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Skin marker-based versus bone morphology-based coordinate systems of the hindfoot and forefoot

Hulshof, Chantal M. (author), Schallig, Wouter (author), van den Noort, Josien C. (author), Streekstra, Geert J. (author), Kleipool, Roeland P. (author), GG Dobbe, Johannes (author), Maas, Mario (author), Harlaar, J. (author), van der Krogt, Marjolein M. (author)

Segment coordinate systems (CSs) of marker-based multi-segment foot models are used to measure foot kinematics, however their relationship to the underlying bony anatomy is barely studied. The aim of this study was to compare marker-based CSs (MCSs) with bone morphology-based CSs (BCSs) for the hindfoot and forefoot. Markers were placed on...

journal article 2024

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Interacting effects of AFO stiffness, neutral angle and footplate stiffness on gait in case of plantarflexor weakness: A predictive simulation study

Waterval, N. F.J. (author), Brehm, M. A. (author), Veerkamp, K. (author), Geijtenbeek, T. (author), Harlaar, J. (author), Nollet, F. (author), van der Krogt, M. M. (author)

To maximize effects of dorsal leaf ankle foot orthoses (AFOs) on gait in people with bilateral plantarflexor weakness, the AFO properties should be matched to the individual. However, how AFO properties interact regarding their effect on gait function is unknown. We studied the interaction of AFO bending stiffness with neutral angle and...

journal article 2023

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Energy cost optimized dorsal leaf ankle-foot-orthoses reduce impact forces on the contralateral leg in people with unilateral plantar flexor weakness

Waterval, N.F.J. (author), Brehm, M. A. (author), Harlaar, J. (author), Nollet, F. (author)

Background: In individuals with unilateral plantar flexor weakness, the second peak of the vertical ground reaction force (GRF) is decreased. This leads to a higher ground reaction force, e.g. impact, of the contralateral leg, potentially explaining quadriceps muscle and/or knee joint pain. Energy cost optimized dorsal leaf ankle-foot...

journal article 2022

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The Amsterdam Foot Model: a clinically informed multi-segment foot model developed to minimize measurement errors in foot kinematics

Schallig, Wouter (author), van den Noort, Josien C. (author), Piening, Marjolein (author), Streekstra, Geert J. (author), Maas, Mario (author), van der Krogt, Marjolein M. (author), Harlaar, J. (author)

Background: Foot and ankle joint kinematics are measured during clinical gait analyses with marker-based multi-segment foot models. To improve on existing models, measurement errors due to soft tissue artifacts (STAs) and marker misplacements should be reduced. Therefore, the aim of this study is to define a clinically informed, universally...

journal article 2022

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Reliability and Validity of IMU-Based Foot Progression Angle Measurement under Different Gait Retraining Strategies

Urbanus, Francine C.A. (author), Grayson, Jane (author), Harlaar, J. (author), Simic, Milena (author)

Load modifying gait retraining strategies, such as changing the foot progression angle (FPA) to toe-in and toe-out gait, are used for people with medial knee osteoarthritis. The FPA can be measured using a pressure sensitive walkway (PSW), but inertial measurement units (IMUs) are considered more suitable for clinical use. This study...

journal article 2022

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Responsiveness of the Foot Profile Score in children with hemiplegia

McCahill, Jennifer (author), Stebbins, Julie (author), Prescott, Robin J. (author), Harlaar, J. (author), Theologis, Tim (author)

Background: The Foot Profile Score (FPS) is a single score that summarises foot posture and dynamic foot motion during the gait cycle based on the kinematic data of the Oxford Foot Model. The FPS enables clinicians and researchers to quantify foot abnormalities during gait, to monitor change in foot/ankle motion over time, and to measure the...

journal article 2022

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The influence of soft tissue artifacts on multi-segment foot kinematics

Schallig, Wouter (author), Streekstra, Geert J. (author), Hulshof, Chantal M. (author), Kleipool, Roeland P. (author), Dobbe, Johannes G.G. (author), Maas, Mario (author), Harlaar, J. (author), van der Krogt, Marjolein M. (author), van den Noort, Josien C. (author)

Movement of skin markers with respect to their underlying bone (i.e. soft tissue artifacts (STAs)) might corrupt the accuracy of marker-based movement analyses. This study aims to quantify STAs in 3D for foot markers and their effect on multi-segment foot kinematics as calculated by the Oxford and Rizzoli Foot Models (OFM, RFM). Fifteen...

journal article 2021

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Reliability testing of the heel marker in three-dimensional gait analysis

McCahill, Jennifer (author), Schallig, Wouter (author), Stebbins, Julie (author), Prescott, Robin (author), Theologis, Tim (author), Harlaar, J. (author)

Introduction: In three-dimensional gait analysis, anatomical axes are defined by and therefore sensitive to marker placement. Previous analysis of the Oxford Foot Model (OFM) has suggested that the axes of the hindfoot are most sensitive to marker placement on the posterior aspect of the heel. Since other multi-segment foot models also use a...

journal article 2021

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Foot progression angle estimation using a single foot-worn inertial sensor

Wouda, Frank J. (author), Jaspar, Stephan L.J.O. (author), Harlaar, J. (author), van Beijnum, Bert Jan F. (author), Veltink, Peter H. (author)

Background: The foot progression angle is an important measure used to help patients reduce their knee adduction moment. Current measurement systems are either lab-bounded or do not function in all environments (e.g., magnetically distorted). This work proposes a novel approach to estimate foot progression angle using a single foot-worn...

journal article 2021

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Marker placement sensitivity of the Oxford and Rizzoli foot models in adults and children

Schallig, Wouter (author), van den Noort, Josien C. (author), Maas, Mario (author), Harlaar, J. (author), van der Krogt, Marjolein M. (author)

Understanding the effect of individual marker misplacements is important to improve the repeatability and aid to the interpretation of multi-segment foot models like the Oxford and Rizzoli Foot Models (OFM, RFM). Therefore, this study aimed to quantify the effect of controlled anatomical marker misplacement on multi-segment foot kinematics (i...

journal article 2021

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Description of orthotic properties and effect evaluation of ankle-foot orthoses in non-spastic calf muscle weakness

Waterval, Niels F.J. (author), Brehm, Merel Anne (author), Harlaar, J. (author), Nollet, Frans (author)

Objective: To describe the orthotic properties and evaluate the effects of ankle-foot orthoses for calf muscle weakness in persons with non-spastic neuromuscular disorders compared with shoes-only. Design: Cross-sectional study. Subjects: Thirty-four persons who used ankle-foot orthoses for non-spastic calf muscle weakness. Methods: The...

journal article 2020

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Ankle foot orthoses in cerebral palsy: Effects of ankle stiffness on trunk kinematics, gait stability and energy cost of walking

Meyns, P. (author), Kerkum, Y. L. (author), Brehm, M. A. (author), Becher, J. G. (author), Buizer, A. I. (author), Harlaar, J. (author)

In children with cerebral palsy (CP), rigid ventral shell ankle-foot orthoses (vAFOs) are often prescribed to reduce excessive knee flexion in stance and lower the energy cost of walking (ECW). However, how vAFOs affect ECW is a complex issue, as vAFOs may have an impact on lower limb biomechanics, upper body movements, and balance. Besides,...

journal article 2020

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Effect of walking with a modified gait on activation patterns of the knee spanning muscles in people with medial knee osteoarthritis

Booij, M. J. (author), Richards, R. (author), Harlaar, J. (author), van den Noort, J. C. (author)

Objective: To evaluate muscle activation patterns and co-contraction around the knee in response to walking with modified gait patterns in patients with medial compartment knee-osteoarthritis (KOA). Design: 40 medial KOA patients walked on an instrumented treadmill. Surface EMG activity from seven knee-spanning muscles (gastrocnemius,...

journal article 2020

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Foot flexibility confounds the assessment of triceps surae extensibility in children with spastic paresis during typical physical examinations

Weide, Guido (author), Huijing, Peter A. (author), Becher, Jules G. (author), Jaspers, Richard T. (author), Harlaar, J. (author)

Accurate assessment of the talo-crural (ankle) joint angle at physical examination is important for assessing extensibility of m. triceps surae (TS) in children with spastic cerebral paresis (SCP). The main aim of this study was to quantify foot flexibility during standardized measurements of TS muscle-tendon complex extensibility (i.e. based...

journal article 2020

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The effect of mono- versus multi-segment musculoskeletal models of the foot on simulated triceps surae lengths in pathological and healthy gait

Zandbergen, Marit A. (author), Schallig, Wouter (author), Stebbins, Julie A. (author), Harlaar, J. (author), van der Krogt, Marjolein M. (author)

Background: Estimating muscle-tendon complex (MTC) lengths is important for planning of soft tissue surgery and evaluating outcomes, e.g. in children with cerebral palsy (CP). Conventional musculoskeletal models often represent the foot as one rigid segment, called a mono-segment foot model (mono-SFM). However, a multi-segment foot model ...

journal article 2020

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Comparing the kinematic output of the Oxford and Rizzoli Foot Models during normal gait and voluntary pathological gait in healthy adults

Schallig, Wouter (author), van den Noort, Josien C. (author), McCahill, Jennifer (author), Stebbins, Julie (author), Leardini, Alberto (author), Maas, Mario (author), Harlaar, J. (author), van der Krogt, Marjolein M. (author)

Background: The Oxford Foot Model (OFM) and Rizzoli Foot Model (RFM) are the two most frequently used multi-segment models to measure foot kinematics. However, a comprehensive comparison of the kinematic output of these models is lacking. Research question: What are the differences in kinematic output between OFM and RFM during normal gait...

journal article 2020

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Stiffness-Optimized Ankle-Foot Orthoses Improve Walking Energy Cost Compared to Conventional Orthoses in Neuromuscular Disorders: A Prospective Uncontrolled Intervention Study

Waterval, Niels F.J. (author), Brehm, Merel Anne (author), Altmann, Viola C. (author), Koopman, Fieke S. (author), Den Boer, Jasper J. (author), Harlaar, J. (author), Nollet, Frans (author)

In persons with calf muscle weakness, walking energy cost is commonly increased due to persistent knee flexion and a diminished push-off. Provided ankle-foot orthoses (AFOs) usually lower walking energy cost. To maximize the reduction in energy cost, AFO bending stiffness should be individually optimized, but this is not common practice....

journal article 2020

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Comprehensive evaluation of gait, spasticity, and muscle morphology: A case report of a child with spastic paresis treated with Botulinum NeuroToxin-A, serial casting, and physiotherapy

Weide, Guido (author), Sloot, Lizeth (author), Oudenhoven, Laura (author), Jaspers, Richard T. (author), Harlaar, J. (author), Buizer, Annemieke (author), Bar-On, Lynn (author)

Comprehensive instrumented muscle and joint assessments should be considered when prescribing Botulinum NeuroToxin-A (BoNT-A) treatment in spastic paresis. In a child with spastic paresis, comprehensive evaluation following treatment with BoNT-A, serial casting, and physiotherapy showed that short-term improvements in gait occurred without...

journal article 2019

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Modifying ankle foot orthosis stiffness in patients with calf muscle weakness: gait responses on group and individual level

Waterval, Niels F.J. (author), Nollet, Frans (author), Harlaar, J. (author), Brehm, Merel Anne (author)

BACKGROUND: To improve gait, persons with calf muscle weakness can be provided with a dorsal leaf spring ankle foot orthosis (DLS-AFO). These AFOs can store energy during stance and return this energy during push-off, which, in turn, reduces walking energy cost. Simulations indicate that the effect of the DLS-AFO on walking energy cost and...

journal article 2019

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Validation of the foot profile score

McCahill, Jennifer (author), Stebbins, Julie (author), Lewis, Andrew (author), Prescott, Robin (author), Harlaar, J. (author), Theologis, Tim (author)

Background: There are numerous static measures of foot posture but there is no published score of dynamic foot motion. Three-dimensional gait analysis can include a multi-segment foot model like the Oxford Foot Model (OFM) to comprehensively quantify foot kinematic deviations across the gait cycle but it lacks an overall score, like the Gait...

journal article 2019