scholarly journals Novel methodology for assessing total recovery time in response to unexpected perturbations while walking

2019 ◽  
Author(s):  
Uri Rosenblum ◽  
Lotem Kribus-Shmiel ◽  
Gabi Zeilig ◽  
Yotam Bahat ◽  
Shani Kimel-Naor ◽  
...  
Keyword(s):  
Recovery Time ◽  
Center Of Mass ◽  
Principal Component ◽  
Random Order ◽  
Step Length ◽  
Step Width ◽  
Total Recovery ◽  
Age Related ◽  
Different Types ◽  
Anterior Posterior

AbstractWalking stability is achieved by adjusting the medio-lateral and anterior-posterior dimensions of the base of support (step length and step width, respectively) to contain an extrapolated center of mass. We aimed to calculate total recovery time after different types of perturbations during walking, and use it to compare young and older adults following different types of perturbations. Walking trials were performed in 12 young (age 26.92 ± 3.40 years) and 12 older (age 66.83 ± 1.60 years) adults. Perturbations were introduced at different phases of the gait cycle, on both legs and in anterior-posterior or medio-lateral directions, in random order. A novel algorithm was developed to determine total recovery time values for regaining stable step length and step width parameters following the different perturbations and compared between the two participant groups under low and high cognitive load conditions, using principal component analysis (PCA). We analyzed 829 perturbations each for step length and step width. The algorithm successfully estimated total recovery time in 91.07% of the runs. PCA and statistical comparisons showed significant differences in step length and step width recovery times between anterior-posterior and medio-lateral perturbations, but no age-related differences. Initial analyses demonstrated the feasibility of comparisons based on total recovery time calculated using our algorithm.

scholarly journals Turning Characteristics of the More-Affected Side in Parkinson’s Disease Patients with Freezing of Gait

Sensors ◽  
2020 ◽  
Vol 20 (11) ◽  
pp. 3098
Author(s):  
Hwayoung Park ◽  
Changhong Youm ◽  
Myeounggon Lee ◽  
Byungjoo Noh ◽  
Sang-Myung Cheon
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Center Of Mass ◽  
Freezing Of Gait ◽  
Step Length ◽  
Control Group ◽  
Maximum Speed ◽  
Step Width ◽  
Affected Side ◽  
Anterior Posterior

This study investigated the turning characteristics of the more-affected limbs in Parkinson’s disease (PD) patients in comparison with that of a control group, and in PD patients with freezing of gait (FOG; freezers) in comparison with those without FOG (non-freezers) for 360° and 540° turning tasks at the maximum speed. A total of 12 freezers, 12 non-freezers, and 12 controls participated in this study. The PD patients showed significantly longer total durations, shorter inner and outer step lengths, and greater anterior–posterior (AP) root mean square (RMS) center of mass (COM) distances compared to those for the controls. The freezers showed significantly greater AP and medial-lateral (ML) RMS COM distances compared to those of non-freezers. The turning task toward the inner step of the more-affected side (IMA) in PD patients showed significantly greater step width, total steps, and AP and ML RMS COM distances than that toward the outer step of the more-affected side (OMA). The corresponding results for freezers revealed significantly higher total steps and shorter inner step length during the 540° turn toward the IMA than that toward the OMA. Therefore, PD patients and freezers exhibited greater turning difficulty in performing challenging turning tasks such as turning with an increased angle and speed and toward the more-affected side.

scholarly journals How does external lateral stabilization constrain normal gait, apart from improving medio-lateral gait stability?

2020 ◽  
Author(s):  
Mohammadreza Mahaki ◽  
Trienke IJmker ◽  
Han Houdijk ◽  
Sjoerd Matthijs Bruijn
Keyword(s):  
Step Length ◽  
Step Width ◽  
Arm Swing ◽  
Gait Stability ◽  
Normal Gait ◽  
Consumption Data ◽  
Gait Features ◽  
Pelvis Rotation ◽  
Set Up ◽  
Anterior Posterior

AbstractBackgroundThe effect of external lateral stabilization on medio-lateral gait stability has been investigated previously. However, existing lateral stabilization devices not only constrains lateral motions, but also transverse and frontal pelvis rotations. This study aimed to investigate the effect of external lateral stabilization with and without constrained transverse pelvis rotation on mechanical and metabolic gait features.MethodsWe undertook 2 experiments with eleven and ten young adult subjects, respectively. Experiment 2 supplemented experiment 1, as it considered several potential confounding factors in the design and set-up of experiment 1. Kinematic, kinetic, and breath-by-breath oxygen consumption data were recorded during 3 walking conditions (normal walking (Normal), lateral stabilization with (Free) and without transverse pelvis rotation (Restricted)) and at 3 speeds (0.83, 1.25, and 1.66 m/s) for each condition.ResultsExternal lateral stabilization significantly reduced the amplitudes of the transverse and frontal pelvis rotations, medio-lateral pelvis displacement, transverse thorax rotation, arm swing, and step width. The amplitudes of free vertical moment, anterior-posterior and vertical pelvis displacements, step length, and energy cost were not significantly influenced by external lateral stabilization. The removal of transverse pelvis rotation restriction by our experimental set-up resulted in significantly higher transverse pelvis rotation, although it remained significantly less than Normal condition. In concert, concomitant gait features such as transverse thorax rotation and arm swing were not significantly influenced by our new set-up.ConclusionExisting lateral stabilization set-ups not only constrain medio-lateral motions (i.e. medio-lateral pelvis displacement), but also constrains other movements such as transverse and frontal pelvis rotations, which leads to several other gait changes such as reduced transverse thorax rotation, and arm swing. Our new setup allowed for more transverse pelvis rotation, however, this did not result in more normal pelvis rotation, arm swing, etc. Hence, to provide medio-lateral support without constraining other gait variables, more elaborate set-ups are needed. Unless such a set-up is realized the observed side effects need to be taken into account when interpreting the effects of lateral stabilization as reported in previous studies.

Effectiveness of three field treatments for induced mild (33.0 degrees C) hypothermia

1987 ◽  
Vol 63 (6) ◽  
pp. 2375-2379 ◽  
Author(s):  
G. G. Giesbrecht ◽  
G. K. Bristow ◽  
A. Uin ◽  
A. E. Ready ◽  
R. A. Jones
Keyword(s):  
Core Temperature ◽  
Recovery Time ◽  
Treatment Effectiveness ◽  
Treadmill Exercise ◽  
Cold Water ◽  
Random Order ◽  
External Heat ◽  
Time Rate ◽  
Total Recovery

Three field applicable treatments for hypothermia were compared. Subjects were cooled in stirred cold water (8.0 degrees C) to a core temperature (Tco) as low as 33 degrees C and rewarmed in a random order by each of three techniques: shivering, external heat, and treadmill exercise. Tco was monitored with an esophageal thermistor probe at the level of the heart. Treatment effectiveness was determined by calculating the amount of Tco afterdrop, length of afterdrop period, rate of Tco increase, and total recovery time. Rate of Tco increase for exercise (4.9 degrees C/h) was significantly higher (P less than 0.05) than shivering (3.5 degrees C/h) but not external heat (3.7 degrees C/h). Exercise afterdrop amount and afterdrop length values (0.95 degrees C and 24 min, respectively) were significantly higher (P less than 0.05) than both shivering (0.33 degrees C, 15 min) and external heat (0.32 degrees C, 14 min). Therefore, although rate of Tco increase during recovery for exercise was faster than for shivering or external heat, as it was preceded by a greater afterdrop length and amount, total recovery time did not differ among the three treatments.

scholarly journals How does external lateral stabilization constrain normal gait, apart from improving medio-lateral gait stability?

2021 ◽  
Vol 8 (3) ◽  
Author(s):  
Mohammadreza Mahaki ◽  
Trienke IJmker ◽  
Han Houdijk ◽  
Sjoerd Matthijs Bruijn
Keyword(s):  
Energy Cost ◽  
Step Length ◽  
Step Width ◽  
Arm Swing ◽  
Gait Stability ◽  
Normal Gait ◽  
Consumption Data ◽  
Gait Features ◽  
Pelvis Rotation ◽  
Anterior Posterior

Background: The effect of external lateral stabilization on medio-lateral gait stability has been investigated previously. However, existing lateral stabilization devices not only constrain lateral motions but also transverse and frontal pelvis rotations. This study aimed to investigate the effect of external lateral stabilization with and without constrained transverse pelvis rotation on mechanical and metabolic gait features. Methods: We undertook two experiments with 11 and 10 young adult subjects, respectively. Kinematic, kinetic and breath-by-breath oxygen consumption data were recorded during three walking conditions (normal walking (Normal), lateral stabilization with (Free) and without transverse pelvis rotation (Restricted)) and at three speeds (0.83, 1.25 and 1.66 m s −1 ) for each condition. In the second experiment, we reduced the weight of the frame, and allowed for longer habituation time to the stabilized conditions. Results: External lateral stabilization significantly reduced the amplitudes of the transverse and frontal pelvis rotations, in addition to medio-lateral, anterior–posterior, and vertical pelvis displacements, transverse thorax rotation, arm swing, step length and step width. The amplitudes of free vertical moment, anterior–posterior drift over a trial, and energy cost were not significantly influenced by external lateral stabilization. The removal of pelvic rotation restrictions by our experimental set-ups resulted in normal frontal pelvis rotation in Experiment 1 and significantly higher transverse pelvis rotation in Experiment 2, although transverse pelvis rotation still remained significantly less than in the Normal condition. Step length increased with the increased transverse pelvis rotation. Conclusion: Existing lateral stabilization set-ups not only constrain medio-lateral motions (i.e. medio-lateral pelvis displacement) but also constrain other movements such as transverse and frontal pelvis rotations, which leads to several other gait changes such as reduced transverse thorax rotation, and arm swing. Our new set-ups allowed for normal frontal pelvis rotation and more transverse pelvis rotation (yet less than normal). However, this did not result in more normal thorax rotation and arm swing. Hence, to provide medio-lateral support without constraining other gait variables, more elaborate set-ups are needed.

A Study on Utilization of Three-Dimensional Sensor Lip Image for Developing a Pronunciation Recognition System

2019 ◽  
Vol 63 (5) ◽  
pp. 50402-1-50402-9 ◽  
Author(s):  
Ing-Jr Ding ◽  
Chong-Min Ruan
Keyword(s):  
Principal Component Analysis ◽  
Automatic Speech Recognition ◽  
Feature Fusion ◽  
Three Dimensional ◽  
Principal Component ◽  
Recognition System ◽  
Geometrical Characteristics ◽  
3D Geometry ◽  
Different Types ◽  
The Disabled

Abstract The acoustic-based automatic speech recognition (ASR) technique has been a matured technique and widely seen to be used in numerous applications. However, acoustic-based ASR will not maintain a standard performance for the disabled group with an abnormal face, that is atypical eye or mouth geometrical characteristics. For governing this problem, this article develops a three-dimensional (3D) sensor lip image based pronunciation recognition system where the 3D sensor is efficiently used to acquire the action variations of the lip shapes of the pronunciation action from a speaker. In this work, two different types of 3D lip features for pronunciation recognition are presented, 3D-(x, y, z) coordinate lip feature and 3D geometry lip feature parameters. For the 3D-(x, y, z) coordinate lip feature design, 18 location points, each of which has 3D-sized coordinates, around the outer and inner lips are properly defined. In the design of 3D geometry lip features, eight types of features considering the geometrical space characteristics of the inner lip are developed. In addition, feature fusion to combine both 3D-(x, y, z) coordinate and 3D geometry lip features is further considered. The presented 3D sensor lip image based feature evaluated the performance and effectiveness using the principal component analysis based classification calculation approach. Experimental results on pronunciation recognition of two different datasets, Mandarin syllables and Mandarin phrases, demonstrate the competitive performance of the presented 3D sensor lip image based pronunciation recognition system.

scholarly journals Modeling, comparison and evaluation of one-DOF six-bar bioinspired jumping leg mechanisms

2021 ◽  
Vol 13 (2) ◽  
pp. 168781402199295
Author(s):  
Ziqiang Zhang ◽  
Qi Yang ◽  
Xingkun Liu ◽  
Chuanzhong Zhang ◽  
Jinnong Liao
Keyword(s):  
Center Of Mass ◽  
Principal Component ◽  
Analysis Method ◽  
Index Distribution ◽  
Inertial Moment ◽  
Structure Index ◽  
Mean And Variance ◽  
Research Objects ◽  
Leg Mechanisms ◽  
Selection Of

One degree-of-freedom (DOF) jumping leg has the advantages of simple control and high stiffness, and it has been widely used in bioinspired jumping robots. Compared with four-bar jumping leg, six-bar jumping leg mechanism can make the robot achieve more abundant motion rules. However, the differences among different configurations have not been analyzed, and the choice of configurations lacks basis. In this study, five Watt-type six-bar jumping leg mechanisms were selected as research objects according to the different selection of equivalent tibia, femur and trunk link, and a method for determining the dimension of the jumping leg was proposed based on the movement law of jumping leg of locust in take-off phase. On this basis, kinematics indices (sensitivity of take-off direction angle and trunk attitude angle), dynamics indices (velocity loss, acceleration fluctuation, and mean and variance of total inertial moment) and structure index (distribution of center of mass) were established, and the differences of different configurations were compared and analyzed in detail. Finally, according to the principal component analysis method, the optimal selection method for different configurations was proposed. This study provides a reference for the design of one DOF bioinspired mechanism.

scholarly journals Inertial Sensor-Based Step Length Estimation Model by Means of Principal Component Analysis

Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3527
Author(s):  
Melanija Vezočnik ◽  
Roman Kamnik ◽  
Matjaz B. Juric
Keyword(s):  
Principal Component Analysis ◽  
Human Body ◽  
Inertial Sensor ◽  
Principal Component ◽  
Step Length ◽  
Component Analysis ◽  
Indoor Positioning ◽  
Estimation Model ◽  
Length Estimation ◽  
Proposed Model

Inertial sensor-based step length estimation has become increasingly important with the emergence of pedestrian-dead-reckoning-based (PDR-based) indoor positioning. So far, many refined step length estimation models have been proposed to overcome the inaccuracy in estimating distance walked. Both the kinematics associated with the human body during walking and actual step lengths are rarely used in their derivation. Our paper presents a new step length estimation model that utilizes acceleration magnitude. To the best of our knowledge, we are the first to employ principal component analysis (PCA) to characterize the experimental data for the derivation of the model. These data were collected from anatomical landmarks on the human body during walking using a highly accurate optical measurement system. We evaluated the performance of the proposed model for four typical smartphone positions for long-term human walking and obtained promising results: the proposed model outperformed all acceleration-based models selected for the comparison producing an overall mean absolute stride length estimation error of 6.44 cm. The proposed model was also least affected by walking speed and smartphone position among acceleration-based models and is unaffected by smartphone orientation. Therefore, the proposed model can be used in the PDR-based indoor positioning with an important advantage that no special care regarding orientation is needed in attaching the smartphone to a particular body segment. All the sensory data acquired by smartphones that we utilized for evaluation are publicly available and include more than 10 h of walking measurements.

scholarly journals Acute Effects of Handheld Loading on Standing Broad Jump in Youth Athletes

2021 ◽  
Vol 18 (9) ◽  
pp. 5046
Author(s):  
Wei-Hsun Tai ◽  
Ray-Hsien Tang ◽  
Chen-Fu Huang ◽  
Shin-Liang Lo ◽  
Yu-Chi Sung ◽  
...  
Keyword(s):  
High Speed ◽  
Center Of Mass ◽  
Reaction Force ◽  
Sampling Rate ◽  
Random Order ◽  
Horizontal Distance ◽  
Acute Effects ◽  
Vertical Ground Reaction Force ◽  
Strength And Conditioning ◽  
Peak Knee

The study aimed to investigate the acute effects of handheld loading on standing broad jump (SBJ) performance and biomechanics. Fifteen youth male athletes (mean age: 14.7 ± 0.9 years; body mass: 59.3 ± 8.0 kg; height: 1.73 ± 0.07 m) volunteered to participate in the study. Participants were assigned to perform SBJ with and without 4 kg dumbbells in a random order. Kinematic and kinetic data were collected using 10 infrared high-speed motion-capture cameras at a 250 Hz sampling rate and two force platforms at a 1000 Hz sampling rate. A paired t-test was applied to all variables to determine the significance between loading and unloading SBJs. Horizontal distance (p < 0.001), take-off distance (p = 0.001), landing distance (p < 0.001), horizontal velocity of center of mass (CoM; p < 0.001), push time (p < 0.001), vertical impulse (p = 0.003), and peak horizontal and vertical ground reaction force (GRF; p < 0.001, p = 0.017) were significantly greater in loading SBJ than in unloading SBJ. The take-off vertical velocity of CoM (p = 0.001), take-off angle (p < 0.001), peak knee and hip velocity (p < 0.001, p = 0.007), peak ankle and hip moment (p = 0.006, p = 0.011), and peak hip power (p = 0.014) were significantly greater in unloading SBJ than in loading SBJ. Conclusions: Acute enhancement in SBJ performance was observed with handheld loading. The present findings contribute to the understanding of biomechanical differences in SBJ performance with handheld loading and are highly applicable to strength and conditioning training for athletes.

scholarly journals Regional Associations of Cortical Thickness With Gait Variability: The Tasmanian Study of Cognition and Gait

2020 ◽  
Vol 4 (Supplement_1) ◽  
pp. 232-233
Author(s):  
Oshadi Jayakody ◽  
Monique Breslin ◽  
Richard Beare ◽  
Velandai Srikanth ◽  
Helena Blumen ◽  
...  
Keyword(s):  
Cortical Thickness ◽  
Step Length ◽  
Gait Variability ◽  
Thickness Ratio ◽  
Sensory Function ◽  
Time Variability ◽  
Step Width ◽  
Time Step ◽  
Cortical Regions ◽  
Regional Associations

Abstract Gait variability is a marker of cognitive decline. However, there is limited understanding of the cortical regions associated with gait variability. We examined associations between regional cortical thickness and gait variability in a population-based sample of older people without dementia. Participants (n=350, mean age 71.9±7.1) were randomly selected from the electoral roll. Variability in step time, step length, step width and double support time (DST) were calculated as the standard deviation of each measure, obtained from the GAITRite walkway. MRI scans were processed through FreeSurfer to obtain cortical thickness of 68 regions. Bayesian regression was used to determine regional associations of mean cortical thickness and thickness ratio (regional thickness/overall mean thickness) with gait variability. Smaller overall cortical thickness was only associated with greater step width and step time variability. Smaller mean thickness in widespread regions important for sensory, cognitive and motor functions were associated with greater step width and step time variability. In contrast, smaller thickness in a few frontal and temporal regions were associated with DST variability and the right cuneus was associated with step length variability. Smaller thickness ratio in frontal and temporal regions important for motor planning, execution and sensory function and, greater thickness ratio in the anterior cingulate was associated with greater variability in all measures. Examining individual cortical regions is important in understanding the relationship between gray matter and gait variability. Cortical thickness ratio highlights that smaller regional thickness relative to global thickness may be important for the consistency of gait.

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