Nanyang Technological University, Rehabilitation Research Institute of Singapore, 11 Mandalay Road, #14-03, 308232, Singapore, Singapore.
Tan Tock Seng Hospital, Centre for Advanced Rehabilitation Therapeutics, 11 Jalan Tan Tock Seng, 308433, Singapore, Singapore.
J Neuroeng Rehabil. 2020 Dec 3;17(1):161. doi: 10.1186/s12984-020-00785-0.
The study of falls and fall prevention/intervention devices requires the recording of true falls incidence. However, true falls are rare, random, and difficult to collect in real world settings. A system capable of producing falls in an ecologically valid manner will be very helpful in collecting the data necessary to advance our understanding of the neuro and musculoskeletal mechanisms underpinning real-world falls events.
A fall inducing movable platform (FIMP) was designed to arrest or accelerate a subject's ankle to induce a trip or slip. The ankle was arrested posteriorly with an electromagnetic brake and accelerated anteriorly with a motor. A power spring was connected in series between the ankle and the brake/motor to allow freedom of movement (system transparency) when a fall is not being induced. A gait phase detection algorithm was also created to enable precise activation of the fall inducing mechanisms. Statistical Parametric Mapping (SPM1D) and one-way repeated measure ANOVA were used to evaluate the ability of the FIMP to induce a trip or slip.
During FIMP induced trips, the brake activates at the terminal swing or mid swing gait phase to induce the lowering or skipping strategies, respectively. For the lowering strategy, the characteristic leg lowering and subsequent contralateral leg swing was seen in all subjects. Likewise, for the skipping strategy, all subjects skipped forward on the perturbed leg. Slip was induced by FIMP by using a motor to impart unwanted forward acceleration to the ankle with the help of friction-reducing ground sliding sheets. Joint stiffening was observed during the slips, and subjects universally adopted the surfing strategy after the initial slip.
The results indicate that FIMP can induce ecologically valid falls under controlled laboratory conditions. The use of SPM1D in conjunction with FIMP allows for the time varying statistical quantification of trip and slip reactive kinematics events. With future research, fall recovery anomalies in subjects can now also be systematically evaluated through the assessment of other neuromuscular variables such as joint forces, muscle activation and muscle forces.
研究跌倒和跌倒预防/干预设备需要记录真实的跌倒发生率。然而，真实的跌倒很少发生，是随机的，并且很难在现实环境中收集。一个能够以生态有效的方式产生跌倒的系统将非常有助于收集必要的数据，以深入了解支撑现实世界跌倒事件的神经和肌肉骨骼机制。
设计了一种跌倒诱发可移动平台（FIMP），用于阻止或加速受试者的踝关节以诱发绊倒或滑倒。踝关节通过电磁制动器向后制动，并通过电动机向前加速。动力弹簧串联连接在踝关节和制动器/电动机之间，以在不诱发跌倒时允许自由运动（系统透明）。还创建了步态相位检测算法，以精确激活跌倒诱发机制。统计参数映射（SPM1D）和单向重复测量方差分析用于评估 FIMP 诱发绊倒或滑倒的能力。
在 FIMP 诱发的绊倒中，制动器在终末摆动或中间摆动步态阶段激活，以分别诱发降低或跳跃策略。对于降低策略，所有受试者都看到了特征性的腿部降低和随后的对侧腿部摆动。同样，对于跳跃策略，所有受试者都用受干扰的腿部向前跳跃。通过使用电动机向踝关节施加不必要的向前加速度，并借助减少摩擦的地面滑动片，FIMP 诱发滑倒。在滑倒过程中观察到关节僵硬，并且受试者普遍在初始滑倒后采用冲浪策略。
结果表明，FIMP 可以在受控的实验室条件下诱发生态有效的跌倒。使用 SPM1D 结合 FIMP 允许对绊倒和滑倒反应运动学事件进行时变统计量化。随着未来的研究，现在还可以通过评估关节力、肌肉激活和肌肉力等其他神经肌肉变量来系统地评估受试者的跌倒恢复异常。
