The objective of this study was to examine the effects of running fatigue on the symmetry of lower limb biomechanical parameters in eighteen male amateur runners. The marker trajectories and ground reaction forces were collected before and after the running-induced fatigue protocol. Symmetry angles (SA) were used to quantify the symmetry of each parameter. Normality tests and Paired sample T-tests were carried out to detect bilateral lower limb differences and SA of parameters between pre- and post-fatigue. One-dimensional statistical parameter mapping (SPM_1d) was used to compare parameters with the characteristic of one-dimensional time series data of lower limbs. After fatigue, the SA of knee extension angles, knee abduction moment, and hip joint flexion moment increased by 17%, 10%, and 11% respectively. In comparison, the flexion angle of the knee joint decreased by 5%. The symmetry of internal rotation of ankle, knee and hip joints increased after fatigued, while the SA of external rotation of the three joints decreased significantly. These findings provide preliminary evidence that fatigue changes lower limb symmetry in running gait and may have implications for understanding running-related injuries and performance.

The aim of this study was to examine whether there are kinematic and kinetic differences in the lower limb and whether the symmetry of the lower extremities is different after prolonged-running. Fifteen healthy male amateur runners (age: 22 ± 1 years, height: 173 ± 8 cm, mass: 65 ± 7 kg, BMI: 21.62 ± 2 kg/m²) were recruited as participants for this study. A Vicon eight-camera motion capture system and Kistler force plate were used to collect kinematic and kinetic parameters. A motorized treadmill, 15-point Borg scale and heart rate bands were used to monitor fatigue during a running-induced fatigue protocol. Paired sample T tests were used to check statistical difference (p = 0.05) between the lower limbs and the symmetry changes in pre-fatigue and post-fatigue running sessions. The symmetry angle (SA) of the knee flexion angle, hip flexion angle and hip extension angle in post-fatigue was significantly greater than in pre-fatigue, increasing by 4.32%, 10.71%, and 23.12%, respectively. Moreover, the SA of hip flexion moment increased by 2.61%. However, the knee extension velocity and hip flexion velocity became more symmetrical than in pre-fatigue (p < 0.05), the SA decreased by 5.91% and 5.45%, respectively. Differences in limb function during post-fatigue may lead to changes of symmetry in the lower limbs. The variables of asymmetry may be used as a compensation mechanism to maintain gait stability. Physical therapy assessment of fatigue injuries and long-distance running training programs may want to consider the changes in symmetry due to limb dominance.

This study presented a systematic review of recent advancements in the application of finite element (FE) methods to running and running shoe biomechanics. It focused on outlining the general approach to build foot-running shoe FE models, exploring their current applications and challenges, and providing directions for future research. The review also aimed to highlight the gap between theoretical mechanical responses in simulations and real-world manifestations of running-related musculoskeletal injuries (RRMI). A comprehensive search of electronic databases, including Web of Science, PubMed, and Scopus, identified 12 eligible articles for inclusion in this review. Current studies have examined the effects of various running shoe design features and conditions on the mechanical response of internal foot tissues using foot-running shoe FE models. These models have gradually evolved from simplified local representations to more realistic and comprehensive models, with the incorporation of experimental data enhancing simulation accuracy. However, to further improve simulation outcomes, key advancements are proposed to reduce development time and enhance model robustness. These include high-fidelity 3D model development, personalized shape transformation, AI-driven automated reconstruction, comprehensive dynamic running simulations, and improved validation methods. More importantly, future research needs to bridge the gap between FE simulations and RRMI risk by addressing the complexities of bone fracture criteria and conducting localized assessments of bone properties. Overall, this review provided valuable insights for biomedical engineers, medical professionals, and researchers, facilitating more accurate investigations of foot-running shoe FE models. Ultimately, these advancements aim to improve footwear design and training programs to reduce the risk of RRMI.