Turning gait is very common in daily lives. However, study of turning is still limited. For researching the differences of the walking characteristics between straight gait and turning gait and between different turning strategies, and for analyzing the endopathic factor, this study selected 10 healthy young men to perform straight walking and 90° turning using two turning strategies (outside leg turning and inside leg turning). The Vicon capture system and plantar pressure capture system were used to measure gait parameters and plantar pressure parameters at the same time. The study showed that stride velocity reduced while stride time and proportion of stance time increased when turning was compared to straight walking. Inside leg turning strategy needed stronger muscle controlling and could promote turning, while outside leg turning strategy was more stable. This results will offer data for projecting gait of biped robot and provide reference value for walking rehabilitation training design and development of walking assistive equipments, etc.
Utilized coefficient of friction (UCOF), which is calculated with ground reaction forces (GRF), is an effective factor to predict the possibility of slip. For researching the UCOF values of different turning strategies and then predicting the possibility of slip, this study selected 10 healthy young men to perform straight walking and 60° and 90° turning using two turning strategies (step turning and spin turning). ATMI force plate was used to collect the data of GRF, and then the UCOF values of different walking conditions were calculated. The study showed that difference of the medial-lateral force in different walking conditions was great; the slip possibility of turning was significantly greater than that of straight walking. For spin turn, turning angle had no significant effect on peak UCOF values. For step turn, the propulsive force decreased with the increase of turning angle, which caused a result that the peak UCOF values of 60° turn were significantly greater than that for 90° turn. This suggests that turning angle had little effect on possibility of slip of spin turning but great effect on that of step turning, and the greater angle led smaller possibility of slip.
Assisting immobile individuals with regular repositioning to adjust pressure distribution on key prominences such as the back and buttocks is the most effective measure for preventing pressure ulcers. However, compared to active self-repositioning, passive assisted repositioning results in distinct variations in force distribution on different body parts. This incongruity can affect the comfort of repositioning and potentially lead to a risk of secondary injury, for certain trauma or critically ill patients. Therefore, it is of considerable practical importance to study the passive turning comfort and the optimal turning strategy. Initially, in this study, the load-bearing characteristics of various joints during passive repositioning were examined, and a wedge-shaped airbag configuration was proposed. The airbags coupled layout on the mattress was equivalently represented as a spring-damping system, with essential model parameters determined using experimental techniques. Subsequently, different assisted repositioning strategies were devised by adjusting force application positions and sequences. A human-mattress force-coupled simulation model was developed based on rigid human body structure and equivalent flexible springs. This model provided the force distribution across the primary pressure points on the human body. Finally, assisted repositioning experiments were conducted with 15 participants. The passive repositioning effectiveness and pressure redistribution was validated based on the simulation results, experimental data, and questionnaire responses. Furthermore, the mechanical factors influencing comfort during passive assisted repositioning were elucidated, providing a theoretical foundation for subsequent mattress design and optimization of repositioning strategies.