to compare the effectiveness of two strength and conditioning programs in improving back muscle characteristics and disabilities in emergency responders (firefighters/paramedics). Participants (n = 24) were randomized into two groups to complete 16 weeks of supervised exercise intervention: 1) Functional training used unilateral movements that mimicked the asymmetrical nature of emergency operations, 2) Conventional training performed bilaterally loaded exercises. Outcome measures were maximum isometric back extension strength, passive muscle stiffness, lumbar extensor fatigability, and revised Oswestry Low Back Pain Questionnaire. A mixed model Analysis of Variance with repeated measures was performed to compare the difference over time and between groups. While the training effects were similar between groups, both programs improved isometric back extension strength (+21.3% functional, +20.3% conventional, p < 0.001, ηp 2 = 0.625) and lumbar extensor muscle fatigability (+17.4% functional, +9.5% conventional, p = 0.009, ηp 2 = 0.191). Bilateral symmetry in muscle stiffness was improved as indicated by reduction in symmetry index (-7.1% functional, -11.8% conventional, p = 0.027, ηp 2 = 0.151). All self-reported pain and disability scores fell within the category of “minimum functional limitation” throughout the intervention and 6-month follow-up periods. For frontline firefighters and paramedics, both functional and conventional strength training are effective for improving back muscle characteristics.

Musculoskeletal disorder (MSD) prevention practices by nurses working in health care settings: Facilitators and barriers to implementation

The incidence of musculoskeletal disorders (MSD) in the healthcare professional population is concerning. In particular, the high incidence of back injuries is an issue for nurses. Although many MSD prevention initiatives are being implemented, these practices are not succeeding in reducing MSDs. Why are these efforts struggling to close the gap between knowledge and practice? This article aims to report on individual and organizational factors that may influence nurses' implementation of MSD prevention practices. A survey was sent to nurses in the Quebec health and social services network. A total of 399 questionnaires were completed and analyzed. The results revealed that nurses have the required knowledge on MSD prevention practices, but have difficulty applying them in their professional context. It would appear that successful implementation of MSD prevention practices relies mainly on organizational factors, including management support, organizational culture, feedback mechanisms, and training that is adapted to the work environment.

P16. Biomechanical assessments of the spine during a 2000M ergometer row test

<h3>BACKGROUND CONTEXT</h3> Ergometer rowing has gained popularity as a "low-impact" form of exercise. Lumbar spine injuries are the most common injury in rowers. Previous studies have shown ergometer training to be associated with an increased risk of injury. Muscular fatigue and spine range of motion may correlate to pain or injury in ergometer rowing. <h3>PURPOSE</h3> The purpose of the present study is to utilize 3D motion capture and electromyography (EMG) assessments to 1) evaluate how muscular activation relates to lumbar spine mechanics; 2) determine the impact of fatigue on back muscle activation and biomechanics. <h3>STUDY DESIGN/SETTING</h3> Prospective analysis. <h3>PATIENT SAMPLE</h3> Seventeen rowers (M=8, F=9) with a mean age of 38 ± 9.1 years and a VO2 max of 44.4 ± 7.8 ml·kg·min-1. <h3>OUTCOME MEASURES</h3> Pull force, kinematics and muscle activation were recorded at 200m, 600m, 1000m, 1400m and 1800m distances. Spine flexion (degrees) was investigated. <h3>METHODS</h3> Seventeen rowers (m=8, F=9; age=38±9.1 years, VO2max=44.4±7.8 ml·kg·min-1) participated and performed a 2000-meter row on an ergometer. Pull force, kinematics and muscle activation were recorded using a load cell, motion capture system and a wireless EMG, respectfully. Data was recorded at 200m, 600m, 1000m, 1400m and 1800m distances. Spine flexion was calculated at three points in the sagittal plane and labeled as upper-, mid- and lower-spine. A mixed-model ANOVA repeated on row distance and a Tukey's post-hoc test was used to compare biomechanical assessments. Type-I error was set at a=0.05. <h3>RESULTS</h3> Average time to complete the test was 8.4 ± 1.0 min. Trapezius and mid-spinal erector activation was maintained through the row. A steady decrease in mean and peak latissimus dorsi activation was observed with increasing distance (p < 0.05), paired with an increase in peak lumbar spinal erector activation (p < 0.05), indicating fatigue of the upper back musculature followed by compensatory reliance on low back muscles to maintain/increase force. Upper spinal flexion (min and max) increased by 1000m, indicating an increase in the overall state of flexion with progressing distance (p < 0.05). Mid-spinal flexion demonstrated increased min flexion (indicating reduced peak extension) beginning at 1400m (P < 0.05). Lumbar spine flexion was maintained throughout the row, indicating that the primary mechanics fatigue change was a result of upper back rounding due to upper back muscle fatigue. Results indicate that low back pain and injuries associated with rowing may not be because of altered flexion/extension of the lumbar spine but rather, a result of increased workload placed on low back musculature to compensate fatiguing muscles and changes in the row mechanics of the upper and mid spine. Although ergometer rowing is often considered "low-impact," given the high number of contractions over a short time (<10min), it may be advisable for rowers to avoid multiple days of fatiguing row ergometer training per week. <h3>CONCLUSIONS</h3> The present findings will provide greater insight into the potential mechanisms of fatigue during ergometer rowing. Results will also give medical professionals a better understanding of the origins and presentation of soft tissue injuries in the spine in recreational rowers. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Towards the estimation of ultimate compression tolerance as a function of cyclic compression loading history: implications for lifting-related low back injury risk assessment

This study aimed to mathematically characterize the ultimate compression tolerance (UCT) as a function of spinal joint posture, loading variation, and loading duration. One hundred and fourteen porcine cervical spinal units were tested. Spinal units were randomly assigned to subthreshold cyclic loading groups that differed by joint posture (neutral, flexed), peak loading variation (10%, 20%, 40%), and loading duration (1000, 3000, 5000 cycles). After the assigned conditioning test, UCT testing was ­performed. Force and actuator position were sampled at 100 Hz. A three-­dimensional relationship between UCT, loading variation, and loading duration was most accurately characterized by a second order polynomial surface (R2 = 0.644, RMSE = 1.246 kN). However, distinct UCT responses were observed for flexed and neutral postures. A single second-order polynomial most accurately characterized the UCT – loading duration relationship (R2 = 0.905, RMSE = 0.718 kN) for flexed postures. For neutral joint postures, separate second-order polynomial equations were developed to characterize the UCT – loading duration relationship for each variation group (R2 = 0.618–0.906, RMSE = 0.617 kN–0.746 kN). These findings suggest that UCT responses are influenced by joint posture and these data may be used to inform ergonomic tools for the assessment of low back injury risk during occupational lifting.

Electroacupuncture of Weizhong (BL-40) Acupoint Inspires Muscular Satellite Cell Regeneration and Promotes Muscle Repair Capacity after Back Muscle Injury in Sprague-Dawley Rat Model.

Background Back muscle injury is the most common illness involved in aged people. Muscular satellite cells, playing a key role in the muscle repairing process, are gradually losing their regenerative ability with aging, which attenuates the injured muscle repairing process. Electroacupuncture at Weizhong acupoint has been widely used in the treatment of young and aged patients with back muscle damage. Its efficacy has been proven by a randomized double-blind placebo clinical trial. However, the rehabilitation mechanisms are largely unknown. This study will explore the possible mechanisms associated with electroacupuncture at the Weizhong acupoint (BL 40) promoting muscle repairing ability. Method A total of 58 male and female Sprague-Dawley rats were divided into a younger group (4-month-old) and an aged group (16-month-old), younger and aged rats were further divided as a sham, injured, injured rats treated with electroacupuncture at Weizhong point or treated with Non-Weizhong point groups. The back muscle injury model was produced in rats as a previously described method with modification. Furthermore, Weizhong acupoints underwent electroacupuncture treatment with 15 V magnitude, 2 Hz/10 Hz frequency density, 1.0 mA current intensity, and 10 min each day for 10 consecutive days using HANS's electroacupuncture apparatus. After the last treatment, the paravertebral muscles and serum of all animals were undergone histological, immunohistochemistry, and flow cytometry analysis. Serum levels of Creatine Kinase (CK) and proinflammatory cytokine, interleukin 6 (IL-6), were measured separately by using ELISA kit. Results Electroacupuncture of Weizhong (BL 40) acupoints significantly attenuated back muscle damage in both young and aged rats, increasing PAX7 (a marker of muscle satellite cells) and MYOD (major marker of myoblasts) cells, simultaneously, reducing serum proinflammatory cytokines, IL-6, and downregulation of p38 MAPK signaling in aged muscular satellite cells. Conclusion Our studies suggest that electroacupuncture of Weizhong (BL 40) acupoints can restore aged back muscular satellite cells and their regeneration capacity. These suggested electroacupuncture may be a potential means of promoting rehabilitation for muscular injury in aged patients.

Use of 3D heads-up display for strabismus surgery

Strabismus surgery can lead to back and neck injuries for surgeons and their assistants due to the adoption of unnatural postures when using the operating microscope or loupes. The surgical team may have difficulty following the flow of surgery when the surgical field is not projected, leading to poor anticipation and efficiency. Heads-up surgical displays have been shown to improve ergonomics in many fields.

The epidemiology of back injuries in elite Gaelic football athletes: An 8-year prospective study

ObjectivesTo describe the epidemiology of back injury in elite male Gaelic football athletes between 2008 and 2016. DesignProspective cohort study. SettingInjury data from the National GAA Injury Surveillance Database. ParticipantsElite male Gaelic football athletes. Main outcome measuresIncidence of injury as a rate per 1000 h of exposure. Results38 datasets were analysed. Out of a total of 1606 time-loss injuries, 76 were back injuries (4.73%, 95% CI 3.80%–5.88%). The incidence of back injuries in match play was 1.72 (CI 95% 1.21 to 2.45) and in training was 0.2 (CI 95% 0.14 to 0.28) injuries per 1000 h of exposure. The majority of back injuries (63.16%, CI 95% 51.93–73.12) were new, as opposed to recurrent (35.53% CI 95% 25.7–46.74). Most back injuries were acute (51.32%, CI 95% 40.29–62.22), compared to chronic (31.58%, CI 95% 22.23–42.7) or overuse (11.84%, CI 95% 6.36–21.00). The majority of back injuries occurred during non-contact player activities (n = 60, 78.94% CI 95% 68.50–86.60). ConclusionsBack injury rates in Gaelic football are similar to soccer and Australian football but less than rugby union. Further research is needed to understand the factors leading to the onset and recurrence of back injury in Gaelic football athletes.

Effects of a Core Strengthening Program on Muscle Activity Patterns, Strength, and Endurance in People with and without a History of Low Back Pain: A Randomized Controlled Trial

Background of Study: Altered patterns of abdominal and low back muscle activity have been reported in people in the sub-acute phase of low back injury. Specifically, higher overall muscle activity and less ability to match activity to task demands have been found. Objective: This study determined if an 8-week group exercise intervention would alter muscle activity, strength, and endurance in people with/without a history of low back pain (LBP). Method: In this randomized controlled trial 46 participants (age 19-55) with a history of LBP were randomized to exercise (LBPEx, n=24) and no-exercise (LBPCon, n=22) groups. 27 participants without a history of LBP (NoLBP) also exercised. 17 LBPEx and 19 NoLBP participants completed the intervention. 19 LBPCon were tested at 8-week follow-up. The exercise intervention was an 8-week, choreographed, 30-minute group exercise intervention (Les Mills CoreTM) focused on building core strength, stability, and endurance. Pre and post-intervention surface electromyograms from abdominal and low back muscles were recorded during a trunk stability task (TST), and analyzed using Principal Component Analysis to extract patterns corresponding to overall amplitude and relative activation during the TST loading phase. Abdominal and back extensor strength and endurance were also measured. Results: It was found that overall abdominal activity decreased for left anterior external oblique (p=0.019 for TST level 3), left lateral external oblique (p=0.012 for TST level 3), and right posterior external oblique (p=0.035 for TST level 3) in LBPEx and for right lateral external oblique (p=0.009 for TST level 2 and p=0.004 for TST level 3) and left posterior external oblique (p=0.014 for TST level 2 and p=0.011 for TST level 3) in NoLBP during the TST. Abdominal strength and endurance, and back extensor endurance increased for LBPEx and NoLBP (p0.05). Back extensor strength increased for NoLBP (p0.05). Relative abdominal activation during the TST level 2 loading phase increased for right upper rectus abdominus (p=0.05), right lateral external oblique (p=0.002), and left posterior external oblique (p=0.006) for NoLBP, and for left anterior external oblique (p=0.042) for LBPEx. Conclusion: Les Mills CoreTM is readily available and may be recommended as a safe, accessible, and effective intervention to increase abdominal strength and endurance, and back extensor endurance, even for people with a history of LBP.

Adjustments in Shoulder and Back Kinematics during Repetitive Palletizing Tasks.

Repetitive task performance is a leading cause of musculoskeletal injuries among order-picking workers in warehouses. The repetition of lifting tasks increases the risk of back and shoulder injuries among these workers. While lifting in this industry is composed of loaded and unloaded picking and placing, the existing literature does not address the separate analysis of the biomechanics of the back and shoulder for these events. To that end, we investigated the kinematics of the back and shoulder movements of nine healthy male participants who performed three sessions of a simulated de/palletization task. Their back and shoulder kinematics were sensed using an optical motion capture system to determine the back inclination and shoulder flexion. Comparison of the kinematics between the first and last sessions indicated statistically significant changes in the timings, angles, coordination between the back and shoulder, and moments around the shoulder (). The majority of the significant changes were observed during the loaded events, which confirms the importance of the separation of these events for biomechanical analysis. This finding suggests that focusing worker evaluation on the loaded periods can provide important information to detect kinematic changes that may affect musculoskeletal injury risk.

Optimization-based biomechanical lifting models for manual material handling: A comprehensive review.

Lifting is a main task for manual material handling (MMH), and it is also associated with lower back pain. There are many studies in the literature on predicting lifting strategies, optimizing lifting motions, and reducing lower back injury risks. This survey focuses on optimization-based biomechanical lifting models for MMH. The models can be classified as two-dimensional and three-dimensional models, as well as skeletal and musculoskeletal models. The optimization formulations for lifting simulations with various cost functions and constraints are reviewed. The corresponding equations of motion and sensitivity analysis are briefly summarized. Different optimization algorithms are utilized to solve the lifting optimization problem, such as sequential quadratic programming, genetic algorithm, and particle swarm optimization. Finally, the applications of the optimization-based lifting models to digital human modeling which refers to modeling and simulation of humans in a virtual environment, back injury prevention, and ergonomic safety design are summarized.

Development of a Stretchable Circuit and its Integration Method on Knit Fabrics for Lower Back Injury Prevention

Advancements in wearable technology and smart textiles have also opened new possibilities in the sports and medical fields. One of the examples of a relevant application case can be found in cycling. This paper expands on previous research on stretchable electronics on knit fabrics. It describes the development of stretchable circuits for the lower back position and motion tracking to prevent back pain in recreational (road) cyclists by combining electrical and textile engineering with insights generated in rehabilitation sciences and sports physiotherapy. The research process included developing and testing of the functional circuit integrated into a cycling jersey. Thermoplastic polyurethane films were used for the textile integration process to achieve maximum comfort and after-life disassembly possibility. Reliability tests, e.g. washing (ISO 6330-2012) and tensile tests, were conducted. It is concluded that while mechanical stress during washing cycles remains a serious concern for reliability and durability, the use of water-repellent thermoplastic polyurethane sealing seriously reduces the damage caused by water and detergents.

Effect of Back Support Belt on Musculoskeletal Discomfort During Simulated Manual Handling of Loads Among Male Agricultural Workers

Introduction: The usage of back support belt for manual handling activities particularly lifting/lowering of loads in occupational setting has been a sore point of conflicting agreement between industrial practitioners and academician on its effectiveness in prevention of back injuries. As such, this pre-test and post-test experimental study was designed to investigate the effectiveness of back support belt in reducing localized musculoskeletal discomfort among male agricultural workers. Methods: A total of 38 subjects were randomly assigned into control and intervention groups (19 subjects in each group). The subjects were required to carry out a series of lifting and lowering of incremental weight load similar to the protocol as described in Progressive Isoinertial Lifting Evaluation (PILE) techniques. After completing each lift, subjects were required to rate the discomfort felt in the back region using the Localized Musculoskeletal Discomfort questionnaire. Results: Results showed that only several pairs showing statistically significant differences with no discernible trend. Within the control group, the median calculated from group data showed an overall increased discomfort rating as the weight load increases except for 19.4kg but an overall decreased discomfort within intervention group. Comparison between control and intervention group for post-test results showed significant difference between 5.9kg and middle back although the trend of LMD ratings across body part investigated may suggest interesting relationship. Conclusion: Despite positive subjective perception amongst the wearer as conveyed by industrial practitioners, the epidemiological data, clinical trials, and various other experimental studies in the past few decades including in this study has not shown sufficient evidence of effectiveness.

Design of a Compact Energy Storage with Rotary Series Elastic Actuator for Lumbar Support Exoskeleton

Lumbar support exoskeletons with active and passive actuators are currently the cutting-edge technology for preventing back injuries in workers while lifting heavy objects. However, many challenges still exist in both types of exoskeletons, including rigid actuators, risks of human–robot interaction, high battery consumption, bulky design, and limited assistance. In this paper, the design of a compact, lightweight energy storage device combined with a rotary series elastic actuator (ES-RSEA) is proposed for use in a lumbar support exoskeleton to increase the level of assistance and exploit the human bioenergy during the two stages of the lifting task. The energy storage device takes the responsibility to store and release passive mechanical energy while RSEA provides excellent compliance and prevents injury from the human body’s undesired movement. The experimental tests on the spiral spring show excellent linear characteristics (above 99%) with an actual spring stiffness of 9.96 Nm/rad. The results demonstrate that ES-RSEA can provide maximum torque assistance in the ascent phase with 66.6 Nm while generating nearly 21 Nm of spring torque during descent without turning on the DC motor. Ultimately, the proposed design can maximize the energy storage of human energy, exploit the biomechanics of lifting tasks, and reduce the burden on human effort to perform lifting tasks.