scholarly journals Multibody Muscle Driven Model of an Instrumented Prosthetic Knee During Squat and Toe Rise Motions

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Antonis P. Stylianou ◽  
Trent M. Guess ◽  
Mohammad Kia
Keyword(s):  
Computational Models ◽  
Muscle Length ◽  
Ground Reaction Forces ◽  
Vertical Force ◽  
Collateral Ligament ◽  
Hexahedral Elements ◽  
Flexion Extension ◽  
Subject Specific ◽  
Reaction Forces

Detailed knowledge of knee joint kinematics and dynamic loading is essential for improving the design and outcomes of surgical procedures, tissue engineering applications, prosthetics design, and rehabilitation. The need for dynamic computational models that link kinematics, muscle and ligament forces, and joint contacts has long been recognized but such body-level forward dynamic models do not exist in recent literature. A main barrier in using computational models in the clinic is the validation of the in vivo contact, muscle, and ligament loads. The purpose of this study was to develop a full body, muscle driven dynamic model with subject specific leg geometries and validate it during squat and toe-rise motions. The model predicted loads were compared to in vivo measurements acquired with an instrumented knee implant. Data for this study were provided by the “Grand Challenge Competition to Predict In-Vivo Knee Loads” for the 2012 American Society of Mechanical Engineers Summer Bioengineering Conference. Data included implant and bone geometries, ground reaction forces, EMG, and the instrumented knee implant measurements. The subject specific model was developed in the multibody framework. The knee model included three ligament bundles for the lateral collateral ligament (LCL) and the medial collateral ligament (MCL), and one bundle for the posterior cruciate ligament (PCL). The implanted tibia tray was segmented into 326 hexahedral elements and deformable contacts were defined between the elements and the femoral component. The model also included 45 muscles on each leg. Muscle forces were computed for the muscle driven simulation by a feedback controller that used the error between the current muscle length in the forward simulation and the muscle length recorded during a kinematics driven inverse simulation. The predicted tibia forces and torques, ground reaction forces, electromyography (EMG) patterns, and kinematics were compared to the experimentally measured values to validate the model. Comparisons were done graphically and by calculating the mean average deviation (MAD) and root mean squared deviation (RMSD) for all outcomes. The MAD value for the tibia vertical force was 279 N for the squat motion and 325 N for the toe-rise motion, 45 N and 53 N for left and right foot ground reaction forces during the squat and 94 N and 82 N for toe-rise motion. The maximum MAD value for any of the kinematic outcomes was 7.5 deg for knee flexion-extension during the toe-rise motion.

scholarly journals Metabolic cost of generating horizontal forces during human running

1999 ◽  
Vol 86 (5) ◽  
pp. 1657-1662 ◽  
Author(s):  
Young-Hui Chang ◽  
Rodger Kram
Keyword(s):  
Body Weight ◽  
Oxygen Consumption ◽  
Metabolic Cost ◽  
Ground Reaction Forces ◽  
Vertical Force ◽  
Order Of Magnitude ◽  
Reaction Forces ◽  
The Cost ◽  
Support Body Weight ◽  
Human Running

Previous studies have suggested that generating vertical force on the ground to support body weight (BWt) is the major determinant of the metabolic cost of running. Because horizontal forces exerted on the ground are often an order of magnitude smaller than vertical forces, some have reasoned that they have negligible cost. Using applied horizontal forces (AHF; negative is impeding, positive is aiding) equal to −6, −3, 0, +3, +6, +9, +12, and +15% of BWt, we estimated the cost of generating horizontal forces while subjects were running at 3.3 m/s. We measured rates of oxygen consumption (V˙o 2) for eight subjects. We then used a force-measuring treadmill to measure ground reaction forces from another eight subjects. With an AHF of −6% BWt,V˙o 2 increased 30% compared with normal running, presumably because of the extra work involved. With an AHF of +15% BWt, the subjects exerted ∼70% less propulsive impulse and exhibited a 33% reduction inV˙o 2. Our data suggest that generating horizontal propulsive forces constitutes more than one-third of the total metabolic cost of normal running.

A Robotic Cadaveric Flatfoot Analysis of Stance Phase

2011 ◽  
Vol 133 (5) ◽  
Author(s):  
Lyle T. Jackson ◽  
Patrick M. Aubin ◽  
Matthew S. Cowley ◽  
Bruce J. Sangeorzan ◽  
William R. Ledoux
Keyword(s):  
Surgical Treatment ◽  
Degrees Of Freedom ◽  
Stance Phase ◽  
Gait Cycle ◽  
Ground Reaction Forces ◽  
Pes Planus ◽  
Reaction Forces ◽  
Vertical Ground

The symptomatic flatfoot deformity (pes planus with peri-talar subluxation) can be a debilitating condition. Cadaveric flatfoot models have been employed to study the etiology of the deformity, as well as invasive and noninvasive surgical treatment strategies, by evaluating bone positions. Prior cadaveric flatfoot simulators, however, have not leveraged industrial robotic technologies, which provide several advantages as compared with the previously developed custom fabricated devices. Utilizing a robotic device allows the researcher to experimentally evaluate the flatfoot model at many static instants in the gait cycle, compared with most studies, which model only one to a maximum of three instances. Furthermore, the cadaveric tibia can be statically positioned with more degrees of freedom and with a greater accuracy, and then a custom device typically allows. We created a six degree of freedom robotic cadaveric simulator and used it with a flatfoot model to quantify static bone positions at ten discrete instants over the stance phase of gait. In vivo tibial gait kinematics and ground reaction forces were averaged from ten flatfoot subjects. A fresh frozen cadaveric lower limb was dissected and mounted in the robotic gait simulator (RGS). Biomechanically realistic extrinsic tendon forces, tibial kinematics, and vertical ground reaction forces were applied to the limb. In vitro bone angular position of the tibia, calcaneus, talus, navicular, medial cuneiform, and first metatarsal were recorded between 0% and 90% of stance phase at discrete 10% increments using a retroreflective six-camera motion analysis system. The foot was conditioned flat through ligament attenuation and axial cyclic loading. Post-flat testing was repeated to study the pes planus deformity. Comparison was then made between the pre-flat and post-flat conditions. The RGS was able to recreate ten gait positions of the in vivo pes planus subjects in static increments. The in vitro vertical ground reaction force was within ±1 standard deviation (SD) of the in vivo data. The in vitro sagittal, coronal, and transverse plane tibial kinematics were almost entirely within ±1 SD of the in vivo data. The model showed changes consistent with the flexible flatfoot pathology including the collapse of the medial arch and abduction of the forefoot, despite unexpected hindfoot inversion. Unlike previous static flatfoot models that use simplified tibial degrees of freedom to characterize only the midpoint of the stance phase or at most three gait positions, our simulator represented the stance phase of gait with ten discrete positions and with six tibial degrees of freedom. This system has the potential to replicate foot function to permit both noninvasive and surgical treatment evaluations throughout the stance phase of gait, perhaps eliciting unknown advantages or disadvantages of these treatments at other points in the gait cycle.

scholarly journals Flèche versus Lunge as the Optimal Footwork Technique in Fencing

2019 ◽  
Vol 16 (13) ◽  
pp. 2315 ◽  
Author(s):  
Zbigniew Borysiuk ◽  
Natalia Markowska ◽  
Mariusz Konieczny ◽  
Krzysztof Kręcisz ◽  
Monika Błaszczyszyn ◽  
...  
Keyword(s):  
Reaction Time ◽  
Movement Time ◽  
Medial Gastrocnemius ◽  
Ground Reaction Forces ◽  
Vertical Force ◽  
Muscular Tension ◽  
Explosive Force ◽  
Reaction Forces ◽  
Gastrocnemius Muscles ◽  
Sensorimotor Responses

The objective of the study reported in this paper involved identifying the fencing attack (flèche versus lunge) that provides greater effectiveness in a real competition. Two hypotheses are presented in the study. The first hypothesis involves the greater effectiveness of the flèche with regard to bioelectric muscular tension, and the second hypothesis involves the reduction of movement time of the flèche. Therefore, analyses were conducted by the application of EMG (electromyography) signal, ground reaction forces, and parameters representing sensorimotor responses (RT—reaction time and MT—movement time). This study included six world-leading female épée fencers (mean age: 24.6 ± 6.2 years). Throughout the procedure, the subjects performed flèche and lunge touches at the command of the coach based on visual stimuli. The experimental results indicated the greater effectiveness of the flèche compared with the lunge with regard to increases in EMG values (p = 0.027) in the lateral and medial gastrocnemius muscles and decreases in the duration of the movement phase (p = 0.049) and vertical force of the rear leg (p = 0.028). In conclusion, higher levels of EMG and ground reaction forces were generated during the flèche compared with the lunge, which promotes an improvement in the explosive force and contributes to a reduction in the movement phase of the entire offensive action.

Ground Reaction Forces in Children’s Gait

1989 ◽  
Vol 1 (1) ◽  
pp. 45-53 ◽  
Author(s):  
Nancy L. Greer ◽  
Joseph Hamill ◽  
Kevin R. Campbell
Keyword(s):  
Sex Differences ◽  
Ground Reaction Force ◽  
Reaction Force ◽  
Ground Reaction Forces ◽  
Vertical Force ◽  
Reaction Forces ◽  
Braking Force ◽  
Force Components ◽  
Age Range ◽  
Minimum Force

Ground reaction force patterns during walking were observed in 18 children 3 and 4 years of age. The children walked barefoot at a self-chosen walking pace. Selected variables representing the vertical, anteroposterior, and mediolateral force components were evaluated. The results indicated that children in this age range contact the ground with greater vertical force measures relative to body mass than do adults. In addition, the minimum vertical force was lower, the transition from braking to propulsion occurred earlier, and the mediolateral force excursions were higher than typically found in adults. When the children were divided into groups on the basis of sex, differences were observed between those groups. The boys exhibited a greater difference in the vertical peak forces, a lower minimum force, a greater braking force, and a higher mediolateral force excursion value. The results indicated that children display a different ground reaction force pattern than do adults and that differences between boys and girls may be observed as early as ages 3 and 4 years.

scholarly journals Various Knee Model Measurement Techniques to Find the Knee Geometries

2016 ◽  
Vol 3 (3) ◽  
pp. 4-6
Author(s):  
Kavinaya C ◽  
Ashuthoshkumar L
Keyword(s):  
Computational Models ◽  
Measurement Techniques ◽  
Knee Kinematics ◽  
Load Measurement ◽  
Knee Simulator ◽  
Subject Specific ◽  
The Subject ◽  
Model Measurement

Computation of knee modeling is a subject-specific techniquethatdefining the zero-load measurements of the cruciate and indemnity ligaments.The dynamic knee simulator was used to test the three carcass knees. The carcass knees also experiencedphysicalsachet of motion testing to discovery their inactivesort of motion in order to regulate the zero-load measurements for everymuscle bundle. Compotation multibody knee representations were shaped for each knee and classical kinematics were likened to investigational kinematics for a replicated walk series. Simple-minded non-linear mechanisminhibition elements were used to characterize cruciate and deposited particles in musclepackages in the knee representations. This learningoriginate that knee kinematics was enormously sensitive to changing of the zero-load measurement. The domino effects also recommendoptimum methods for describing each of the muscle bundle zero-load measurements, irrespective of the subject. These consequencesvalidate the significance ofthe zero-load length when modeling the knee united and verify that physicalcloak of motion dimensions can be usedto determine the passive range of motion of the knee joint. It is also supposed that the method defined here forresponsible zero-load measurement can be used for in vitro or in vivo subject-specific computational models.

Obesity: Effects on Gait in an Osteoarthritic Population

1996 ◽  
Vol 12 (2) ◽  
pp. 161-172 ◽  
Author(s):  
Stephen P. Messier ◽  
Walter H. Ettinger ◽  
Thomas E. Doyle ◽  
Timothy Morgan ◽  
Margaret K. James ◽  
...  
Keyword(s):  
Older Adults ◽  
High Speed ◽  
Ground Reaction Forces ◽  
Vertical Force ◽  
Kinematic Data ◽  
Knee Oa ◽  
Significant Relationships ◽  
Gait Mechanics ◽  
Reaction Forces ◽  
Walking Velocity

The purpose of our study was to examine the association between obesity and gait mechanics in older adults with knee osteoarthritis (OA). Subjects were 101 older adults (25 males and 76 females) with knee OA. High-speed video analysis and a force platform were used to record sagittal view lower extremity kinematic data and ground reaction forces. Increased body mass index (BMI) was significantly related to both decreases in walking velocity and knee maximum extension. There were no significant relationships between BMI and any of the hip or ankle kinematic variables. BMI was directly related to vertical force minimum and maximum values, vertical impulse, and loading rate. Increases in braking and propulsive forces were significantly correlated with increased BMI. Maximum medially and laterally directed ground reaction forces were positively correlated with BMI. Our results suggests that, in subjects with knee OA, obesity is associated with an alteration in gait.

A Finite Element Analysis of a Subject Specific Single-Leg Drop Landing at Varied Heights

2011 ◽  
Author(s):  
Chi-Yin Tse ◽  
Hamid Nayeb-Hashemi ◽  
Ashkan Vaziri ◽  
Paul K. Canavan
Keyword(s):  
Knee Flexion ◽  
Reaction Force ◽  
Acl Injury ◽  
Ground Reaction Forces ◽  
Vertical Ground Reaction Force ◽  
Element Analysis ◽  
Drop Landing ◽  
Subject Specific ◽  
Reaction Forces ◽  
Vertical Ground

The pathomechanics of knee anterior cruciate ligament (ACL) injury related to the female athlete is of high interest due to the high incidence of injury compared to males participating in the same sport. The mechanisms of ACL injury are still not completely understood, but it is known that single-leg landings, stopping and cutting at high velocity are some of the non-contact mechanisms that are causing these injuries. This study analyzed a subject specific analysis of a single-leg drop landing that was performed by a female subject at 60%, 80% and 100% of her maximum vertical jump. The femur, tibia, articular cartilage, and menisci were modeled as 3-D structures and the data collected from the motion analysis was used to obtain the knee joint contact stresses in finite element analysis (FEA). The four major ligaments of the knee were modeled as non-linear springs. Material properties of previously published studies were used to define the soft tissue structures. The articular cartilage was defined as isotropic elastic and the menisci were defined as transverse isotropic elastic. Two different styles of single-leg landings were compared to one another, resembling landing from a basketball rebound. The first landing style, single-leg arms up (SLAU), produced larger knee flexion angles at peak ground reaction forces, while single-leg arms across (SLAX) landings produced higher peak vertical ground reaction forces along with lower knee flexion angles. The mean peak vertical ground reaction force was 2.9–3.5 bodyweight for SLAU landings, while they were 3.0–3.8 for SLAX landings. The time to peak vertical ground reaction force with SLAU landings were 69 ms (60%), 60 ms (80%), and 55 ms (100%); SLAX landings were 61 ms (60%), 61 ms (80%), and 51 ms (100%).

scholarly journals Subject-Specific Inverse Dynamics of the Head and Cervical Spine During in Vivo Dynamic Flexion-Extension

2013 ◽  
Vol 135 (6) ◽  
Author(s):  
William J. Anderst ◽  
William F. Donaldson ◽  
Joon Y. Lee ◽  
James D. Kang
Keyword(s):  
Finite Element ◽  
Cervical Spine ◽  
Inverse Dynamics ◽  
Total Force ◽  
Finite Element Models ◽  
Moment Arms ◽  
Flexion Extension ◽  
Subject Specific

The effects of degeneration and surgery on cervical spine mechanics are commonly evaluated through in vitro testing and finite element models derived from these tests. The objectives of the current study were to estimate the load applied to the C2 vertebra during in vivo functional flexion-extension and to evaluate the effects of anterior cervical arthrodesis on spine kinetics. Spine and head kinematics from 16 subjects (six arthrodesis patients and ten asymptomatic controls) were determined during functional flexion-extension using dynamic stereo X-ray and conventional reflective markers. Subject-specific inverse dynamics models, including three flexor muscles and four extensor muscles attached to the skull, estimated the force applied to C2. Total force applied to C2 was not significantly different between arthrodesis and control groups at any 10 deg increment of head flexion-extension (all p values ≥ 0.937). Forces applied to C2 were smallest in the neutral position, increased slowly with flexion, and increased rapidly with extension. Muscle moment arms changed significantly during flexion-extension, and were dependent upon the direction of head motion. The results suggest that in vitro protocols and finite element models that apply constant loads to C2 do not accurately represent in vivo cervical spine kinetics.

Measurement of ground reaction forces in cats 1 year after femoral head and neck ostectomy

2020 ◽  
pp. 1098612X2094814
Author(s):  
Eva Schnabl-Feichter ◽  
Sophia Schnabl ◽  
Alexander Tichy ◽  
Michaela Gumpenberger ◽  
Barbara Bockstahler
Keyword(s):  
Femoral Head ◽  
Head And Neck ◽  
Small Animal ◽  
Control Group ◽  
Total Force ◽  
Ground Reaction Forces ◽  
Vertical Force ◽  
Gait Abnormality ◽  
Pressure Sensitive ◽  
Reaction Forces

Objectives The objective of this study was to compare ground reaction forces (GRFs) of a group of cats after femoral head and neck ostectomy (FHO) with those of a historical control group. Methods We searched the database of the Small Animal Clinic of the Veterinary University in Vienna for cats that had undergone unilateral FHO at least 1 year previously. Owners were telephoned and invited to the clinic with their cats for a re-examination. An in-house owner questionnaire-based evaluation, complete orthopaedic examination, hip radiography and gait analysis with a pressure-sensitive plate were performed, and results were compared within and between groups (FHO group and control group [CG]). Results Seventeen cats that had undergone FHO (FHO group) at least 1 year previously and 15 healthy cats (CG) from a previous study were included. Measured GRFs (peak vertical force and vertical impulse [IFz] normalised to total force [%TF]) of the FHO legs were lower than those of the other legs of the FHO group and the legs of the CG. Results of the owner questionnaire were generally good and did not match the results of the GRF comparison. Furthermore, the gaits evaluated during the orthopaedic examination did not correlate with the measured GRFs where we identified a certain degree of lameness (reduced IFz, %TF) in all cats. Cats with limb shortening (dorsally displaced major trochanter major) were not revealed to have different GRF measurements. Conclusions and relevance This is the first study to assess GRFs in a large group of cats that had undergone FHO, comparing findings with those in healthy cats. Even if the differences are statistically significant, but rather small, our findings point to a long-term residual gait abnormality that could be detected using a pressure-sensitive plate but not always with an orthopaedic examination, in cats 1 year after FHO.

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