Pub Date : 2016-01-02DOI: 10.1080/21577323.2015.1046093
V. Gawron
OCCUPATIONAL APPLICATIONS For both civilian and military pilots, sleep duration and time of day are consistently related to fatigue rating. Fatigue is greater when pilots have fewer hours of sleep or travel later at night or earlier in the morning. Fatigue is also greater as the number of flights flown and the length of flights increase. In addition two-person crews report significantly higher fatigue than three-person crews for long duration flights. Finally, errors increase with less sleep and accident risk becomes higher, especially for duty hours 13 hours or longer. These findings can be used to design fatigue management systems for airline and military aviation operations. TECHNICAL ABSTRACT Background: Fatigue has been on the National Transportation Safety Board's “most wanted list” since 1990 and remains a topic of investigation to this day. Of special interest is the effect of fatigue on aviation safety, especially since fatigue was a contributing factor to several hull loss and fatal aircraft accidents. In 2011, the U.S. Federal Aviation Administration issued the Flight Crew Member Duty and Rest Requirements, which mandated several aspects related to policy, education and awareness training, reporting and monitoring, and performance evaluation. Purpose: Available data on pilot fatigue are summarized to provide input for the development of the mandated fatigue risk management systems. Methods: A literature search was conducted using multiple terms directly and indirectly associated with fatigue. Additionally, outreach was conducted to identify current research that would not yet be in the literature. Results: Studies of aircrew fatigue have been performed on civilian and military aircrews across a wide range of missions and methods, including data collection in flights, simulators, laboratories, surveys of operational pilots, and accident data analysis. For civilian and military pilots, sleep duration and time of day are consistently related to fatigue rating. Fatigue is greater when pilots have fewer the hours of sleep or travel later at night or earlier in the morning. Furthermore, fatigue is greater when the number of flights flown and the length of the flights increase, and errors increase with less sleep. Conclusions: Fatigue is affected by operational factors and can cause degraded performance that can lead to fatal accidents. Some operational factors can be addressed through scheduling of aircrews and flights. This includes addressing aircrew hours of sleep; the number of successive, early wake-ups required for flights; the number of flights flown within a short period; duty length; and the number of pilots per long-haul flight.
{"title":"Summary of Fatigue Research for Civilian and Military Pilots","authors":"V. Gawron","doi":"10.1080/21577323.2015.1046093","DOIUrl":"https://doi.org/10.1080/21577323.2015.1046093","url":null,"abstract":"OCCUPATIONAL APPLICATIONS For both civilian and military pilots, sleep duration and time of day are consistently related to fatigue rating. Fatigue is greater when pilots have fewer hours of sleep or travel later at night or earlier in the morning. Fatigue is also greater as the number of flights flown and the length of flights increase. In addition two-person crews report significantly higher fatigue than three-person crews for long duration flights. Finally, errors increase with less sleep and accident risk becomes higher, especially for duty hours 13 hours or longer. These findings can be used to design fatigue management systems for airline and military aviation operations. TECHNICAL ABSTRACT Background: Fatigue has been on the National Transportation Safety Board's “most wanted list” since 1990 and remains a topic of investigation to this day. Of special interest is the effect of fatigue on aviation safety, especially since fatigue was a contributing factor to several hull loss and fatal aircraft accidents. In 2011, the U.S. Federal Aviation Administration issued the Flight Crew Member Duty and Rest Requirements, which mandated several aspects related to policy, education and awareness training, reporting and monitoring, and performance evaluation. Purpose: Available data on pilot fatigue are summarized to provide input for the development of the mandated fatigue risk management systems. Methods: A literature search was conducted using multiple terms directly and indirectly associated with fatigue. Additionally, outreach was conducted to identify current research that would not yet be in the literature. Results: Studies of aircrew fatigue have been performed on civilian and military aircrews across a wide range of missions and methods, including data collection in flights, simulators, laboratories, surveys of operational pilots, and accident data analysis. For civilian and military pilots, sleep duration and time of day are consistently related to fatigue rating. Fatigue is greater when pilots have fewer the hours of sleep or travel later at night or earlier in the morning. Furthermore, fatigue is greater when the number of flights flown and the length of the flights increase, and errors increase with less sleep. Conclusions: Fatigue is affected by operational factors and can cause degraded performance that can lead to fatal accidents. Some operational factors can be addressed through scheduling of aircrews and flights. This includes addressing aircrew hours of sleep; the number of successive, early wake-ups required for flights; the number of flights flown within a short period; duty length; and the number of pilots per long-haul flight.","PeriodicalId":73331,"journal":{"name":"IIE transactions on occupational ergonomics and human factors","volume":"4 1","pages":"1 - 18"},"PeriodicalIF":0.0,"publicationDate":"2016-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/21577323.2015.1046093","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60125143","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2016-01-02DOI: 10.1080/21577323.2016.1184196
Mahboobeh Ghesmaty Sangachin, Woodrow Gustafson, L. Cavuoto
OCCUPATIONAL APPLICATION: We assessed workload and performance when using two active workstations. Our results, consistent with earlier evidence, indicates that active workstations do not increase physical activity at the expense of reduced performance and operator workload, if these workstations are used for simple tasks that do not require great attention or fine motor control. Active workstations also allowed for more variability in posture and reduced static posture. However, reinforcement of ergonomics recommendations in terms of reducing non-neutral postures may be necessary. TECHNICAL ABSTRACT Background: Over the past 30 years, work has become more sedentary due to increased computer desk work, which has led to the development of major health consequences such as obesity and diabetes. One promising intervention for decreasing sedentariness is the incorporation of active workstations. Objective: We investigated the impact of two active workstations (standing and walking) on workload, task performance, and postural and physiological responses during standard office work tasks. Methods: Using a counterbalanced, within-subjects design, 30 subjects (aged 23.2 [3.1] years) were tested in three workstations: sitting, standing, and walking. A battery of simulated office tasks, including mousing, keyboarding, and cognition tasks, were presented in a randomized order during each trial. Subjective workload was assessed using the NASA-Task Load Index. Performance outcomes included reaction time, number of errors, and total task time. Physiological responses included percent heart rate reserve and heart rate variability. Neck, trunk, and shoulder inclination angles were analyzed to identify differences between workstations with respect to working posture. Results: Compared to sitting, standing and walking both resulted in significantly higher objective measures of workload. While use of walking workstation led to significantly decreased performance on fine motor control tasks, standing did not reduce performance and resulted in improved mousing performance. Both standing and walking allowed for more variability in posture. There was also an indication of more deviation from idle sitting posture while standing and walking compared to sitting. Conclusions: This study contributes to the guidance needed for the use of active workstations, to take advantage of the potential health benefits without sacrificing performance or substantially increasing workload. A standing workstation, properly adjusted based on user anthropometry and ergonomics recommendations, decreased sedentary time, allowed for more postural variability, and enhanced performance on some mousing and cognition tasks, while perceived workload remained consistent with levels while seated.
{"title":"Effect of Active Workstation Use on Workload, Task Performance, and Postural and Physiological Responses","authors":"Mahboobeh Ghesmaty Sangachin, Woodrow Gustafson, L. Cavuoto","doi":"10.1080/21577323.2016.1184196","DOIUrl":"https://doi.org/10.1080/21577323.2016.1184196","url":null,"abstract":"OCCUPATIONAL APPLICATION: We assessed workload and performance when using two active workstations. Our results, consistent with earlier evidence, indicates that active workstations do not increase physical activity at the expense of reduced performance and operator workload, if these workstations are used for simple tasks that do not require great attention or fine motor control. Active workstations also allowed for more variability in posture and reduced static posture. However, reinforcement of ergonomics recommendations in terms of reducing non-neutral postures may be necessary. TECHNICAL ABSTRACT Background: Over the past 30 years, work has become more sedentary due to increased computer desk work, which has led to the development of major health consequences such as obesity and diabetes. One promising intervention for decreasing sedentariness is the incorporation of active workstations. Objective: We investigated the impact of two active workstations (standing and walking) on workload, task performance, and postural and physiological responses during standard office work tasks. Methods: Using a counterbalanced, within-subjects design, 30 subjects (aged 23.2 [3.1] years) were tested in three workstations: sitting, standing, and walking. A battery of simulated office tasks, including mousing, keyboarding, and cognition tasks, were presented in a randomized order during each trial. Subjective workload was assessed using the NASA-Task Load Index. Performance outcomes included reaction time, number of errors, and total task time. Physiological responses included percent heart rate reserve and heart rate variability. Neck, trunk, and shoulder inclination angles were analyzed to identify differences between workstations with respect to working posture. Results: Compared to sitting, standing and walking both resulted in significantly higher objective measures of workload. While use of walking workstation led to significantly decreased performance on fine motor control tasks, standing did not reduce performance and resulted in improved mousing performance. Both standing and walking allowed for more variability in posture. There was also an indication of more deviation from idle sitting posture while standing and walking compared to sitting. Conclusions: This study contributes to the guidance needed for the use of active workstations, to take advantage of the potential health benefits without sacrificing performance or substantially increasing workload. A standing workstation, properly adjusted based on user anthropometry and ergonomics recommendations, decreased sedentary time, allowed for more postural variability, and enhanced performance on some mousing and cognition tasks, while perceived workload remained consistent with levels while seated.","PeriodicalId":73331,"journal":{"name":"IIE transactions on occupational ergonomics and human factors","volume":"4 1","pages":"67 - 81"},"PeriodicalIF":0.0,"publicationDate":"2016-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/21577323.2016.1184196","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60126194","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-10-02DOI: 10.1080/21577323.2015.1034382
S. Fischer, H. P. Greene, Robin H. Hampton, M. Cochran, W. Albert
OCCUPATIONAL APPLICATIONS This study indicates that males and females altered their lifting technique equivalently over time, as they fatigued. Time-dependent changes in lifting mechanics were dependent on the phase of the lifting task. At the initiation of the lift from the floor, participants adapted to increasing trunk fatigue by altering their lower body movements to help maintain a more upright trunk posture. When placing the load on the chest height shelf, participants seemed to adapt to growing upper extremity fatigue by holding the load closer to the body, using more elbow flexion, and less upper arm extension. As a result of this adaptation, participants began to use more forward lean. Therefore, as participants fatigued, they seemed to sacrifice balance (more leaning) in order to preserve muscular capability, which was diminishing with fatigue. This suggests that fatigued lifters may not only be at an increased risk of suffering from an overexertion injury, but they may also be more likely to suffer a slip or fall. TECHNICAL ABSTRACT Background: People working in repetitive manual materials handling jobs are at an increased risk of developing spine and shoulder injuries. To address this concern, it is important to understand how different factors, such as gender, can affect the loading on the body when performing high risk repetitive lifting tasks. Purpose: The purpose of this study was to determine if males and females altered their lifting mechanics in similar ways when exposed to a prolonged fatiguing bout of lifting. Method: Thirty-one participants (n = 15 female) performed a repetitive lifting task for 75 minutes. Isometric shoulder and trunk strength were measured pre- and post-lifting, while upper body kinematics were recorded throughout. Results: Exposure time had a similar effect on lifting kinematics for males and females. At the lift origin, participants transitioned over time toward a posture that had a mean (SD) of 7.2° (2.6°) less torso flexion. At the lift destination, participants transitioned toward a posture with 5.9° (1.7°) less shoulder flexion and 10.1° (2.3°) more elbow flexion. Such changes were consistent with a goal of trying to bring the load closer to the torso. Additionally, isometric strength decreased following the 75-minute lifting protocol by 7.9 (1.2) Nm and 52.4 (10.9) Nm at the shoulder and trunk, respectively. Conclusions: Both males and females adapted their kinematics similarly over time, during repetitive lifting. This study suggests that kinematic adaptions may be driven by participants' consideration of the changing relative demands on their body (e.g., increasing fatigue). The presence of kinematic adaptions, in both males and females, invites the opportunity to consider movement analysis methods as a screening tool for detecting fatigue in the workplace. The ability to recognize and address fatigue earlier may help ergonomists in reducing overexertion-based work related injuries.
{"title":"Gender-Based Differences in Trunk and Shoulder Biomechanical Changes Caused by Prolonged Repetitive Symmetrical Lifting","authors":"S. Fischer, H. P. Greene, Robin H. Hampton, M. Cochran, W. Albert","doi":"10.1080/21577323.2015.1034382","DOIUrl":"https://doi.org/10.1080/21577323.2015.1034382","url":null,"abstract":"OCCUPATIONAL APPLICATIONS This study indicates that males and females altered their lifting technique equivalently over time, as they fatigued. Time-dependent changes in lifting mechanics were dependent on the phase of the lifting task. At the initiation of the lift from the floor, participants adapted to increasing trunk fatigue by altering their lower body movements to help maintain a more upright trunk posture. When placing the load on the chest height shelf, participants seemed to adapt to growing upper extremity fatigue by holding the load closer to the body, using more elbow flexion, and less upper arm extension. As a result of this adaptation, participants began to use more forward lean. Therefore, as participants fatigued, they seemed to sacrifice balance (more leaning) in order to preserve muscular capability, which was diminishing with fatigue. This suggests that fatigued lifters may not only be at an increased risk of suffering from an overexertion injury, but they may also be more likely to suffer a slip or fall. TECHNICAL ABSTRACT Background: People working in repetitive manual materials handling jobs are at an increased risk of developing spine and shoulder injuries. To address this concern, it is important to understand how different factors, such as gender, can affect the loading on the body when performing high risk repetitive lifting tasks. Purpose: The purpose of this study was to determine if males and females altered their lifting mechanics in similar ways when exposed to a prolonged fatiguing bout of lifting. Method: Thirty-one participants (n = 15 female) performed a repetitive lifting task for 75 minutes. Isometric shoulder and trunk strength were measured pre- and post-lifting, while upper body kinematics were recorded throughout. Results: Exposure time had a similar effect on lifting kinematics for males and females. At the lift origin, participants transitioned over time toward a posture that had a mean (SD) of 7.2° (2.6°) less torso flexion. At the lift destination, participants transitioned toward a posture with 5.9° (1.7°) less shoulder flexion and 10.1° (2.3°) more elbow flexion. Such changes were consistent with a goal of trying to bring the load closer to the torso. Additionally, isometric strength decreased following the 75-minute lifting protocol by 7.9 (1.2) Nm and 52.4 (10.9) Nm at the shoulder and trunk, respectively. Conclusions: Both males and females adapted their kinematics similarly over time, during repetitive lifting. This study suggests that kinematic adaptions may be driven by participants' consideration of the changing relative demands on their body (e.g., increasing fatigue). The presence of kinematic adaptions, in both males and females, invites the opportunity to consider movement analysis methods as a screening tool for detecting fatigue in the workplace. The ability to recognize and address fatigue earlier may help ergonomists in reducing overexertion-based work related injuries.","PeriodicalId":73331,"journal":{"name":"IIE transactions on occupational ergonomics and human factors","volume":"3 1","pages":"165 - 176"},"PeriodicalIF":0.0,"publicationDate":"2015-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/21577323.2015.1034382","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60124606","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-10-02DOI: 10.1080/21577323.2015.1047064
Jennifer L Garza, N. Fallentin, J. Dennerlein
OCCUPATIONAL APPLICATIONS While completing a sub-maximum forceful wrist flexion task for two 1-hour sessions, the temporal patterns of forearm muscle activity of 10 females changed along with corresponding changes in torque, duty-cycle, and torque-time integral. These temporal changes in muscle activity promote variation in muscle activity during repetitive tasks, and as a result may prove to be a protection mechanism for musculoskeletal disorder development. In addition, the changes observed in torque, duty-cycle, or torque-time integral indicate that even during very defined simulated occupational tasks, workers may find ways to interject variation into a task that may also contribute to this protection. TECHNICAL ABSTRACT Background: Jobs requiring repetitive motion are common in many industries, and such jobs can be associated with the development of musculoskeletal disorders. Temporal changes in muscle activity patterns throughout repetitive tasks, if they occur, may promote variation in muscle activity and therefore may prevent the development of musculoskeletal disorders during repetitive work. Purpose: To assess temporal changes in activity patterns of the forearm muscles during a prolonged (2-hour) repetitive wrist flexion task. Methods: Ten females completed a repeated-measures study by performing a task requiring 80° wrist flexions at a rate of 15 flexions per minute overcoming a resistant force set at 25% of their maximum voluntary isometric wrist flexion torque for two 1-hour sessions, with a 5-minute break between the two sessions. Muscle activity of six forearm flexor and extensor muscles was measured using surface electromyography during the first and last 5 minutes of each of the 2-hour sessions. Task performance parameters including torque, cycle time, angle, duty cycle, work, and torque-time integral were also recorded and calculated during the 5-minute periods. Results: Compared to the first 5 minutes of the first hour, mean extensor carpi ulnaris activity was significantly lower during the last 5 minutes of both hours, and the muscle activity percentage of time in gaps was significantly higher for the last 5 minutes of the first hour and both 5-minute periods of the second hour. Torque, duty cycle, and torque-time integral were also significantly lower during the last 5 minutes of the first hour and both 5-minute periods of the second hour compared to the first 5 minutes of the first hour. Conclusions: The observed temporal changes indicate some variation in muscle activity during the repetitive task, which may affect musculoskeletal disorder development. These results provide some preliminary insight into mechanisms that may prevent the development of musculoskeletal disorder development during repetitive tasks.
{"title":"Patterns of Forearm Muscle Activity and Task Parameters Change During a Repetitive Sub-Maximum Forceful Wrist Flexion Task","authors":"Jennifer L Garza, N. Fallentin, J. Dennerlein","doi":"10.1080/21577323.2015.1047064","DOIUrl":"https://doi.org/10.1080/21577323.2015.1047064","url":null,"abstract":"OCCUPATIONAL APPLICATIONS While completing a sub-maximum forceful wrist flexion task for two 1-hour sessions, the temporal patterns of forearm muscle activity of 10 females changed along with corresponding changes in torque, duty-cycle, and torque-time integral. These temporal changes in muscle activity promote variation in muscle activity during repetitive tasks, and as a result may prove to be a protection mechanism for musculoskeletal disorder development. In addition, the changes observed in torque, duty-cycle, or torque-time integral indicate that even during very defined simulated occupational tasks, workers may find ways to interject variation into a task that may also contribute to this protection. TECHNICAL ABSTRACT Background: Jobs requiring repetitive motion are common in many industries, and such jobs can be associated with the development of musculoskeletal disorders. Temporal changes in muscle activity patterns throughout repetitive tasks, if they occur, may promote variation in muscle activity and therefore may prevent the development of musculoskeletal disorders during repetitive work. Purpose: To assess temporal changes in activity patterns of the forearm muscles during a prolonged (2-hour) repetitive wrist flexion task. Methods: Ten females completed a repeated-measures study by performing a task requiring 80° wrist flexions at a rate of 15 flexions per minute overcoming a resistant force set at 25% of their maximum voluntary isometric wrist flexion torque for two 1-hour sessions, with a 5-minute break between the two sessions. Muscle activity of six forearm flexor and extensor muscles was measured using surface electromyography during the first and last 5 minutes of each of the 2-hour sessions. Task performance parameters including torque, cycle time, angle, duty cycle, work, and torque-time integral were also recorded and calculated during the 5-minute periods. Results: Compared to the first 5 minutes of the first hour, mean extensor carpi ulnaris activity was significantly lower during the last 5 minutes of both hours, and the muscle activity percentage of time in gaps was significantly higher for the last 5 minutes of the first hour and both 5-minute periods of the second hour. Torque, duty cycle, and torque-time integral were also significantly lower during the last 5 minutes of the first hour and both 5-minute periods of the second hour compared to the first 5 minutes of the first hour. Conclusions: The observed temporal changes indicate some variation in muscle activity during the repetitive task, which may affect musculoskeletal disorder development. These results provide some preliminary insight into mechanisms that may prevent the development of musculoskeletal disorder development during repetitive tasks.","PeriodicalId":73331,"journal":{"name":"IIE transactions on occupational ergonomics and human factors","volume":"3 1","pages":"236 - 245"},"PeriodicalIF":0.0,"publicationDate":"2015-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/21577323.2015.1047064","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60125291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-10-02DOI: 10.1080/21577323.2015.1095255
M. Phillips, C. Starnes, R. Shapiro, B. Bazrgari
OCCUPATIONAL APPLICATIONS Despite the proven effectiveness of new-generation body armor against ballistic threats, small arms, and improvised explosive devices, such body armor has become a source of concern for warfighters' performance and musculoskeletal injuries. Prolonged periods of performing physical activities, with versus without body armor, were found to alter knee neuromuscular behavior. With body armor, the maximum strength of the knee flexors and the extensor-to-flexor strength ratio were found, respectively, to reduce and increase than in conditions without body armor. Such changes in knee neuromuscular behavior are known to adversely affect physical performance and risk of knee injury. Quantitative information related to changes in knee neuromuscular behavior induced by body armor can be used in the design of injury risk assessment tools, physical training programs that decrease or correct a particular imbalance, and to establish return to service (i.e., post injury) standards for dismounted warfighters. TECHNICAL ABSTRACT Background: Knee injuries among military service members have a substantially high prevalence. Dismounted warfighters often must navigate diverse environments while wearing body armor. Purpose: Given the suggested role of body armor mass on a warfighter's performance and risk of injury, the immediate and prolonged effects of body armor on the neuromuscular behavior of knee flexors and extensors were investigated. Methods: Body armor-induced changes in selected measures related to isometric and isokinetic behaviors of the knee were quantified using a commercial dynamometer. This was done in two testing sessions, with and without body armor, by assessing neuromuscular behaviors of the knee before and after participants completed a battery of basic and military-inspired tests, as well as a 45-minute brisk walking protocol. Results: Completing tests with body armor versus no armor was found to cause a greater change (i.e., reduction of ∼10 N·m) in maximum isometric strength of the knee flexors. It also was found to be associated with a significant increase in conventional/functional strength ratios. While there was no significant difference in maximum isometric knee extensor strength between genders at baseline, females demonstrated a significant reduction (∼16 N·m) following completion of tests regardless of the body armor condition. Conclusion: In general, the prolonged duration of wearing body armor was found to cause changes in the neuromuscular behavior of knee flexors and extensors that have been suggested in the literature to be associated with a higher risk of injury and reduced warfighter performance.
{"title":"The Effects of Military Body Armor on Isometric and Isokinetic Knee Behaviors","authors":"M. Phillips, C. Starnes, R. Shapiro, B. Bazrgari","doi":"10.1080/21577323.2015.1095255","DOIUrl":"https://doi.org/10.1080/21577323.2015.1095255","url":null,"abstract":"OCCUPATIONAL APPLICATIONS Despite the proven effectiveness of new-generation body armor against ballistic threats, small arms, and improvised explosive devices, such body armor has become a source of concern for warfighters' performance and musculoskeletal injuries. Prolonged periods of performing physical activities, with versus without body armor, were found to alter knee neuromuscular behavior. With body armor, the maximum strength of the knee flexors and the extensor-to-flexor strength ratio were found, respectively, to reduce and increase than in conditions without body armor. Such changes in knee neuromuscular behavior are known to adversely affect physical performance and risk of knee injury. Quantitative information related to changes in knee neuromuscular behavior induced by body armor can be used in the design of injury risk assessment tools, physical training programs that decrease or correct a particular imbalance, and to establish return to service (i.e., post injury) standards for dismounted warfighters. TECHNICAL ABSTRACT Background: Knee injuries among military service members have a substantially high prevalence. Dismounted warfighters often must navigate diverse environments while wearing body armor. Purpose: Given the suggested role of body armor mass on a warfighter's performance and risk of injury, the immediate and prolonged effects of body armor on the neuromuscular behavior of knee flexors and extensors were investigated. Methods: Body armor-induced changes in selected measures related to isometric and isokinetic behaviors of the knee were quantified using a commercial dynamometer. This was done in two testing sessions, with and without body armor, by assessing neuromuscular behaviors of the knee before and after participants completed a battery of basic and military-inspired tests, as well as a 45-minute brisk walking protocol. Results: Completing tests with body armor versus no armor was found to cause a greater change (i.e., reduction of ∼10 N·m) in maximum isometric strength of the knee flexors. It also was found to be associated with a significant increase in conventional/functional strength ratios. While there was no significant difference in maximum isometric knee extensor strength between genders at baseline, females demonstrated a significant reduction (∼16 N·m) following completion of tests regardless of the body armor condition. Conclusion: In general, the prolonged duration of wearing body armor was found to cause changes in the neuromuscular behavior of knee flexors and extensors that have been suggested in the literature to be associated with a higher risk of injury and reduced warfighter performance.","PeriodicalId":73331,"journal":{"name":"IIE transactions on occupational ergonomics and human factors","volume":"3 1","pages":"210 - 220"},"PeriodicalIF":0.0,"publicationDate":"2015-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/21577323.2015.1095255","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60125571","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-10-02DOI: 10.1080/21577323.2015.1042096
K. Fewster, J. Potvin
OCCUPATIONAL APPLICATIONS The purpose of this study was to investigate hand leaning forces and the preferred leaning postures when completing tasks with various task hand locations, force demands, and effort directions. Twenty female participants completed a variety of different exertions with a leaning surface available. The hand leaning force magnitude changed as task hand location, force direction, and force level changed. These forces were significantly higher during pulling tasks and increased with increasing task hand load. The leaning hand height was slightly higher when task locations were at shoulder height, compared to the umbilical height. The findings are important, as current ergonomic tools neglect to consider that different task characteristics may change how and when a worker leans with their hands. These findings are of particular use to industry, as ergonomists now have representative forces and heights, to help guide leaning estimates during proactive risk assessments. TECHNICAL ABSTRACT Background: Leaning occurs in many automotive manufacturing tasks and provides various benefits to the worker. Leaning may allow for a more effective posture for task completion or reduce loading on the spine. Ergonomic assessments of tasks with leaning can be problematic because there is not sufficient data to predict leaning hand forces or the location of the leaning hand. Therefore, this study was completed to investigate leaning hand forces to help ergonomists make better predictions of how a leaning hand might be used during various industrial tasks. Purpose: The purpose of this study was to investigate hand leaning characteristics and the preferred leaning postures when completing tasks with constrained reaches. Methods: Twenty female participants completed exertions with 24 combinations of load (27.5 and 55 N), force direction (push, pull, and down), horizontal reach (95% and 120% of arm length), and vertical height (shoulder and umbilical height). A large leaning surface was available to use while completing the task. Results: The height of the leaning hand ranged between 106.6 and 116.3 cm across all conditions. The leaning hand force was affected by task hand location, force direction, and force demand. Leaning hand forces increased with increasing task hand load and ranged from 13.8 to 79.6 N of force. Task hand pulls had higher leaning hand forces compared to push and down exertion directions, regardless of task hand location or force demand. Conclusion: The findings of this study will be of particular use to industry as ergonomists now have representative leaning forces and heights to help guide leaning estimates during proactive risk assessments.
{"title":"An Investigation of Leaning Behaviors During One-Handed Submaximal Exertions with Extended Reaches","authors":"K. Fewster, J. Potvin","doi":"10.1080/21577323.2015.1042096","DOIUrl":"https://doi.org/10.1080/21577323.2015.1042096","url":null,"abstract":"OCCUPATIONAL APPLICATIONS The purpose of this study was to investigate hand leaning forces and the preferred leaning postures when completing tasks with various task hand locations, force demands, and effort directions. Twenty female participants completed a variety of different exertions with a leaning surface available. The hand leaning force magnitude changed as task hand location, force direction, and force level changed. These forces were significantly higher during pulling tasks and increased with increasing task hand load. The leaning hand height was slightly higher when task locations were at shoulder height, compared to the umbilical height. The findings are important, as current ergonomic tools neglect to consider that different task characteristics may change how and when a worker leans with their hands. These findings are of particular use to industry, as ergonomists now have representative forces and heights, to help guide leaning estimates during proactive risk assessments. TECHNICAL ABSTRACT Background: Leaning occurs in many automotive manufacturing tasks and provides various benefits to the worker. Leaning may allow for a more effective posture for task completion or reduce loading on the spine. Ergonomic assessments of tasks with leaning can be problematic because there is not sufficient data to predict leaning hand forces or the location of the leaning hand. Therefore, this study was completed to investigate leaning hand forces to help ergonomists make better predictions of how a leaning hand might be used during various industrial tasks. Purpose: The purpose of this study was to investigate hand leaning characteristics and the preferred leaning postures when completing tasks with constrained reaches. Methods: Twenty female participants completed exertions with 24 combinations of load (27.5 and 55 N), force direction (push, pull, and down), horizontal reach (95% and 120% of arm length), and vertical height (shoulder and umbilical height). A large leaning surface was available to use while completing the task. Results: The height of the leaning hand ranged between 106.6 and 116.3 cm across all conditions. The leaning hand force was affected by task hand location, force direction, and force demand. Leaning hand forces increased with increasing task hand load and ranged from 13.8 to 79.6 N of force. Task hand pulls had higher leaning hand forces compared to push and down exertion directions, regardless of task hand location or force demand. Conclusion: The findings of this study will be of particular use to industry as ergonomists now have representative leaning forces and heights to help guide leaning estimates during proactive risk assessments.","PeriodicalId":73331,"journal":{"name":"IIE transactions on occupational ergonomics and human factors","volume":"3 1","pages":"188 - 196"},"PeriodicalIF":0.0,"publicationDate":"2015-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/21577323.2015.1042096","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60125121","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-10-02DOI: 10.1080/21577323.2015.1093041
Adam K. Piper, G. T. Holman, Jerry Davis, R. Sesek, Eric J. Boelhouwer
OCCUPATIONAL APPLICATION Warnings are an important component of hazard control strategies in use in all types of industry. Properly designed warning symbols improve the likelihood that a warning will be recognized and understood, and they may even increase the likelihood that the warning will be heeded. Unfortunately, many commonly used warning symbols are poorly understood and may not meet accepted criteria for comprehension testing. Improving the process by which symbols are developed could affect a variety of future symbol designs. We propose new technological enhancements to traditional warning symbol design strategies—including semantic annotation, mathematical clustering, and evolutionary computation—that may improve the effectiveness of symbols designed in the future. TECHNICALABSTRACT Background:Warning symbols must comm-unicate effectively to a wide range of people. To achieve this goal, two major challenges must be overcome. First, designers must acquire user input while minimizing any unnecessary design input needed from non-users. Second, designers must develop symbols with a high likelihood of communicating effectively to a population of users that may be diverse in culture, language, and country of origin. Purpose: We evaluated clustering algorithms as a means to enhance the judgment required by designers using the stereotype production method for symbol development. Methods: Sixty-six symbol sketches, 35 from U.S. participants and 31 from Indian participants, were evaluated for the warning referent “Hot Exhaust.” A panel of three certified safety professionals semantically annotated the sketches and developed a frequency matrix that associated the presence of graphical attributes with each sketch. Direct clustering and Simple K-Means clustering were performed on the matrix. Results: Mathematical clustering was successful in identifying population stereotypes. The Simple K-Means analysis of the combined nationality matrix produced five clusters, each characterized by a hypothetical centroid symbol analogous to the population stereotypes of the participant group. Only three of the original 35 attributes were contained among these centroids, meaning that the primary differentiators of the population stereotypes were these three primary attributes. Direct clustering found the same three primary attributes—“pipe/stack,” “emission lines,” and “flame.” Further, clustering the nationalities separately revealed that some attributes were universal between the two nationalities, while others seemed to have a culture or country-of-origin sensitivity. Conclusions: Clustering can be used by designers to group sketches into similar families and to identify the attributes of most interest for final symbols. Furthermore, some attributes appear to be “recessive” while others appear to be “dominant” with regard to culture.
{"title":"Towards Incorporating Technology to Enhance the Stereotype Production Method in Warning Symbol Design","authors":"Adam K. Piper, G. T. Holman, Jerry Davis, R. Sesek, Eric J. Boelhouwer","doi":"10.1080/21577323.2015.1093041","DOIUrl":"https://doi.org/10.1080/21577323.2015.1093041","url":null,"abstract":"OCCUPATIONAL APPLICATION Warnings are an important component of hazard control strategies in use in all types of industry. Properly designed warning symbols improve the likelihood that a warning will be recognized and understood, and they may even increase the likelihood that the warning will be heeded. Unfortunately, many commonly used warning symbols are poorly understood and may not meet accepted criteria for comprehension testing. Improving the process by which symbols are developed could affect a variety of future symbol designs. We propose new technological enhancements to traditional warning symbol design strategies—including semantic annotation, mathematical clustering, and evolutionary computation—that may improve the effectiveness of symbols designed in the future. TECHNICALABSTRACT Background:Warning symbols must comm-unicate effectively to a wide range of people. To achieve this goal, two major challenges must be overcome. First, designers must acquire user input while minimizing any unnecessary design input needed from non-users. Second, designers must develop symbols with a high likelihood of communicating effectively to a population of users that may be diverse in culture, language, and country of origin. Purpose: We evaluated clustering algorithms as a means to enhance the judgment required by designers using the stereotype production method for symbol development. Methods: Sixty-six symbol sketches, 35 from U.S. participants and 31 from Indian participants, were evaluated for the warning referent “Hot Exhaust.” A panel of three certified safety professionals semantically annotated the sketches and developed a frequency matrix that associated the presence of graphical attributes with each sketch. Direct clustering and Simple K-Means clustering were performed on the matrix. Results: Mathematical clustering was successful in identifying population stereotypes. The Simple K-Means analysis of the combined nationality matrix produced five clusters, each characterized by a hypothetical centroid symbol analogous to the population stereotypes of the participant group. Only three of the original 35 attributes were contained among these centroids, meaning that the primary differentiators of the population stereotypes were these three primary attributes. Direct clustering found the same three primary attributes—“pipe/stack,” “emission lines,” and “flame.” Further, clustering the nationalities separately revealed that some attributes were universal between the two nationalities, while others seemed to have a culture or country-of-origin sensitivity. Conclusions: Clustering can be used by designers to group sketches into similar families and to identify the attributes of most interest for final symbols. Furthermore, some attributes appear to be “recessive” while others appear to be “dominant” with regard to culture.","PeriodicalId":73331,"journal":{"name":"IIE transactions on occupational ergonomics and human factors","volume":"3 1","pages":"221 - 235"},"PeriodicalIF":0.0,"publicationDate":"2015-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/21577323.2015.1093041","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60125410","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-10-02DOI: 10.1080/21577323.2015.1128238
Associate Editors: Catherine Burns, University of Waterloo, Canada Marco J.M. Hoozemans, VU Amsterdam, The Netherlands David Kaber, North Carolina State University, USA W. Patrick Neumann, Ryerson University, Canada Jim Potvin, Department of Kinesiology, McMaster University, Canada Ling Rothrock, Pennsylvania State University, USA Jeffrey C. Woldstad, Department of Biological Systems Engineering, University of Nebraska-Lincoln, USA
{"title":"End-of-Volume Editorial Board","authors":"","doi":"10.1080/21577323.2015.1128238","DOIUrl":"https://doi.org/10.1080/21577323.2015.1128238","url":null,"abstract":"Associate Editors: Catherine Burns, University of Waterloo, Canada Marco J.M. Hoozemans, VU Amsterdam, The Netherlands David Kaber, North Carolina State University, USA W. Patrick Neumann, Ryerson University, Canada Jim Potvin, Department of Kinesiology, McMaster University, Canada Ling Rothrock, Pennsylvania State University, USA Jeffrey C. Woldstad, Department of Biological Systems Engineering, University of Nebraska-Lincoln, USA","PeriodicalId":73331,"journal":{"name":"IIE transactions on occupational ergonomics and human factors","volume":"3 1","pages":"ebi - ebi"},"PeriodicalIF":0.0,"publicationDate":"2015-10-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/21577323.2015.1128238","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60125428","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-09-11DOI: 10.1080/21577323.2015.1040559
David Claudio, M. Velazquez, Wilfredo Bravo-Llerena, G. Okudan, A. Freivalds
OCCUPATIONAL APPLICATIONS Patients and nurses had positive reactions with respect to perceived usefulness and ease of use of a wireless wearable sensor-based system in two emergency departments. Results showed that patients' perceptions on the ease of use of the technology were more favorable and less variable than nurses' perception. The results are encouraging for the implementation of such technology in emergency department settings as they seem to promote the use of the technology for continuous monitoring of vital signs. TECHNICAL ABSTRACT Background: The use of wearable sensor-based systems in healthcare settings has been proposed and implemented in previous studies. While their application seems promising, the perceived usefulness and ease of use of such systems have not been assessed in detail in emergency departments. User feedback is critical as it can determine the attitude toward using the technology and ultimately predict its success. Purpose: This article presents an empirical pilot study in which the perceived usefulness and ease of use of a wireless wearable sensor-based system was assessed from the perspective of patients and nurses in emergency departments. The wireless wearable sensors were used to monitor patients' heart rate, respiration rate, temperature, oxygen level, and blood pressure. Methods: The study was conducted in two clinical settings; a total of 40 patients and 20 nurses participated in the study. After a 30-minute use and testing period, patients provided feedback through a survey. Similarly, nurses were asked to provide their feedback after their experience with four patients. Results: Participants reported that the wearable sensor-based technology was very useful and easy to use. Results also showed that mean scores for perceived usefulness and ease of use were higher for patients. Conclusions: Overall, patients and nurses had positive reactions with respect to perceived usefulness and ease of use, which is encouraging for the implementation of such technology in emergency department settings. Although it is not possible to directly predict or infer the degree of acceptability, the results of this study provide a sense of how the prospective users would feel about the usefulness of continuous monitoring as well as the ease of use of the monitoring devices.
{"title":"Perceived Usefulness and Ease of Use of Wearable Sensor-Based Systems in Emergency Departments","authors":"David Claudio, M. Velazquez, Wilfredo Bravo-Llerena, G. Okudan, A. Freivalds","doi":"10.1080/21577323.2015.1040559","DOIUrl":"https://doi.org/10.1080/21577323.2015.1040559","url":null,"abstract":"OCCUPATIONAL APPLICATIONS Patients and nurses had positive reactions with respect to perceived usefulness and ease of use of a wireless wearable sensor-based system in two emergency departments. Results showed that patients' perceptions on the ease of use of the technology were more favorable and less variable than nurses' perception. The results are encouraging for the implementation of such technology in emergency department settings as they seem to promote the use of the technology for continuous monitoring of vital signs. TECHNICAL ABSTRACT Background: The use of wearable sensor-based systems in healthcare settings has been proposed and implemented in previous studies. While their application seems promising, the perceived usefulness and ease of use of such systems have not been assessed in detail in emergency departments. User feedback is critical as it can determine the attitude toward using the technology and ultimately predict its success. Purpose: This article presents an empirical pilot study in which the perceived usefulness and ease of use of a wireless wearable sensor-based system was assessed from the perspective of patients and nurses in emergency departments. The wireless wearable sensors were used to monitor patients' heart rate, respiration rate, temperature, oxygen level, and blood pressure. Methods: The study was conducted in two clinical settings; a total of 40 patients and 20 nurses participated in the study. After a 30-minute use and testing period, patients provided feedback through a survey. Similarly, nurses were asked to provide their feedback after their experience with four patients. Results: Participants reported that the wearable sensor-based technology was very useful and easy to use. Results also showed that mean scores for perceived usefulness and ease of use were higher for patients. Conclusions: Overall, patients and nurses had positive reactions with respect to perceived usefulness and ease of use, which is encouraging for the implementation of such technology in emergency department settings. Although it is not possible to directly predict or infer the degree of acceptability, the results of this study provide a sense of how the prospective users would feel about the usefulness of continuous monitoring as well as the ease of use of the monitoring devices.","PeriodicalId":73331,"journal":{"name":"IIE transactions on occupational ergonomics and human factors","volume":"3 1","pages":"177 - 187"},"PeriodicalIF":0.0,"publicationDate":"2015-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/21577323.2015.1040559","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60124922","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2015-08-18DOI: 10.1080/21577323.2015.1022283
J. Parr, Michael E. Miller, J. Colombi, C. M. Kabban, J. Pellettiere
OCCUPATIONAL APPLICATIONS In this study, a lateral impact (Gy accelerative input), upper-neck, multi-axial, neck injury criterion is developed. This criterion could be used to evaluate the safety of U.S. Air Force ejection systems incorporating helmet-mounted displays or other applications where neck injury risk from side impact occurs (e.g., automotive and civilian fixed-wing or rotary-wing aircraft). Development of the criterion was motivated by military aviation, which increasingly incorporates head-supported mass and an expanded pilot population, including smaller pilots (to 47 kg), raising concerns for pilot safety during ejection. Neck injury criteria based on risk functions constructed with human subject and postmortem human subject data allow system designers to quantify the injury risk and design acceptably safe systems. A maximum allowable value for the criterion applicable to U.S. Air Force ejection aircraft is proposed to limit neck injury risk to a 5% probability of moderate injury. However, the underlying risk function allows practitioners to customize the criterion for their desired level of injury risk and injury classification. TECHNICAL ABSTRACT Background: Neck injury remains a concern in ejection seat–equipped military aircraft with the growing use of helmet-mounted displays (HMDs) worn for entire mission durations, as well as in the automotive and civilian aircraft domains. Existing U.S. Department of Defense criteria are overly complex and not clearly tied to injury risk and thus require improvement. Purpose: This study developed a lateral (Gy) impact, upper neck injury criterion for use in the design and test of U.S. Department of Defense escape systems and HMDs. Methods: A multi-axial lateral impact risk function, referred to as MANIC(Gy), was constructed using the survival analysis of a data set that combined human subject (N = 56) and postmortem human (N = 9) data. The human subject data were analyzed to assess criterion sensitivity to anthropometric factors. Additionally, a risk function was applied to quantify the risk associated with changes in HMD mass and acceleration input. Results: A lateral impact (Gy), upper neck injury criterion is proposed, which yields a 5% risk of Abbreviated Injury Scale (AIS) 2 or greater injury at a criterion value of 0.48 (95% confidence intervals of 0.28 and 0.67, respectively). At an injury level of AIS 3 or greater, a risk function was generated that yields a 5% risk at a criterion value of 0.53 (95% confidence intervals of 0.24 and 0.82, respectively). Conclusions: This initial multi-axial risk function could be applied to quantify the risk of neck injury posed by lateral acceleration. Criterion values were correlated with body mass and related anthropometric factors, indicating that the critical values incorporated in this study may require improvement. This same criterion may be useful for analyzing side impact safety in other vehicle systems (e.g., automotive and civilian fixed wi
{"title":"Development of a Side-Impact (Gy) Neck Injury Criterion for Use in Aircraft and Vehicle Safety Evaluation","authors":"J. Parr, Michael E. Miller, J. Colombi, C. M. Kabban, J. Pellettiere","doi":"10.1080/21577323.2015.1022283","DOIUrl":"https://doi.org/10.1080/21577323.2015.1022283","url":null,"abstract":"OCCUPATIONAL APPLICATIONS In this study, a lateral impact (Gy accelerative input), upper-neck, multi-axial, neck injury criterion is developed. This criterion could be used to evaluate the safety of U.S. Air Force ejection systems incorporating helmet-mounted displays or other applications where neck injury risk from side impact occurs (e.g., automotive and civilian fixed-wing or rotary-wing aircraft). Development of the criterion was motivated by military aviation, which increasingly incorporates head-supported mass and an expanded pilot population, including smaller pilots (to 47 kg), raising concerns for pilot safety during ejection. Neck injury criteria based on risk functions constructed with human subject and postmortem human subject data allow system designers to quantify the injury risk and design acceptably safe systems. A maximum allowable value for the criterion applicable to U.S. Air Force ejection aircraft is proposed to limit neck injury risk to a 5% probability of moderate injury. However, the underlying risk function allows practitioners to customize the criterion for their desired level of injury risk and injury classification. TECHNICAL ABSTRACT Background: Neck injury remains a concern in ejection seat–equipped military aircraft with the growing use of helmet-mounted displays (HMDs) worn for entire mission durations, as well as in the automotive and civilian aircraft domains. Existing U.S. Department of Defense criteria are overly complex and not clearly tied to injury risk and thus require improvement. Purpose: This study developed a lateral (Gy) impact, upper neck injury criterion for use in the design and test of U.S. Department of Defense escape systems and HMDs. Methods: A multi-axial lateral impact risk function, referred to as MANIC(Gy), was constructed using the survival analysis of a data set that combined human subject (N = 56) and postmortem human (N = 9) data. The human subject data were analyzed to assess criterion sensitivity to anthropometric factors. Additionally, a risk function was applied to quantify the risk associated with changes in HMD mass and acceleration input. Results: A lateral impact (Gy), upper neck injury criterion is proposed, which yields a 5% risk of Abbreviated Injury Scale (AIS) 2 or greater injury at a criterion value of 0.48 (95% confidence intervals of 0.28 and 0.67, respectively). At an injury level of AIS 3 or greater, a risk function was generated that yields a 5% risk at a criterion value of 0.53 (95% confidence intervals of 0.24 and 0.82, respectively). Conclusions: This initial multi-axial risk function could be applied to quantify the risk of neck injury posed by lateral acceleration. Criterion values were correlated with body mass and related anthropometric factors, indicating that the critical values incorporated in this study may require improvement. This same criterion may be useful for analyzing side impact safety in other vehicle systems (e.g., automotive and civilian fixed wi","PeriodicalId":73331,"journal":{"name":"IIE transactions on occupational ergonomics and human factors","volume":"3 1","pages":"151 - 164"},"PeriodicalIF":0.0,"publicationDate":"2015-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1080/21577323.2015.1022283","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"60124472","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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