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We have previously shown evidence that some individuals seem to consistently minimize low back loads when lifting. while others do not. However, it is unknown why. Individual differences in ability to perceive relevant sensory information may explain differences in minimization of low back loads during lifting, consistent with considering load reduction in one's movement objective in an optimal feedback control theory framework. The purpose of this study was to investigate whether individuals' ability to perceive proprioceptive information (both force- and posture-senses) at the low back was associated with peak low back loads when performing generic or occupation-specific lifts. Seventy-two participants were recruited to perform 10 barbell (generic) and backboard (occupation-specific) lifts, while whole-body kinematics and ground reaction forces were collected. Peak low back compression and anteroposterior shear forces normalized to body mass were calculated as dependent variables. Both posture matching ability and force matching ability at the heavier force targets were associated with lower means and variability of peak low-back loads in both lift types, albeit with small effect sizes (R² 5.17). These findings support the utility of an optimal feedback control theory framework to explore factors explaining interindividual differences in low back loads during lifting. Further, this evidence suggests improving proprioceptive ability may be a useful strategy in lift training programs designed for workplace injury prevention. [ABSTRACT FROM AUTHOR]

It is unknown how structural (sex, stature, body mass) and functional (strength, flexibility) personal factors influence lifting strategy in paramedic work. We explored whether variance in peak low back forces and kinematic coordination patterns could be explained by structural and functional personal factors in paramedic lifting tasks. Seventy-two participants performed backboard and stretcher lifts. Peak low back forces normalised to body mass, as well as kinematic coordination patterns, were calculated as dependent variables. Being female, stronger, shorter, having higher body mass, and/or having greater lower body range of motion (ROM) were all independently associated with lower normalised low back forces across backboard and stretcher lifting. Females and stronger individuals seemed to define a movement objective to consistently minimise compressive forces, while individuals with greater hip ROM consistently minimised anteroposterior shear forces. The efficacy of improving strength and hip ROM to reduce low back forces in paramedic lifting should be investigated. Practitioner summary: Females, stronger individuals, and individuals with greater hip range of motion consistently exhibited lower normalised low back forces in paramedic lifting. Improving strength and hip range of motion via training is a potential proactive ergonomics approach to reduce peak low back forces in paramedic lifting tasks. [ABSTRACT FROM AUTHOR]

Purpose: Non-neutral neck positions are important initial conditions in impact scenarios, associated with a higher incidence of injury. Repositioning in finite element (FE) neck models is often achieved by applying external boundary conditions (BCs) to the head while constraining the first thoracic vertebra (T1). However, in vivo, neck muscles contract to achieve a desired head and neck position generating initial loads and deformations in the tissues. In the present study, a new muscle-based repositioning method was compared to traditional applied BCs using a contemporary FE neck model for forward head flexion of 30°. Methods: For the BC method, an external moment (2.6 Nm) was applied to the head with T1 fixed, while for the muscle-based method, the flexors and extensors were co-contracted under gravity loading to achieve the target flexion. Results: The kinematic response from muscle contraction was within 10% of the in vivo experimental data, while the BC method differed by 18%. The intervertebral disc forces from muscle contraction were agreeable with the literature (167 N compression, 12 N shear), while the BC methodology underpredicted the disc forces owing to the lack of spine compression. Correspondingly, the strains in the annulus fibrosus increased by an average of 60% across all levels due to muscle contraction compared to BC method. Conclusion: The muscle repositioning method enhanced the kinetic response and subsequently led to differences in tissue-level responses compared to the conventional BC method. The improved kinematics and kinetics quantify the importance of repositioning FE neck models using active muscles to achieve non-neutral neck positions. [ABSTRACT FROM AUTHOR]

Objective: To explore whether the optimal objective function weightings change when using a digital human model (DHM) to predict origin and destination lifting postures under unfatigued and fatigued states. Background: The ability to predict human postures can depend on state-based influences (e.g., fatigue). Altering objective function weightings within a predictive DHM could improve the ability to predict tasks specific lifting postures under unique fatigue states. Method: A multi-objective optimization-based DHM was used to predict origin and destination lifting postures for ten anthropometrically scaled avatars by using different objective functions weighting combinations. Predicted and measured postures were compared to determine the root mean squared error. A response surface methodology was used to identify the optimal objective function weightings, which was found by generating the posture that minimized error between measured and predicted lifting postures. The resultant weightings were compared to determine if the optimal objective function weightings changed for different lifting postures or fatigue states. Results: Discomfort and total joint torque weightings were affected by posture (origin/destination) and fatigue state (unfatigued/fatigued); however, post-hoc differences between fatigue states and lifting postures were not sufficiently large to be detected. Weighting the discomfort objective function alone tended to predict postures that generalized well to both postures and fatigue states. Conclusion: Lift postures were optimal predicted using the minimization of discomfort objective function regardless of fatigue state. Application: Weighting the discomfort objective can predict unfatigued postures, but more research is needed to understand the optimal objective function weightings to predict postures during a fatigued state. [ABSTRACT FROM AUTHOR]

Background: Chronic Neck Pain (CNP) among rotary-wing aircrew is thought to stem from night vision goggles (NVG) and counterweight (CW) systems which displace the centre of mass of the head. This investigation aimed to quantify the loads acting on the neck as a function of movement magnitude (MM), helmet conditions, and movement axes in rapid movements. Methods: Cervical spine kinematics during rapid head repositioning tasks for flexion-extension (FE) and axial rotation (AR) movements were measured from 15 males and 15 females. Participants moved in either a 35° (Near MM) or 70° arc (Far MM), while donning a helmet, helmet with NVG, helmet with NVG and a typical CW, and a CW Liner (CWL). Measured EMG from three muscles bilaterally and used to drive a biomechanical model to quantify the compression and shear acting at the C5-C6 joint. Results: In AR, the NVGs were associated with the largest compression magnitudes, 252 (24) N. CW conditions decreased the maximum compression to 249 (53) N. For FE, the compression was 340 N for the Far MM trials and 246 N for Near MMs. Changing the helmet configuration only modestly influenced these magnitudes in FE. Conclusion: Every 30° of MM increased compression by 57 to 105 N. The reduction of the moment of inertia by 16% in the CWL did not reduce reaction forces. Joint loads scaled proportionately with head-supported weight by a factor of 2.05. The magnitudes of loads suggest a cumulative loading pathway for CNP development. [ABSTRACT FROM AUTHOR]

To gain a greater understanding of motor variability (MV) as an individual trait, the effect of task type on MV and individual consistency in MV across three tasks was investigated. Twenty participants performed repetitive carrying, lifting, and simulated sawing tasks. MV was assessed using the linear measure of mean point-by-point standard deviation in three-dimensional upper body joint angles. Task type affected MV, where carrying showed higher MV compared to sawing (23–29%) and lifting (12–19%). Furthermore, MV was higher in lifting compared to sawing (12–25%). Poor to moderate individual consistency (ICC = 0.42–0.63) was found across tasks. Task type determined MV and only some support for MV as an individual trait across tasks was found. Based on this work, differences in degrees of freedom afforded by the task influence the opportunity to exploit MV, and possibly individual consistency in MV magnitude is specific to the degrees of freedom afforded by the task. Practitioner summary: In repetitive tasks, movement variability has been proposed as an individual characteristic independent of task characteristics, where repeaters show consistently low variability, while replacers show consistently high variability. In the current study, only moderate support was demonstrated for variability as a consistent individual characteristic across different manual tasks. Abbreviation MV: Motor variability; WRMSDs: Work-related musculoskeletal disorders; DOF: Degrees of freedom; meanSD: Mean standard deviation; SD: Standard deviation; H: Handle (of simulated sawing setup); T: Track (of simulated sawing setup); F: Frame (of simulated sawing setup); ICC: Intraclass correlation; UE: Upper extremity; MMH: Manual material handling; EMG: Electromyography [ABSTRACT FROM AUTHOR]

Multi-objective optimization digital human models permit users to predict postures that follow performance criteria, such as minimizing torques. Currently, it is unknown how to weight different objective functions to best predict postures. Objective one was to describe a response surface method to determine optimal objective function weightings to predict lift postures. Objective two was to evaluate the sensitivity of different error calculation methods. Our response surface approach has utility for determining optimal objective function weightings when using a digital human model to evaluate human-system interactions in early design stages. The approach was not dependent on variations in error calculation methods. [ABSTRACT FROM AUTHOR]

For military rotary-wing aircrew, little is known about the interactive effects of vibration exposure and the addition of head supported mass (HSM) on target acquisition performance, head kinematics, and muscular demand. Sixteen healthy male participants wore an aviator helmet with replica night vision goggles and completed rapid aiming head movements to acquire visual targets in axial and off-axis movement trajectories while secured in a Bell-412 helicopter seat mounted to a human-rated shaker platform. HSM configuration (with or without a counterweight (CW)) and vertical whole-body vibration (WBV) conditions (vibration or no vibration exposure) were manipulated as independent variables. WBV exposure degraded target acquisition performance and lengthened time to peak velocity of head movements. For yaw peak velocity in the axial movement trajectory, peak velocity was 9.9%, 11.6%, and 8.4% higher in the noCW + WBV condition compared to the CW + WBV, CW + noWBV, and noCW + noWBV conditions, respectively. Practitioner summary: The majority of military helicopter aircrew use a counterweight to counteract the anteriorly displaced load of night vision googles. This study was undertaken to better understand how helicopter vibration and counterweight use interactively affect performance and health-related measures during rapid scanning head movements. [ABSTRACT FROM AUTHOR]

Individual responses to fatigue have been observed in lifting kinematics, suggesting a subject-specific approach is necessary for fatigue identification. One-class support vector machines (OCSVM) may provide an objective method to classify fatigue-related kinematic changes during repetitive lifting. Participants completed a repetitive lifting protocol while motion capture recorded lifting motions. Subject-specific kinematics from participants' first 35% of lifts trained OCSVM decision boundaries. The remaining lifts were separated into test sets and classified against the decision boundary to identify the percentage of outlier lifts within each test set. Spearman's correlation assessed if the test sets' percentage of outlier lifts increased concurrently with participants' rating of perceived exertion (RPE). Significant positive associations were found for participants who demonstrated evidence of fatigue, while no significant associations were found for participants who did not demonstrate evidence of fatigue. These results demonstrate the prospective efficacy of an outlier detection tool for fatigue detection during repetitive lifting. Practitioner Summary: An objective subject-specific fatigue detection method is desired for workplace tasks, such as lifting. An outlier detection machine learning approach was identified when lifting movement patterns changed from baseline throughout a repetitive lifting protocol. Participants who demonstrated an increase in outlier movement patterns had a concurrent increase in self-reported fatigue. [ABSTRACT FROM AUTHOR]

The purposes of this study were to determine if 1) recurrent neural networks designed for multivariate, time-series analyses outperform traditional linear and non-linear machine learning classifiers when classifying athletes based on competition level and sport played, and 2) athletes of different sports move differently during non-sport-specific movement screens. Optical-based kinematic data from 542 athletes were used as input data for nine different machine learning algorithms to classify athletes based on competition level and sport played. For the traditional machine learning classifiers, principal component analysis and feature selection were used to reduce the data dimensionality and to determine the best principal components to retain. Across tasks, recurrent neural networks and linear machine learning classifiers tended to outperform the non-linear machine learning classifiers. For all tasks, reservoir computing took the least amount of time to train. Across tasks, reservoir computing had one of the highest classification rates and took the least amount of time to train; however, interpreting the results is more difficult compared to linear classifiers. In addition, athletes were successfully classified based on sport suggesting that athletes competing in different sports move differently during non-sport specific movements. Therefore, movement assessment screens should incorporate sport-specific scoring criteria. [ABSTRACT FROM AUTHOR]

BACKGROUND: It is well-known that psychosocial health status of paramedics may be altered by their job demands. However, it is unknown whether psychosocial health status can affect occupational performance. OBJECTIVE: The goal of this study was to explore whether a paramedic's symptom severity of Occupational Stress Injury (OSI) was related to simulated patient-care performance. METHODS: Nineteen paramedics with 15.0±8.7 years of paramedic experience participated in this study. Participants completed both an OSI symptom severity questionnaires, and a patient-care simulation. Vagal activity was also collected during the patient-care simulation. The simulation was used to assess experienced paramedics in a realistic stressful setting. Based on the provincial standard in New Brunswick, an experienced paramedic instructor graded the patient-care simulation using the provincial standard charts, observing performance videos and assessing data from the manikin. RESULTS: The current study suggests that paramedics who self-reported elevated symptoms of OSI were less likely to successfully complete the simulated patient-care scenario. CONCLUSION: This research suggests that the presence of self-reported elevated symptoms of OSI negatively impacts paramedics' performance during a stressful work task simulation. Therefore, to help paramedics maintain optimal performance, it may be important to ensure that paramedics have access to appropriate resources to monitor and improve their psychosocial health. [ABSTRACT FROM AUTHOR]

Paramedics represent a unique occupational group where the nature of their work, providing prehospital emergency care, makes workplace modifications to manage and control injury risks difficult. Therefore, the provision of workplace education and training to support safe lifting remains a viable and important approach. There is, however, a lack of evidence describing movement strategies that may be optimal for paramedic work. The purpose of this study was to determine if a strategy leveraging a greater contribution of work from the lower body relative to the torso was associated with lower biomechanical exposures on the spine. Twenty-five active duty paramedics performed 3 simulated lifting activities common to paramedic work. Ground reaction forces and whole body kinematics were recorded to calculate: peak spine moment and angle about the L4/L5 flexion-extension axis as indicators of biomechanical exposure; and, joint work, integrated from net joint power as a measure of technique inclusive of movement dynamics. Paramedics generating more work from the lower body, relative to the trunk, were more likely to experience lower peak L4/L5 spine moments and angles. These data can inform the development of workplace training and education on safe lifting that focuses on paramedics generating more work from the lower body. [ABSTRACT FROM AUTHOR]

Purpose The objective of this study was to determine the agreement of kinematic parameters calculated from motion data collected via a 2D video-based pose-estimation (markerless motion capture) approach and a laboratory-based 3D motion capture approach during a floor-to-waist height functional lifting test. Method Twenty healthy participants each performed three floor-to-waist height lifts. Participants' lifts were captured simultaneously using 2D video (camcorder) in the sagittal plane and 3D motion capture (Vicon, Oxford, UK). The three lifts were representative of a perceived light, medium, and heavy load. Post-collection, video data were processed through a pose-estimation software (i.e., markerless motion capture). Motion data from 3D motion capture and video-based markerless motion capture were each used to calculate objective measures of interest relevant to a functional capacity evaluation (i.e., posture, balance, distance of the load from the body, and coordination). Bland–Altman analyses were used to calculate agreement between the two methods. Results Bland–Altman analysis revealed that mean differences ranged from 1.9° to 22.1° for posture and coordination-based metrics calculated using markerless and 3D motion capture, respectively. Limits of agreement for most posture and coordination measures were approximately + 20°. Conclusions 2D video-based pose estimation offers a strategy to objectively measure movement and subsequently calculated metrics of interest within an FCE context and setting, but at present the agreement between metrics calculated using 2D video-based methods and 3D motion capture is insufficient. Therefore, continued effort is required to improve the accuracy of 2D-video based pose estimation prior to inclusion into functional testing paradigms. [ABSTRACT FROM AUTHOR]

Purpose The Epic Lift Capacity (ELC) test is used to determine a worker's maximum lifting capacity. In the ELC test, maximum lifting capacity is often determined as the maximum weight lifted without exhibiting a visually appraised "high-risk workstyle." However, the criteria for evaluating lifting mechanics have limited justification. This study applies feature detection and biomechanical analysis to motion capture data obtained while participants performed the ELC test to objectively identify aspects of movement that may help define "high-risk workstyle". Method In this cross-sectional study, 24 participants completed the ELC test. We applied Principal Component Analysis, as a feature detection approach, and biomechanical analysis to motion capture data to objectively identify movement features related to biomechanical exposure on the low back and shoulders. Principal component scores were compared between high and low exposure trials (relative to median exposure) to determine if features of movement differed. Features were interpreted using single component reconstructions of principal components. Results Statistical testing showed that low exposure lifts and lowers maintained the body closer to the load, exhibited squat-like movement (greater knee flexion, wider base of support), and remained closer to neutral posture at the low back (less forward flexion and axial twist) and shoulder (less flexion and abduction). Conclusions Use of feature detection and biomechanical analyses revealed movement features related to biomechanical exposure at the low back and shoulders. The objectively identified criteria could augment the existing scoring criteria for ELC test technique assessment. In the future, such features can inform the design of classifiers to objectively identify "high-risk workstyle" in real-time. [ABSTRACT FROM AUTHOR]

BACKGROUND: Mass, moment of inertia, and amplitude of neck motion were altered during a reciprocal scanning task to investigate how night vision goggles (NVGs) use mechanistically is associated with neck trouble among rotary-wing aircrew. METHODS: There were 30 subjects measured while scanning between targets at 2 amplitudes (near and far) and under 4 head supported mass conditions (combinations of helmet, NVGs, and counterweights). Electromyography (EMG) was measured bilaterally from the sternocleidomastoid and upper neck extensors. Kinematics were measured from the trunk and head. RESULTS: Scanning between the far amplitude targets required higher peak angular accelerations (;7% increase) and neck EMG (between 1.2-4.5% increase), lower muscle cocontraction ratios (;6.7% decrease), and fewer gaps in EMG (up to a 59% decrease) relative to the near targets. Increasing the mass of the helmet had modest effects on neck EMG, while increasing the moment of inertia did not. DISCUSSION: Target amplitude, not head supported mass configuration, had a greater effect on exposure metrics. Use of NVGs restricts field-of-view, requiring an increased amplitude of neck movement. This may play an important role in understanding links between neck trouble and NVG use. [ABSTRACT FROM AUTHOR]

Servicing and maintaining wind turbines may expose wind turbine technicians (wind techs) to musculoskeletal disorder (MSD) hazards. We aimed to characterise MSD hazard exposures and identify work elements that should be prioritised for MSD prevention efforts. A cross-sectional online survey methodology gathered data from 144 wind techs based on a convenience, non-probability sampling approach. The survey was developed using resources from the Ontario MSD Prevention Guideline, where cognitive interviewing yielded wind tech specific modifications. Climbing was the most physically demanding task, followed by torqueing/tensioning and manual materials handling (MMH). However, working in awkward and constrained postures emerged as the task most likely to cause or aggravate discomfort. Injecting ergonomic and human factors principles into wind turbine design should be a high priority. Re-engineering tools like torque tensioning devices may reduce MSD hazard exposures associated with tasks including torqueing/tensioning and MMH. We know little about musculoskeletal disorder (MSD) hazards associated with green jobs. By surveying wind turbine technicians, we learned that MSD hazards exists, and can be addressed by better considering human factors/ergonomics principles in the design of wind turbines and the tools required for service and maintenance operations. Abbreviations: MSD: musculoskeletal disorder; MMH: manual materials handling; Wind techs: wind turbine technicians; CRE-MSD: centre of research expertise for the prevention of musculoskeletal disorders; CanWEA: Canadiarn wind energy association; HFE: human factors/ergonomics; ASME: American Society of Mechanical Engineers; CSA: Canadian Standards Association [ABSTRACT FROM AUTHOR]

This study examined the influence of frequency and direction of force application on psychophysically acceptable forces for simulated work tasks. Fifteen male participants exerted psychophysically acceptable forces on a force transducer at 1, 3, or 5 repetitions per minute by performing both a downward press and a pull toward the body. These exertions were shown previously to be strength and balance limited, respectively. Workers chose acceptable forces at a lower percentage of their maximum voluntary force capacity during downward (strength-limited) exertions than during pulling (balance-limited) exertions at all frequencies (4% to 11%, P = .035). Frequency modulated acceptable hand force only during downward exertions, where forces at five repetitions per minute were 13% less (P = .005) than those at one exertion per minute. This study provides insight into the relationship between biomechanically limiting factors and the selection of acceptable forces for unilateral manual tasks. [ABSTRACT FROM AUTHOR]

This study examined the influence of frequency and direction of force application on psychophysically acceptable forces for simulated work tasks. Fifteen male participants exerted psychophysically acceptable forces on a force transducer at 1, 3, or 5 repetitions per minute by performing both a downward press and a pull toward the body. These exertions were shown previously to be strength and balance limited, respectively. Workers chose acceptable forces at a lower percentage of their maximum voluntary force capacity during downward (strength-limited) exertions than during pulling (balance-limited) exertions at all frequencies (4% to 11%, P = .035). Frequency modulated acceptable hand force only during downward exertions, where forces at five repetitions per minute were 13% less (P = .005) than those at one exertion per minute. This study provides insight into the relationship between biomechanically limiting factors and the selection of acceptable forces for unilateral manual tasks. [ABSTRACT FROM AUTHOR]

Exerting manual forces is critical during occupational performance. Therefore, being able to estimate maximum force capacity is particularly useful for determining how these manual exertion demands relate to available capacity. To facilitate this type of prediction requires a complete understanding of how maximum force capacity is governed biomechanically. This research focused on identifying how factors including joint moment strength, balance and shoe-floor friction affected hand force capacity during pulling, pressing downward and pushing medially. To elucidate potential limiting factors, joint moments were calculated and contrasted with reported joint strength capacities, the balancing point within the shoe-floor interface was calculated and expressed relative to the area defined by the shoe-floor interface, and the net applied horizontal forces were compared with the available friction. Each of these variables were calculated as participants exerted forces in a series of conditions designed to systematically control or restrict certain factors from limiting hand force capacity. The results demonstrated that hand force capacity, in all tested directions, was affected by the experimental conditions (up to 300%). Concurrently, biomechanical measures reached or surpassed reported criterion thresholds inferring specific biomechanical limitations. Downward exertions were limited by elbow strength, whereas pulling exertions were often limited by balance along the anterior-posterior axis. No specific limitations were identified for medial exertions. [ABSTRACT FROM AUTHOR]

Exerting manual forces is critical during occupational performance. Therefore, being able to estimate maximum force capacity is particularly useful for determining how these manual exertion demands relate to available capacity. To facilitate this type of prediction requires a complete understanding of how maximum force capacity is governed biomechanically. This research focused on identifying how factors including joint moment strength, balance and shoe-floor friction affected hand force capacity during pulling, pressing downward and pushing medially. To elucidate potential limiting factors, joint moments were calculated and contrasted with reported joint strength capacities, the balancing point within the shoe-floor interface was calculated and expressed relative to the area defined by the shoe-floor interface, and the net applied horizontal forces were compared with the available friction. Each of these variables were calculated as participants exerted forces in a series of conditions designed to systematically control or restrict certain factors from limiting hand force capacity. The results demonstrated that hand force capacity, in all tested directions, was affected by the experimental conditions (up to 300%). Concurrently, biomechanical measures reached or surpassed reported criterion thresholds inferring specific biomechanical limitations. Downward exertions were limited by elbow strength, whereas pulling exertions were often limited by balance along the anterior-posterior axis. No specific limitations were identified for medial exertions. [ABSTRACT FROM AUTHOR]

BACKGROUND: Literature reports that paramedics represent an at-risk occupation for the development of health problems. At least half of the paramedic population presents at least one risk factor associated with a negative health condition. These reports may suffer a "mono-method bias" where most reported outcomes are based on a single screening tool approach (may attenuate or inflate the prevalence). OBJECTIVE: The current study characterizes the health status of a cohort of twenty-five experienced New Brunswick (Canadian province) paramedics. METHODS: To understand possible limitations of past research, health status was characterized using four different methods: two methods using only one health measure and two were combined methods, integrating outcomes from at least two health measures to determine the prevalence of a given health status. RESULTS: Mono-bias was observed when using the single health measure methods. The difference among the four methods highlighted that a third of the cohort seemed unaware of their health condition. This result shed additional light on paramedics' health, where a high proportion of paramedics worked without knowledge of their health conditions. Based on a two health measures combined method, it was observed that only two-fifths of the current sample had no health conditions or could otherwise be considered as a "healthy". CONCLUSIONS: Because the literature has focused on single screening methods, our results were difficult to compare. However, there was a consensus that paramedics represent an at-risk occupation comprised of health problems. This study was exploratory and should be the basis for further research. [ABSTRACT FROM AUTHOR]

BACKGROUND: Most ambulance collisions happen in emergency driving conditions and are caused by human factors. OBJECTIVE: This study investigated the influence of human factors associated with time pressure, patient-care intervention, and health status on the physiological responses of simulated emergency driving tasks. METHODS: A cohort of seventeen experienced paramedics performed a battery of three simulated diving tasks. The driving tasks were a non-urgent and two urgent driving simulations (one to the scene and one to the hospital). The second urgent driving task was preceded by a patient-care simulation (unstable cardiac patient with cardiopulmonary resuscitation). RESULTS: The physiological responses between the three driving tasks were not significantly different due to time pressure and patient-care intervention. It is postulated that the physiological response of experienced paramedics was influenced by the fact that they are accustomed to handling stressful situations daily. Furthermore, it was observed that paramedics with health conditions were more physiologically aroused during the urgent driving scenarios (pre and post-intervention), suggesting they might have an elevated risk of collision when they drive with urgency. Paramedics with health conditions also had higher physiological responses for the post-intervention baseline, leading to a longer recovery time period, which might represent an elevated risk of developing chronic health problems or amplifying existing ones. CONCLUSIONS: The findings of this research suggest that experienced paramedics manage the influence of time pressure and the impact of challenging patient-care well. Paramedics with health conditions represent an elevated risk of collision. [ABSTRACT FROM AUTHOR]

Generalised predictive tests may be viable screening tools to evaluate job candidate workability if movement strategy used in assessment is consistent with movement strategy used in work. This study investigated if deep squat (DS) kinematics could predict floor-to-waist height lifting kinematics. Participants performed three DS repetitions, and 10 lifts of both a 10 kg and 20 kg box. Whole body kinematics were collected to calculate knee, hip and low back angles, and coordination as measured by relative phase angles. Movement features of lower extremity control, including knee and hip angles and coordination, were significantly correlated (r = 0.43–0.85) between the DS and lifting. However, low back movement features, measures linked to injury risk, were not significantly correlated between the DS and lifting. These findings do not support the DS as a suitable movement screen to predict lifting strategy, specifically when considering low back control. Practitioner summary: This study investigated whether lifting strategy could be inferred from deep squat performance. Knee and hip movement strategies were associated between the deep squat and lifting. However, inconsistencies in low back control between the deep squat and lifting limit the deep squat's injury risk assessment potential. [ABSTRACT FROM AUTHOR]

Objective: To quantify differences in physical workload afforded by turn-assist surfaces relative to manual patient turns, and between nursing caregivers (turn-away vs. turn-toward) while performing partnered patient turning.Background: Nurse caregivers experience an increased risk of musculoskeletal injuries at the back or shoulders when performing patient-handling activities. Use of turn-assist surfaces can reduce the physical burden and risk on caregivers.Method: Whole-body motion capture and hand force measures were collected from 25 caregivers (17 female) while performing partnered manual and technology-facilitated turns. Shoulder and low back angles and L4/L5 joint contact forces were calculated at the instant of peak hand force application for both caregivers.Results: Hand force requirements for the turn-away caregiver were 93% of the estimated maximum acceptable force when performing a manual turn. Use of a turn-assist surface eliminated hand forces required to initiate the patient turn for the turn-away caregiver, where their role was reduced to inserting appropriate wedging behind the patient once the facilitated turn was complete. This reduced shoulder moments by 21.3 Nm for the turn-away caregiver, a reduction in exposure from 70% of maximum shoulder strength capacity to 15%. Spine compression exposures were reduced by 302.1 N for the turn-toward caregiver when using a turn-assist surface.Conclusion: Use of a turn-assist surface reduced peak hand force and shoulder-related exposures for turning away and reduced spine-related exposures for turning toward.Application: Turn-assist devices should be recommended to decrease the risk of musculoskeletal disorder hazards for both caregivers when performing a partnered patient turn. [ABSTRACT FROM AUTHOR]

The article discusses a study which looked at the effectiveness and benefits of turn-assist technology to reposition bedridden patients and decrease the risk for pressure ulcers (PUs). It notes that the turn angle and pressure distribution, or interface pressure, were measured. According to the article, participants involved in the study were asked to lie on two different hospital bed surfaces and were turned using manual and turn-assist facilitated techniques.

The Ottawa Paramedic Physical Ability Test (OPPAT) is a physical employment standard (PES) that candidates must pass as a pre-hire requirement and that incumbents may have to pass prior to returning to work after absence, to demonstrate their physical capabilities as required to safely meet the demands of paramedic work. Consistent with best practice guidelines for PES development, it is important to establish reliability and to investigate sex-based performance differences. Active duty paramedics completed the OPPAT twice while candidates completed the OPPAT six times. Across all participants, a median improvement of 76.0 s was observed in OPPAT performance (922.0–846.0 s) between trial 1 and trial 2. Among candidates, OPPAT performance stabilised by the fourth trial confirming reliability. Sex-based analyses revealed median differences in OPPAT performance time of 39.0 and 63.0 s between males and females during the first and second trials respectively. Practitioner summary: Active duty paramedics and candidates performed the Ottawa Paramedic Physical Ability Test (OPPAT) faster following familiarisation. Among candidates, performance time stabilised by the fourth trial. Performance time was slower among females, but this had less impact on females' ability to meet the OPPAT standard. [ABSTRACT FROM AUTHOR]

BACKGROUND: Physical employment standards (PES) ensure that candidates can demonstrate the physical capacity required to perform duties of work. However, movement competency, or an individual's movement strategy, can relate to injury risk and safety, and therefore should be considered in PES. OBJECTIVE: Demonstrate the utility of using artificial intelligence (AI) to detect risk-potential of different movement strategies within PES. METHODS: Biomechanical analysis was used to calculate peak flexion angles and peak extensor moment about the lumbar spine during participants' performance of a backboard lifting task. Lifts performed with relatively lower and higher exposure to postural and moment loading on the spine were characterized as "low" or "high" exposure, respectively. An AI model including principal component and linear discriminant analyses was then trained to detect and classify backboard lifts as "low" or "high". RESULTS: The AI model accurately classified over 85% of lifts as "low" or "high" exposure using only motion data as an input. CONCLUSIONS: This proof-of-principle demonstrates that movement competency can be assessed in PES using AI. Similar classification approaches could be used to improve the utility of PES as a musculoskeletal disorders (MSD) prevention tool by proactively identifying candidates at higher risk of MSD based on movement competency. [ABSTRACT FROM AUTHOR]

BACKGROUND: The Ottawa Paramedic Physical Ability Test (OPPAT™) is a physical employment standard for the paramedic sector. If a candidate is unsuccessful in meeting the OPPAT™ performance standard they should be provided with an appropriate accommodation, such as a strength and conditioning program, to improve performance. OBJECTIVE: Develop, implement and evaluate the effectiveness of a 4-week strength and conditioning program on improving OPPAT™ performance and associated fitness measures in paramedic candidates. METHODS: A 4-week strength and conditioning program was developed to focus on strength and power improvements. Based on initial OPPAT™ performance, participants were divided into high and low performing groups; only the low performing group received the training intervention. OPPAT™ completion times and relevant fitness measures were compared pre- to post- intervention and between groups. RESULTS: Over the 4-weeks, peak lower body power and grip strength did not significantly improve in the intervention group, however OPPAT™ performance improved by 10%. The control group had significantly lower OPPAT™ completion times both pre- and post-intervention (19% and 11% lower respectively), as well as greater grip strength and peak lower body power. CONCLUSIONS: Implementation of a targeted strength and conditioning program successfully improved OPPAT™ performance in low performing candidates. [ABSTRACT FROM AUTHOR]

BACKGROUND: Whole body sprint-interval training (WB-SIT) represents a mode of exercise training that is both time-efficient and does not require access to an exercise facility. OBJECTIVE: The current study examined the feasibility of implementing a WB-SIT intervention in a workplace setting. METHODS: A total of 747 employees from a large office building were invited to participate with 31 individuals being enrolled in the study. Anthropometrics, aerobic fitness, core and upper body strength, and lower body mobility were assessed before and after a 12-week exercise intervention consisting of 2–4 training sessions per week. Each training session required participants to complete 8, 20-second intervals (separated by 10 seconds of rest) of whole body exercise. RESULTS: Proportion of participation was 4.2% while the response rate was 35% (11/31 participants completed post training testing). In responders, compliance to prescribed training was 83±17%, and significant (p < 0.05) improvements were observed for aerobic fitness, push-up performance and lower body mobility. CONCLUSION: These results demonstrate the efficacy of WB-SIT for improving fitness and mobility in an office setting, but highlight the difficulties in achieving high rates of participation and response in this setting. [ABSTRACT FROM AUTHOR]

Background Tree planters are at a high risk for wrist injury due to awkward postures and high wrist loads experienced during each planting cycle, specifically at shovel-ground impact. Wrist joint stiffness provides a measure that integrates postural and loading information. Objective The purpose of this study was to evaluate wrist joint stiffness requirements at the instant of shovel-ground impact during tree planting and determine if a wrist brace could alter muscular contributions to wrist joint stiffness. Method Planters simulated tree planting with and without wearing a brace on their planting arm. Surface electromyography (sEMG) from six forearm muscles and wrist kinematics were collected and used to calculate muscular contributions to joint rotational stiffness about the wrist. Results Wrist joint stiffness increased with brace use, an unanticipated and negative consequence of wearing a brace. As a potential benefit, planters achieved a more neutrally oriented wrist angle about the flexion/extension axis, although a less neutral wrist angle about the ulnar/radial axis was observed. Muscle activity did not change between conditions. Conclusion The joint stiffness analysis, combining kinematic and sEMG information in a biologically relevant manner, revealed clear limitations with the interface between the brace grip and shovel handle that jeopardized the prophylactic benefits of the current brace design. This limitation was not as evident when considering kinematics and sEMG data independently. Application A neuromechanical model (joint rotational stiffness) enhanced our ability to evaluate the brace design relative to kinematic and sEMG parameter-based metrics alone. [ABSTRACT FROM AUTHOR]

BACKGROUND: In Canada, functional capacity evaluations (FCEs) are commonly administered by several health care professions including kinesiologists. Kinesiologists have been recently regulated as health care professionals in Ontario and we know little about their demographics, the frequency of FCE administration, or the types of FCEs used by this group. OBJECTIVE: The purposes of this study were to identify: 1) the demographic characteristics and FCE education of kinesiology FCE practitioners; 2) the FCE systems most used by these practitioners and 3) the constructs from assessments used to determine functional capacity. METHODS:Asurveywas distributed to members of the Canadian Kinesiology Alliance. Descriptive statistics and frequency distributions were calculated from the survey responses (n = 77). RESULTS: FCE practitioners were represented by kinesiologists (79%) practicing more than 15 years and 1-5 years, who received FCE training from a certification course. ARCON (23%) was the most common FCE system used. Lowlevel lifting (43%), mid-lift (38%), pulling (38%) and walking (38%) are the most common FCE task components used to assess functional capacity. Although kinesiologists consider multiple factors when making decisions about task component endpoints, biomechanical observations/body mechanics are the primary methods used. CONCLUSIONS: Kinesiologists are conducting FCEs for the primary purpose of preparing return-to-work or workplace accommodation recommendations. Although functional capacity is determined using multiple factors, there is an emphasis on biomechanics and body mechanics. Focusing FCE training and research on these constructs may provide opportunities to further strengthen the reliability and validity of FCE outcomes. [ABSTRACT FROM AUTHOR]

The Oswestry Disability Index (ODI) is a self-report-based outcome measure used to quantify the extent of disability related to low back pain (LBP), a substantial contributor to workplace absenteeism. The ODI tool has been adapted for use by patients in several non-English speaking nations. It is unclear, however, if these adapted versions of the ODI are as credible as the original ODI developed for English-speaking nations. The objective of this study was to conduct a review of the literature to identify culturally adapted versions of the ODI and to report on the adaptation process, construct validity, test–retest reliability and internal consistency of these ODIs. Following a pragmatic review process, data were extracted from each study with regard to these four outcomes. While most studies applied adaptation processes in accordance with best-practice guidelines, there were some deviations. However, all studies reported high-quality psychometric properties: group mean construct validity was 0.734 ± 0.094 (indicated via a correlation coefficient), test–retest reliability was 0.937 ± 0.032 (indicated via an intraclass correlation coefficient) and internal consistency was 0.876 ± 0.047 (indicated via Cronbach’s alpha). Researchers can be confident when using any of these culturally adapted ODIs, or when comparing and contrasting results between cultures where these versions were employed.Implications for RehabilitationLow back pain is the second leading cause of disability in the world, behind only cancer.The Oswestry Disability Index (ODI) has been developed as a self-report outcome measure of low back pain for administration to patients.An understanding of the various cross-cultural adaptations of the ODI is important for more concerted multi-national research efforts.This review examines 16 cross-cultural adaptations of the ODI and should inform the work of health care and rehabilitation professionals. [ABSTRACT FROM AUTHOR]

Neck pain occurs at a significant rate in the military helicopter community. It is often attributed to the use of night vision goggles (NVG) and toa number of additional factors such as anthropometrics, posture, vibration, mission length, physical fitness, and helmet fit or load. A number of research studies have addressed many aspects of this epidemic, but an up-to-date and comprehensive review of the literature is not currently available. This paper reviews the spinal anatomy in general and then summarizes what is known about the incidence and prevalence of neck injuries, how the operational environments and equipment may contribute to these injuries, and what can be done to address them from a prevention and/or rehabilitation perspective. [ABSTRACT FROM AUTHOR]

Accurate estimation of occupational performance capability facilitates better job (re-) design by informing workplace parties about the potential mismatches between job demands and the capability of their labour force. However, estimating occupational performance requires consideration of multiple factors that may govern capacity. In this paper, a novel model is described that uses a stochastic algorithm to estimate how variability in underlying biomechanical constraints affects hand force capability. In addition, the model estimates psychophysically acceptable hand force capacity thresholds by applying a biomechanical weakest link approach. Model estimates were tested against experimentally determined maximal and psychophysically determined hand forces in two exertion directions in constrained postures. The model underestimated maximum hand force capacity relative to measured maximum hand force by 30% and 35% during downward pressing and horizontal pulling, respectively. These values are consistent with those observed using previous two-dimensional models. Psychophysically acceptable hand forces were also underestimated by 29% during both pressing and pulling. Since the psychophysical estimates were scaled as a percentage of the estimated maximum capacity, this suggests that the underestimation in both predictions may be corrected by improving estimates of maximum hand force. Psychophysically acceptable forces were observed to be partially governed by demands at the biomechanical weakest link. [ABSTRACT FROM AUTHOR]

The use of principal component analysis (PCA) as a multivariate statistical approach to reduce complex biomechanical data-sets is growing. With its increased application in biomechanics, there has been a concurrent divergence in the use of criteria to determine how much the data is reduced (i.e. how many principal factors are retained). This short communication presents power equations to support the use of a parallel analysis (PA) criterion as a quantitative and transparent method for determining how many factors to retain when conducting a PCA. Monte Carlo simulation was used to carry out PCA on random data-sets of varying dimension. This process mimicked the PA procedure that would be required to determine principal component (PC) retention for any independent study in which the data-set dimensions fell within the range tested here. A surface was plotted for each of the first eight PCs, expressing the expected outcome of a PA as a function of the dimensions of a data-set. A power relationship was used to fit the surface, facilitating the prediction of the expected outcome of a PA as a function of the dimensions of a data-set. Coefficients used to fit the surface and facilitate prediction are reported. These equations enable the PA to be freely adopted as a criterion to inform PC retention. A transparent and quantifiable criterion to determine how many PCs to retain will enhance the ability to compare and contrast between studies. [ABSTRACT FROM AUTHOR]

Objective: Increasing evidence suggests that one in four sign language interpreters (SLIs) may experience symptoms of musculoskeletal disorders (MSDs) severe enough to modify their activities. This systematic review examined published research on SLIs and the development of MSD pathology, seeking to identify injury pathways to MSDs and work-related factors with the largest impact in targeted MSD-reduction intervention. Methods: Embase and Medline electronic databases were searched from their inception until March 2009, finding 23 eligible peer-reviewed papers related to MSD pathology in SLIs, including narrative reviews, intervention studies, and qualitative and quantitative research. Results: Three factors were shown to have limited support as increasing the risk for MSD pathology in SLI: increased mechanical exposure, stress, and speaker's pace (a contributor to movement rate). Overall, the published literature was rated medium to low quality, with limited statistical methods and power, often lacking description of how dependent variables were measured, and how risk of biasing or confounding was minimized. Conclusions: A conceptual model was developed to integrate the multi-factorial elements of MSD pathology development among SLIs. However, to strengthen development of evidence-based practice and policy-driven initiatives, higher-quality research is warranted to examine MSD pathology amongst SLIs. [ABSTRACT FROM AUTHOR]

The goal of the current investigation was to propose and evaluate a method for estimating cumulative spinal loading based on the hypothesis that cumulative loading for a single task will be linearly proportional to its cycle time. The association between cumulative spinal loading and low-back pain has driven ergonomists and researchers to develop new methods for estimating cumulative workplace exposure. Despite new advances that reduce the amount of data for analysis, methods are still quite labour intensive and prohibitive for widespread industrial usage. In order to assess the proposed method, 15 workers performing six tasks from four different job cells were analysed by video analysis. Two equations to predict cumulative loading of a task based on the known cumulative loading of a similar task were developed. An ‘interpolation’ equation used a task with a longer cycle time to predict cumulative spinal loading for a similar task with a shorter cycle time. An ‘extrapolation’ equation allowed for the opposite prediction to occur. These estimates were compared to a criterion measure produced from the video analysis. There were no significant differences between the criterion measure and the estimated output from the proposed prediction method for four of the five cumulative loading variables. Cumulative compression was the most accurately predicted variable (3.9%). A large range of relative per cent errors (23–202.4%) were found for cumulative shear and extension moment. The proposed method produced promising results for estimating cumulative loading in tasks that differ in length but have similar musculoskeletal demands, especially when combined with other methods of data reduction and has the potential to be used to proactively estimate cumulative loading and quickly screen for tasks that are in need of a full, in depth analysis. Further investigation into defining criteria for ‘similar’ tasks, the influence of task constituent components, and its use in other areas of industry is necessary before the approach should be widely employed. [ABSTRACT FROM PUBLISHER]

The extent to which specific muscles may limit maximum isometric force production is largely unknown. This study investigated shoulder muscle activity in six muscles and maximum force generation at the hand in three directions, while in eight different working positions. Ten right hand dominant, university-aged female participants completed twenty-four maximal isometric force hand exertions against a handle positioned by a robot arm within a 3-dimensional simulated workspace. A multivariate, full factorial ANOVA indicated a reach distance main effect where 11% greater force production occurred at the lesser reach distance. A target handle elevation and force direction interaction effect on maximum force production also existed. These findings add to normative static strength data for hand locations typical of an operating work envelope. Although hand force was significantly influenced by position in each direction (p < 0.05), muscle EMG was not influenced in any of the six muscles measured. No muscle achieved 100% MVE in any of the tested conditions, with the highest total muscle activity recorded at 86% MVE for the Pectoralis Major - sternal origin. Collectively, these data better demonstrate that the location and direction of work presentation influences force outputs more than specific muscle demands (of those measured), and should be considered in evaluating workstations. [ABSTRACT FROM AUTHOR]