Filtering Ground Reaction Force Data Affects the Calculation and Interpretation of Joint Kinetics and Energetics During Drop Landings

2013 ◽  
Vol 29 (6) ◽  
pp. 804-809 ◽  
Author(s):  
Steven T. McCaw ◽  
Jacob K. Gardner ◽  
Lindsay N. Stafford ◽  
Michael R. Torry
Keyword(s):  
Hip Joint ◽  
Inverse Dynamics ◽  
Sagittal Plane ◽  
Reaction Force ◽  
Joint Moment ◽  
Inverse Dynamic ◽  
Joint Kinetics ◽  
Marker Data ◽  
High Frequency Oscillations ◽  
Subsequent Calculation

An inverse dynamic analysis and subsequent calculation of joint kinetic and energetic measures is widely used to study the mechanics of the lower extremity. Filtering the kinematic and kinetic data input to the inverse dynamics equations affects the calculated joint moment of force (JMF). Our purpose was to compare selected integral values of sagittal plane ankle, knee, and hip joint kinetics and energetics when filtered and unfiltered GRF data are input to inverse dynamics calculations. Six healthy, active, injury-free university student (5 female, 1 male) volunteers performed 10 two-legged landings. JMFs were calculated after two methods of data filtering. Unfiltered: marker data were filtered at 10 Hz, GRF data unfiltered. Filtered: both GRF and marker data filtered at 10 Hz. The filtering of the GRF data affected the shape of the knee and hip joint moment-time curves, and the ankle, knee and hip joint mechanical power-time curves. We concluded that although the contributions of individual joints to the support moment and to total energy absorption were not affected, the attenuation of high-frequency oscillations in both JMF and JMP time curves will influence interpretation of CNS strategies during landing.

scholarly journals The effect of stride length on lower extremity joint kinetics at various gait speeds

2018 ◽  
Author(s):  
Robert L. McGrath ◽  
Melissa L. Ziegler ◽  
Margaret Pires-Fernandes ◽  
Brian A. Knarr ◽  
Jill S. Higginson ◽  
...  
Keyword(s):  
Lower Extremity ◽  
Gait Speed ◽  
Stride Length ◽  
Inverse Dynamics ◽  
Sagittal Plane ◽  
Gait Training ◽  
Joint Moment ◽  
Joint Moments ◽  
Joint Kinetics ◽  
Trailing Limb Angle

AbstractRobot-assisted training is a promising tool under development for improving walking function based on repetitive goal-oriented task practice. The challenges in developing the controllers for gait training devices that promote desired changes in gait is complicated by the limited understanding of the human response to robotic input. A possible method of controller formulation can be based on the principle of bio-inspiration, where a robot is controlled to apply the change in joint moment applied by human subjects when they achieve a gait feature of interest. However, it is currently unclear how lower extremity joint moments are modulated by even basic gaitspatio-temporal parameters.In this study, we investigated how sagittal plane joint moments are affected by a factorial modulation of two important gait parameters: gait speed and stride length. We present the findings obtained from 20 healthy control subjects walking at various treadmill-imposed speeds and instructed to modulate stride length utilizing real-time visual feedback. Implementing a continuum analysis of inverse-dynamics derived joint moment profiles, we extracted the effects of gait speed and stride length on joint moment throughout the gait cycle. Moreover, we utilized a torque pulse approximation analysis to determine the timing and amplitude of torque pulses that approximate the difference in joint moment profiles between stride length conditions, at all gait speed conditions.Our results show that gait speed has a significant effect on the moment profiles in all joints considered, while stride length has more localized effects, with the main effect observed on the knee moment during stance, and smaller effects observed for the hip joint moment during swing and ankle moment during the loading response. Moreover, our study demonstrated that trailing limb angle, a parameter of interest in programs targeting propulsion at push-off, was significantly correlated with stride length. As such, our study has generated assistance strategies based on pulses of torque suitable for implementation via a wearable exoskeleton with the objective of modulating stride length, and other correlated variables such as trailing limb angle.

The Validity of Summing Lower Extremity Individual Joint Kinetic Measures

2005 ◽  
Vol 21 (2) ◽  
pp. 181-188 ◽  
Author(s):  
Sean P. Flanagan ◽  
George J. Salem
Keyword(s):  
Lower Extremity ◽  
Inverse Dynamics ◽  
Sagittal Plane ◽  
Human Movement ◽  
Joint Moment ◽  
Biomechanical Analysis ◽  
Lower Extremity Function ◽  
Single Measure ◽  
Work Task ◽  
Joint Kinetics

In the analysis of human movement, researchers often sum individual joint kinetics to obtain a single measure of lower extremity function. The extent to which these summed measures relate to the mechanical objectives of the task has not been formally validated. The criterion validity of these measures was established with comparisons to the mechanical objective of two multiple-joint tasks. For the Work task 18 participants performed a loaded barbell squat using 4 resistances while instrumented for biomechanical analysis. For the Power they performed 2 predetermined amounts of work at both self-selected and fast speeds. Using inverse dynamics techniques, the peak net joint moment (PM) was calculated bilaterally in the sagittal plane at the ankle, knee, and hip and was summed into a single measure. This measure was correlated with the task objectives using simple linear regression. Similar procedures were used for the average net joint moment (AM), peak (PP), and average (AP) net joint moment power, and the net joint moment impulse (IM) and work (IP). For the Work task all 6 measures were significantly correlated with the task objective, but only AM, PM, and IP had correlation coefficients above 0.90. For the Power task, IM was not significantly correlated with the task objective, and only AP had a correlation coefficient above 0.90. These findings indicate that the validity of summing individual kinetic measures depends on both the measure chosen and the mechanical objective of the task.

scholarly journals Lower Limb Joint Kinetics During a Side-Cutting Task in Participants With or Without Chronic Ankle Instability

2020 ◽  
Vol 55 (2) ◽  
pp. 169-175 ◽  
Author(s):  
Jeffrey D. Simpson ◽  
Ethan M. Stewart ◽  
Alana J. Turner ◽  
David M. Macias ◽  
Harish Chander ◽  
...  
Keyword(s):  
Hip Joint ◽  
Lower Limb ◽  
Stance Phase ◽  
Sagittal Plane ◽  
Ankle Instability ◽  
Reaction Force ◽  
Joint Stiffness ◽  
Control Group ◽  
Joint Kinetics ◽  
3 Dimensional

Context Individuals with chronic ankle instability (CAI) demonstrate altered lower limb movement dynamics during jump landings, which can contribute to recurrent injury. However, the literature examining lower limb movement dynamics during a side-cutting task in individuals with CAI is limited. Objective To assess lower limb joint kinetics and sagittal-plane joint stiffness during the stance phase of a side-cutting task in individuals with or without CAI. Design Cohort study. Setting Motion-capture laboratory. Patients or Other Participants Fifteen physically active, young adults with CAI (7 men, 8 women; age = 21.3 ± 1.6 years, height = 171.0 ± 11.2 cm, mass = 73.4 ± 15.2 kg) and 15 healthy matched controls (7 men, 8 women; age = 21.5 ± 1.5 years, height = 169.9 ± 10.6 cm, mass = 75.5 ± 13.0 kg). Intervention(s) Lower limb 3-dimensional kinematic and ground reaction force data were recorded while participants completed 3 successful trials of a side-cutting task. Net internal joint moments, in addition to sagittal-plane ankle-, knee-, and hip-joint stiffness, were computed from 3-dimensional kinematic and ground reaction force data during the stance phase of the side-cutting task and analyzed. Main Outcome Measure(s) Data from each participant's stance phase were normalized to 100% from initial foot contact (0%) to toe-off (100%) to compute means, standard deviations, and Cohen d effect sizes for all dependent variables. Results The CAI group exhibited a reduced ankle-eversion moment (39%–81% of stance phase) and knee-abduction moment (52%–75% of stance phase) and a greater ankle plantar-flexion moment (3%–16% of stance phase) than the control group (P range = .009–.049). Sagittal-plane hip-joint stiffness was greater in the CAI than in the control group (t28 = 1.978, P = .03). Conclusions Our findings suggest that altered ankle-joint kinetics and increased hip-joint stiffness were associated when individuals with CAI performed a side-cutting task. These lower limb kinetic changes may contribute to an increased risk of recurrent lateral ankle sprains in people with CAI. Clinicians and practitioners can use these findings to develop rehabilitation programs for improving maladaptive movement mechanics in individuals with CAI.

scholarly journals Dynamic input to determine hip joint moments, power and work on the prosthetic limb of transfemoral amputees: ground reaction vs knee reaction

2011 ◽  
Vol 35 (2) ◽  
pp. 140-149 ◽  
Author(s):  
Laurent Frossard ◽  
Laurence Cheze ◽  
Raphael Dumas
Keyword(s):  
Hip Joint ◽  
Inverse Dynamics ◽  
Joint Moments ◽  
Foot Placement ◽  
Joint Kinetics ◽  
Prosthetic Limb ◽  
Wide Range ◽  
Realistic Assessment ◽  
Risk Of Falls ◽  
Analysis System

Background: Calculation of lower limb kinetics is limited by floor-mounted force-plates. Objectives: Comparison of hip joint moments, power and mechanical work on the prosthetic limb of a transfemoral amputee calculated by inverse dynamics using either the ground reactions (force-plates) or knee reactions (transducer). Study design: Comparative analysis. Methods: Kinematics, ground reaction and knee reaction data were collected using a motion analysis system, two force-plates, and a multi-axial transducer mounted below the socket, respectively. Results: The inverse dynamics using ground reaction underestimated the peaks of hip energy generation and absorption occurring at 63% and 76% of the gait cycle (GC) by 28% and 54%, respectively. This method also overestimated by 24% a phase of negative work at the hip (37%–56% GC), and underestimated the phases of positive (57%–72% GC) and negative (73%–98%GC) work at the hip by 11% and 58%, respectively. Conclusions: A transducer mounted within the prosthesis has the capacity to provide more realistic kinetics of the prosthetic limb because it enables assessment of multiple consecutive steps and a wide range of activities without the issue of foot placement on force-plates. Clinical relevance The hip is the only joint an amputee controls directly to set the prosthesis in motion. Hip joint kinetics are associated with joint degeneration, low back pain, risk of falls, etc. Therefore, realistic assessment of hip kinetics over multiple gait cycles and a wide range of activities is essential.

Minimal Kinematic Model for Inverse Dynamic Analysis of Gait

2014 ◽  
Author(s):  
D. S. Mohan Varma ◽  
S. Sujatha
Keyword(s):  
Inverse Dynamics ◽  
Sagittal Plane ◽  
Center Of Mass ◽  
Reaction Force ◽  
Kinematic Model ◽  
Parameter Estimates ◽  
Dynamics Model ◽  
Kinematic Data ◽  
Segment Model ◽  
Internal Joint

The objective of this work is to develop an inverse dynamics model that uses minimal kinematic inputs to estimate the ground reaction force (GRF). The human body is modeled with 14 rigid segments and a circular ankle-foot-roll-over shape (AFROS) for the foot-ground interaction. The input kinematic data and body segment parameter estimates are obtained from literature. Optimization is used to ensure that the kinematic data satisfy the constraint that the swing leg clears the ground in the single support (SS) phase. For the SS phase, using the segment angles as the generalized degrees of freedom (DOF), the kinematic component of the GRF is expressed analytically as the summation of weighted kinematics of individual segments. The weighting functions are constants that are functions of the segment masses and center of mass distances. Using this form of the equation for GRF, it is seen that the kinematics of the upper body segments do not contribute to the vertical component GRFy in SS phase enabling the reduction of a 16-DOF 14-segment model to a 10-DOF 7-segment model. It is seen that the model can be further reduced to a 3-DOF model for GRFy estimation in the SS phase of gait. The horizontal component GRFx is computed assuming that the net GRF vector passes through the center of mass (CoM). The GRF in double support phase is assumed to change linearly from one foot to the other. The sagittal plane internal joint forces and moments acting at the ankle, knee and hip are computed using the 3-DOF model and the 10-DOF model and compared with the results from literature. An AFROS and measurements of the stance shank and thigh rotations in the sagittal plane, and of the lower trunk (or pelvis) in the frontal plane provide sufficient kinematics in an inverse dynamics model to estimate the GRF and joint reaction forces and moments. Such a model has the potential to simplify gait analysis.

DEALING WITH SKIN MOTION AND WOBBLING MASSES IN INVERSE DYNAMICS

2003 ◽  
Vol 03 (03n04) ◽  
pp. 309-335 ◽  
Author(s):  
MICHAEL GÜNTHER ◽  
VIKTOR A. SHOLUKHA ◽  
DANNY KESSLER ◽  
VEIT WANK ◽  
REINHARD BLICKHAN
Keyword(s):  
Soft Tissue ◽  
Dynamic Analysis ◽  
Dynamic Model ◽  
Hip Joint ◽  
Inverse Dynamics ◽  
Time History ◽  
Joint Torque ◽  
Inverse Dynamic ◽  
Inverse Dynamic Model ◽  
The Impact

Inverse dynamics is a standard analysis in biomechanics to reconstruct time histories of internal driving forces and torques from measured external forces and segmental kinematics. The main sources of inconsistency leading to analytical artefacts in this process are skin marker and soft tissue motion. These potentially artificial high frequency fluctuations in the joint torques may serve as an erroneous basis of (misleading) assumptions with respect to muscular activity. Here we suggest techniques to reduce these errors. In both parts of this study, high-speed video and force platform data were acquired. In one part, 69 sequences of human barefoot running were sampled followed by an inverse dynamic analysis of the stance leg. The time history of the hip joint torque in the sagittal plane served as a sensitive "detector" of dynamic analysis artefacts. We show that the most important error — the relative skin to bone motion especially of the knee marker — can be reduced significantly by processing kinematic data using bone rigidity (constant segment lengths) and bony contour (frontal knee edge) information. Further on, neglecting significantly initiated soft tissue dynamics in the inverse dynamic model introduces another inconsistency in the analytical process. Therefore, in a second part of this study, soft tissue kinematics from 14 jumping sequences were identified. These data provided a set of coupling parameters of wobbling masses to the bone that were ready to be implemented in the inverse dynamic model. Using realistic bone kinematics mainly avoids phase shifts in the acceleration scenario within the leg, and thus artifical hip torque fluctuations within the whole contact period. In human running, accounting for soft tissue dynamics mainly affects the calculated timing of the hip joint torque during the impact phase.

The Relationship between Joint Kinetic Factors and the Walk–Run Gait Transition Speed during Human Locomotion

2008 ◽  
Vol 24 (2) ◽  
pp. 149-157 ◽  
Author(s):  
Alan Hreljac ◽  
Rodney T. Imamura ◽  
Rafael F. Escamilla ◽  
W. Brent Edwards ◽  
Toran MacLeod
Keyword(s):  
Inverse Dynamics ◽  
Sagittal Plane ◽  
Reaction Force ◽  
Human Locomotion ◽  
Force Platform ◽  
Gait Transition ◽  
Transition Speed ◽  
The Right ◽  
Preferred Transition Speed

The primary purpose of this project was to examine whether lower extremity joint kinetic factors are related to the walk–run gait transition during human locomotion. Following determination of the preferred transition speed (PTS), each of the 16 subjects walked down a 25-m runway, and over a floor-mounted force platform at five speeds (70, 80, 90, 100, and 110% of the PTS), and ran over the force platform at three speeds (80, 100, and 120% of the PTS) while being videotaped (240 Hz) from the right sagittal plane. Two-dimensional kinematic data were synchronized with ground reaction force data (960 Hz). After smoothing, ankle and knee joint moments and powers were calculated using standard inverse dynamics calculations. The maximum dorsiflexor moment was the only variable tested that increased as walking speed increased and then decreased when gait changed to a run at the PTS, meeting the criteria set to indicate that this variable influences the walk–run gait transition during human locomotion. This supports previous research suggesting that an important factor in changing gaits at the PTS is the prevention of undue stress in the dorsiflexor muscles.

scholarly journals Relationship between Asymmetry of Gait and Muscle Torque in Patients after Unilateral Transfemoral Amputation

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Alicja Rutkowska-Kucharska ◽  
Mateusz Kowal ◽  
Sławomir Winiarski
Keyword(s):  
Hip Joint ◽  
Reaction Force ◽  
Transfemoral Amputation ◽  
Gait Symmetry ◽  
Symmetry Index ◽  
Muscle Torque ◽  
Effective Form ◽  
Gait Asymmetry ◽  
Torque Values ◽  
Therapy Programme

Many studies have shown that unilateral transfemoral amputation involves asymmetric gait. Transfemoral amputation leads to muscle atrophy in a tight stump resulting in asymmetry in muscle torque between the amputated and intact limb. This research is aimed at verifying if a relationship between torque values of hip joint flexors and extensors and gait asymmetry in patients with TFA exists. Fourteen adult subjects with unilateral TFA took part in the experiment. Gait symmetry was evaluated based on the ground reaction force (GRF). Measurements of muscle torque of hip flexors and extensors were taken with a Biodex System. All measurements were taken under isokinetic (60°/s and 120°/s) and isometric conditions. The symmetry index of vertical GRF components was from 7.5 to 11.5%, and anterio-posterior GRF from 6.2 to 9.3%. The symmetry index for muscle torque was from 24.3 to 44% for flexors, from 39 to 50.5% for extensors, and from 28.6 to 50% in the flexor/extensor ratio. Gait asymmetry correlated with muscle torque in hip joint extensors. Therapy which enhances muscle torque may be an effective form of patient therapy. The patient needs to undergo evaluation of their muscle strength and have the therapy programme adjusted to their level of muscle torque deficit.

scholarly journals Balancing on a narrow ridge: biomechanics and control

1999 ◽  
Vol 354 (1385) ◽  
pp. 869-875 ◽  
Author(s):  
E. Otten
Keyword(s):  
Hip Joint ◽  
Ground Reaction Force ◽  
Inverted Pendulum ◽  
Reaction Force ◽  
Angular Acceleration ◽  
Centre Of Mass ◽  
Inverted Pendulum Model ◽  
Pendulum Model ◽  
Narrow Ridge ◽  
Standing Humans

The balance of standing humans is usually explained by the inverted pendulum model. The subject invokes a horizontal ground–reaction force in this model and controls it by changing the location of the centre of pressure under the foot or feet. In experiments I showed that humans are able to stand on a ridge of only a few millimetres wide on one foot for a few minutes. In the present paper I investigate whether the inverted pendulum model is able to explain this achievement. I found that the centre of mass of the subjects sways beyond the surface of support, rendering the inverted pendulum model inadequate. Using inverse simulations of the dynamics of the human body, I found that hip–joint moments of the stance leg are used to vary the horizontal component of the ground–reaction force. This force brings the centre of mass back over the surface of support. The subjects generate moments of force at the hip–joint of the swing leg, at the shoulder–joints and at the neck. These moments work in conjunction with a hip strategy of the stance leg to limit the angular acceleration of the head–arm–trunk complex. The synchrony of the variation in moments suggests that subjects use a motor programme rather than long latency reflexes.

Inverse Dynamic Analysis and Linearisation of a High Speed Parallel Mechanism

2005 ◽  
Author(s):  
M. Necip Sahinkaya ◽  
Yanzhi Li
Keyword(s):  
Dynamic Analysis ◽  
Parallel Mechanism ◽  
High Speed ◽  
Inverse Dynamics ◽  
Motion Path ◽  
Model Parameters ◽  
Control Input ◽  
Inverse Dynamic ◽  
Inverse Dynamic Analysis ◽  
Dynamics Models

Inverse dynamic analysis of a three degree of freedom parallel mechanism driven by three electrical motors is carried out to study the effect of motion speed on the system dynamics and control input requirements. Availability of inverse dynamics models offer many advantages, but controllers based on real-time inverse dynamic simulations are not practical for many applications due to computational limitations. An off-line linearisation of system and error dynamics based on the inverse dynamic analysis is developed. It is shown that accurate linear models can be obtained even at high motion speeds eliminating the need to use computationally intensive inverse dynamics models. A point-to-point motion path for the mechanism platform is formulated by using a third order exponential function. It is shown that the linearised model parameters vary significantly at high motion speeds, hence it is necessary to use adaptive controllers for high performance.

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