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Radar Micro-Doppler Signatures for Characterization of Human Motion
Published in Moeness G. Amin, Through-the-Wall Radar Imaging, 2017
Victor C. Chen, Graeme E. Smith, Karl Woodbridge, Chris J. Baker
When studying radar scattering from human motion, the non-rigid human body can be modeled as a number of rigid body parts. Even if human body is composed of a number of rigid components connected to each other by hinge joints, the whole body motion is still a non-rigid body motion due to complex articulation and flexibility. The locomotive motion of limbs in human body can be characterized by periodic motion that repeats itself in a certain time period. Walking is a highly coordinated periodic movement. The human gait cycle consists of a stance phase and a swing phase. During the stance phase, the foot is on the ground with heel strike and toe off. In the swing phase, the foot is lifted from the ground with acceleration as well as deceleration. The micro-Doppler signature of a walking person was reported in 2000 [1,18].
Continuous-Wave Doppler Radar for Human Gait Classification
Published in Moeness G. Amin, Radar for Indoor Monitoring, 2017
Fok Hing Chi Tivive, Abdesselam Bouzerdoum, Bijan G. Mobasseri
Recently, the research focus has been diverted to the classification of human gait. Human gait refers to the walking manner achieved through the movement of the torso, legs, and arms. It is defined by the gait cycle consisting of two main phases: stance and swing. Stance phase is the period between heel strike and toe off of the same foot and consists of three phases: heel strike, mid stance, and toe off. Swing phase begins when the foot is no longer in contact with the ground and consists of an initial acceleration of the limb followed by deceleration to position the foot for heel strike. Human gait classification using µ-D signals has numerous potential civilian and military applications. For example, µ-D radar technology can be used for countering terrorism, conducting urban military operations, providing urban border security, rescuing hostages, and detecting human movement in a forest. This radar technology can also be used for in-home monitoring of the elderly to provide immediate assistance after a fall [14].
Differences in Physiology, Biomechanics and Motor Control of Walking With Backpack Loads Between Children and Adults
Published in Youlian Hong, Routledge Handbook of Ergonomics in Sport and Exercise, 2013
Spatio-temporal parameters are often described by the changes within a complete gait cycle. They are often used to assess gait development in children and to identify potential disorders. The analysis of these parameters, in addition to evaluating aspects of pathological gait, also assists in quantifying post-surgical improvement (Sorsdahl et al., 2008; Stolze et al., 1998). A gait cycle is defined as the time interval between two successive recurrences of the same event of the same limb (e.g. right heel strike to the next right heel strike). Some typical spatio-temporal parameters are velocity (or speed), cadence (or step frequency, SF), step length (or stride length, SL); single stance time (percentage of time one leg is in contact with the floor during a gait cycle, SST); and double support time (percentage of time both legs are in contact with the floor during a gait cycle, DST).
Gender-specific visual perturbation effects on muscle activation during incline treadmill walking: a virtual reality study
Published in Ergonomics, 2023
Jie Hao, Robin High, Ka-Chun Siu
The Trigno™ wireless electromyography (EMG) system (Delsys Inc., Natick, MA) was used to record the muscle activation sampling at 2000 Hz. Trigno™ EMG Sensors were placed at the vastus lateralis (VL), medial hamstring (MH), tibialis anterior (TA), and the lateral gastrocnemius (LG) of the right leg according to the established guideline (Hermens et al. 2000). The locations of above EMG sensors placement followed the instructions on http://www.seniam.org/ and are illustrated in Figure 2. Gait events (heel-strike and toe-off) for each gait cycle were identified by the experimenter using the built-in accelerometer signals from the Trigno™ sensor on the TA muscle. We adopted the approach by this study (Godfrey et al. 2015) and manually identified the initial contact and final contact to divide each gait cycle into stance and swing phases. The stance phase begins when the foot first contacts the ground and ends when the same foot leaves the ground, which constitutes approximately 60% of the total gait cycle; the swing phase begins as the foot is lifted from the ground and ends when it contacts the ground again, which constitutes the remaining approximately 40% of the total gait cycle (Kharb et al. 2011).
Design of a powered ankle-foot prosthesis with an adjustable stiffness toe joint
Published in Advanced Robotics, 2020
Haotian She, Jinying Zhu, Ye Tian, Yanchao Wang, Qiang Huang
A complete gait cycle is divided into three phases: preswing phase, swing phase, and stance phase (see Figure 4). The preswing phase begins when the toe joint angle reaches a specific value and ends with toe off. The swing phase begins at toe off and ends with heel strike. The stance phase was divided into three substates: ST-A, ST-B, and ST-C. The stance phase begins at heel strike (ST-A), then the toe contacts the ground (ST-B), and finally, it ends with bending of the toe joint (ST-C). From PS-A to PS-B, the ankle joint pushes the body forward. SW-A is the state when the knee begins to swing forward. SW-B begins after SW-A and ends with heel strike.
How prosthetic design influences knee kinematics: a narrative review of tibiofemoral kinematics of healthy and joint-replaced knees
Published in Expert Review of Medical Devices, 2019
Fanhe Meng, Sebastian Jaeger, Robert Sonntag, Stefan Schroeder, Sydney Smith-Romanski, J. Philippe Kretzer
Generally, the most common activity is the gait. Therefore, an increasing number of research studies have focused on this activity. The gait cycle can be divided into a stance phase and a swing phase [44]. Most research tends to focus on the stance phase because it is the period of the weight-bearing position [4]. Therefore, the following description focuses on the stance phase.