scholarly journals Inertial sensor-based knee flexion/extension angle estimation

2009 ◽  
Vol 42 (16) ◽  
pp. 2678-2685 ◽  
Author(s):  
Glen Cooper ◽  
Ian Sheret ◽  
Louise McMillian ◽  
Konstantinos Siliverdis ◽  
Ning Sha ◽  
...  
Keyword(s):  
Knee Flexion ◽  
Inertial Sensor ◽  
Angle Estimation ◽  
Flexion Extension

Erratum to “Inertial sensor-based knee flexion/extension angle estimation” [J. Biomech. 42 (2009) 2678–2685]

2010 ◽  
Vol 43 (3) ◽  
pp. 598 ◽  
Author(s):  
Glen Cooper ◽  
Ian Sheret ◽  
Louise McMillan ◽  
Konstantinos Siliverdis ◽  
Ning Sha ◽  
...  
Keyword(s):  
Knee Flexion ◽  
Inertial Sensor ◽  
Angle Estimation ◽  
Flexion Extension

Cardiovascular and Metabolic Responses to Electrical Stimulation-Induced Leg Exercise in Spinal Cord Injury

1997 ◽  
Vol 36 (04/05) ◽  
pp. 372-375 ◽  
Author(s):  
J. R. Sutton ◽  
A. J. Thomas ◽  
G. M. Davis
Keyword(s):  
Spinal Cord ◽  
Heart Rate ◽  
Spinal Cord Injury ◽  
Cardiac Output ◽  
Electrical Stimulation ◽  
Knee Flexion ◽  
Flexion Extension ◽  
Cord Injury ◽  
Leg Exercise ◽  
Leg Muscle

Abstract:Electrical stimulation-induced leg muscle contractions provide a useful model for examining the role of leg muscle neural afferents during low-intensity exercise in persons with spinal cord-injury and their able-bodied cohorts. Eight persons with paraplegia (SCI) and 8 non-disabled subjects (CONTROL) performed passive knee flexion/extension (PAS), electrical stimulation-induced knee flexion/extension (ES) and voluntary knee flexion/extension (VOL) on an isokinetic dynamometer. In CONTROLS, exercise heart rate was significantly increased during ES (94 ± 6 bpm) and VOL (85 ± 4 bpm) over PAS (69 ± 4 bpm), but no changes were observed in SCI individuals. Stroke volume was significantly augmented in SCI during ES (59 ± 5 ml) compared to PAS (46 ± 4 ml). The results of this study suggest that, in able-bodied humans, Group III and IV leg muscle afferents contribute to increased cardiac output during exercise primarily via augmented heart rate. In contrast, SCI achieve raised cardiac output during ES leg exercise via increased venous return in the absence of any change in heart rate.

Forces at the Anterior Meniscus Attachments Strongly Increase Under Dynamic Knee Joint Loading

2021 ◽  
Vol 49 (4) ◽  
pp. 994-1004
Author(s):  
Andreas Martin Seitz ◽  
Florian Schall ◽  
Steffen Paul Hacker ◽  
Stefan van Drongelen ◽  
Sebastian Wolf ◽  
...  
Keyword(s):  
Knee Flexion ◽  
Muscle Force ◽  
Meniscal Tear ◽  
In Vitro Tests ◽  
Jump Landing ◽  
Medial Meniscectomy ◽  
Attachment Structures ◽  
Flexion Extension ◽  
Longitudinal Tear

Background: The anatomic appearance and biomechanical and clinical importance of the anterior meniscus roots are well described. However, little is known about the loads that act on these attachment structures under physiological joint loads and movements. Hypotheses: As compared with uniaxial loading conditions under static knee flexion angles or at very low flexion-extension speeds, more realistic continuous movement simulations in combination with physiological muscle force simulations lead to significantly higher anterior meniscus attachment forces. This increase is even more pronounced in combination with a longitudinal meniscal tear or after total medial meniscectomy. Study Design: Controlled laboratory study. Methods: A validated Oxford Rig–like knee simulator was used to perform a slow squat, a fast squat, and jump landing maneuvers on 9 cadaveric human knee joints, with and without muscle force simulation. The strains in the anterior medial and lateral meniscal periphery and the respective attachments were determined in 3 states: intact meniscus, medial longitudinal tear, and total medial meniscectomy. To determine the attachment forces, a subsequent in situ tensile test was performed. Results: Muscle force simulation resulted in a significant strain increase at the anterior meniscus attachments of up to 308% ( P < .038) and the anterior meniscal periphery of up to 276%. This corresponded to significantly increased forces ( P < .038) acting in the anteromedial attachment with a maximum force of 140 N, as determined during the jump landing simulation. Meniscus attachment strains and forces were significantly influenced ( P = .008) by the longitudinal tear and meniscectomy during the drop jump simulation. Conclusion: Medial and lateral anterior meniscus attachment strains and forces were significantly increased with physiological muscle force simulation, corroborating our hypothesis. Therefore, in vitro tests applying uniaxial loads combined with static knee flexion angles or very low flexion-extension speeds appear to underestimate meniscus attachment forces. Clinical Relevance: The data of the present study might help to optimize the anchoring of meniscal allografts and artificial meniscal substitutes to the tibial plateau. Furthermore, this is the first in vitro study to indicate reasonable minimum stability requirements regarding the reattachment of torn anterior meniscus roots.

scholarly journals Accent Stabilizes 1:2 Sensorimotor Synchronization of Rhythmic Knee Flexion-Extension Movement in Upright Stance

2019 ◽  
Vol 10 ◽  
Author(s):  
Takahide Etani ◽  
Akito Miura ◽  
Masahiro Okano ◽  
Masahiro Shinya ◽  
Kazutoshi Kudo
Keyword(s):  
Knee Flexion ◽  
Sensorimotor Synchronization ◽  
Upright Stance ◽  
Flexion Extension

scholarly journals Effects of selectively assisting impaired subtasks of walking in chronic stroke survivors

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Simone S. Fricke ◽  
Hilde J. G. Smits ◽  
Cristina Bayón ◽  
Jaap H. Buurke ◽  
Herman van der Kooij ◽  
...  
Keyword(s):  
Knee Flexion ◽  
Step Length ◽  
Gait Training ◽  
Chronic Stroke ◽  
Stroke Survivors ◽  
Baseline Trial ◽  
Gait Parameters ◽  
Flexion Extension ◽  
Spatiotemporal Parameters ◽  
Length Width

Abstract Background Recently developed controllers for robot-assisted gait training allow for the adjustment of assistance for specific subtasks (i.e. specific joints and intervals of the gait cycle that are related to common impairments after stroke). However, not much is known about possible interactions between subtasks and a better understanding of this can help to optimize (manual or automatic) assistance tuning in the future. In this study, we assessed the effect of separately assisting three commonly impaired subtasks after stroke: foot clearance (FC, knee flexion/extension during swing), stability during stance (SS, knee flexion/extension during stance) and weight shift (WS, lateral pelvis movement). For each of the assisted subtasks, we determined the influence on the performance of the respective subtask, and possible effects on other subtasks of walking and spatiotemporal gait parameters. Methods The robotic assistance for the FC, SS and WS subtasks was assessed in nine mildly impaired chronic stroke survivors while walking in the LOPES II gait trainer. Seven trials were performed for each participant in a randomized order: six trials in which either 20% or 80% of assistance was provided for each of the selected subtasks, and one baseline trial where the participant did not receive subtask-specific assistance. The influence of the assistance on performances (errors compared to reference trajectories) for the assisted subtasks and other subtasks of walking as well as spatiotemporal parameters (step length, width and height, swing and stance time) was analyzed. Results Performances for the impaired subtasks (FC, SS and WS) improved significantly when assistance was applied for the respective subtask. Although WS performance improved when assisting this subtask, participants were not shifting their weight well towards the paretic leg. On a group level, not many effects on other subtasks and spatiotemporal parameters were found. Still, performance for the leading limb angle subtask improved significantly resulting in a larger step length when applying FC assistance. Conclusion FC and SS assistance leads to clear improvements in performance for the respective subtask, while our WS assistance needs further improvement. As effects of the assistance were mainly confined to the assisted subtasks, tuning of FC, SS and WS can be done simultaneously. Our findings suggest that there may be no need for specific, time-intensive tuning protocols (e.g. tuning subtasks after each other) in mildly impaired stroke survivors.

scholarly journals Validation of Novel Relative Orientation and Inertial Sensor-to-Segment Alignment Algorithms for Estimating 3D Hip Joint Angles

Sensors ◽  
2019 ◽  
Vol 19 (23) ◽  
pp. 5143 ◽  
Author(s):  
Lukas Adamowicz ◽  
Reed Gurchiek ◽  
Jonathan Ferri ◽  
Anna Ursiny ◽  
Niccolo Fiorentino ◽  
...  
Keyword(s):  
Range Of Motion ◽  
Hip Joint ◽  
Inertial Sensor ◽  
Estimation Error ◽  
Relative Orientation ◽  
Joint Angles ◽  
Alignment Algorithms ◽  
Sensor Orientation ◽  
Flexion Extension ◽  
Optical Motion

Wearable sensor-based algorithms for estimating joint angles have seen great improvements in recent years. While the knee joint has garnered most of the attention in this area, algorithms for estimating hip joint angles are less available. Herein, we propose and validate a novel algorithm for this purpose with innovations in sensor-to-sensor orientation and sensor-to-segment alignment. The proposed approach is robust to sensor placement and does not require specific calibration motions. The accuracy of the proposed approach is established relative to optical motion capture and compared to existing methods for estimating relative orientation, hip joint angles, and range of motion (ROM) during a task designed to exercise the full hip range of motion (ROM) and fast walking using root mean square error (RMSE) and regression analysis. The RMSE of the proposed approach was less than that for existing methods when estimating sensor orientation ( 12 . 32 ∘ and 11 . 82 ∘ vs. 24 . 61 ∘ and 23 . 76 ∘ ) and flexion/extension joint angles ( 7 . 88 ∘ and 8 . 62 ∘ vs. 14 . 14 ∘ and 15 . 64 ∘ ). Also, ROM estimation error was less than 2 . 2 ∘ during the walking trial using the proposed method. These results suggest the proposed approach presents an improvement to existing methods and provides a promising technique for remote monitoring of hip joint angles.

scholarly journals Knee Flexion and Daily Activities in Patients following Total Knee Replacement: A Comparison with ISO Standard 14243

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Markus A. Wimmer ◽  
William Nechtow ◽  
Thorsten Schwenke ◽  
Kirsten C. Moisio
Keyword(s):  
Total Knee Replacement ◽  
Knee Replacement ◽  
Knee Flexion ◽  
Daily Activities ◽  
Wear Testing ◽  
Significant Difference ◽  
Flexion Extension ◽  
Total Knee ◽  
Stair Walking ◽  
The Many

Walking is only one of many daily activities performed by patients following total knee replacement (TKR). The purpose of this study was to examine the hypotheses (a) that subject activity characteristics are correlated with knee flexion range of motion (ROM) and (b) that there is a significant difference between the subject’s flexion/extension excursion throughout the day and the ISO specified input for knee wear testing. In order to characterize activity, the number of walking and stair stepping cycles, the time spent with dynamic and stationary activities, the number of activity sequences, and the knee flexion/extension excursion of 32 TKR subjects were collected during daily activity. Flexion/extension profiles were compared with the ISO 14243 simulator input profile using a level crossing classification algorithm. Subjects took an average of 3102 (range: 343–5857) walking cycles including 65 (range: 0–319) stair stepping cycles. Active and passive ROMs were positively correlated with stair walking time, stair step counts, and stair walking sequences. Simulated knee motion according to ISO showed significantly fewer level crossings at the flexion angles 20–40° and beyond 50° than those measured with the monitor. This suggests that implant wear testing protocols should contain more cycles and a variety of activities requiring higher knee flexion angles with incorporated resting/transition periods to account for the many activity sequences.

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