Effect of hip abduction assistance on metabolic cost and balance during human walking.

The use of wearable robots to provide walking assistance has rapidly grown over the past decade, with notable advances made in robot design and control methods toward reducing physical effort while performing an activity. The reduction in walking effort has mainly been achieved by assisting forward progression in the sagittal plane. Human gait, however, is a complex movement that combines motions in three planes, not only the sagittal but also the transverse and frontal planes. In the frontal plane, the hip joint plays a key role in gait, including balance. However, wearable robots targeting this motion have rarely been investigated. In this study, we developed a hip abduction assistance wearable robot by formulating the hypothesis that assistance that mimics the biological hip abduction moment or power could reduce the metabolic cost of walking and affect the dynamic balance. We found that hip abduction assistance with a biological moment second peak mimic profile reduced the metabolic cost of walking by 11.6% compared with the normal walking condition. The assistance also influenced balance-related parameters, including the margin of stability. Hip abduction assistance influenced the center-of-mass movement in the mediolateral direction. When the robot assistance was applied as the center of mass moved toward the opposite leg, the assistance replaced some of the efforts that would have otherwise been provided by the human. This indicates that hip abduction assistance can reduce physical effort during human walking while influencing balance.

Reducing sprint time with exosuit assistance in the real world.

Hip extension assistance with the aid of exosuits can reduce sprinting time.

The Effects of a Custom-Designed High-Collar Shoe on Muscular Activity, Dynamic Stability, and Leg Stiffness: A Biomimetic Approach Study.

High-collar shoes are a biomimetic approach to preventing lateral ankle injuries during high-demand activities; however, the influence of collar stiffness (CS) on parameters related to lateral ankle sprain prevention during running remains unclear. In this study, we investigated the effects of a custom-designed shoe CS on muscular activity, dynamic stability, and leg stiffness (Kleg) during running using a biomimetic design approach inspired by the mechanisms of ankle sprain prevention. Sixteen healthy male participants ran on a treadmill while wearing a custom-designed high-collar shoe with low, medium, and high CS conditions, measured using circumferential ankle pressure (CAP). Lower extremity kinematics and electromyography (EMG) data were recorded simultaneously. One-way repeated-measures ANOVA was conducted to compare the CS conditions. Results indicate that high and medium CS conditions significantly reduce sagittal and frontal ankle ranges of motion (ROMs) compared to the low CS condition, providing improved stability and support against lateral ankle sprain; moreover, there was a trend towards higher dynamic stability and Kleg with increasing CS. Our study highlights the importance of considering the CAP in regulating high-collar stiffness properties and how higher CS may provide better support for the ankle during running. Nevertheless, additional research is necessary to validate the efficacy of the current design in preventing ankle sprains during high-demand activities.

Differences in Physical Activity Patterns among Korean Adolescents during and after COVID-19.

Due to the COVID-19-induced social distancing restrictions, adolescents' physical activity declined and their level of health and fitness decreased. In March 2023, the Korean government established the beginning of the post-COVID-19 era by declaring that indoor masks were now "recommended" rather than "mandatory". Consequently, adolescents, whose physical activity decreased during COVID-19, began to participate in such activities again. This study aimed to verify the differences in adolescent physical activity during COVID-19 and after COVID-19. To achieve the study's purpose, an online survey was conducted twice, using the International Physical Activity Questionnaire, for 1143 Korean adolescents in 2022 and 2023. The following results were derived through frequency analysis, descriptive statistical analysis, and an independent variables t-test. First, moderate-to-vigorous physical activity was higher during the post-COVID-19 period than during COVID-19 (p = 0.018). Second, high-intensity (p = 0.018), moderate-intensity (p = 0.030), and low-intensity (p = 0.002) physical activities and total leisure-time physical activities (p = 0.003) were all higher during the post-COVID-19 period than during COVID-19. Third, high-intensity (p = 0.005), moderate-intensity (p = 0.003), low-intensity (p = 0.003) activities and total physical activities in school (p = 0.001) were all higher during the post-COVID-19 period than during COVID-19. Fourth, there was no difference in the commuting times for cycling (p = 0.515) and walking (p = 0.484) and the total physical activities during commuting (p = 0.375) during and after COVID-19. Based on these results, the methods to help adolescents form correct habits for leading a healthy life are discussed.

Influence of circumferential ankle pressure of shoe collar on the kinematics, dynamic stability, electromyography, and plantar pressure during normal walking.

BACKGROUND: The shoe's collar plays a significant role in supporting the ankle during walking. Since the protective effect of the collar requires the circular embracing of the ankle and shank, a stiffer collar might be involved with increased circumferential ankle pressure (CAP). It is not clear how collar CAP affects walking performance. Therefore, this study was aimed at examining the influence of the collar CAP on the kinematics, dynamic stability, electromyography (EMG), and plantar pressure during normal walking. METHOD: Sixteen healthy male participants walked on a treadmill while wearing a custom-designed high-collar shoe with 10 (low), 30 (medium), and 60 mmHg (high) CAP conditions, and the joint angles, dynamic stability index, EMG, and plantar pressure were measured. RESULT: While the low CAP condition did not affect the ankle range of motion (ROM), The high CAP condition restricted both the ankle sagittal and frontal ROM, whereas the medium CAP condition limited only the ankle frontal ROM. The knee and hip ROM did not differ between conditions. The dynamic stability for the high and medium CAP cases was comparable but significantly higher than that of the low CAP condition. The ankle muscle activity and corresponding co-contraction increased with increasing CAP for gastrocnemius medialis (GM), soleus (SOL), peroneus longus (PL), tibialis anterior (TA) muscles in the weight acceptance and push-off phases but not in the single limb support. Knee muscle activity, including vastus lateralis (VL) and semitendinosus (SEMI) was similar between all conditions. A higher relative pressure was observed under the lateral aspect of the heel when walking in the high CAP condition. CONCLUSION: The results suggest that a high-collar shoe with a high CAP may not be an appropriate choice for walking owing to the injury risk factors and limited walking efficiency. A medium CAP is associated with certain advantages and, thus, a superior choice for high-collar shoe design.

Association of Basic Psychological Need Fulfillment and School Happiness with Obesity Levels and Intensity of Physical Activity during Physical Education Classes in South Korean Adolescents.

This study examined the relationship between basic psychological need fulfillment (BPNF) and school happiness in relation to the intensity of physical activity exhibited by adolescents during physical education (PE) classes and their obesity levels. We measured BPNF and school happiness using a questionnaire administered to 600 junior high school students. After exclusion, 532 questionnaires were analyzed. A 3D accelerometer (GT3X model) from Actigraph and the body mass index were used to measure physical activity intensity and obesity, respectively. The findings of this study indicate that BPNF and school happiness were significantly associated with physical activity intensity. Specifically, students who engaged in high-intensity physical activity exhibited higher levels of BPNF and school happiness. Additionally, BPNF and school happiness were not significantly related to obesity, whereas a significant relationship was observed between BPNF, school happiness, and the interaction between physical activity intensity and obesity level. This finding implies that adolescents with higher physical activity intensity and lower obesity reported higher levels of BPNF and school happiness. These findings suggest that physical activity intensity during PE classes significantly influences emotional development. Therefore, incorporating moderate-to-vigorous physical activity into PE may serve as a strategy for promoting emotional development in adolescents.

Regression models for the quantification of Parkinsonian bradykinesia.

The aim of this study was to develop regression models for the quantification of parkinsonian bradykinesia. Forty patients with Parkinson's disease participated in this study. Angular velocity was measured using gyro sensor during finger tapping, forearm-rotation, and toe tapping tasks and the severity of bradykinesia was rated by two independent neurologists. Various characteristic variables were derived from the sensor signal. Stepwise multiple linear regression analysis was performed to develop models predicting the bradykinesia score with the characteristic variables as input. To evaluate the ability of the regression models to discriminate different bradykinesia scores, ANOVA and post hoc test were performed. Major determinants of the bradykinesia score differed among clinical tasks and between raters. The regression models were better than any single characteristic variable in terms of the ability to differentiate bradykinesia scores. Specifically, the regression models could differentiate all pairs of the bradykinesia scores (p<0.05) except for one pair in the finger tapping task and one pair in the toe tapping task. In contrast, any single characteristic variable was found not sensitive enough to discriminate many of the pairs, especially in case of the toe tapping task. The results suggest that the multiple regression models reflecting these differences would be beneficial for the quantification of bradykinesia because the cardinal features included in the determination of bradykinesia score differ among tasks as well as among the raters.