The structure, function, and significance of the triceps surae-tendon unit (MTU), along with its biomechanical adaptations during running and in vivo measurement methods were outlined. During running, forefoot striking and wearing shoes with greater stiffness, such as carbon plate running shoes, could optimize the behavior of the MTU and reduce energy consumption caused by muscle contraction. However, adopting forefoot striking, barefoot running, or wearing minimalist shoes during running could increase the biomechanical loads on the complex. Runners who engage in such running styles should take foot function training and gradually transition to prevent injuries. The gait retraining has a certain effect on improving the biomechanical properties of the MTU, while the impact of other training methods on it is relatively poor, and the research in this area is still not sufficient. Therefore, future research should focus on optimizing the biomechanical properties of the MTU through changes in movement patterns, equipment, and training methods to enhance athletic performance and reduce its injuries. For the methods for measuring the MTU biomechanical properties, although the two-dimensional dynamic ultrasound technique excels in behavioral measurements during quasi-static and dynamic conditions, the development of a three-dimensional dynamic ultrasound technique may be necessary in the future to address its limitations in identifying dynamic changes in muscle spatial dynamics. Improvement in precision in calculating and indirectly measuring MTU force remains a significant challenge.