scholarly journals Predicting tibiotalar and subtalar joint angles from skin-marker data with dual-fluoroscopy as a reference standard

2016 ◽  
Vol 49 ◽  
pp. 136-143 ◽  
Author(s):  
Jennifer A. Nichols ◽  
Koren E. Roach ◽  
Niccolo M. Fiorentino ◽  
Andrew E. Anderson
Keyword(s):  
Subtalar Joint ◽  
Reference Standard ◽  
Joint Angles ◽  
Marker Data ◽  
Skin Marker

Dynamic in Vivo Subtalar Joint Kinematics Measured Using a Skin Marker–Based Protocol

2014 ◽  
Vol 104 (4) ◽  
pp. 357-364 ◽  
Author(s):  
Ivan Birch ◽  
Kevin Deschamps
Keyword(s):  
Subtalar Joint ◽  
Stance Phase ◽  
Face Validity ◽  
Exclusion Criteria ◽  
In Vivo Kinematics ◽  
Skin Marker ◽  
The Face ◽  
And Function ◽  
Interpatient Variation

Background The subtalar joint allows complex motion of the foot relative to the leg, the analysis of which has presented a major challenge for researchers. The considerable interpatient variation in structure and function of the subtalar joint highlights the importance of developing a protocol to assess the kinematics in individuals rather than developing an overarching description of function. The use of skin-mounted markers is, therefore, preferable, allowing the noninvasive collection of data. We sought to assess the face validity of a skin-mounted marker–based protocol to measure the in vivo kinematics of the subtalar joint. Methods Thirty participants were recruited using minimal exclusion criteria. A previously tested skin-mounted marker placement protocol was used in conjunction with two CODA MPX 30 sensors to capture data during walking. The data produced were compared with those from previous studies that used bone-mounted markers. Results The results in all three planes represented feasible outcomes compared with those of previous studies, the data falling within the ranges published. Patterns of movement demonstrated are similar to, although not the same as, those shown by previous investigations. Conclusions This study did not produce patterns of movement that exactly matched those of previous investigations. The results were, however, within the ranges previously published, and the patterns of movement shown were feasible. The results suggest the face validity of the method as a means of assessing the in vivo kinematics of the subtalar joint during the stance phase of gait.

scholarly journals Quantification of Skin Marker Movement at the Malleoli and Talar Heads

2011 ◽  
Vol 101 (6) ◽  
pp. 497-504 ◽  
Author(s):  
Ivan Birch ◽  
Kevin Deschamps
Keyword(s):  
Subtalar Joint ◽  
Three Dimensional ◽  
Frontal Plane ◽  
Joint Kinematics ◽  
Single Subject ◽  
Bony Landmarks ◽  
Skin Marker ◽  
Angular Measurements ◽  
Foot Function ◽  
Radiopaque Markers

Background: Quantifying subtalar joint kinematics during locomotion is a major challenge but is critical to understanding foot function. The difficulty of modeling the subtalar joint is demonstrated by the plethora of three-dimensional multisegment foot models lacking specific consideration of the subtalar joint. Scientific attempts to develop an adequate method of quantifying subtalar joint kinematics should include investigation of the movement of skin-mounted markers. This study reports on a single-subject investigation into this topic. Methods: Radiopaque markers were attached to the skin overlying the medial and lateral malleoli and the medial and lateral talar heads of a single subject. Frontal, sagittal, and transverse plane radiographs were taken with the foot in the fully pronated and fully supinated positions. Parallax corrected measurements were taken of the displacement of the markers from the bony landmarks. Measurements were also taken of the effect of these displacements on angular calculations. Results: Skin movement at the four anatomical locations was not uniform, with displacements varying from 0.61 to 22.18 mm. Movement of the malleolar markers was found to be less than that of the talar head markers. The distortion of angular measurements caused by movement of the skin markers relative to the bony landmarks was found to be only 1° in the sagittal and transverse planes and 5° in the frontal plane. Conclusions: For this subject, skin-mounted markers could be used to assess subtalar joint motion. Further studies are necessary to investigate the implications of these findings to the wider population. (J Am Podiatr Med Assoc 101(6): 497–504, 2011)

scholarly journals A marker registration method to improve joint angles computed by constrained inverse kinematics

PLoS ONE ◽  
2021 ◽  
Vol 16 (5) ◽  
pp. e0252425
Author(s):  
James J. Dunne ◽  
Thomas K. Uchida ◽  
Thor F. Besier ◽  
Scott L. Delp ◽  
Ajay Seth
Keyword(s):  
Inverse Kinematics ◽  
Humanoid Robot ◽  
Reference Frames ◽  
Joint Angles ◽  
Registration Method ◽  
User Input ◽  
Marker Data ◽  
Model Match ◽  
Mass Properties ◽  
Optical Markers

Accurate computation of joint angles from optical marker data using inverse kinematics methods requires that the locations of markers on a model match the locations of experimental markers on participants. Marker registration is the process of positioning the model markers so that they match the locations of the experimental markers. Markers are typically registered using a graphical user interface (GUI), but this method is subjective and may introduce errors and uncertainty to the calculated joint angles and moments. In this investigation, we use OpenSim to isolate and quantify marker registration–based error from other sources of error by analyzing the gait of a bipedal humanoid robot for which segment geometry, mass properties, and joint angles are known. We then propose a marker registration method that is informed by the orientation of anatomical reference frames derived from surface-mounted optical markers as an alternative to user registration using a GUI. The proposed orientation registration method reduced the average root-mean-square error in both joint angles and joint moments by 67% compared to the user registration method, and eliminated variability among users. Our results show that a systematic method for marker registration that reduces subjective user input can make marker registration more accurate and repeatable.

scholarly journals Effects of Prosthetic Design Parameters on Running of Unilateral Transfemoral Amputee

2020 ◽  
Author(s):  
Cem Guzelbulut ◽  
Katsuyuki Suzuki ◽  
Satoshi Shimono ◽  
Hiroaki Hobara
Keyword(s):  
Computational Model ◽  
Response Surface ◽  
Response Surface Method ◽  
Horizontal Velocity ◽  
Human Model ◽  
Design Parameters ◽  
Joint Angles ◽  
Important Place ◽  
Marker Data ◽  
Surface Method

Abstract Carbon fiber running-specific prostheses (RSP) are widely used among lower-limb amputee runners. However, which prosthesis provides the best performance for a runner remains as an unanswered question. In this purpose, a computational model of the human body with prosthesis was created and the effect of prosthetic parameters on performance was investigated. Firstly, motion capture systems were used to collect data from the amputee running motion. Marker data and force plate data were obtained to create a digital human model. Kinematic data such as length of limbs, joint angles, etc. were calculated by using marker data. Then, inertial properties were estimated to conduct forward and inverse dynamic analyses. After building a computational model of amputee sprinting, joint positions and ground reaction forces (GRF) were compared with experimental results. The design parameters of the prosthesis were introduced to understand the effect of prosthesis on motion and performance. Response surface method was used to express motion adaption regarding geometry and stiffness of the prosthesis. Hip and knee sagittal joint angles were updated based on the response surface method to simulate joint motion adaptations of prosthesis worn. Then, average horizontal velocity, horizontal velocity change over one period, vertical and horizontal impulse was considered as performance functions. An evaluation parameter was proposed to generalize the idea of performance. Prosthetic knee moment and closest point of the prosthesis to the ground during the swing phase were defined as design constraints to consider knee-buckling and tripping of the prosthetic leg, respectively. The effect of design parameters on the performance and constraint functions was investigated. A method to determine and design suitable prostheses for an individual was proposed. It was revealed that the selection and design of prostheses holds an important place to increase performance.

scholarly journals Effect of Limb Position at the Time of Skin Marker Application on Sagittal Plane Kinematics of the Dog

2017 ◽  
Vol 30 (06) ◽  
pp. 438-443 ◽  
Author(s):  
Sun-Young Kim ◽  
Bryan Torres ◽  
Gabriella Sandberg ◽  
Steven Budsberg
Keyword(s):  
Repeated Measures ◽  
Sagittal Plane ◽  
Function Analysis ◽  
Kinematic Model ◽  
Plane Motion ◽  
Waveform Analysis ◽  
Joint Angles ◽  
Limb Position ◽  
Skin Marker ◽  
Joint Range

Abstract Objectives To evaluate the effect of limb position during initial skin marker application on sagittal plane kinematics of the hindlimb. Methods Six healthy dogs (20–30 kg) were evaluated. An established two-dimensional kinematic model of the pelvic limb was utilized to describe sagittal plane motion. Kinematic markers were applied separately for each dog while standing in three different positions: (1) the limb extended cranially, (2) a normal standing limb position and (3) the limb extended caudally. Following marker application at each of the three positions, dynamic gait was recorded at a walk (velocity, 0.9–1.2 m/s; acceleration, 0.5m/s2). Five valid trials were used for comparison. Complete waveform analysis was performed with generalized indicator function analysis (GIFA). Maximum and minimum joint angles and joint range of motion were compared with a one-way repeated measures ANOVA with significance at p < 0.05. Results Significant differences were found between stifle waveforms. No differences were found between the hip or tarsus waveforms. Minimum and maximum joint angles were significantly different for the hip and stifle but not for the tarsus. No differences were found between ranges of motion for any joint evaluated. Clinical Significance Limb position at the time of skin marker application affects gait data and is an important consideration for kinematic analysis of the hindlimb in dogs.

ANTI-OVULATORY ACTIVITY OF STEROIDS ADMINISTERED BY GAVAGE IN THE ADULT OESTRUS RABBIT

1963 ◽  
Vol 42 (2_Suppl) ◽  
pp. S17-S30
Author(s):  
Fred A. Kind ◽  
Ralph I. Dorfman
Keyword(s):  
Dose Response ◽  
Active Compound ◽  
Subcutaneous Injection ◽  
Response Curve ◽  
Parent Compound ◽  
Dose Response Curve ◽  
Relative Potency ◽  
Reference Standard ◽  
Highly Active ◽  
Dose Levels

ABSTRACT Thirty-seven steroids have been studied as orally effective inhibitors of ovulation in the mated oestrus rabbit. Norethisterone served as the reference standard and a dose response curve was established between the 0.31 and 1.25 mg dose levels. Nine highly active anti-ovulatory compounds are described listed in a decreasing order of potency with norethisterone having the arbitrary value of one: 6-chloro-Δ6-dehydro-17α-acetoxyprogesterone (35), 6α-methyl-Δ1-dehydro-17α-acetoxyprogesterone (≥ 10), 6-fluoro-Δ6-dehydro-17α-acetoxyprogesterone(9), 6-methyl-Δ6-dehydro-17α-acetoxyprogesterone (5), Δ6-dehydro-17α-acetoxyprogesterone (≥ 3), 6α-methyl-17α-acetoxyprogesterone (2.6), 6-chloro-Δ1,6-bisdehydro-17α-acetoxyprogesterone (≥ 2), 2-hydroxymethyl-17α-methyl-17β-hydroxyandrostan-3-one (≥ 2), and 6α-fluoro-16α-methyl-17α-acetoxyprogesterone (≥ 1.25). The anti-ovulatory activity of a compound was not related necessarily to the progestational activity of a compound nor to the anti-gonadotrophic activity as measured in parabiotic rats. 6-Chloro-Δ60dehydro-17-acetoxyprogesterone was as effective by gavage as previously shown by subcutaneous injection. 2-Hydroxymethyl-17α-methyl-17β-hydroxyandrostan-3-one was at least 2.5 times more active by gavage than by injection. While 17α-acetoxyprogesterone was a very weak anti-ovulatory steroid, modifications of the structure by addition of methyl or halogen at the 6α position with or without unsaturation greatly increased the activity. 6-Chloro-Δ6-dehydro-27α-acetoxyprogesterone was the most active compound in this series showing a relative potency of 3500 times that of the parent compound 17α-acetoxyprogesterone.

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