Restricting lumbar spine flexion redistributes and changes total mechanical energy expenditure during lifting.

Minimizing lumbar spine flexion during lifting requires greater lower extremity joint motion. However, the effects of these kinematic changes on lumbar and lower extremity joint kinetics are unknown. Further, it is unclear whether the distribution of biomechanical demands throughout the lumbar spine and lower extremity during lumbar spine flexion restricted lifting are modulated by task factors like lift origin height and object mass. This study examined the influence of restricting lumbar spine flexion during lifting on the distribution of biomechanical demands, operationalized as mechanical energy expenditure (MEE), across the lumbar spine and lower extremity joints during lifting tasks. Twenty participants performed a series of lifting tasks that varied by lift origin height, object mass and presence or absence of lumbar spine motion restricting harness. MEE was quantified for the lumbar spine and lower extremity joints and summed across all joints to represent the total MEE. Distributions of MEE were compared across combinations of the three task factors. Total MEE was greater when lifting with restricted spine motion (p < 0.001). MEE was redistributed away from the lumbar spine and predominantly to the hips in the spine restricted conditions (p < 0.001). The nature and magnitude of this effect was modulated by lift origin height for the lumbar spine (p < 0.001) and hips (p < 0.001). Findings demonstrated that biomechanical demands can be shifted from the lumbar spine to the lower extremity when lifting with restricted spine flexion, which might help mitigate overuse injuries through coordinative variability.

Equivalent weight: Application of the assessment method on real task conducted by railway workers wearing a back support exoskeleton.

Commonly used risk indexes, such as the NIOSH Lifting Index, do not capture the effect of exoskeletons. This makes it difficult for Health and Safety professionals to rigorously assess the benefit of such devices. The community requires a simple method to assess the effectiveness of back-support exoskeleton's (BSE) in possibly reducing ergonomic risk. The method introduced in this work is termed "Equivalent Weight" (EqW) and it proposes an interpretation of the effect built on the benefit delivered through reduced activation of the erector spinae (ES). This manifests itself as an apparent reduction of the lifted load perceived by the wearer. This work presents a pilot study where a practical application of the EqW method is used to assess the ergonomic risk in manual material handling (MMH) when using a back support exoskeleton (StreamEXO). The results are assessed by combining observational measurements from on-site testing with five different workers and quantitative measures of the muscle activity reduction achieved during laboratory evaluation with ten workers. These results will show that when lifting, lowering, and carrying a 19 kg load the StreamEXO can reduce risk by up to two levels (from "high" to "low") in the target sub-tasks. The Lifting index (LI) was reduced up to 64% when examining specific sub-tasks and the worker's movement conduction.

Adaptive Lifting Index (aLI) for Real-Time Instrumental Biomechanical Risk Assessment: Concepts, Mathematics, and First Experimental Results.

When performing lifting tasks at work, the Lifting Index (LI) is widely used to prevent work-related low-back disorders, but it presents criticalities pertaining to measurement accuracy and precision. Wearable sensor networks, such as sensorized insoles and inertial measurement units, could improve biomechanical risk assessment by enabling the computation of an adaptive LI (aLI) that changes over time in relation to the actual method of carrying out lifting. This study aims to illustrate the concepts and mathematics underlying aLI computation and compare aLI calculations in real-time using wearable sensors and force platforms with the LI estimated with the standard method used by ergonomists and occupational health and safety technicians. To reach this aim, 10 participants performed six lifting tasks under two risk conditions. The results show us that the aLI value rapidly converges towards the reference value in all tasks, suggesting a promising use of adaptive algorithms and instrumental tools for biomechanical risk assessment.

Lifting all boats: strategies to promote equitable bidirectional research training opportunities to enhance global health reciprocal innovation.

Inequities in global health research are well documented. For example, training opportunities for US investigators to conduct research in low-income and middle-income countries (LMIC) have exceeded opportunities for LMIC investigators to train and conduct research in high-income countries. Reciprocal innovation addresses these inequities through collaborative research across diverse global settings.The Fogarty International Center of the US National Institutes of Health (NIH) promotes research capacity building in LMICs. Fogarty K-grants for mentored career development in global health are available for both US and LMIC investigators, whereas the D43 is the standard grant to support institutional training programmes in LMIC. Other NIH institutes fund T32 training grants to support biomedical research training in the USA, but very few have any global health component. Most global health training partnerships have historically focused on research conducted solely in LMIC, with few examples of bidirectional training partnerships. Opportunities may exist to promote global health reciprocal innovation (GHRI) research by twinning K-awardees in the USA with those from LMIC or by intentionally creating partnerships between T32 and D43 training programmes.To sustain independent careers in GHRI research, trainees must be supported through the path to independence known as the K (mentored grantee)-to-R (independent grantee) transition. Opportunities to support this transition include comentorship, research training at both LMIC and US institutions and protected time and resources for research. Other opportunities for sustainability include postdoctoral training before and after the K-award period, absorption of trained researchers into home institutions, South-South training initiatives and innovations to mitigate brain drain.

Mechanomyographic Analysis for Muscle Activity Assessment during a Load-Lifting Task.

The purpose of this study was to compare electromyographic (EMG) with mechanomyographic (MMG) recordings during isometric conditions, and during a simulated load-lifting task. Twenty-two males (age: 25.5 ± 5.3 years) first performed maximal voluntary contractions (MVC) and submaximal isometric contractions of upper limb muscles at 25%, 50% and 75% MVC. Participants then executed repetitions of a functional activity simulating a load-lifting task above shoulder level, at 25%, 50% and 75% of their maximum activity (based on MVC). The low-frequency part of the accelerometer signal (<5 Hz) was used to segment the six phases of the motion. EMG and MMG were both recorded during the entire experimental procedure. Root mean square (RMS) and mean power frequency (MPF) were selected as signal extraction features. During isometric contractions, EMG and MMG exhibited similar repeatability scores. They also shared similar RMS vs. force relationship, with RMS increasing to 75% MVC and plateauing to 100%. MPF decreased with increasing force to 75% MVC. In dynamic condition, RMSMMG exhibited higher sensitivity to changes in load than RMSEMG. These results confirm the feasibility of MMG measurements to be used during functional activities outside the laboratory. It opens new perspectives for future applications in sports science, ergonomics and human-machine interface conception.

Comparison of ACGIH lifting threshold limit values to validated low back disorder lifting assessment methods outcomes.

BACKGROUND: Work-related low back pain (LBP) increases the workforce disability and healthcare costs. This study evaluated the LBD risk level associated with handling the ACGIH TLVs in lifting tasks corresponding to various horizontal and vertical zones. OBJECTIVE: The aim of this study was to compare the low-risk ACGIH TLV to risk outcomes from various validated lifting assessment methods, including the OSU LBD Risk Model, NIOSH Lifting Equation, and LiFFT. METHODS: Twenty-four subjects were recruited for this study to perform various lifting conditions. The various ergonomic assessment methods were then used to obtain the risk assessment outcomes. RESULTS: The selected assessment methods showed that the ACGIH-defined TLVs are associated with less than high-risk for LBD for all the assessed tasks. The findings showed a moderate agreement (Kendall's W = 0.477) among the various assessment methods risk outcomes. The highest correlation (ρ= 0.886) was observed between the NIOSH Lifting Equation and LiFFT methods risk assessment outcomes. CONCLUSION: The findings showed that ACGIH-defined TLVs possesses less than high-risk for LBD. The outcomes of the selected ergonomic assessment methods moderately agree to each other.

Experimental Study of Fully Passive, Fully Active, and Active-Passive Upper-Limb Exoskeleton Efficiency: An Assessment of Lifting Tasks.

Recently, robotic exoskeletons are gaining attention for assisting industrial workers. The exoskeleton power source ranges from fully passive (FP) to fully active (FA), or a mixture of both. The objective of this experimental study was to assess the efficiency of a new active-passive (AP) shoulder exoskeleton using statistical analyses of 11 quantitative measures from surface electromyography (sEMG) and kinematic data and a user survey for weight lifting tasks. Two groups of females and males lifted heavy kettlebells, while a shoulder exoskeleton helped them in modes of fully passive (FP), fully active (FA), and active-passive (AP). The AP exoskeleton outperformed the FP and FA exoskeletons because the participants could hold the weighted object for nearly twice as long before fatigue occurred. Future developments should concentrate on developing sex-specific controllers as well as on better-fitting wearable devices for women.

A novel design of low-cost hearing aid devices using an efficient lifting filter bank with a modified variable filter.

OBJECTIVES: In recent years, audio signal processing begins its outbreak on a global scale, which has altered the global market and has rapidly extended out as a fundamental design in various industries. Lifting based method is frequently implemented in many applications such as image processing and audio processing because it has some advantages that faster implementation with minimum computational cost. METHODS: In this proposed work, a Novel Lifting based Filter Bank (NLFB) is proposed using a modified variable filter aimed at digital hearing aid devices. This filter bank design has some mandatory constraints, such as hardware complexity, power consumption, and delay. The proposed method is designed with four lifting steps such as split, predict, update and merge to make the perfect reconstruction in analysis and decomposition in synthesis bank. The performance analysis of the proposed method is discussed in this article. RESULTS: The proposed method consumes less power, up to 45mW, and a minimum delay between 85ns and 91.1ns when compared to traditional methods. CONCLUSION: The proposed design output consumes 32 % of minimum hardware components, 12% of low power compared to interpolated filter bank and 6% of delay is reduced using Modified Variable Filter (MVFB).

Centre of pressure parameters for the assessment of biomechanical risk in fatiguing frequency-dependent lifting activities.

Lifting tasks, among manual material handling activities, are those mainly associated with low back pain. In recent years, several instrumental-based tools were developed to quantitatively assess the biomechanical risk during lifting activities. In this study, parameters related to balance and extracted from the Centre of Pressure (CoP) data series are studied in fatiguing frequency-dependent lifting activities to: i) explore the possibility of classifying people with LBP and asymptomatic people during the execution of task; ii) examine the assessment of the risk levels associated with repetitive lifting activities, iii) enhance current understanding of postural control strategies during lifting tasks. Data were recorded from 14 asymptomatic participants and 7 participants with low back pain. The participants performed lifting tasks in three different lifting conditions (with increasing lifting frequency and risk levels) and kinetic and surface electromyography (sEMG) data were acquired. Kinetic data were used to calculated the CoP and parameters extracted from the latter show a discriminant capacity for the groups and the risk levels. Furthermore, sEMG parameters show a trend compatible with myoelectric manifestations of muscular fatigue. Correlation results between sEMG and CoP velocity parameters revealed a positive correlation between amplitude sEMG parameters and CoP velocity in both groups and a negative correlation between frequency sEMG parameters and CoP velocity. The current findings suggest that it is possible to quantitatively assess the risk level when monitoring fatiguing lifting tasks by using CoP parameters as well as identify different motor strategies between people with and without LBP.

An ergonomic assessment tool for evaluating the effect of back exoskeletons on injury risk.

Low back disorders (LBDs) are a leading injury in the workplace. Back exoskeletons (exos) are wearable assist devices that complement traditional ergonomic controls and reduce LBD risks by alleviating musculoskeletal overexertion. However, there are currently no ergonomic assessment tools to evaluate risk for workers wearing back exos. Exo-LiFFT, an extension of the Lifting Fatigue Failure Tool, is introduced as a means to unify the etiology of LBDs with the biomechanical function of exos. We present multiple examples demonstrating how Exo-LiFFT can assess or predict the effect of exos on LBD risk without costly, time-consuming electromyography studies. For instance, using simulated and real-world material handling data we show an exo providing a 30 Nm lumbar moment is projected to reduce cumulative back damage by ∼70% and LBD risk by ∼20%. Exo-LiFFT provides a practical, efficient ergonomic assessment tool to assist safety professionals exploring back exos as part of a comprehensive occupational health program.

Long-term Follow-up of Affected Residents After Lifting Evacuation Orders in Fukushima Prefecture, Japan: Findings from an Interview-Based Psychological Survey.

We examined the relationship between social support and psychological variables, and investigated the status of social support among villagers whose evacuation order had been lifted. The survey used for the analysis is the data of FY 2018 and 2019. In fiscal year 2018, a written questionnaire was posted to 4828 registered residents of Iitate Village and 1405 valid responses were received. The main finding (in joint assessment by local and external experts) was the 'need for professional support' (191 respondents, 13.6%). Multivariate analysis found that among those living in permanent housing outside the village, the need for support was significantly more likely for those without emotional support, or instrumental support, and those not providing support. The 2019 follow-up showed a slight improvement in perceived social support (PSS). The associations between perceived social support and living environment suggest the need to strengthen social support measures in areas where evacuation orders are yet to be lifted, which will provide useful information with which to examine the effects of future support efforts.

Lifting and Toning of Arms and Calves Using High-Intensity Focused Electromagnetic Field (HIFEM) Procedure Documented by Ultrasound Assessment.

OBJECTIVE: The HIFEM procedure demonstrates positive outcomes on abdomen and buttock. This multi-center study aims to investigate its effect on adipose tissue and muscle mass located in upper arms and calves. MATERIALS AND METHODS: Twenty subjects (45.10±15.19 years, 24.44±3.22 kg/m2) who underwent a HIFEM procedure (4 sessions; 20 minutes per muscle group) on arms and calves were evaluated. Overall, 7 patients were treated over biceps and triceps, 4 patients over calves, and 9 patients underwent treatment of both upper arms and calves. The changes in adipose and muscle tissue of musculus biceps brachii, triceps brachii, and gastrocnemius were evaluated by using ultrasound. The results from a 1-month, 3-month, and 6-month follow-up were compared to the baseline. Digital photographs, weight measurements, satisfaction, and comfort questionnaires were assessed at baseline and follow-ups. RESULTS: Ultrasound images revealed a significant (P<0.05) increase in the muscle mass of all studied muscles, with the most noticeable improvement in biceps brachii (+16.13% at 3 months). The fat deposits over arms and calves showed significant improvement (P<0.05), reaching -15.12% at 3 months. The results peaked at 3 months and were sustained up to 6 months with a slight but insignificant decline. Aesthetic enhancement of treated areas was documented while patients were highly satisfied. CONCLUSIONS: The achieved outcomes showed that the HIFEM procedure is effective for muscle toning and fat reduction in arms and calves. The results suggest that the use of the HIFEM procedure is not limited only to abdominal and buttock shaping but is also effective for toning of arms and calves. J Drugs Dermatol. 2021;20(7):755-759. doi:10.36849/JDD.5878.

Work-Related Risk Assessment According to the Revised NIOSH Lifting Equation: A Preliminary Study Using a Wearable Inertial Sensor and Machine Learning.

Many activities may elicit a biomechanical overload. Among these, lifting loads can cause work-related musculoskeletal disorders. Aspiring to improve risk prevention, the National Institute for Occupational Safety and Health (NIOSH) established a methodology for assessing lifting actions by means of a quantitative method based on intensity, duration, frequency and other geometrical characteristics of lifting. In this paper, we explored the machine learning (ML) feasibility to classify biomechanical risk according to the revised NIOSH lifting equation. Acceleration and angular velocity signals were collected using a wearable sensor during lifting tasks performed by seven subjects and further segmented to extract time-domain features: root mean square, minimum, maximum and standard deviation. The features were fed to several ML algorithms. Interesting results were obtained in terms of evaluation metrics for a binary risk/no-risk classification; specifically, the tree-based algorithms reached accuracies greater than 90% and Area under the Receiver operating curve characteristics curves greater than 0.9. In conclusion, this study indicates the proposed combination of features and algorithms represents a valuable approach to automatically classify work activities in two NIOSH risk groups. These data confirm the potential of this methodology to assess the biomechanical risk to which subjects are exposed during their work activity.

The Sensor-Based Biomechanical Risk Assessment at the Base of the Need for Revising of Standards for Human Ergonomics.

Due to the epochal changes introduced by "Industry 4.0", it is getting harder to apply the varying approaches for biomechanical risk assessment of manual handling tasks used to prevent work-related musculoskeletal disorders (WMDs) considered within the International Standards for ergonomics. In fact, the innovative human-robot collaboration (HRC) systems are widening the number of work motor tasks that cannot be assessed. On the other hand, new sensor-based tools for biomechanical risk assessment could be used for both quantitative "direct instrumental evaluations" and "rating of standard methods", allowing certain improvements over traditional methods. In this light, this Letter aims at detecting the need for revising the standards for human ergonomics and biomechanical risk assessment by analyzing the WMDs prevalence and incidence; additionally, the strengths and weaknesses of traditional methods listed within the International Standards for manual handling activities and the next challenges needed for their revision are considered. As a representative example, the discussion is referred to the lifting of heavy loads where the revision should include the use of sensor-based tools for biomechanical risk assessment during lifting performed with the use of exoskeletons, by more than one person (team lifting) and when the traditional methods cannot be applied. The wearability of sensing and feedback sensors in addition to human augmentation technologies allows for increasing workers' awareness about possible risks and enhance the effectiveness and safety during the execution of in many manual handling activities.

Biomechanical assessment of two back-support exoskeletons in symmetric and asymmetric repetitive lifting with moderate postural demands.

Two passive back-support exoskeleton (BSE) designs were assessed in terms of muscular activity, energy expenditure, joint kinematics, and subjective responses. Eighteen participants (gender-balanced) completed repetitive lifting tasks in nine different conditions, involving symmetric and asymmetric postures and using two BSEs (along with no BSE as a control condition). Wearing both BSEs significantly reduced peak levels of trunk extensor muscle activity (by ~9-20%) and reduced energy expenditure (by ~8-14%). Such reductions, though, were more pronounced in the symmetric conditions and differed between the two BSEs tested. Participants reported lower perceived exertion using either BSE yet raised concerns regarding localized discomfort. Minimal changes in lifting behaviors were evident when using either BSE, and use of both BSEs led to generally positive usability ratings. While these results are promising regarding the occupational use of BSEs, future work is recommended to consider inter-individual differences to accommodate diverse user needs and preferences.

Wearable Sensor Network for Biomechanical Overload Assessment in Manual Material Handling.

The assessment of risks due to biomechanical overload in manual material handling is nowadays mainly based on observational methods in which an expert rater visually inspects videos of the working activity. Currently available sensing wearable technologies for motion and muscular activity capture enables to advance the risk assessment by providing reliable, repeatable, and objective measures. However, existing solutions do not address either a full body assessment or the inclusion of measures for the evaluation of the effort. This article proposes a novel system for the assessment of biomechanical overload, capable of covering all areas of ISO 11228, that uses a sensor network composed of inertial measurement units (IMU) and electromyography (EMG) sensors. The proposed method is capable of gathering and processing data from three IMU-based motion capture systems and two EMG capture devices. Data are processed to provide both segmentation of the activity and ergonomic risk score according to the methods reported in the ISO 11228 and the TR 12295. The system has been tested on a challenging outdoor scenario such as lift-on/lift-off of containers on a cargo ship. A comparison of the traditional evaluation method and the proposed one shows the consistency of the proposed system, its time effectiveness, and its potential for deeper analyses that include intra-subject and inter-subjects variability as well as a quantitative biomechanical analysis.

Validation of a wearable system for 3D ambulatory L5/S1 moment assessment during manual lifting using instrumented shoes and an inertial sensor suit.

This study aimed to evaluate the accuracy of 3D L5/S1 moment estimates from an ambulatory measurement system consisting of a wearable inertial motion capture system (IMC) and instrumented force shoes (FSs), during manual lifting. Reference L5/S1 moments were calculated using an inverse dynamics bottom-up laboratory model (buLABmodel), based on data from a measurement system comprising optical motion capture (OMC) and force plates (FPs). System performance of (1) a bottom-up ambulatory model (buAMBmodel) using lower-body kinematic IMC and FS data, and (2) a top-down ambulatory model (tdAMBmodel) using upper-body kinematic IMC data and hand forces (HFs) were compared. HFs were estimated using full-body kinematic IMC data and FS forces. Eight males and eight females lifted a 10-kg box from different initial vertical/horizontal positions using either a free or an asymmetric lifting style. As a measure of system performance, root-mean-square (RMS) errors were calculated between the reference (buLABmodel) and ambulatory (tdAMBmodel &buAMBmodel) moments. The results showed two times smaller errors for the tdAMBmodel (averaged RMS errors < 20 Nm or 10% of peak extension moment) than for the buAMBmodel (average RMS errors < 40 Nm or 20% of peak extension moment). In conclusion, for ambulatory L5/S1 moment assessment with an IMC + FS system, using a top-down inverse dynamics approach with estimated hand forces is to be preferred over a bottom-up approach.

Assessment instruments of movement quality in patients with non-specific low back pain: A systematic review and selection of instruments.

BACKGROUND: Observing and analyzing movement quality (MQ) in patients with non-specific low back pain (NS-LBP) is important in the clinical reasoning of primary care physiotherapists and exercise therapists. However, there is no standardized form of assessment. RESEARCH QUESTION: which MQ domains are measured with which instruments, and which activities are relevant, appropriate and methodologically sound for assessing MQ in patients with NS-LBP? METHODS: The study had three phases. In phase 1 we conducted a systematic review in PubMed, CINAHL and SPORTDiscus of literature published until October 2018. The selected studies measured MQ domains with instruments that enabled us to 1) compare MQ in self-paced dynamic activities of patients with NS-LBP and healthy controls, and/or 2) determine change over time of MQ in patients with NS-LBP. In phase 2 we established relevant dynamic activities to assess in patients with NS-LBP. In phase 3 we determined appropriateness and methodological qualities of the selected instruments. RESULTS: Thirty cross-sectional and three pre-post-test studies were eligible. The instruments consisted of complex (n = 19) and simple (n = 7) instrumented motion analysis systems and standardized observational tests (n = 7). We identified three domains representative for MQ: range of motion (ROM), inter-segmental coordination, and whole-body movements. In these domains, patients with NS-LBP significantly differed from healthy controls, respectively 7/12, 12/13 and 13/20 studies. Moreover, ROM and whole-body movements significantly improved over time in patients with NS-LBP (3/3 studies). Based on phase 3, we concluded that none of the instruments are appropriate to assess MQ in patients with NS-LBP in primary care. SIGNIFICANCE: Forward bending, lifting, and walking seem the most relevant activities to evaluate in patients with NS-LBP. However, we found no suitable instruments to measure ROM, inter-segmental coordination, or whole-body movements as determinants of MQ in these activities in daily practice. We therefore recommend such an instrument be developed.