The movement patterns appropriate for exercise and manual labor do not always correspond to what people instinctively choose for better comfort. Without expert guidance, people can even increase the risk of injury by choosing a comfortable posture rather than the appropriate one, notably when lifting objects. Even in situations where squatting is accepted as a desirable lifting strategy, people tend to choose the more comfortable strategy of stooping or semisquatting. The common approach to correcting lifting posture, immobilizing vulnerable joints via fixation, is insufficient for preventing back injuries sustained from repetitive lifting. Instead, when lifting small but heavy objects, the entire kinetic chain should cooperate to achieve a series of squat-lifting patterns. Inspired by the observation that force fields affect the coordination of voluntary human motion, we devised a passive exosuit embedded with a body-powered variable-impedance mechanism. The exosuit adds impedance to the human joints according to how far the wearer’s movement is from the squat-lifting trajectories so that it hinders stooping but facilitates squatting. In an experiment that entailed lifting a small 10-kg box, 10 first-time users changed their voluntary lifting motion closer to squatting on average. Simulation results based on recorded kinematic and kinetic data showed that this postural change reduced the compression force, shear force, and moment on the lumbosacral joint. Our work demonstrates the potential of using an exosuit to help people move in a desirable manner without requiring a complicated, bulky mechanical system.

适合锻炼和体力劳动的运动模式并不总是符合人们为了更好的舒适而本能地选择的。如果没有专家指导，人们甚至可以通过选择舒适的姿势而不是适当的姿势来增加受伤的风险，尤其是在举起物体时。即使在深蹲被认为是一种理想的举重策略的情况下，人们也倾向于选择更舒适的弯腰或半蹲策略。纠正举重姿势的常用方法，通过固定来固定脆弱的关节，不足以防止因重复举重而造成的背部损伤。取而代之的是，在举起小而重的物体时，整个动力链应该配合，以实现一系列深蹲举的模式。受力场影响人体随意运动协调的观察的启发，我们设计了一种嵌入身体动力可变阻抗机制的被动式外装。外装护具根据穿着者的运动距离深蹲提升轨迹的远近增加人体关节的阻抗，从而阻止弯腰但促进深蹲。在一项需要举起一个 10 公斤重的小盒子的实验中，10 名初次使用者将他们的自愿举起动作改为更接近于平均蹲下。基于记录的运动学和动力学数据的模拟结果表明，这种姿势变化降低了腰骶关节的压缩力、剪切力和力矩。我们的工作证明了使用外装帮助人们以理想的方式移动而不需要复杂、笨重的机械系统的潜力。