An End-to-End Dynamic Posture Perception Method for Soft Actuators Based on Distributed Thin Flexible Porous Piezoresistive Sensors.

This paper proposes a method for accurate 3D posture sensing of the soft actuators, which could be applied to the closed-loop control of soft robots. To achieve this, the method employs an array of miniaturized sponge resistive materials along the soft actuator, which uses long short-term memory (LSTM) neural networks to solve the end-to-end 3D posture for the soft actuators. The method takes into account the hysteresis of the soft robot and non-linear sensing signals from the flexible bending sensors. The proposed approach uses a flexible bending sensor made from a thin layer of conductive sponge material designed for posture sensing. The LSTM network is used to model the posture of the soft actuator. The effectiveness of the method has been demonstrated on a finger-size 3 degree of freedom (DOF) pneumatic bellow-shaped actuator, with nine flexible sponge resistive sensors placed on the soft actuator's outer surface. The sensor-characterizing results show that the maximum bending torque of the sensor installed on the actuator is 4.7 Nm, which has an insignificant impact on the actuator motion based on the working space test of the actuator. Moreover, the sensors exhibit a relatively low error rate in predicting the actuator tip position, with error percentages of 0.37%, 2.38%, and 1.58% along the x-, y-, and z-axes, respectively. This work is expected to contribute to the advancement of soft robot dynamic posture perception by using thin sponge sensors and LSTM or other machine learning methods for control.

Kinect-based rapid movement training to improve balance recovery for stroke fall prevention: a randomized controlled trial.

BACKGROUND: Falls are more prevalent in stroke survivors than age-matched healthy older adults because of their functional impairment. Rapid balance recovery reaction with adequate range-of-motion and fast response and movement time are crucial to minimize fall risk and prevent serious injurious falls when postural disturbances occur. A Kinect-based Rapid Movement Training (RMT) program was developed to provide real-time feedback to promote faster and larger arm reaching and leg stepping distances toward targets in 22 different directions. OBJECTIVE: To evaluate the effectiveness of the interactive RMT and Conventional Balance Training (CBT) on chronic stroke survivors' overall balance and balance recovery reaction. METHODS: In this assessor-blinded randomized controlled trial, chronic stroke survivors were randomized to receive twenty training sessions (60-min each) of either RMT or CBT. Pre- and post-training assessments included clinical tests, as well as kinematic measurements and electromyography during simulated forward fall through a "lean-and-release" perturbation system. RESULTS: Thirty participants were recruited (RMT = 16, CBT = 14). RMT led to significant improvement in balance control (Berg Balance Scale: pre = 49.13, post = 52.75; P = .001), gait control (Timed-Up-and-Go Test: pre = 14.66 s, post = 12.62 s; P = .011), and motor functions (Fugl-Meyer Assessment of Motor Recovery: pre = 60.63, post = 65.19; P = .015), which matched the effectiveness of CBT. Both groups preferred to use their non-paretic leg to take the initial step to restore stability, and their stepping leg's rectus femoris reacted significantly faster post-training (P = .036). CONCLUSION: The RMT was as effective as conventional balance training to provide beneficial effects on chronic stroke survivors' overall balance, motor function and improving balance recovery with faster muscle response. TRIAL REGISTRATION: The study was registered at Clinicaltrials.gov ( https://clinicaltrials.gov/ct2/show/NCT03183635 , NCT03183635) on 12 June 2017.

Effects of camera viewing angles on tracking kinematic gait patterns using Azure Kinect, Kinect v2 and Orbbec Astra Pro v2.

BACKGROUND: Depth sensors could be a portable, affordable, marker-less alternative to three-dimension motion capture systems for gait analysis, but the effects of camera viewing angles on their joint angle tracking performance have not been fully investigated. RESEARCH QUESTIONS: This study evaluated the accuracies of three depth sensors [Azure Kinect (AK); Kinect v2 (K2); Orbbec Astra (OA)] for tracking kinematic gait patterns during treadmill walking at five camera viewing angles (0°/22.5°/45°/67.5°/90°). METHODS: Ten healthy subjects performed fifteen treadmill walking trials (3 speeds × 5 viewing angles) using the three depth sensors to measure joint angles in sagittal hip, frontal hip, sagittal knee, and sagittal ankle. Ten walking steps were recorded and averaged for each walking trial. Range of motion in terms of maximum and minimum joint angles measured by the depth sensors were compared with the Vicon motion capture system as the gold standard. Depth sensors tracking accuracies were compared against the Vicon reference using root-mean-square error (RMSE) on the joint angle time series. Effects of different walking speeds, viewing angles, and depth sensors on the tracking accuracy were observed using three-way repeated-measure analysis of variance (ANOVA). RESULTS: ANOVA results on RMSE showed significant interaction effects between viewing angles and depth sensors for sagittal hip [F(8,72) = 4.404, p = 0.005] and for sagittal knee [F(8,72)=13.211, p < 0.001] joint angles. AK had better tracking performance when subjects walked at non-frontal camera viewing angles (22.5°/45°/67.5°/90°); while K2 performed better at frontal viewing angle (0°). The superior tracking performance of AK compared with K2/OA might be attributed to the improved depth sensor resolution and body tracking algorithm. SIGNIFICANCE: Researchers should be cautious about camera viewing angle when using depth sensors for kinematic gait measurements. Our results demonstrated Azure Kinect had good tracking performance of sagittal hip and sagittal knee joint angles during treadmill walking tests at non-frontal camera viewing angles.

Effectiveness of taping on functional performance in elite athletes: A systematic review.

Taping has been showing its effect on the rehabilitation aspect with numerous reviews. However, there is lack of evidence on the effect of taping on functional performance, espectially in elite sports settings. This review aimed to evaluate the effectiveness of taping intervention on sports-related functional performance among the elite athlete population. Online databases such as Ovid MEDLINE, ProQuest, PubMed, ScienceDirect, Scopus, SPORTDiscus, and Web of Science were searched. Eligibility criteria were listed as follows: (i) English, (ii) academic journal, (iii) research article, (iv) elite or professional athletes, (v) experimental research design, (vi) sport, (vii) taping, and (viii) functional performance. Specific emphases were targeted on within-subject comparison and healthy subjects. The PEDro scale was utilized for appraising on the statistical information, as well as internal and external validity. The Cohen's d effect size with 95 percent confidence intervals was used to compare taped versus not-taped condition. Nine studies were included in this review and 25 comparisons were extracted. Positive effects were found on balance performance with rigid tape, and horizontal jump performance with elastic tape. Alternatively, negative effects were found on vertical jump performance. An interesting finding was noted on the effect of taping applied after 24 h. Overall, taping could be a beneficial practice for elite sports performance.

Effects of exercise and nutrition supplementation in community-dwelling older Chinese people with sarcopenia: a randomized controlled trial.

BACKGROUND: Limited trials examining the effect of exercise and nutrition supplementation in older people with sarcopenia are available. OBJECTIVES: to assess the impact of resistance exercise program targeting muscle strength and power with and without nutrition supplementation on gait speed, body composition, physical function and quality of life. METHODS: this trial randomized 113 community-dwelling older Chinese adults aged ≥65 and with sarcopenia defined using the Asian Criteria into one of the three groups: exercise program alone, combined-exercise program and nutrition supplement or waitlist control. The exercise program consisted of 90-min group training twice weekly and one-home session weekly for 12 weeks. Participants in the combined group were additionally asked to consume nutrition supplement twice daily for 12 weeks. Both groups were encouraged to keep home exercise after intervention period for another 12 weeks to detect sustained effect. The primary outcome was gait speed. RESULTS: at 12 and 24 weeks, gait speed did not differ significantly between groups. Significant improvement in leg extension, and five-chair stand test occurred in both intervention groups that persisted to 24 weeks. Physical Activity Scale for the Elderly improved in both intervention groups that persisted until 24 weeks only in the combined group. Lower limb muscle and appendicular skeletal muscle mass increased significantly in the combined group but the increase was not sustained to 24 weeks. CONCLUSION: the exercise program with and without nutrition supplementation had no significant effect on the primary outcome of gait speed but improved the secondary outcomes of strength and the five-chair stand test in community-dwelling Chinese sarcopenic older adults. CLINICALTRIALS.GOV IDENTIFIER: NCT02374268.

Children with Physical Disabilities at School and Home: Physical Activity and Contextual Characteristics.

The purpose of this study was to assess the physical activity (PA) of children with physical disabilities (PD) in school and home settings and to simultaneously examine selected contextual characteristics in relation to PA in those settings. Children with PD (N = 35; Mean age = 15.67 ± 4.30 years; 26 boys) were systematically observed using BEACHES (Behaviors of Eating and Activity for Children's Health: Evaluation System) at school (before school, recess, lunch break, after class) and at home (before dinner) during four normal school days. The children spent most of their time in all five settings being physically inactive, but had slightly more PA during recess and lunch break periods. Hierarchical multiple regression revealed that selected contextual characteristics explained 18.9-56.0% (p < 0.01) of the variance predicting moderate-to-vigorous physical activity (MVPA) after controlling for demographic variables. Prompts to be active were positively associated with MVPA at school and the presence of fathers and fathers being motivators at home. This study highlights how little PA that children with PD receive and identifies the importance of the provision of prompts for PA at both school and home with this special population.