Erik B Simonsen

• PhD
• University of Copenhagen

Purpose The purpose of the study was to determine which of the ankle, knee or hip joint is the most important contributor to horizontal velocity during maximal sprint running. Furthermore, it was undertaken to quantify the fraction of propulsive power and work produced at each of the three joints. Methods Seven athletes of national class served as...

Running economy (RE) at a given submaximal running velocity is defined as oxygen consumption per minute per kg body mass. We investigated RE in a group of 12 male elite runners of national class. In addition to RE at 14 and 18 km h−1 we measured the maximal oxygen consumption (VO2max) and anthropometric measures including the moment arm of the Achi...

Objective Externally applied abduction and rotational loads are major contributors to the knee joint injury mechanism; yet, how muscles work together to stabilize the knee against these loads remains unclear. Our study sought to evaluate lower limb functional muscle synergies in healthy young adults such that muscle activation can be directly relat...

The gray matter of the spinal cord is the seat of somata of various types of neurons devoted to the sensory and motor activities of the limbs and trunk as well as a part of the autonomic nervous system. The volume of the spinal gray matter is an indicator of the local neuronal processing and this can decrease due to atrophy associated with degenera...

The gray matter of the spinal cord is the seat of somata of various types of neurons devoted to the sensory and motor activities of the limbs and trunk as well as a part of the autonomic nervous system. The volume of the spinal gray matter is an indicator of the local neuronal processing and this can decrease due to atrophy associated with degenera...

The forward lunge (FL) may be a promising movement to assess functional outcome after ACL reconstruction. Thus, we aimed to investigate the FL movement pattern before and after ACL reconstruction with a comparison to healthy controls to determine if differences were present. Twenty-eight ACL injured participants and 28 matched healthy controls were...

Purpose To examine if occupational lifting assessed as cumulative years as a baggage handler is associated with first-time hospital diagnosis or treatment for low back disorders. Methods This study is based on the Copenhagen Airport Cohort consisting of male baggage handlers performing heavy lifting every day and a reference group of unskilled men...

Purpose: This study aimed to quantify the relationship between objective and subjective measures of functional ability and determine if measures in the deficient (ACLd) state were correlated to, and capable of predicting a patient's objective and subjective measures in the reconstructed (ACLr) state. Methods: Twenty ACL injured participants comp...

Background: Knee osteoarthritis is a common and often disabling disorder, which has been related to knee-straining work. However, exposure response relations are uncertain and there are few prospective studies. We studied prospectively if incident knee osteoarthritis is associated with cumulative exposure as an airport baggage handler, lifting on...

Background: There is a lack of objective dynamic knee joint control measures that can be related to the status of the anterior cruciate ligament (ACL). The purpose of this study was to introduce two novel measures and apply a third to determine how dynamic knee joint control changes in relation to ACL status during dynamic movements. Methods: Tw...

Background: Voluntary activation deficit of the quadriceps muscle group is a common symptom in populations with knee joint injury. Musculoskeletal modeling and simulations can improve our understanding of pathological conditions; however, they are mathematically complex which can limit their clinical application. A practical subject-specific model...

Purpose The purpose of this study was to identify high-functioning anterior cruciate ligament-deficient patients and assess the effects of reconstruction on their self-reported functionality, muscle activations and biomechanical properties. Methods Twenty young and active patients participated pre- (11.5 ± 14.3 months post-injury) and again 10.5 ±...

Anterior cruciate ligament injury (ACLi) reduces mechanical knee joint stability. Differences in muscle activation patterns are commonly identified between ACLi individuals and uninjured controls (CON); however, how and which of these differences are adaptions to protect the knee or adversely increase risk of joint instability remain unclear. Since...

Background: Sex-related neuromuscular differences have been linked to greater risk of anterior cruciate ligament injuries in females. Despite this, it remains unclear if sex-related differences are present after injury. This study sought to determine if sex differences are present in the functional roles of knee joint muscles in an anterior cruciat...

Musculoskeletal shoulder load among baggage handlers measured by combining duration and intensity based on biomechanical and epidemiological information may be a stronger predictor of subacromial shoulder disorders than baggage handler seniority. In 2012, a cohort of baggage handlers employed at Copenhagen Airport in 1990–2012, and a cohort of unsk...

Purpose Copenhagen Airport Cohort 1990–2012 presents a unique data source for studies of health effects of occupational exposure to air pollution (ultrafine particles) and manual baggage handling among airport employees. We describe the extent of information in the cohort and in the follow-up based on data linkage to the comprehensive Danish nation...

Introduction: Knee muscles are commonly labelled as flexors or extensors and aptly stabilize the knee against sagittal plane loads. However, how these muscles stabilize the knee against adduction-abduction and rotational loads remains unclear. Our study sought to: (1) classify muscle roles as they relate to joint stability by quantifying the relat...

Introduction Outdoor air pollution is associated with exacerbations of obstructive lung diseases, but the role of air pollution in the incidence of these diseases is unclear. At Copenhagen Airport a high number of particles have been measured especially on the apron at the terminal gates where many persons work with ground handling services. Aims...

Introduction Knee osteoarthrosis is characterised by pain and increasing disability with impact on life quality and ability to work. The work of baggage handlers is characterised by daily heavy lifting in a standing or kneeling/squatting position. Aims To evaluate the impact of employment as baggage handler on the incidence of knee osteoarthrosis....

Purpose: To assess the influence of cumulative employment as baggage handler on the risk of incident subacromial shoulder disorders. Baggage handling is characterized by repetitive work primarily consisting of heavy lifting in awkward positions and time pressure. Methods: This cohort study is based on the Copenhagen Airport Cohort consisting of...

The present study investigated lower limb joint work, lower limb joint energy transport and intra-subject variation of the joint dynamics during countermovement jumps in children and adults. Twelve healthy men and eleven healthy boys performed ten maximal countermovement jumps. Three dimensional kinematics and kinetics were recorded in synchrony. H...

Meniscal lesions are common and may contribute to the development of knee arthrosis. A few case-control and cross-sectional studies have identified knee-straining work as risk factors for meniscal lesions, but exposure-response relations and the role of specific exposures are uncertain, and previous results may be sensitive to reporting and selecti...

Questionnaires. (DOCX)

Photogrammetric measurements of bodily dimensions and analysis of gait patterns in CCTV are important tools in forensic investigations but accurate extraction of the measurements are challenging. This study tested whether manual annotation of the joint centers on 3D reconstructions could provide reliable recognition. Sixteen participants performed...

The purpose of the present study was to investigate the coordination pattern and coordination variability (intra-subject and inter-subject) in children and adults during vertical countermovement jumps. Ten children (mean age: 11.5±1.8years) and ten adults (mean age: 26.1±4.9years) participated in the experiment. Lower body 3D-kinematics and kinetic...

We investigated muscle activity, intra-subject variability in muscle activity and co-contraction during vertical jumps and landings in children and adults. Ten male children and 10 male adults completed 10 countermovement jumps (CMJ), 10 drop jumps (DJ) from 30 cm, 10 low and high landings from 30 and 60 cm for the children and 60 and 90 cm for the...

Biomechanical movement analysis in 3D requires estimation of joint centres in the lower extremities and this estimation is based on extrapolation from markers placed on anatomical landmarks. The purpose of the present study was to quantify the accuracy of three established set of equations and provide new improved equations to predict the joint cen...

The incidence of knee injuries has been recorded to be as high as 4.6 times greater in females than in males [1] and the underlying cause for this disparity is still relatively unknown. Since muscles are the only active contributors to dynamic knee joint stability, it is quite feasible that the observed injury differences could be attributed to var...

Estimating 3D joint rotations in the lower extremities accurately and reliably remains unresolved in markerless motion capture, despite extensive studies in the past decades. The main problems have been ascribed to the limited accuracy of the 3D reconstructions. Accordingly, the purpose of the present study was to develop a new approach based on hi...

Purpose: The present study aimed to estimate possible differences in upper body muscular load between male and female house painters performing identical work tasks. Sex-related differences in muscular load may help explain why women, in general, have more musculoskeletal complaints than men. Methods: In a laboratory setting, 16 male and 16 fema...

Introduction: To assess the effect of aging on stretch reflex modulation during walking, soleus H-reflexes obtained in 15 middle-aged (mean age 56.4±6.9 years) and 15 young (mean age 23.7±3.9 years) subjects were compared. Methods: The H-reflex amplitude, muscle activity (EMG) of the soleus and tibialis anterior muscles, and EMG/H-reflex gain we...

This thesis is based on ten published articles. The experimental work was carried out at the Faculty of Health Sciences, University of Copenhagen. The aim was to investigate and describe a number of basic mechanical and physiological mechanisms behind human walking. The methodologies used were biomechanical movement analysis and electrophysiology....

Closed circuit television (CCTV) footage is often available from crime scenes and may be used to compare perpetrators with suspects. Usually, the footage comprises incomplete gait cycles at different velocities, making gait pattern identification from crimes difficult. This study investigated the concurrence of joint angles throughout a gait cycle...

Closed-circuit television (CCTV) footage is used in criminal investigations to compare perpetrators with suspects. Usually, incomplete gait cycles are collected, making evidential gait analysis challenging. This study aimed to analyze the discriminatory power of joint angles throughout a gait cycle. Six sets from 12 men were collected. For each man...

Anthropometric measurements (e.g. the height to the head, nose tip, eyes or shoulders) of a perpetrator based on video material may be used in criminal cases. However, several height measurements may be difficult to assess as the perpetrators may be disguised by clothes or headwear. The eye height (EH) measurement, on the other hand, is less prone...

To study differences in gait patterns in 10-year-old children with Generalized Joint Hypermobility (GJH) and with no GJH (NGJH). A total of 37 children participated (19 GJH, 18 NGJH, mean age 10.2 (SD 0.5) years). Inclusion criteria for GJH were a Beighton score of >=5, with at least one hypermobile knee joint; for NGJH a Beighton score of <=4, and...

Heavy lifting is associated with musculoskeletal disorders but it is unclear whether it is related to acute reversible effects or to chronic effects from cumulated exposure. The aim of this study was to examine whether musculoskeletal symptoms in Danish airport baggage handlers were associated with their seniority as baggage handler, indicating chr...

Introduction: We investigated muscle activation strategy and performance of knee extensor and flexor muscles in children and adults with generalized joint hypermobility (GJH) and compared them with controls. Methods: Muscle activation, torque steadiness, electromechanical delay, and muscle strength were evaluated in 39 children and 36 adults dur...

Markerless motion capture is a pronounced topic in computer vision. In forensic science, markerless motion capture can be an important tool for identification through gait analysis. Recent studies of gait analysis in forensic science have shown that individuals can be identified when analysing the postures from a sagittal viewpoint. Although integr...

This study examined the effects of 4 weeks of intensive drop jump training in well-trained athletes on jumping performance and underlying changes in biomechanics and neuromuscular adaptations. Nine well-trained athletes at high national competition level within sprinting and jumping disciplines participated in the study. The training was supervised...

Objectives To assess ergonomic exposures in a historical cohort study on musculoskeletal disorders among baggage handlers using production statistics from the airport and the involved handling company. In historical cohort studies information on exposures is typically based on self-reports or assumptions of previous exposures. This may lead to misc...

Objectives To investigate associations between heavy lifting and musculo-skeletal disorders in a group of baggage handlers. It is generally accepted that heavy lifting and lifting in kneeling and stooped positions are risk factors for musculo-skeletal disorders in the shoulders, knees and lower back region. However, the influence of magnitude and t...

Diverging results have been reported regarding the modulation and amplitude of the soleus H-reflex measured during human walking and running. A possible explanation to this could be the use of too high stimulus strength in some studies while not in others. During activities like walking and running it is necessary to use a small M-wave to control t...

This study investigated the function of the cruciate ligaments during a forward lunge movement. The mechanical roles of the anterior and posterior cruciate ligament (ACL, PCL) during sagittal plane movements, such as forward lunging, are unclear. A forward lunge movement contains a knee joint flexion and extension that is controlled by the quadrice...

It is unclear how rotations of the lower limb affect the knee joint compression forces during walking. Increases in the frontal plane knee moment have been reported when walking with internally rotated feet and a decrease when walking with externally rotated feet. The aim of this study was to investigate the knee joint compressive forces during wal...

The human locomotor system is flexible and enables humans to move without falling even under less than optimal conditions. Walking with high-heeled shoes constitutes an unstable condition and here we ask how the nervous system controls the ankle joint in this situation? We investigated the movement behavior of high-heeled and barefooted walking in...

A hip joint flexor moment in the last half of the stance phase during walking has repeatedly been reported. However, the purpose of this moment remains uncertain and it is unknown how it is generated. Nine male subjects were instructed to walk at 4.5 km/h with their upper body in three different positions: normal, inclined and reclined. Net joint m...

We measured the soleus and the gastrocnemius H-reflex modulation in seven subjects during walking at 4.5 km/h and during running at 8, 12 and 15 km/h. The recordings in the medial gastrocnemius were corrected for cross-talk from the soleus muscle. The gastrocnemius H-reflex was in general lower than the soleus H-reflex. In both muscles the H-reflex...

Purpose: Knee function is reduced in patients with Benign Joint Hypermobility Syndrome. The aim was to study knee function in children and adults with Generalised Joint Hypermobility (GJH) and Non-GJH (NGJH)). Materials and methods: In a matched comparative study, 39 children and 36 adults (mean age children 10.2 years; adults 40.3 years) were i...

The majority of adults with Generalised Joint Hypermobility experience symptoms such as pain and joint instability, which is likely to influence their gait pattern. Accordingly, the purpose of the present project was to perform a biomechanical gait analysis on a group of patients with Generalised Joint Hypermobility and compare them to a group of h...

The aim of the study was to investigate the distribution of net joint moments in the lower extremities during walking on high-heeled shoes compared with barefooted walking at identical speed. Fourteen female subjects walked at 4 km/h across three force platforms while they were filmed by five digital video cameras operating at 50 frames/second. Bot...

Coactivation of the hamstring muscles during dynamic knee extension may compensate for increased knee joint laxity in anterior cruciate ligament (ACL) deficient subjects. This study examined if antagonist muscle coactivation during maximal dynamic knee extension was elevated in subjects with anterior cruciate ligament (ACL) deficiency compared to a...

Introduction: Previous studies of bone stresses in the human lumbar spine have relied on simplified models when modeling the spinal musculature, even though muscle forces are likely major contributors to the stresses in the vertebral bones. Detailed musculoskeletal spine models have recently become available and show good correlation with experimen...

Previous investigations have suggested considerable inter-individual variability in the time course pattern of net joint moments during normal human walking, although the limited sample sizes precluded statistical analyses. The purpose of the present study was to obtain joint moment patterns from a group of normal subjects and to test whether or no...

The purpose of the study was to investigate with what accuracy the soleus H-reflex modulation and excitability could be measured during human walking on two occasions separated by days. The maximal M-wave (Mmax) was measured at rest in the standing position. During treadmill walking every stimulus elicited an M-wave of 25 ± 10% of Mmax in the soleu...

The purpose of the study was to analyze the distribution of net joint moments in the lower extremities in patients walking with a drop-foot compared to a group of healthy subjects. A drop-foot causes the patient to walk with a characteristic limp and it was hypothesized that the drop-foot could lead to increased loadings of one or more joints. Six...

Rupture of the anterior cruciate ligament (ACL) causes changes in the walking pattern. ACL deficient subjects classified as copers and non-copers have been observed to adopt different post-injury walking patterns. How these different patterns affect the knee compression and shear forces is unresolved. Thus, the aim of the present study was to inves...

Walking with hiking poles has become a popular way of exercising. Walking with poles is advocated as a physical activity that significantly reduces the loading of the hip, knee and ankle joints. We have previously observed that pole walking does not lead to a reduction of the load on the knee joint. However, it is unclear whether an increased force...

Photogrammetry and recognition of gait patterns are valu-able tools to help identify perpetrators based on surveillance recordings. We have found that stature but only few other measures have a satisfying reproducibility for use in forensics. Several gait variables with high recognition rates were found. Especially the variables located in the fron...

Recognition of gait patterns has been studied only moderately during the last decades. Different gait strategies have been described by applying different waveform anal-ysis techniques to biomechanical gait data and it has been shown that individuals can be identified using joint angles in the sagittal plane. However, little is known about addi-tio...

The forward lunge movement may be used as a functional performance test of anterior cruciate ligament (ACL) deficient and reconstructed subjects. The purposes were 1) to determine the test-retest reliability of a forward lunge in healthy subjects and 2) to determine the required numbers of repetitions necessary to yield satisfactory reliability. Ni...

Hip and knee functions are intimately connected and reduced hip abductor function might play a role in development of knee osteoarthritis (OA) by increasing the external knee adduction moment during walking. The purpose of this study was to test the hypothesis that reduced function of the gluteus medius (GM) muscle would lead to increased external...

Photogrammetry is used in forensic science to help identify perpetrators from crime scenes by way of surveillance video, but the reproducibility of manually locating hidden body-points such as the joints remains to be established. In this study, we quantified the inter- and intra-observer variability of bodily measures of clothed individuals in two...

The purpose of this study was to investigate whether the knee joint dynamics during a forward lunge could be modulated by experimentally induced vastus medialis pain in healthy subjects. Randomised cross-over study. Biomechanical movement laboratory. 20 healthy subjects were included. One subject was excluded during data collection. The subjects pe...

Recordings from video surveillance systems are used as evidence from crime scenes. It would be useful to perform comparisons between disguised perpetrators and suspects based on their gait. We applied functional anatomical and biomechanical knowledge to analyze the gait of perpetrators, as recorded on surveillance video. Using a structured checklis...

Background: Knee joint osteoarthritis is painful and with an overweight of female incidence. The cardinal symptom is pain, which causes compensatory gait changes, and gender differences in pain sensitivity exist. Impact loadings at heel strike during walking are suspected as a co-factor in development of knee osteoarthritis. Thus the purpose of th...

IntroductionBiomechanical equipmentBiomechanical analysisExamples of biomechanical investigationsSummaryMultiple choice questions

We propose a model, based on functional principal component analysis (FPCA) using a truncated Fourier basis, which can be applied to angular rotation data. Further the possibilities and limitations of FPCA are discussed. As an example the gender effect on flexion/extension of the knee is examined using the model.

Pain is a cardinal symptom in musculoskeletal diseases involving the knee joint, and aberrant movement patterns and motor control strategies are often present in these patients. However, the underlying neuromuscular mechanisms linking pain to movement and motor control are unclear. To investigate the functional significance of muscle pain on knee j...

The objective of this work is to present a musculo-skeletal model of the lumbar spine, which can be shared and lends itself to investigation in many locations by different researchers. This has the potential for greater reproducibility and subsequent improvement of its quality from the combined effort of different research groups. The model is defi...

Since the 1990s photogrammetry has been used in forensic medicine to help identifying perpetrators from crime scenes covered with surveillance video. Some case studies [1,2] have shown promising results measuring both heights and segment lengths. Photogrammetry is used with high precision when measuring clearly defined points but less is known abou...

We have combined the basic human ability to recognize other individuals with functional anatomical and biomechanical knowledge, in order to analyze the gait of perpetrators as recorded on surveillance video. The perpetrators are then compared with similar analyses of suspects. At present we give a statement to the police as to whether the perpetrat...

Joint pain is a primary symptom in knee osteoarthritis (OA), but the effect of pain and pain relief on the knee joint mechanics of walking is not clear. In this study, the effects of local knee joint analgesia on knee joint loads during walking were studied in a group of knee osteoarthritis patients. A group of healthy subjects was included as a re...

Impulsive forces in the knee joint have been suspected to be a co-factor in the development and progression of knee osteoarthritis. We thus evaluated the impulsive sagittal ground reaction forces (iGRF), shock waves and lower extremity joint kinematics at heel strike during walking in knee osteoarthritis (OA) patients and compared them to those in...

This article describes the development of a musculoskeletal model of the human lumbar spine with focus on back muscles. It includes data from literature in a structured form. To review the anatomy and biomechanics of the back muscles related to the lumbar spine with relevance for biomechanical modeling. To reduce complexity, muscle units have been...

Periacetabular osteotomy improves radiographic predictors of osteoarthrosis and diminishes pain and functional impairment. No changes in function quantified by gait analysis have yet been documented. We evaluated the functional outcome of periacetabular osteotomy in relation to gait. The gait pattern of 9 women (median age 39 years) with hip dyspla...

The rollator is a very popular walking aid. However, knowledge about how a rollator affects the walking patterns is limited. Thus, the purpose of the study was to investigate the biomechanical effects of walking with and without a rollator on the walking pattern in healthy subjects. The walking pattern during walking with and without rollator was a...

It is believed that nurses risk the development of back pain as a consequence of sudden loadings during tasks in which they are handling patients. Forward dynamics simulations of sudden loads (applied to the arms) during dynamic lifting tasks were performed on a two-dimensional whole-body model. Loads were in the range of -80 kg to 80 kg, with the...

Knowledge of the gait dynamics in patients with hip dysplasia may help to understand the consequences of the mechanical changes in the hip. We evaluated the walking pattern of 14 women with hip dysplasia (median age 39 (24-50) years) before periacetabular osteotomy and compared it with a control group of 12 healthy women (median age 35 (24-56) year...

The purpose of the present study was to investigate whether different walking patterns in healthy subjects and in coper and non-coper subjects with deficient anterior cruciate ligaments could be quantified. An inverse dynamics approach was used to calculate joint kinematics and kinetics for flexion and extension. EMG signals of the hamstrings and q...

To determine whether differences in the knee joint movement pattern of a forward lunge could be quantified in healthy subjects and in anterior cruciate ligament deficient subjects who were able to return to the same activity level as before their injury (copers) and in those who were not (non-copers). The movement patterns of the injured leg of the...