Martin Schepers

Xsens · Research

Knee osteoarthritis is a major cause of pain and disability in the elderly population with many daily living activities being difficult to perform as a result of this disease. The present study aimed to estimate the knee adduction moment and tibiofemoral joint contact force during daily living activities using a musculoskeletal model with inertial...

Inverse dynamic analysis using musculoskeletal modeling is a powerful tool, which is utilized in a range of applications to estimate forces in ligaments, muscles, and joints, non-invasively. To date, the conventional input used in this analysis is derived from optical motion capture (OMC) and force plate (FP) systems, which restrict the application...

Background: Gait retraining interventions using real-time biofeedback have been proposed to alter the loading across the knee joint in patients with knee osteoarthritis. Despite the demonstrated benefits of these conservative treatments, their clinical adoption is currently obstructed by the high complexity, spatial demands, and cost of optical mo...

The MTw Awinda is the second generation wireless inertial-magnetic motion tracker by Xsens. The MTw enables real-time 3D kinematic applications with multiple motion track-ers by providing highly accurate orientation through an unobtrusive setup. This whitepaper presents the basic working principles and architecture of the Xsens MTw Awinda system. F...

Xsens MVN is an easy to use, cost efficient system that captures full-body human motion in any environment. It is based on small, unobtrusive inertial and magnetic sensors combined with advanced algorithms and biomechanical models. The newly released motion capture engine is immune to magnetic distortions and is available either as MVN Animate for...

Inverse dynamic analysis using musculoskeletal modeling is a powerful tool, which is utilized in a range of applications to estimate forces in ligaments, muscles, and joints, non-invasively. To date, the conventional input used in this analysis is derived from optical motion capture (OMC) and force plate (FP) systems, which restrict the application...

Ground reaction forces and moments (GRF&M) are important measures used as input in biomechanical analysis to estimate joint kinetics, which often are used to infer information for many musculoskeletal diseases. Their assessment is conventionally achieved using laboratory-based equipment that cannot be applied in daily life monitoring. In this study...

Emerging microelectromechanical system (MEMS)-based sensors become much more applicable for on-body measurement purposes lately. Especially, the development of a finger tip-sized tri-axial force sensor gives the opportunity to measure interaction forces between the human hand and environmental objects. We have developed a new prototype device that...

Background An important objective of rehabilitation care is to regain adequate balance function to safely ambulate in community. However, in rehabilitation practice, it remains unclear if a stroke survivor functionally recovers by restitution or by learning to compensate for the lack of restoration of body function. Aim of this study is to propose...

Processed data files. A compressed folder containing three files. First file is a text file containing additional information on opening the data file. Second file is a MATLAB® data file which contains all study data: kinematic and kinetic reconstructions, and participant information. All data is within one structure, including data for all partici...

Distribution of asymmetry in lateral margin of stability. Distribution of asymmetry in lateral margin of stability of all participants during periods of straight line walking (filled bullets) and during periods of turning (open bullets) of both TUG tests. A = affected side, NA = non-affected side. Black vertical lines indicate Asymmetry MoSml range...

Medial-lateral margin of stability MoSml. Medial-lateral margin of stability MoSml. MoSml distribution for all participants while standing on their affected side (green) and non-affected side (red) leg, during the whole periods of straight line walking (upper graph) or the whole periods of turning (lower graph) of both TUG tests. Black vertical lin...

Gait laboratories impose important restrictions in the biomechanical analysis procedure, such as limited marker tracking volume, limited force plate area, and requirement of a laboratory environment. Recent improvements in biomechanics techniques allowed the estimation of GRF&M from kinematics. However, the necessity of a laboratory still remains a...

A novel instrumentation is proposed to estimate hand and finger movements. Current dataglove systems often measure a reduced set of joint angles and lack a position and orientation measure of the hand with respect to the trunk. Our proposed system, based on inertial and magnetic sensing, is fully ambulatory, light weighted, has a low energy consump...

Tracking human body motions using inertial sensors has become a well-accepted method in ambulatory applications since the subject is not confined to a lab-bounded volume. However, a major drawback is the inability to estimate relative body positions over time because inertial sensor information only allows position tracking through strapdown integr...

High knee joint-loading increases the risk and progression of knee osteoarthritis (OA). Mechanical loading on the knee is reflected in the external knee adduction moment (KAdM) that can be measured during gait with laboratory-based measurement systems. However, clinical application of these systems is limited. Ambulatory movement analysis systems,...

For the assessment of body balance, foot placement (i.e. relative foot position), is a crucial variable. In this study, the relative foot positions estimated using Xsens MVN Biomech were compared with position measurements of the optical reference system, Vicon. The results show a good correspondence of the relative foot positions during the double...

Current methods for center-of-mass (CoM) estimation are restricted to gait laboratories. The aim of this study was to estimate CoM displacement under ambulatory conditions with inertial sensors. A sacral inertial sensor (SIS method) was used to estimate the CoM displacement by double integration of the acceleration. Overestimation of the displaceme...

Dynamic interaction between the human body and the environment can be assessed by measuring force and estimating velocity at their interface. A sensorized glove with movement and force sensing is developed in which this principles is applied

Inertial and magnetic sensors, attached to various segments of the human hand, can be used to measure movements of the hand. This paper proposes a new method to assess hand kinematics by applying an Extended Kalman Filter in which prior information of the hand is fused with actual measurements obtained from various sensors.

The external knee adduction moment (KAdM) during gait is an important parameter in patients with knee osteoarthritis (OA). KAdM measurement is currently restricted to instruments only available in gait laboratories. However, ambulatory movement analysis technology, including instrumented force shoes (IFS) and inertial and magnetic measurement syste...

Osteoarthritis (OA) of the knee is associated with alterations in gait. As an alternative to force plates, instrumented force shoes (IFSs) can be used to measure ground reaction forces. This study evaluated the influence of IFS on gait pattern in patients with knee OA. Twenty patients with knee OA walked in a gait laboratory on IFS and control shoe...

This study proposes a method to assess foot placement during walking using an ambulatory measurement system consisting of orthopaedic sandals equipped with force/moment sensors and inertial sensors (accelerometers and gyroscopes). Two parameters, lateral foot placement (LFP) and stride length (SL), were estimated for each foot separately during wal...

Ground reaction forces (GRFs) are often used in inverse dynamics analyses to determine joint loading. These GRFs are usually measured using force plates (FPs). As an alternative, instrumented force shoes (FSs) can be used, which have the advantage over FPs that they do not constrain foot placement. This study tested the FS system in one normal weig...

This study presents a stochastic magnetic measurement model that can be used to estimate relative position and orientation. The model predicts the magnetic field generated by a single source coil at the location of the sensor. The model was used in a fusion filter that predicts the change of position and orientation by integration of acceleration a...

This paper presents a method to estimate power transfer between the human body and the environment during short interactions and relatively arbitrary movements with net displacement and varying loads (mass and spring), and appeared to be accurate within 4%.

Over the last years, inertial sensing has proven to be a suitable ambulatory alternative to traditional human motion tracking based on optical position measurement systems, which are generally restricted to a laboratory environment. Besides many advantages, a major drawback is the inherent drift caused by integration of acceleration and angular vel...

The power transferred between the human body and the environment at any time and the work performed are important quantities to be estimated when evaluating and optimizing the physical interaction between the human body and the environment in sports, physical labor, and rehabilitation. It is the objective of the current paper to present a concept f...

Traditional human movement analysis systems consist of an optical position measurement system with one or more 6D force plates mounted in a laboratory. Although clinically accepted as `the golden standard' for the assessment of human movement, the restriction to a laboratory environment with its limited measurement volume prevents these systems to...

Gait analysis is commonly done in gait laboratories, where several gait variables are estimated using measurement systems installed in the laboratory. Two important variables to characterize human gait are the Center of Mass (CoM) and the Center of Pressure (CoP). The major drawback of existing measurement systems is their restriction to the labora...

During an asymmetric lifting task, forceplate and instrumented shoe measurements were compared with respect to the determination of ground reaction forces, center of pressure and the resulting 3D L5-S1 moments. Good correspondence was found between the forceplate and instrumented shoe measurements. 1. INTRODUCTION Low back pain is a major economic...

Traditionally, human body movement analysis is done in socalled ‘gait laboratories’, equipped with several measurement systems such as optical position measurement systems, EMG or force plates. The measured signals are used to estimate important gait variables. An important variable is the center of mass, an imaginary point at which the total body...

Gait analysis is commonly done in gait laboratories, where several gait variables are estimated using measurement systems installed in the laboratory. The major drawback of these measurement systems is their restriction to the laboratory. This study shows the possibilities of an ambulatory measurement system: the forceshoe. The forceshoe consists o...

INTRODUCTION Traditionally, human body movement analysis is done in so-called 'gait laboratories'. In these laboratories, body movement is measured by a camera system using optical markers, the ground reaction force by a force plate fixed in the floor, and the muscle activity by EMG. From the body movements and ground reaction forces, joint moments...

Estimation of knee adduction moment (AdM) during gait is important in osteoarthritis patients. The accuracy of an ambulatory system to measure the AdM, referenced to a laboratory based system, ranges between 2 and 18%. The sensitivity analysis of the model showed that a change in medio-lateral joint position of one cm causes a RMS difference in AdM...

During an asymmetric lifting task, forceplate and instrumented shoe measurements were compared with respect to the determination of ground reaction forces, center of pressure and the resulting 3D L5-S1 moments. Good correspondence was found between the forceplate and instrumented shoe measurements. 1. INTRODUCTION Low back pain is a major economic...

Ground reaction force (GRF) measurement is important in the analysis of human body movements. The main drawback of the existing measurement systems is the restriction to a laboratory environment. This paper proposes an ambulatory system for assessing the dynamics of ankle and foot, which integrates the measurement of the GRF with the measurement of...

Study of the dynamic interaction with the environment and loading of the human body is important in ergonomics, sports and rehabilititation. This paper presents a method to estimate power transfer between the human body and the environment during short interactions and relatively arbitrary movements using a combination of inertial and force sensing...

Analysis of foot dynamics is important, especially for patients with foot impairments. However, this analysis is difficult with commonly used systems. This study presents an ambulatory system for the estimation of ankle and foot power using an instrumented shoe equipped with six degrees-of-freedom force/moment sensors and miniature intertial sensor...

Human body movement analysis is commonly done in so-called 'gait laboratories’. In these laboratories, body movement is masured using optically based systems like Vicon, Optrotrak. The major drawback of these systems is the restriction to a laboratory environment. Therefore research is required to find ways for performing these measurements outside...

Human body movement analysis is done in so-called 'gait-laboratories' where several gait variables are estimated by measurement systems such as optical position measurement systems, EMG or force plates. The accuracy of the ambulatory system is verified by comparing it to an optical reference system based on the semental kinematics method.

Ground reaction force measurement is important in the analysis of human body movements. A major drawback of the existing measurement systems is the restriction to a laboratory environment. This paper proposes an ambulatory system for the measurement of the complete ground reaction force and the center of pressure. In addition, the moment around the...