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Objective Lumbar mobilization is a standard intervention for the management of low back pain, yet ways to quantify lumbar mobilization are limited. An inertial measurement unit (IMU) is a small and inexpensive device that can be used to quantify lumbar mobilization. The objective of this study was to determine the validity and reliability of an IMU in measuring the amplitude of displacement of a clinician's hand movement during oscillatory lumbar mobilization. Methods An IMU was secured on a clinician's hand during application of mobilization forces at the L4 segment of 16 healthy participants. The validity of the IMU was tested against common laboratory methods of measurements (force plate and motion capture system). The reliability of the IMU measurements was determined between 2 clinicians (inter-rater reliability) and between 2 sessions (intra-rater reliability) by calculating percent error of measurement (%e) and limits of agreement (LOA). The reliability was considered high when |%e| ≤ 10% and |LOA| ≤ 20%; moderate when |%e| 10% to 20% and |LOA| 21% to 40%; and non-acceptable when |%e| > 20% and |LOA| > 40%. Results The IMU measurements had high correlation with the force plate measurements (rs = 0.94) and high agreement with the motion capture system measurements (%e = 4%, LOA = -11% and 20%). Both the inter-rater reliability (%e = 6%, LOA = -25% and 37%) and the intrarater reliability (%e = -1%, LOA = -29% and 27%) of IMU measurements were moderate. Conclusion The IMU seems to be a valid device to measure the amplitude of a clinician's hand movement. The moderate reliability found in this study may not reflect poor reliability of the IMU as much as inconsistency in reapplication of lumbar mobilization.

In order to meet the needs of industry, graduate schools should consider adding design-based programs to their curriculum. A majority of Ph.D. students in bio-engineering and biomedical engineering (BME) seek employment outside of academia, implying that these students will need to be able to leverage their dissertation research for other types of positions. Here, curriculum elements are examined from several graduate programs across the United States and a strategy is proposed that combines bio-engineering design-based research and education at the doctoral level. Ideally, a design-based Ph.D. includes: traditional engineering and scientific coursework, coursework focused on the design and commercialization process, industry and clinical experiences, and design-centric research. A design-based dissertation leverages the design process into specific aims that build on each other to complete a body of work. These aims can occur at different points in the design process and should include evaluation of the technology against user needs. It is possible to orient the in-depth research of a doctoral dissertation to the design of an innovative medical product that can be of a benefit to patients.

Treatment of vision-threating elevated intraocular pressure (IOP) for severe glaucoma may require implantation of a glaucoma drainage device (GDD) to shunt aqueous humor (AH) from the anterior chamber of the eye and lower IOP to acceptable levels between 8 and 21 mm Hg. Nonvalved GDDs (NVGDDs) cannot maintain IOP in that acceptable range during the early postoperative period and require intra-operative modifications for IOP control during the first 30 days after surgery. Other GDDs have valves to overcome this issue, but are less successful with maintaining long-term IOP. Our research goal is to improve NVGDD postoperative performance. Little rigorous research has been done to systematically analyze flow/pressure characteristics in NVGDDs. We describe an experimental system developed to assess the pressure drop for physiologic flow rates through NVGDD-like microtubes of various lengths/diameters, some with annular inserts. Experimental pressure measurements for flow through hollow microtubes are within predictive theory's limits. For instance, a 50.4 μm inner diameter microtube yields an average experimental pressure of 33.7 mm Hg, while theory predicts 31.0–64.2 mm Hg. An annular example, with 358.8 μm outside and 330.7 μm inside diameters, yields an experimental pressure of 9.6 mm Hg, within theoretical predictions of 4.2–19.2 mm Hg. These results are repeatable and consistent over 25 days, which fits the 20–35 day period needed for scar tissue formation to achieve long-term IOP control. This work introduces a novel method for controlling IOP and demonstrates an experiment to examine this over 25 days. Future efforts will study insert size and degradable inserts.

Lumbar mobilization is a standard intervention for lower back pain (LBP). However, its effect on the activity of back muscles is not well known.To investigate the effects of lumbar mobilization on the activity/contraction of erector spinae (ES) and lumbar multifidus (LM) muscles in people with LBP.Randomized controlled study.21 subjects with LBP received either grade III central lumbar mobilization or placebo (light touch) intervention on lumbar segment level 4 (L4). Surface electromyography (EMG) signals of ES and ultrasound (US) images of LM were captured before and after the intervention. The contraction of LM was calculated from US images at L4 level. The normalized amplitude of EMG signals (nEMG) and activity onset of ES were calculated from the EMG signals at both L1 and L4 levels.Significant differences were found between the mobilization and placebo groups in LM contraction (p=0.03), nEMG of ES at L1 (p=0.01) and L4 (p=0.05), and activity onset of ES at L1 (p=0.02).Lumbar mobilization decreased both the activity amplitude and the activity onset of ES in people with LBP. However, the significant difference in LM contraction was small and may not have clinical significance.

People with chronic low back pain (CLBP) tend to have altered postural control. Visual biofeedback may be used to restore postural control. The purpose of this pilot study was to investigate the effect of visual biofeedback on seated postural trunk control in subjects with CLBP, and to investigate the relationship between the postural control parameters and clinical tests.Ten CLBP subjects (8 female, 2 male; age 40.6±5 yrs; BMI 25.06±2.93) and 10 healthy matched controls (8 female, 2 male; age 41.2±5.88 yrs; BMI 24.61±3.17) underwent seated postural assessment. Center of pressure (COP) parameters were collected under three experimental conditions: eyes-open, visual biofeedback, and eyes-closed.The results revealed that COP velocity was significantly different between healthy and CLBP subjects for each condition, both healthy and CLBP subjects had no differences in COP parameters between eyes-open and visual biofeedback conditions, and in subjects with CLBP, the straight leg raise clinical test had a strong negative correlation with all COP parameters.Our results suggest that 30-second visual biofeedback training did not improve the seated postural control of CLBP subjects, potentially due to the short duration of training, and that hamstrings muscle tightness or decreased sciatic nerve mobility was associated with worse postural control.

Objective The purpose of this study was to investigate the effect of grade IV lumbar mobilization on the activity/contraction of erector spinae (ES) and lumbar multifidus (LM) muscles in healthy people. Methods A randomized, repeated-measures design was used. Sixteen healthy subjects attended 3 testing sessions with a different intervention in each session (no intervention, grade IV central lumbar mobilization at L4, and placebo/light touch). Lying in a prone position, subjects lifted a light weight with their right arm while ultrasound images of LM and surface electromyography signals of ES were captured before and immediately after application of the intervention in the session. The contraction of LM was calculated from US images, and the root mean square was calculated from the electromyography signals of ES and used as outcome measures. Results A significant difference was found in LM contraction between the placebo and mobilization intervention (difference = 0.04, P = .02). There was no difference for the root mean square of electromyography signals between the interventions. Conclusion The significant difference in LM contraction was small and may not have clinical significance. Lumbar mobilization did not change the activity of ES in healthy people. Future studies with larger samples are needed to confirm our findings and to investigate the effect of mobilization on back muscles in people with low back pain.

Background While adolescent idiopathic scoliosis (AIS) produces well characterized deformation in spinal form, the effect on spinal function, namely mobility, is not well known. Better understanding of scoliotic spinal mobility could yield better treatment targets and diagnoses. The purpose of this study was to characterize the spinal mobility differences due to AIS. It was hypothesized that the AIS group would exhibit reduced mobility compared to the typical adolescent (TA) group. Methods Eleven adolescents with right thoracic AIS, apices T6-T10, and eleven age- and gender-matched TAs moved to their maximum bent position in sagittal and coronal plane bending tasks. A Trakstar (Ascension Technologies Burlington, VT) was used to collect position data. The study was approved by the local IRB. Using MATLAB (MathWorks, Natick, MA) normalized segmental angles were calculated for upper thoracic (UT) from T1-T3, mid thoracic (MT) from T3-T6, lower thoracic (LT) from T6-T10, thoracolumbar (TL) from T10-L1, upper lumbar (UL) from L1-L3, and thoracic from T1-L1 by subtracting the standing position from the maximum bent position and dividing by number of motion units in each segment. Mann Whitney tests (α = 0.05) were used to determine mobility differences. Results The findings indicated that the AIS group had comparatively increased mobility in the periapical regions of the spine. The AIS group had an increase of 1.2° in the mid thoracic region (p = 0.01) during flexion, an increase of 1.0° in the mid thoracic region (p = 0.01), 1.5° in the thoracolumbar region (p = 0.02), and 0.7° in thoracic region (p = 0.04) during left anterior-lateral flexion, an increase of 6.0° in the upper lumbar region (p = 0.02) during right anterior-lateral flexion, and an increase of 2.2° in the upper lumbar region during left lateral bending (p

Tasks involving flexed torso postures have a high incidence of low back injuries. Changes in the ability to sense and adequately control low back motion may play a role in these injuries. Previous studies examining position sense errors of the lumbar spine with torso flexion found significant increases in error with flexion. However, there has been little research on the effect of lumbar angle. In this study, the aim of the study was to examine how position sense errors would change with torso flexion as a function of the target lumbar angle. Fifteen healthy volunteers were asked to assume three different lumbar angles (maximum, minimum and mid-range) at three different torso flexion angles. A reposition sense protocol was used to determine a subject’s ability to reproduce the target lumbar angles. Reposition sense error was found to increase 69% with increased torso flexion for mid-range target curvatures. With increasing torso flexion, the increase in reposition sense errors suggests a reduction in sensation and control in the lumbar spine that may increase risk of injury. However, the reposition error was smaller at high torso flexion angles in the extreme target curvatures. Higher sensory feedback at extreme lumbar angles would be important in preventing over-extension or over-flexion. These results suggest that proprioceptive elements in structures engaged at limits (such as the ligaments and facet joints), may provide a role in sensing position at extreme lumbar angles. Sensory elements in the muscles crossing the joint may also provide increased feedback at the edges of the range of motion.

Occupational whole-body vibration has long been associated with low back injuries. However, the mechanism of these injuries is not well understood. In this paper, the effect of whole-body vibration on proprioception and dynamic stability was examined. Subjects exposed to 20 min of vertical, seated, whole-body vibration were found to have a 1.58-fold increase in position-sense errors after vibration relative to controls exposed to 20 min of the same seated posture without vibration exposure. To understand the potential effect of a sensory loss on dynamic low back stability, a lumped parameter model of the trunk and neuromotor response was created. Using this model, an increase in the threshold of the sensory system was predicted to increase trunk flexion and delay neuromotor response with a sudden, unexpected perturbation. These predictions were demonstrated in a second experiment where subjects exhibited both an 11.9% increase in trunk flexion and an 11.2% increase in time to peak paraspinal muscle response (measured using integrated electromyographic activity) after exposure to 20 min of vertical, seated, whole-body vibration. Relevance to Industry For workers exposed to whole-body vibration (WBV), this research suggests that a loss in the ability to sense and control lumbar posture may occur. After exposure, unexpected perturbations during manual materials handling could lead to injury. Reducing vibration exposure or a break between exposure and manual materials handling could be used to reduce this risk.

Proprioception plays an important role in appropriate sensation of spine position, movement, and stability. Previous research has demonstrated that position sense error in the lumbar spine is increased in flexed postures. This study investigated the change in position sense as a function of altered trunk flexion and moment loading independently. Reposition sense of lumbar angle in 17 subjects was assessed. Subjects were trained to assume specified lumbar angles using visual feedback. The ability of the subjects to reproduce this curvature without feedback was then assessed. This procedure was repeated for different torso flexion and moment loading conditions. These measurements demonstrated that position sense error increased significantly with the trunk flexion (40%,p< .05) but did not increase with moment load (p= .13). This increased error with flexion suggests a loss in the ability to appropriately sense and therefore control lumbar posture in flexed tasks. This loss in proprioceptive sense could lead to more variable lifting coordination and a loss in dynamic stability that could increase low back injury risk. This research suggests that it is advisable to avoid work in flexed postures.

Inertial and magnetic sensors are commonly used to determine orientation as they do not rely on a line of sight [1, 2]. There are many different techniques to fuse inertial measurement unit (IMU) data and obtain useful rotational data [1–3]. This study uses two separate data fusion techniques; a direction cosine matrix-based (DCM) technique and a quaternion-based Extended Kalman Filter (EKF) technique [1–3]. These techniques were altered based on performance metrics to weight sensor data when certain sensors proved not as reliable as others [2]. IMU sensors were tested on a hand mannequin and filters were developed using MATLAB software. Simulation results displayed a root-mean-squared error of less than .06° for each rotation angle. Experimental results maintained errors of less than 8° in each rotation angle.Copyright © 2015 by ASME

As torso flexion and repetitive lifting are known risk factors for low back pain and injury, it is important to investigate lifting techniques that might reduce injury during repetitive lifting. By normalizing lumbar posture to a subject's range of motion (ROM), as a function of torso flexion, this research examined when subjects approached their range of motion limits during dynamic lifting tasks. For this study, it was hypothesized that experienced lifters would maintain a more neutral lumbar angle relative to their range of motion, while novice lifters would approach the limits of their lumbar ROM during the extension phase of a straight-leg lift. The results show a statistically significant difference in lifting patterns for these two groups supporting this hypothesis. The novice group maintained a much more kyphotic lumbar angle for both the flexion (74% of the lumbar angle ROM) and extension phases (86% of the lumbar angle ROM) of the lifting cycle, while the experienced group retained a more neutral curvature throughout the entire lifting cycle (37% of lumbar angle ROM in flexion and 48% of lumbar angle ROM in extension). By approaching the limits of their range of motion, the novice lifters could be at greater risk of injury by placing greater loads on the supporting soft tissues of the spine. Future research should examine whether training subjects to assume more neutral postures during lifting could indeed lower injury risks.

Abdominal belts are sometimes used as a low-cost, low back injury prevention measure in industry. Claims for the effectiveness have suggested that such belts may enhance proprioception and therefore improve low back stability. In this study, this claim was examined by using a previously established low back reposition sense protocol to assess the change in position sense with use of an elastic back belt in both an upright and a flexed posture. The results of this study demonstrate no overall improvement of position sense with back belt. However, significant improvement was observed at a torso flexion angle of 45 degrees. While future studies in other conditions are suggested, this study suggest that back belts may be useful only when highly flexed postures are required for manual materials handling.

STUDY DESIGN Reposition sense of lumbar curvature was assessed as a function of trunk flexion, trunk asymmetry, and target lumbar curvature using a repeated-measures design and an active-active proprioception paradigm. OBJECTIVE The objectives of the research were to measure the ability of the subjects to sense and control the lumbar curvature in different lifting postures and to see if error in the lumbar curvature would increase in high-risk postures. SUMMARY OF BACKGROUND DATA The risk of low back disorders (LBDs) is related to trunk posture, with greater risk reported in flexed and asymmetric trunk positions. Spinal posture, including trunk position and lumbar lordosis, influences spinal stability. Hence, the ability to accurately sense and control spinal curvature may be an important factor in the control of LBD risk. METHODS Eleven subjects were trained to assume specified lumbar curvatures using visual feedback. The ability of the subjects to reproduce this curvature without feedback was then assessed. This procedure was repeated for different trunk postures, including flexion and asymmetry, and with different target lumbar curvatures. RESULTS These measurements demonstrated reposition error was increased in flexed trunk positions but was unchanged with trunk asymmetry. This increase in reposition error with flexion was diminished when the target posture and lumbar curvature were highly flexed and kyphotic. CONCLUSIONS This research suggests that it may be difficult to control spinal curvature in flexed positions, leading to an increased risk of injury. For jobs in which flexed working postures are unavoidable, therefore, it is important to minimize potentially unstable events such as slipping or shifting loads to avoid injury.

Active females demonstrate increased risk for musculoskeletal injuries relative to equivalently-trained males. Although gender differences in factors such as passive laxity, skeletal geometry and kinematics have been examined, the effect of gender on active muscle stiffness has not been reported. Stiffness of the active quadriceps and hamstrings musculature were recorded during isometric knee flexion and extension exertions from twelve male and eleven female subjects. A second-order biomechanical model of joint dynamics was used to quantify stiffness from the transient motion response to an angular perturbation of the lower-leg. Female subjects demonstrated reduced active stiffness relative to male subjects at all torque levels, with levels 56–73% of the males. Effective stiffness increased linearly with the torque load, with stiffness increasing at a rate of 3.3 Nm/rad per unit of knee moment in knee flexion exertions (hamstrings) and 6.6 Nm/rad per unit of knee moment extension exertions (quadriceps). To account for gender differences in applied moment associated with leg mass, regressions analyses were completed that demonstrated a gender difference in the slope of stiffness-versus-knee moment relation. Further research is necessary to identify the cause of the observed biomechanical difference and implications for controlling injury.

Leg stiffness was compared between age-matched males and females during hopping at preferred and controlled frequencies. Stiffness was defined as the linear regression slope between the vertical center of mass (COM) displacement and ground-reaction forces recorded from a force plate during the stance phase of the hopping task. Results demonstrate that subjects modulated the vertical displacement of the COM during ground contact in relation to the square of hopping frequency. This supports the accuracy of the spring-mass oscillator as a representative model of hopping. It also maintained peak vertical ground-reaction load at approximately three times body weight. Leg stiffness values in males (33.9+/-8.7 kN/m) were significantly (p

Risk of occupational low-back disorders may be related to spinal stability achieved during manual materials handling. Stability is controlled and influenced by trunk muscle stiffness, antagonistic co-contraction and reflex response. Fatigue influences each of these factors, suggesting that fatigue may compromise spinal stability. A biomechanical model of spinal stability and experimental data were implemented to evaluate the effects of fatigue. EMG and trunk kinematics from 21 healthy subjects were recorded during static trunk extension exertions and sudden-load trials in fatigued and unfatigued states. The model predicted dramatic reduction in spinal stability associated with fatigue related decrement in paraspinal muscle stiffness and force generating capacity. Empirical data supported the model predictions, demonstrating increased antagonistic co-contraction during fatigued exertions. Results suggest risk of low-back injury from loss of spinal stability is increased during fatigue from manual materials handling.

Risk of low back disorders (LBD) is related to spinal posture with greater risk reported in flexed and asymmetric trunk positions. Spinal posture, including trunk position and lumbar lordosis, influences spinal load and stability. Hence, the ability to accurately sense and control spinal curvature may be an important factor in the control LBD risk. Current measurement demonstrated error in spinal reposition sense was increased in flexed trunk positions but was not found to change significantly with trunk asymmetry. Reposition sense error was also found to be reduced in more kyphotic flexed postures (relative to more lordotic flexed postures) possibly due to position sense feedback from ligamentous strain. This research suggests that it may be difficult to control spinal curvature in flexed positions, leading to an increased risk of injury. Fully flexed, kyphotic postures (“stooped postures”) have an improved reposition sensitivity, making this posture easier to control. However these postures may be more susceptible to viscoelastic strain and injury of the ligamentous tissue.

Design and development of new biomedical products in an entrepreneurial environment requires technical expertise as well as an understanding of clinical applications, business considerations and regulatory aspects, and the ability to work across multidisciplinary boundaries. Advanced engineering skills must also interface with clinical needs and requirements.Copyright © 2013 by ASME

During the delivery of a fetus, an obstetrician assists by applying gentle axial downward traction on the head until the shoulders clear the pubic bone followed by catching and supporting the delivered infant body. If the shoulders become lodged behind the maternal pelvis (shoulder dystocia), the physician may be required to perform additional maneuvers to free the shoulders (1,2). Of significant concern is the potential for injury of the fetus during this process. It is believed that hyperextension, misalignment of forces on the head, or excessive applied forces can result in injuries to the brachial plexus nerves running through the neck and shoulder resulting in temporary or permanent Erb’s of Klumpke’s palsies for the infant. It is important to recognize there are delivery forces that originate with uterine contractions and maternal val salvo. To better understand the forces exerted during delivery in order to prevent these injuries, our long-term research goal is to create a tool that can accurately quantify these forces to improve understanding of them and to create training tools for medical trainees. The research goal of this project was to examine what hand pressures are typical during this traction phase in a normal delivery and where they are applied on the hand of the obstetrician. A secondary research question was whether there are any differences between fully trained obstetricians and residents in these pressures.

The study aimed to determine the prevalence of low back pain (LBP) among nursing students at various recall time points and compare the rates with physiotherapy (PT) and engineering students. Data were collected from 214 undergraduate and graduate students using a prevalence questionnaire via REDCap. LBP prevalence rates were found to be high at all recall time points in all the three disciplines. Nursing students had similar 12-month, 30-day and 7-day LBP prevalence rates as the PT students while the engineering students had the lowest prevalence rates at all the time points. Students from all three disciplines attributed the majority of their LBP to prolonged sitting. In addition, lifting patients and sports activities were also listed as other major causes for their LBP. Lack of awareness of correct sitting posture (p

Computational modeling is a growing area of mechanical engineering that focuses on the use of numerical simulation to examine complex phenomena. Computational modeling includes work in finite element analysis, computational fluid dynamics, and multi-body dynamics modeling. Intrinsic to most of these modeling efforts are common elements including: 1. Assumptions that are made to reduce a problem to a solvable mathematical problem, 2. Formulation of a mathematical representation based on scientific principles, 3. Reduction of the mathematical representation through the removal of terms of small effect (neglected terms) 4. Collection and use of input data, 5. Algorithm development using numerical methods and discretization of the mathematical problem, 6. Implementation of the algorithm in computer code, 7. Creating representations of the model results, 8. External validation of the model, and 9. Dissemination of the model and model computer code.

Recent research in ethics education shows a potentially problematic variation in content, curricular materials, and instruction. While ethics instruction is now widespread, studies have identified significant variation in both the goals and methods of ethics education, leaving researchers to conclude that many approaches may be inappropriately paired with goals that are unachievable. This paper speaks to these concerns by demonstrating the importance of aligning classroom-based assessments to clear ethical learning objectives in order to help students and instructors track their progress toward meeting those objectives. Two studies at two different universities demonstrate the usefulness of classroom-based, formative assessments for improving the quality of students’ case responses in computational modeling and research ethics.

Vibration exposure has been known to have both negative and positive effects on human dynamics in a variety of clinical and occupational applications. Whole body vibration is known to be associated with low back pain and low back disorders [1]. It has been shown that whole body vibration and vibration of the lumbar musculature can result in loss of proprioceptive accuracy and delays in muscular response to sudden loading [24]. Conversely, vibration of the musculature has also been proposed as a means to improve the effects of training and exercise on strength and endurance [5–7]. Vibration has a number of known effects on proprioception in particular. These include kinesthetic illusions during vibration exposure [8] and altered proprioception post-vibration exposure [3, 9]. Understanding the neural pathways that contribute to these effects is important in better understanding the clinical and occupational implications of vibration exposure. Therefore, the objective of the current study was to examine brain activity using functional magnetic resonance imaging (fMRI) during a dynamic, proprioceptive task, both during and after vibration exposure in order to observe changes in activation that might contribute to these effects.

Functional Magnetic Resonance Imaging (fMRI) promises to grant motor control researchers opportunities to more directly explore neuromotor system dynamics including the role of proprioception. The effects of vibration on proprioception have been well documented including changes in perceived muscle length and lengthening velocity and altered muscle spindle organ firing [1–4]. As such, the combination of vibration of the muscle-tendon with fMRI of the brain can be used to better understand how proprioceptive signals are managed in the brain. However, the strength of the magnetic environment of the fMRI does not easily allow for traditional vibration technologies, such as a DC motor with offset mass, to be used to create the necessary vibratory stimulus to perturb the proprioceptive system. Several researchers have nonetheless successfully designed and implemented various vibration devices to probe the brain in the fMRI environment [5–7].Copyright © 2011 by ASME

Regulating spinal motion requires proprioceptive feedback. While studies have investigated the sensing of static lumbar postures, few have investigated sensing lumbar movement speed. In this study, proprioceptive contributions to lateral trunk motion were examined during paraspinal muscle vibration. Seventeen healthy subjects performed lateral trunk flexion movements while lying prone with pelvis fixed. A 44.5-Hz vibratory stimulus was applied to the paraspinal muscles at the L3 level. Subjects attempted to match target paces of 9.5, 13.5, and 17.5 deg/s with and without paraspinal muscle vibration. Vibration of the paraspinal musculature was found to result in slower overall lateral flexion. This effect was found to have a greater influence in the difference of directional velocities with vibration applied to the left musculature. These changes reflect the sensitivity of lumbar velocity sense to applied vibration leading to the perception of faster muscle lengthening and ultimately resulting in slower movement velocities. This suggests that muscle spindle organs modulate the ability to sense velocity of motion and are important in the control of dynamic motion of the spine.

Training in the responsible conduct of research (RCR) has become an increasing concern of federal funding agencies such as NIH and NSF. In 2000, the Office of Research Integrity published the policy of instruction in responsible conduct of research for NIH funded research. This policy mandates that all research staff participate in RCR instruction. In 2007, the COMPETES Act was signed by President Bush mandating RCR instruction of all NSF-funded undergraduate students, graduate students, and post-doctoral researchers. Such training can and does take many forms, from online tutorials and study guides to seminar series to semester long classes. Core instructional areas in such training include appropriate data management, mentor-trainee relationships, publication practices and authorship, peer review, human and animal subjects and conflict of interest.

Low back disorders are very common affecting up to 80% of the population in their lifetime [1]. Whole body vibration (WBV) exposure has long been identified as an important risk factor for low back disorders in industrial workers [2]. A potential mechanism has been proposed by which vibration may lead to injury. Namely, vibration-induced losses in proprioception may lead to inappropriate stabilization and poor dynamic control of the lumbar spine [3]. Increases in proprioceptive errors and in delays in neuormotor response have been demonstrated with 5 Hz, vertical seatpan vibration [3]. While vertical vibration exposure is a common occupational exposure, in some cases, such as off road vehicles and construction vehicles horizontal (fore-aft) vibration may dominate [4]. In this study, the objective was to investigate how the whole body, horizontal, seatpan vibration affects muscle response and to compare these results with the previously studied whole body vertical vibration.Copyright © 2008 by ASME

Loss in dynamic stability of the low back has been identified as a potential factor in the etiology of low back injuries. A number of factors are important in the ability of a person to maintain an upright trunk posture including the preparatory stiffness of the trunk and the magnitude and timing of the neuromotor response. A neuromotor response requires appropriate sensing of joint motion. In this research, the role of this sensory ability in dynamic performance of the trunk was examined using a simple pendulum model of the trunk with neuromotor feedback. An increased sensory threshold was found to lead to increased torso flexion and increased delay in neuromotor response. This was confirmed experimentally using paraspinal muscle vibration which is known to alter proprioception of the muscle spindle organs. Before, during and after exposure to bilateral, paraspinal muscle vibration for 20minutes, the dynamic response of subjects to an unexpected torso flexion load was examined. Subjects were found to have a 19.5% slower time to peak muscle activity and a 16.1% greater torso flexion during exposure to paraspinal muscle vibration. Torso flexion remained significantly increased after vibration exposure relative to before exposure. These results suggest that the neuromotor response plays an important role in trunk dynamics. Loss in sensitivity of the sensory system can have a detrimental effect on trunk dynamics, increasing delays in neuromotor response and increasing the motion of the trunk in response to an unexpected load.

Low back pain is one of the most costly and common musculoskeletal disorders, affecting up to 80% of the adults in their lifetime [1]. Whole body vibration (WBV) has been found to be a major risk factor in the etiology of low back pain with WBV increasing low back disorder risk from 1.2 to 39.5 fold depending on the occupational exposure duration and magnitude [2–3]. Recent research has demonstrated that exposure to sinusoidal whole body vibration of 5 Hz leads to increased propriceptive errors and delayed neuromotor response to external perturbation [4]. These results suggest a potential mechanism for low back injuries, namely that vibration may alter neuromotor control leading to poor stabilization and control of low back motion, increasing the risk of injury. However, the methods used to assess these changes in proprioception are static measures, require a good deal of equipment and setup time, and have a high variance, particularly with removal of electrodes and sensors, that make them impractical for the industrial setting. In addition, previous studies have only examined the effect of pure sinusoidal vibration exposure rather than the mixture of frequencies seen in occupational settings. Therefore, the goal of this project was to develop a dynamic measure of lumbar sensory accuracy and neuromotor control that could be used easily in the workplace and to examine the effects of WBV vibration on the measure using an occupationally-relevant vibration exposure.Copyright © 2008 by ASME

Spine motion has been described to have two regions, a neutral zone where lumbar rotation can occur with little resistance and an elastic zone where structures such as ligaments, facet joints and intervertebral disks resist rotation. In vivo, the passive musculature can contribute to further limiting the functional neutral range of lumbar motion. Movement out of this functional neutral range could potentially put greater loads on these structures. In this study, the range of lumbar curvature rotation was examined in twelve healthy, untrained volunteers at four torso inclination angles. The lumbar curvature during straight-leg lifting tasks was then defined as a percentage of this range of possible lumbar curvatures. Subjects were found to remain neutrally oriented during the flexion phase of a lifting task. During the extension phase of the lifting task, however, subjects were found to assume a more kyphotic posture, approaching the edge of the functional range of motion. This was found to be most pronounced for heavy lifting tasks. By allowing the lumbar curvature to go into a highly kyphotic posture, subjects may be taking advantage of stretch-shortening behavior in extensor musculature and associated tendons to reduce the energy required to raise the torso. Such a kyphotic posture during extension, however, may put excessive loading on the elastic structures of the spine and torso musculature increasing the risk of injury.

Effective stiffness of the musculoskeletal system was examined as a function of the characteristics of an external load. Thirteen healthy subjects provided active contraction of the ankle plantarflexion musculature in a neutral ankle posture to support an external load. Musculoskeletal stiffness was computed from kinetic data recorded in response to dorsiflexion/plantarflexion perturbations. Ankle dynamics were recorded while supporting external loads of 19 and 38 kg with and without antagonistic co-contraction. External loads were applied using pure gravitational mass. In separate trials external loads were applied from stretch of steel springs in parallel with the plantarflexion musculature that also provided added parallel stiffness to the system. Adding external stiffness of 4.9 and 8.1 kN/m surprisingly failed to significantly change the stiffness of the ankle-plus-spring system. This suggests contributions from intrinsic muscle stiffness and reflex stiffness declined in response to added external stiffness. This could not be explained by load magnitudes, ankle postures, or co-activation as these were similar between the inertial and elastic loading conditions. However, non-linear parametric analyses suggest mean intrinsic stiffness of 35.5 kN/m and reflex gain of 11.6 kN/m with a constant reflex delay of 70 ms accurately described the empirical results. The phase response between the mechanical dynamics of the musculoskeletal system and delayed neuromotor feedback combine to provide robust control of system behavior.

Changes in electroencephalogram (EEG) were analyzed at different levels of halothane anesthesia. Five experiments were carried out on mongrel dogs. Four channels of EEG data were recorded, at different anesthetic levels. A tenth-order autoregressive (AR) model was used to represent the EEG signal. The AR model parameters were used as input to a three-layer perceptron feedforward neural network, and the network was trained and tested on different sets of data. The network was able to correctly classify the anesthetic levels in 83% of the cases with a testing tolerance of 0.1. The results indicate that the changes in AR model parameters representing the EEG signal can be used for decision-making during administration of general anesthetics. >

Active females demonstrate increased risk for musculoskeletal injuries relative to equivalently-trained males. Although gender differences in factors such as passive laxity, skeletal geometry and kinematics have been examined, the effect of gender on active muscle stiffness has not been reported. Stiffness of the active quadriceps and hamstrings musculature were recorded during isometric knee flexion and extension exertions from twelve male and eleven female subjects. A second-order biomechanical model of joint dynamics was used to quantify stiffness from the transient motion response to an angular perturbation of the lower-leg. Female subjects demonstrated reduced active stiffness relative to male subjects at all torque levels, with levels 56-73% of the males. Effective stiffness increased linearly with the torque load, with stiffness increasing at a rate of 3.3 Nm/rad per unit of knee moment in knee flexion exertions (hamstrings) and 6.6 Nm/rad per unit of knee moment extension exertions (quadriceps). To account for gender differences in applied moment associated with leg mass, regressions analyses were completed that demonstrated a gender difference in the slope of stiffness-versus-knee moment relation. Further research is necessary to identify the cause of the observed biomechanical difference and implications for controlling injury.

Objective. The influence of trunk posture on musculoskeletal stability of the spine was investigated. Design. A biomechanical model was developed to evaluate the influence of posture on spinal stability. Model performance was assessed by comparing predicted muscle recruitment patterns with measured EMG activity from the trunk muscles during static lifting exertions. Method. An inverted double-pendulum model of the spine controlled by 12 muscle equivalents of the trunk was implemented to determine spinal load and stability. Model input included trunk posture and lifted mass, output included muscle recruitment patterns necessary to achieve stability of the spine and spinal load. EMG activity recorded from the trunk muscles of 10 subjects were recorded during static exertions in various trunk flexion and asymmetric postures to compare with model output. Stable spinal load was examined as a function of trunk flexion and asymmetry during the lifting exertions. Results. Antagonsitic co-contraction was necessary to achieve spinal stability, particularly in upright postures. Stable spinal load was increased in asymmetric postures as a result of antagonistic muscle recruitment, suggesting greater neuromuscular control is necessary to maintain stability in asymmetric lifting postures. As trunk flexion angle increased, stability improved but spinal load was greater. Conclusions. Results illustrate that muscle recruitment patterns are more accurately explained by stability than by equilibrium alone. Spinal stability is influenced by posture. Specifically, control of spinal stability is reduced in asymmetric postures associated with low-back disorder risk. Relevance Traditional assessment of low-back disorder risk have focussed on spinal loading. Results illustrate that postural risk factors for low-back pain may be partially attributable to stability considerations.

The ability of the spine to carry load depends on the structural capacity of the vertebrae and on the loading conditions that arise from activities of daily living or trauma. The ratio of the load on the spine to the failure load of the bone is called the factor of risk, a value that indicates whether fracture is likely during a given activity. A high factor of risk can result from weak bone that has a low failure load or from a risk activity that generates a large force. The failure load of the vertebral body depends on the density and architecture of the trabecular bone and on the shape, size, and organization of the vertebral body. Spine bone mineral density determined by dual-energy x-ray absorptiometry correlates strongly with the compressive failure load and therefore should be a convenient and specific indicator of the compressive strength of the vertebrae in vivo. The magnitude of a load applied to the spine depends on the specific activity. Bending and lifting activities generate loads on the spine that exceed the failure load of vertebrae with very low bone mineral density. Biomechanical indications for prevention of age-related fractures point to the need to strengthen bone by maintaining or increasing density and the need to lower the magnitude of forces applied to the spine in the elderly by avoiding such risk activities as lifting.