scholarly journals Examination of Inertial Sensor-Based Estimation Methods of Lower Limb Joint Moments and Ground Reaction Force: Results for Squat and Sit-to-Stand Movements in the Sagittal Plane

Sensors ◽  
2016 ◽  
Vol 16 (8) ◽  
pp. 1209 ◽  
Author(s):  
Jun Kodama ◽  
Takashi Watanabe
Sensors ◽  
2019 ◽  
Vol 19 (1) ◽  
pp. 141 ◽  
Author(s):  
Rob Van der Straaten ◽  
Amber K. B. D. Bruijnes ◽  
Benedicte Vanwanseele ◽  
Ilse Jonkers ◽  
Liesbet De Baets ◽  
...  

This study evaluates the reliability and agreement of the 3D range of motion (ROM) of trunk and lower limb joints, measured by inertial measurement units (MVN BIOMECH Awinda, Xsens Technologies), during a single leg squat (SLS) and sit to stand (STS) task. Furthermore, distinction was made between movement phases, to discuss the reliability and agreement for different phases of both movement tasks. Twenty healthy participants were measured on two testing days. On day one, measurements were conducted by two operators to determine the within-session and between-operator reliability and agreement. On day two, measurements were conducted by the same operator, to determine the between-session reliability and agreement. The SLS task had lower within-session reliability and agreement compared with between-session and between-operator reliability and agreement. The reliability and agreement of the hip, knee, and ankle ROM in the sagittal plane were good for both phases of the SLS task. For both phases of STS task, within-session reliability and agreement were good, and between-session and between-operator reliability and agreement were lower in all planes. As both tasks are physically demanding, differences may be explained by inconsistent movement strategies. These results show that inertial sensor systems show promise for use in further research to investigate (mal)adaptive movement strategies.


2019 ◽  
Vol 126 (5) ◽  
pp. 1315-1325 ◽  
Author(s):  
Andrew B. Udofa ◽  
Kenneth P. Clark ◽  
Laurence J. Ryan ◽  
Peter G. Weyand

Although running shoes alter foot-ground reaction forces, particularly during impact, how they do so is incompletely understood. Here, we hypothesized that footwear effects on running ground reaction force-time patterns can be accurately predicted from the motion of two components of the body’s mass (mb): the contacting lower-limb (m1 = 0.08mb) and the remainder (m2 = 0.92mb). Simultaneous motion and vertical ground reaction force-time data were acquired at 1,000 Hz from eight uninstructed subjects running on a force-instrumented treadmill at 4.0 and 7.0 m/s under four footwear conditions: barefoot, minimal sole, thin sole, and thick sole. Vertical ground reaction force-time patterns were generated from the two-mass model using body mass and footfall-specific measures of contact time, aerial time, and lower-limb impact deceleration. Model force-time patterns generated using the empirical inputs acquired for each footfall matched the measured patterns closely across the four footwear conditions at both protocol speeds ( r2 = 0.96 ± 0.004; root mean squared error  = 0.17 ± 0.01 body-weight units; n = 275 total footfalls). Foot landing angles (θF) were inversely related to footwear thickness; more positive or plantar-flexed landing angles coincided with longer-impact durations and force-time patterns lacking distinct rising-edge force peaks. Our results support three conclusions: 1) running ground reaction force-time patterns across footwear conditions can be accurately predicted using our two-mass, two-impulse model, 2) impact forces, regardless of foot strike mechanics, can be accurately quantified from lower-limb motion and a fixed anatomical mass (0.08mb), and 3) runners maintain similar loading rates (ΔFvertical/Δtime) across footwear conditions by altering foot strike angle to regulate the duration of impact. NEW & NOTEWORTHY Here, we validate a two-mass, two-impulse model of running vertical ground reaction forces across four footwear thickness conditions (barefoot, minimal, thin, thick). Our model allows the impact portion of the impulse to be extracted from measured total ground reaction force-time patterns using motion data from the ankle. The gait adjustments observed across footwear conditions revealed that runners maintained similar loading rates across footwear conditions by altering foot strike angles to regulate the duration of impact.


Author(s):  
Akbar Hojjati Najafabadi ◽  
Saeid Amini ◽  
Farzam Farahmand

Physical problems caused by fractures, aging, stroke, and accidents can reduce foot power; these, in the long term, can dwindle the muscles of the waist, thighs, and legs. These conditions provide the basis for the invalidism of the harmed people. In this study, a saddle-walker was designed and evaluated to help people suffering from spinal cord injury and patients with lower limb weakness. This S-AD works based on body weight support against the previously report designs. This saddle-walker consisted of a non-powered four-wheel walker helping to walk and a powered mechanism for the sit-to-stand (STS) transfer. A set of experiments were done on the STS in the use of the standard walker and the saddle-assistive device(S-AD). A comparison of the results showed that this device could reduce the vertical ground reaction force (GRF) of the legs up to 70%. Using this device could help a wide range of patients with lower limb weakness and SCI patients in changing from sitting to standing.


2011 ◽  
Vol 43 (Suppl 1) ◽  
pp. 930-931
Author(s):  
Taishi Tsuji ◽  
Tomohiro Okura ◽  
Kenji Tsunoda ◽  
Yasuhiro Mitsuishi ◽  
Naruki Kitano ◽  
...  

2005 ◽  
Vol 29 (3) ◽  
pp. 255-267 ◽  
Author(s):  
J. M. van Velzen ◽  
H. Houdijk ◽  
W. Polomski ◽  
C. A. M. van Bennekom

The purpose of the study was to investigate which systematic effects of prosthetic misalignment could be observed with the use of the SYBAR system. The alignment of the prosthesis of five well-trained unilateral trans-tibial amputees was changed 158 in magnitude in varus, valgus, flexion, extension, endorotation, exorotation, dorsal flexion, and plantar flexion. Subjects walked over a distance of 8 m at a self-selected walking speed with the alignment of the prosthesis as it was at the start of the experiment (reference) and with each changed alignment. Two video cameras (frontal and sagittal) and a force plate of the SYBAR system (Noldus Information Technology, The Netherlands) were used to capture gait characteristics of the subjects. Temporal and spatial characteristics, the magnitude and timing of the ground reaction force (GRF), and the external joint moments were derived from these data. Despite the substantial perturbations to prosthetic alignment, only a few effects were observed in the temporal and spatial characteristics of gait, the magnitude and timing of the GRF, and the external joint moments. Only the pattern of the ground reaction force in the mediolateral direction and the joint moment around the ankle in the frontal plane during terminal stance showed a systematic effect when the alignment was set into varus and valgus or exorotation. It was concluded that using the SYBAR system in this study revealed little effect of perturbations in prosthetic alignment, for this group of patients, and for the selected parameters. It was questioned whether this is due to the relatively low resolution of the SYBAR system or the capacity of the well-trained subjects to compensate for the disturbance in alignment. It was suggested that the usability of the SYBAR system in clinical settings should be further explored.


2000 ◽  
Author(s):  
Nader Arafati ◽  
Jean Yves Lazennec ◽  
Roger Ohayon

Abstract Human movement modeling has been the object of much research for the past 30 years. In these models the position of foot link was fixed on the ground. We propose to model the feet links as variable, since the position of foot pressure center changes from heel to toes. The ground reaction forces could also be analyzed in real time. We examined this model for some static postures. In standing anatomical position, the maximum articular forces are localized in hip and knee joints. In sagittal plane, the ground reaction force vectors are positioned nearly under ankle joints. The pathological postures like body with pes cavus or with global spine kyphosis increase the articular and muscular forces. In these cases, the position of ground reaction force vectors is moved toward the toes.


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