Biomechanical Gait Analysis Research Articles

A Data-Driven Approach to Running Gait Assessment Using Inertial Measurement Units

Background: Running is an extremely common exercise, both recreationally and competitively. Combined with clinical assessment, technology-driven biomechanical gait analysis can be used to examine markers of performance and injury risk in runners. Indications: The indication is to provide clinicians and sports science researchers a framework for using inertial measurement units (IMU) for data-driven, quantitative gait assessments. Technique Description: This video details practical application of IMU use in biomechanical gait assessments. Details on participant and equipment setup, in-session protocols, and selection of gait variables are included. Results: Following collection of demographic and anthropometric outcomes, IMUs should be placed on rigid segments of the lower extremity, sacrum, and trunk. In our model, we place IMUs on the foot, shank, thigh, sacrum, and lower thoracic spine. Following static anatomical calibration, running gait biomechanics are evaluated at multiple speeds using IMUs, 2-dimensional high-speed video cameras, and an instrumented treadmill. The high-speed video and IMU data are analyzed together at various parts of the gait cycle, including foot strike, mid-stance, toe-off, and flight. Many kinematic and kinetic variables (ie, unilateral discrete joint angles, joint excursions, joint moments, spatiotemporal outcomes, etc) can be selected for analysis, ideally via a collaboration between the sports science, athletic, and sports medicine teams. A collaborative approach should also be used to determine how this information will be used to alter training programs or influence injury risk in the running athlete. Discussion/Conclusion: This report details how to use a data-driven approach to evaluate running gait biomechanics using IMU technology. This framework for gait analysis is most applicable, and effective, when the team of researchers works in conjunction with coaches, sport scientists, and athletes. Utilizing this framework, training can be adapted based on the objective and clinical assessment to reduce injury risk and improve performance in the gait assessment.

Development of a Protocol for Biomechanical Gait Analysis in Asian Elephants Using the Triaxial Inertial Measurement Unit (IMU).

Simple SummaryIn general practice, the veterinarian and caregiver usually detect lameness in elephants from observation of any discomforting characteristics when walking. Currently, motion analysis can offer an objective method to evaluate normal and abnormal gait accurately, thus identifying changes in some characteristics when walking. This report aimed to introduce a recent technology utilizing wireless sensors for quantitative analysis of joint angles during the gait cycle in Asian elephants. To enable three-dimensional limb segment motion, a triaxial inertial measurement unit (IMU) is equipped with three sensor types: an accelerometer, a gyroscope, and a magnetometer. Therefore, we hope that this portable sensor-based system can help clinicians in diagnosis, especially in the early stages of lameness. Moreover, with wireless signal transmission, the system is clinically applicable for use in all areas where electricity is available.Gait analysis is a method of gathering quantitative information to assist in determining the cause of abnormal gait for the purpose of making treatment decisions in veterinary medicine. Recent technology has offered the wearable wireless sensor of an inertial measurement unit (IMU) for determining gait parameters. This study proposed the use of a triaxial IMU, comprising an accelerometer, a gyroscope, and a magnetometer, for detecting three-dimensional limb segment motion (XYZ axis) during the gait cycle in Asian elephants. A new algorithm was developed to estimate the kinematic parameter that represents each limb segment of the forelimbs and hindlimbs while walking at a comfortable speed. For future use, this study aimed to create a new prototype of the IMU with a configuration that is tailored to the elephant and apply machine learning in an effort to achieve greater precision.

Comparison of Biomechanical Gait Parameters and Patient-Reported Outcome in Patients After Total Knee Arthroplasty With the Use of Fixed-Bearing Medial Pivot and Multi-radius Design Implants-Retrospective Matched-Cohort Study.

BackgroundTotal knee arthroplasty (TKA) is considered to be highly successful in treatment of end-stage osteoarthritis. There are multiple implant designs available on the market, and it is difficult to point which one is the best. The aim of this study was to compare the clinical and functional outcomes and gait pattern after TKA with the use of fixed-bearing medial pivot (K-Mod) vs multi-radius design (NexGen) implants and to compare them to norms for healthy patients with no osteoarthritis or arthroplasty procedure in anamnesis.MethodsA group of 30 patients who received the medial pivot (MP) TKA and 33 patients who received the posterior-stabilized (PS) TKA between May and August of 2018 were included. All surgeries were performed in the level III academic hospital by a single surgeon. Every patient was asked to fulfill the The Western Ontario and McMaster Universities Arthritis Index (WOMAC) questionnaire preoperatively and 2 years postoperatively. Standard X-ray, biomechanical gait analysis using a motion capture system, and statistical analysis were performed at 2 years postoperatively.ResultsA total of 28 patients from either MP cohort (93%) or PS (85%) matched-control cohort completed the whole assessment at the final follow-up. There were statistically significant differences in a few gait parameters such as shorter mean step length both in operated and healthy limb, lower mean gait velocity, and lower mean walking cadence than the norm in both MP and PS groups. As to the WOMAC score, there was statistically significant improvement in both groups comparing preoperative and postoperative outcomes. Nevertheless, in the MP group, there was a significantly higher score, indicating worse outcomes, in the stiffness part of the WOMAC score than in the PS group. No significant differences were found between groups during radiological evaluation.ConclusionsThere were satisfying and promising clinical, radiographic, and patient-reported outcomes in both MP and PS groups with very little difference in relation to norm values. However, both implants failed in fully restoring gait patterns similar to the healthy limb of the same patient.

Limited knee extension during gait after total knee arthroplasty is related to a low Oxford Knee Score

BackgroundAfter total knee replacement (TKR) some patients report low self-perceived function, which is clinically measured using patient reported outcome measures (PROMs). However, PROMs, e.g. the Oxford Knee Score (OKS), inherently lack objective parameters of knee function. Biomechanical gait analysis is an objective and reliable measurement to quantitatively assess joint function. Therefore, the aim of this study was to explore the relationship between biomechanical gait parameters and the OKS. MethodsGait analyses were recorded in 37 patients at least one year after primary TKR and in 24 healthy controls. Parameters from this analysis were calculated for hip, knee and ankle joint angles and joint moments in the sagittal and frontal plane including initial contact, early, late stance and swing. For the patients these parameters were expressed as its difference to control values at matched walking speed. Linear regression analyses were performed between the parameters from gait analysis and the OKS, with speed as covariate. ResultsThe difference in knee extension angle at initial contact and late stance between patients and controls was significantly related to the OKS. Per one degree knee extension difference increase, the OKS reduced with 1.0 to 1.6 points. Overall, patients extended their knee less than controls. Neither ankle and hip gait parameters, nor joint moments showed a relation with OKS. ConclusionsAll patients with a submaximal score on the OKS showed limited knee extension during gait, even without a mechanical constraint in knee extension. This could be related to motor control limitations in this patient group.

Biomechanical Analysis of an Improvement of Prosthetic Liner using Polyurethane Focusing at the Anterior-Distal Part of Residual Limb: A Case Study

Most transtibial prosthesis users always experience pain sensation at the distal of the residual limb due to bony prominences and nerve endings. Many initiatives have been taken to resolve this problem, including using softer materials such as silicone or gel liner and designing a distal off load prosthetic socket. Another promising approach is to incorporate polyurethane foam in the manufacturing of prosthetic liner. This study aimed to design a new prosthetic liner using polyurethane at the anterior-distal part of the residual limb as a Pelite replacement and to compare the biomechanical gait analysis between the new modified polyurethane liner and the common Pelite liner. A unilateral transtibial amputee was recruited as the subject. Two Patellar Tendon Bearing transtibial prostheses with different liners were fabricated for the subject, which were Pelite liner and a modified polyurethane foam liner. The modified liner using polyurethane foam consisted of Ethylene vinyl-acetate – Polyurethane – Ethylene vinyl-acetate sandwich placed at the anterior-distal part of the residual limb. The Ethylene vinyl-acetate – Polyurethane – Ethylene vinyl-acetate sandwich function was to improve the walking gait and compensate for the pain sensation experienced by the subject when wearing the Pelite liner. Biomechanical analysis was done using the Vicon Motion Analysis System on the subject when using the two newly fabricated transtibial prostheses and the subject’s original prosthesis with Pelite liner. During the loading response phase, the original liner exerted a slightly higher force than the Pelite and the modified liner. At 30% and 50% of the gait cycle, the original liner exerted low force than the Pelite liner and the modified liner for Ground Reaction Force at the amputated side. However, no significant difference (p>0.05) was found between all prosthetic liners for Ground Reaction Force (Non-Amputated). The biomechanical analysis showed that the modified liner using polyurethane foam improved the prosthesis user gait cycle and the walking gait of the prosthesis user.

Faster or longer steps: Maintaining fast walking in older adults at risk for mobility disability.

The ability to walk at various speeds is essential to independence for older adults. Maintaining fast walking requires changes in spatial-temporal measures, increasing step length and/or decreasing step time. It is unknown how mobility affects the parameters that change between preferred and fast walking. How does preferred walking performance and measures of strength and mobility relate to the approach (decreasing step time or increasing step length) older adults at risk for mobility disability use to maintain fast walking speeds?. Peak isokinetic dynamometry of knee and ankle and several mobility evaluations, including the Timed Up-and-Go, Short Physical Performance Battery, and Dynamic Gait Index, assessed mobility and strength in 57 participants, aged 65-80. Biomechanical gait analysis was used to analyze step length, step time, gait speed at preferred and fast gait speeds and ground reaction force during preferred walking. A score combining the differences between step length and time at fast and preferred speeds (Length-Time Difference) separated participants into two groups: (1) Length, representing a predominant increase in step length to walk fast and (2) Time, a predominant decrease in step time. Those who decreased step time to produce increased speed performed worse during repeated chair stands (p = .006) with no difference in isokinetic strength (p ≥ .15). During preferred walking, the Time group displayed increased propulsive impulse compared to the Length group (p = .007), despite no differences in preferred speed, step length, or time (p ≥ .50). While kinetics of preferred walking differed between groups separated by Length-Time Difference, basic spatial-temporals of preferred walking did not in this homogenous population. Length-Time Difference relates to a common mobility assessment and could be easily calculated by clinicians to provide a quantitative and more sensitive measure of ambulatory performance.

Association of Machine Learning-Based Predictions of Medial Knee Contact Force With Cartilage Loss Over 2.5 Years in Knee Osteoarthritis.

The relationship between in vivo knee load predictions and longitudinal cartilage changes has not been investigated. We undertook this study to develop an equation to predict the medial tibiofemoral contact force (MCF) peak during walking in persons with instrumented knee implants, and to apply this equation to determine the relationship between the predicted MCF peak and cartilage loss in patients with knee osteoarthritis (OA). In adults with knee OA (39 women, 8 men; mean ± SD age 61.1 ± 6.8 years), baseline biomechanical gait analyses were performed, and annualized change in medial tibial cartilage volume (mm3 /year) over 2.5 years was determined using magnetic resonance imaging. In a separate sample of patients with force-measuring tibial prostheses (3 women, 6 men; mean ± SD age 70.3 ± 5.2 years), gait data plus in vivo knee loads were used to develop an equation to predict the MCF peak using machine learning. This equation was then applied to the knee OA group, and the relationship between the predicted MCF peak and annualized cartilage volume change was determined. The MCF peak was best predicted using gait speed, the knee adduction moment peak, and the vertical knee reaction force peak (root mean square error 132.88N; R2 = 0.81, P < 0.001). In participants with knee OA, the predicted MCF peak was related to cartilage volume change (R2 = 0.35, β = -0.119, P < 0.001). Machine learning was used to develop a novel equation for predicting the MCF peak from external biomechanical parameters. The predicted MCF peak was positively related to medial tibial cartilage volume loss in patients with knee OA.

Validation of the wearable sensor system - MoveSole® smart insoles

Biomechanical analysis of gait is commonly used in physiotherapy. Ground reaction forces during phases of gait is one element of kinetic analysis. In this article, we analyze if the MoveSole® smart insole is valid and accurate equipment for measuring ground reaction forces in clinical physiotherapy. MoveSole® StepLab is a mobile measurement system for instant underfoot force measurements during gait. Unique electromagnetic film (EMFI) based sensor technology and printed electronics production technology is integrated in the MoveSole® StepLab measurement system. The MoveSole® StepLab measures plantar ground reaction force distribution over the sensors and provides an estimation of the maximum total ground reaction force. We developed a two phase validation process to extract relevant parameters and compared the results to a Kistler force plate using the BioWare® analyzing program as a reference method. Our results show that MoveSole® smart insoles reach the strong level of accuracy needed in clinical work concerning highest ground reaction forces during step (Pearson correlation .822 - .875). The correlation of the time when the maximum ground reaction force occurred was moderate, e.g. during heel strike or toe-off (Pearson correlation natural gait speed .351 - .462, maximum gait speed .430). Our conclusion is that MoveSole® smart insoles are a potential tool for analyzing and monitoring gait ground reaction forces during physiotherapy processes.

Comparison Method of Biomechanical Analysis of Trans-Tibial Amputee Gait with a Mechanical Test Machine Simulation

Energy-storing-and-returning prosthetic feet are frequently recommended for lower limb amputees. Functional performance and stiffness characteristics are evaluated by state-of-the-art biomechanical testing, while it is common practice for design engineers and researchers to use test machines to measure stiffness. The correlation between user-specific biomechanical measures and machine evaluation has not been thoroughly investigated, and mechanical testing for ramps is limited. In this paper, we propose a novel test method to assess prosthetic foot stiffness properties in the sagittal plane. First, biomechanical data were collected on five trans-tibial users using a variable stiffness prosthetic foot on a split-belt treadmill. Gait trials were performed on level ground and on an incline and a decline of 7.5°. The same prosthetic foot was tested on a roll-over test machine for the three terrains. The sagittal ankle moment and angle were compared for the two test methods. The dorsiflexion moment and angle were similar, while more variability was observed in the plantarflexion results. A good correlation was found for level-ground walking, while decline walking showed the largest differences in the results of the maximum angles. The roll-over test machine is a useful tool to speed up design iterations with a set design goal prior to user testing.

Mobile Robot-Based Gait Training after Total Hip Arthroplasty (THA) Improves Walking in Biomechanical Gait Analysis.

There are multiple attempts to decrease costs in the healthcare system while maintaining a high treatment quality. Digital therapies receive increasing attention in clinical practice, mainly relating to home-based exercises supported by mobile devices, eventually in combination with wearable sensors. The aim of this study was to determine if patients following total hip arthroplasty (THA) could benefit from gait training on crutches conducted by a mobile robot in a clinical setting. Method: This clinical trial was conducted with 30 patients following total hip arthroplasty. Fifteen patients received the conventional physiotherapy program in the clinic (including 5 min of gait training supported by a physiotherapist). The intervention group of 15 patients passed the same standard physiotherapy program, but the 5-min gait training supported by a physiotherapist was replaced by 2 × 5 min of gait training conducted by the robot. Length of stay of the patients was set to five days. Biomechanical gait parameters of the patients were assessed pre-surgery and upon patient discharge. Results: While before surgery no significant difference in gait parameters was existent, patients from the intervention group showed a significant higher absolute walking speed (0.83 vs. 0.65 m/s, p = 0.029), higher relative walking speed (0.2 vs. 0.16 m/s, p = 0.043) or shorter relative cycle time (3.35 vs. 3.68 s, p = 0.041) than the patients from the control group. Conclusion: The significant higher walking speed of patients indicates that such robot-based gait training on crutches may shorten length of stay (LOS) in acute clinics. However, the number of patients involved was rather small, thus calling for further studies.

Assessment of biomechanical deficits in individuals with a trans-tibial amputation during level gait using one-dimensional statistical parametric mapping.

Most previous studies reported biomechanical deficits in individuals with a trans-tibial amputation (TTA) during gait using zero-dimensional analyses. However, these analyses do not allow to precisely determine during which part of the gait cycle these deficits occur. There is a need to use more appropriate methods to map the differences, such as one-dimensional statistical parametric mapping. What are the most relevant phases of the gait cycle during which the biomechanical deficits in TTA occur? Eight TTA and 15 healthy counterparts (CON) underwent one biomechanical gait analysis. Pelvis, hip, knee and ankle kinematics, total support moment (TSM) and gastrocnemius lateralis, vastus lateralis and tibialis anterior muscle activity were compared between the amputated (AmLL), the intact (InLL) and the control (CnLL) lower limbs using one-dimensional statistical parametric mapping. More ankle dorsiflexion and knee flexion were observed for the AmLL compared to the InLL and CnLL (ankle only) from the end of the stance phase to the beginning of the swing phase. Less knee flexion was also found for the AmLL during early stance phase. More pelvis posterior tilt and rotation toward the contralateral limb was observed during most of the gait cycle for the AmLL compared to the InLL. TSM was smaller for the AmLL compared to the CnLL during early stance phase. Using a one-dimensional statistical parametric mapping approach for TTA gait analysis, this study provides novel insights on their biomechanical gait deficits compared to CON. Greater reliance on the InLL was observed in TTA as suggested by the asymmetric kinematic and kinetic profiles.

A comprehensive clinico-radiological, neuropsychological and biomechanical analysis approach to patients with idiopathic normal pressure hydrocephalus

BackgroundA systematic approach to patients with suspected idiopathic normal pressure hydrocephalus (iNPH) is essential to recognize the subset of patients who may benefit from ventriculoperitoneal shunt surgery (VPS). Quantitative biomechanical analysis of gait and balance (QBAGB) may help objectify the response to the cerebrospinal fluid tap test (CSF-TT) and VPS outcome after 3 months and support identification of candidates for VPS. MethodsWe retrospectively reviewed data from all patients with probable iNPH who 1) underwent clinico-radiological and neuropsychological assessments using validated scales (iNPH Scale and iNPH Radscale) at our centre in the period from January to December 2018; and 2) had completed QBAGB before CSF-TT (‘baseline’), shortly after CSF-TT, and at three months after either VPS or conservative treatment. ResultsAt the time-points ‘after CSF-TT’ and ‘3 months’, patients with iNPH and VPS (n = 11) significantly improved on the Kiefer Scale score, iNPH Scale total score and gait domain score, as well as in gait velocity and step length measured by QBAGB. In contrast, patients without surgery (n = 10) had unchanged iNPH Scale scores and motor performance throughout. Using data from all patients, we calculated cut-off levels for substantial improvements in gait velocity, step length, and the iNPH Scale domain gait score at the time-point ‘after CSF-TT’. ConclusionQBAGB helps to objectify the response to CSF-TT to select candidates for VPS and corroborates clinico-radiological and neuropsychological data derived from validated scales. The QBAGB cut-off values for substantial improvement after CSF-TT need further elucidation in larger, preferably prospective studies.

Functional assessment of outcome of surgery to correct patellofemoral instability in human patients

A case-control study with 6 months of patient follow up. This study sought to determine if surgery followed by rehabilitation for patellar instability could restore normal gait function. A previous study has established abnormalities in gait pattern and joint congruence in patients with a history of patellar instability. We hypothesised that surgery for patellofemoral instability would improve knee function. Eight human patients (mean age 29, range 17-42) who were awaiting patella stabilisation surgery (5 tibial tuberosity osteotomy, 2 medial patellofemoral ligament reconstruction, 1 trochleoplasty) were compared against eight normal Controls (mean age 28, range 19-31). Patients were assessed pre-operatively and six months after surgery by biomechanical gait analysis. Gait trials involved simultaneous collection of kinematic and force data. Patients were grouped into two subgroups pre-operatively based on knee joint net moment during stance, and their joint moments during stance pre- and post-operatively were compared against the Control subjects. In pre-operative gait analysis, four patients (P1) produced some extensor moment in early stance and four (P2) demonstrated a severe gait deficiency with failure to generate a knee extensor moment during stance. Normalisation in gait pattern was observed in all patients post-operatively. Those who had the most severe gait abnormality (P2) demonstrated the most improvement in their knee joint moments. Improvements were observed in the milder (P1) cases, but these were less dramatic. Patella stabilisation by surgery can restore normal gait function. Normalising the anatomy of the knee extensor mechanism is the objective of surgery. Normal anatomy facilitates the rehabilitation objectives of optimising extensor function during the weight-bearing phase of gait.

Functional evaluation of patients with anterior cruciate ligament injury. A transversal analytical study

ObjectiveTo evaluate, by means of biomechanical analysis, functional alterations of gait and balance of patients with anterior cruciate ligament (ACL) injury. Material and methodsTransversal analytical study on 64 people, 27 health subjects and 37 patients with ACL injury. Biomechanical analysis of gait in all individuals was performed by means of four tests: (1) kinematic test, to characterize gait pattern; (2) kinetic test, to characterize forces against the floor, duration of treads, symmetry of both legs, and the reproducibility of the gait; (3) pivot-shift test, to analyze the rotational stability of the knee on the sagittal axis; and (4) equilibrium test. ResultsAlterations in kinematic and kinetic analysis were found in both the injured knee and the healthy knee compared to the control group. In the pivot-shift gait test there is a tendency to increase the forces on the three axes, both in the support leg and in the exit leg in patients with ACL injury, in comparison with healthy subjects. ConclusionACL injury-induced changes in gait pattern, changes in forces against the floor, duration of treads, symmetry of both legs, and the reproducibility of gait and changes in rotational stability of the knee on the sagittal axis.

Evaluación funcional de los pacientes con rotura del ligamento cruzado anterior. Estudio analítico transversal

ObjectiveTo evaluate, by means of biomechanical analysis, functional alterations of gait and balance of patients with anterior cruciate ligament (ACL) injury. Material and methodsTransversal analytical study on 64 people, 27 health subjects and 37 patients with ACL injury. Biomechanical analysis of gait in all individuals was performed by means of four tests: 1) kinematic test, to characterize gait pattern; 2) kinetic test, to characterize forces against the floor, duration of treads, symmetry of both legs, and the reproducibility of the gait; 3) pivot-shift test, to analyze the rotational stability of the knee on the sagittal axis; and 4) equilibrium test. Resultsalterations in kinematic and kinetic analysis were found in both the injured knee and the healthy knee compared to the control group. In the pivot-shift gait test there is a tendency to increase the forces on the three axes, both in the support leg and in the exit leg in patients with ACL injury, in comparison with healthy subjects. ConclusionACL injury-induced changes in gait pattern, changes in forces against the floor, duration of treads, symmetry of both legs, and the reproducibility of gait and changes in rotational stability of the knee on the sagittal axis.

Design, Analysis, and Fabrication of a Piezoelectric Force Tray for Total Knee Replacements.

Force plates have been widely adopted in biomechanical gait analysis to measure reaction forces and the center of pressure. In this work, the force plate concept is miniaturized and extended for use within the polyethylene bearing insert of a total knee replacement (TKR). A simplified rectangular-shaped force plate with multiple integrated piezoelectric sensors, including designs with six and eight transducers, is presented in this work. The performance of the sensory system is investigated through finite element analysis and experimental validation. Initially, the ability of the two designs in sensing compartmental forces and contact point locations on one side of the force plate is numerically investigated. Selected designs of the force plate are then fabricated and used to experimentally validate the performance of the system. The results show a maximum error of less than 6% and 4.5% in compartmental force amplitude sensing for the force plates with six and eight transducers, respectively. The force plates were able to detect the contact point location with maximum errors of less than 1 mm. The relatively small sensing error quantities show the potential of using a piezoelectric force plate sensor design in TKR as well as other force sensing applications.

Design of a Series Elastic Tendon Actuator Based on Gait Analysis for a Walking Assistance Exosuit

Exosuits are wearable robots that enhance a person’s muscular strength from outside the body. Many exosuits use tendon actuators with multiple wires that work similarly to human muscles to minimize user unfamil-iarity caused by the discrepancy between the human body’s degree of freedom and the influence of the mass of the exoskeleton. This paper describes the design of a series elastic tendon actuator (SETA) to be used in exosuits. The SETA performs the agonist and antagonist functions of human muscles using two internal wires as well as elastic elements (springs) to measure the human-robot interaction force and overcome differences in variations occurring between the wires. We defined design objectives and selected the main components based on biomechanical gait analysis to design a small SETA. Moreover, we conducted an experiment to verify the basic performance of our SETA design.

Protocolo de valoración biomecánica de las alteraciones de la marcha

Biomechanical gait analysis is a novel and useful tool for the assessment of gait alteration in persons with spinal cord injury. It allows quantify and determine deviations from normal gait pattern and supports the therapeutic decision making. The most usual techniques, kinematic, kinetic and surface electromyography analysis, are described in the current protocol. Finally, biomechanical gait recording procedure is explained.

Sheep Gait Biomechanics and the Assessment of Musculoskeletal Conditions: A Systematic Review

In recent years, sheep have been reported as the ideal animal model to study osteoporosis, hence it is important to identify instruments, tools and ideal parameters needed to assess the effects of different treatments. In previous studies conducted in other animal models with osteoporosis, the most common parameters used for evaluation concerned primarily bone properties, such as the dual X-ray absorptiometry. However, biomechanical gait analysis as an integrative functional parameter and a non-invasive method, will be an important tool in research and clinical applications. This research review was performed using the PubMed database and included studies related to sheep with outcome measures concerning functional performance assessed during gait in vivo; and excluded studies related with cardiovascular disease and sperm properties, which include other animal species, with outcomes not related with functional locomotor evaluation. Only studies related with bone properties were analyzed. The most frequent and relevant included parameters were the following: mean peak vertical ground force reaction, gait cycle and stance/swing phase duration, percentage of stance/swing phase in a gait cycle, stride length and the stifle joint angles during a gait cycle. Gait biomechanical parameters have been established for the assessment of some clinical orthopedic condition using sheep models but not currently for osteoporosis.

Host Mesh Fitting of a Generic Musculoskeletal Model of the Lower Limbs to Subject-Specific Body Surface Data: A Validation Study.

Challenges remain in accurately capturing the musculoskeletal geometry of individual subjects for clinical and biomechanical gait analysis. The aim of this study was to use and validate the Host Mesh Fitting (HMF) technique for fitting a generic anatomically based musculoskeletal model to 3D body surface data of individual subjects. The HMF technique is based on the free-form idea of deforming geometrically complex structures according to the deformation of a surrounding volumetric mesh. Using the HMF technique, an anatomically based model of the lower limbs of an adult female subject (29 years) was customized to subject-specific skin surface data of five typically developing children (mean age 10.2 years) and six children with Cerebral Palsy (CP) (mean age 9.6 years). The fitted lengths and volumes of six muscle-tendon structures were compared against measures from Magnetic Resonance (MR) images for validation purposes. The HMF technique resulted in accurate approximations of the lower limb shapes of all subjects in both study groups. The average error between the MR data and the fitted muscle-tendon lengths from HMF was 4 ± 4% in children without CP and 7 ± 5% in children with CP, respectively. The average error between the MR data and the fitted muscle volumes from HMF was 28 ± 19% in children without CP and 27 ± 28% in children with CP, respectively. This study presents a crucial step towards personalized musculoskeletal modelling for gait analysis by demonstrating the feasibility of fitting a generic anatomically based lower limb model to 3D body surface data of children with and without CP using the HMF technique. Additional improvements in the quality of fit are expected to be gained by developing age-matched generic models for different study groups, accounting for subject-specific variations in subcutaneous body fat, as well as considering supplementary data from ultrasound imaging to better capture physiological muscle tissue properties.