Struzik Artur, Karamanidis Kiros, Lorimer Anna, Keogh Justin W L, Gajewski Jan
Department of Biomechanics, Wroclaw University of Health and Sport Sciences, Poland.
Sport and Exercise Science Research Centre, School of Applied Sciences, London South Bank University, UK.
Appl Bionics Biomech. 2021 Oct 21;2021:9914278. doi: 10.1155/2021/9914278. eCollection 2021.
Stiffness, the resistance to deformation due to force, has been used to model the way in which the lower body responds to landing during cyclic motions such as running and jumping. Vertical, leg, and joint stiffness provide a useful model for investigating the store and release of potential elastic energy via the musculotendinous unit in the stretch-shortening cycle and may provide insight into sport performance. This review is aimed at assessing the effect of vertical, leg, and joint stiffness on running performance as such an investigation may provide greater insight into performance during this common form of locomotion. PubMed and SPORTDiscus databases were searched resulting in 92 publications on vertical, leg, and joint stiffness and running performance. Vertical stiffness increases with running velocity and stride frequency. Higher vertical stiffness differentiated elite runners from lower-performing athletes and was also associated with a lower oxygen cost. In contrast, leg stiffness remains relatively constant with increasing velocity and is not strongly related to the aerobic demand and fatigue. Hip and knee joint stiffness are reported to increase with velocity, and a lower ankle and higher knee joint stiffness are linked to a lower oxygen cost of running; however, no relationship with performance has yet been investigated. Theoretically, there is a desired "leg-spring" stiffness value at which potential elastic energy return is maximised and this is specific to the individual. It appears that higher "leg-spring" stiffness is desirable for running performance; however, more research is needed to investigate the relationship of all three lower limb joint springs as the hip joint is often neglected. There is still no clear answer how training could affect mechanical stiffness during running. Studies including muscle activation and separate analyses of local tissues (tendons) are needed to investigate mechanical stiffness as a global variable associated with sports performance.
刚度，即因受力而产生的抗变形能力，已被用于模拟下半身在跑步和跳跃等周期性运动中对落地的反应方式。垂直刚度、腿部刚度和关节刚度为研究通过肌肉肌腱单元在拉长-缩短周期中储存和释放潜在弹性能量提供了一个有用的模型，并且可能有助于深入了解运动表现。本综述旨在评估垂直刚度、腿部刚度和关节刚度对跑步表现的影响，因为这样的研究可能会为这种常见的运动形式中的表现提供更深入的见解。对PubMed和SPORTDiscus数据库进行了检索，得到了92篇关于垂直刚度、腿部刚度和关节刚度以及跑步表现的出版物。垂直刚度随跑步速度和步频增加。较高的垂直刚度使精英跑者与表现较差的运动员区分开来，并且还与较低的氧气消耗相关。相比之下，腿部刚度随着速度增加保持相对恒定，并且与有氧需求和疲劳没有强烈关联。据报道，髋关节和膝关节刚度随速度增加，较低的踝关节刚度和较高的膝关节刚度与较低的跑步氧气消耗相关；然而，尚未研究其与表现的关系。从理论上讲，存在一个理想的“腿部弹簧”刚度值，在该值下潜在弹性能量的回返最大化，并且这是因人而异的。似乎较高的“腿部弹簧”刚度对跑步表现是有利的；然而，由于髋关节常常被忽视，需要更多研究来探究所有三个下肢关节弹簧之间的关系。关于训练如何影响跑步过程中的机械刚度仍然没有明确答案。需要开展包括肌肉激活以及对局部组织（肌腱）进行单独分析的研究来探究作为与运动表现相关的全局变量的机械刚度。
