ECSS Paris 2023: OP-BM15
INTRODUCTION: Several biomechanical models for skeletal muscles have seen extensive use. Nonetheless, the model employed in sports biomechanics relied on a non-dynamic equation and was only applicable under quasi-static conditions. This research seeks to develop a skeletal muscle model based on the semi-phenomenological model (SPM) of a sarcomere and employ it in dynamic modeling utilizing the results of kinetic calculations in OpenSim. Subsequently, it aims to validate the precision and dependability of the SPM by comparing joint moment calculations based on the SPM in OpenSim and gravitational resis METHODS: In this study, the biceps femoris long head was selected as the subject. Kinetic data, sEMG signals, and external joint moments were recorded, collected, computed, and analyzed. The One-dimensional Statistical Parameter Mapping (SPM1D) algorithm was utilized to compare the net knee bending moment and mechanical output calculated in the SPM and OpenSim models through a paired t-test at a significance level of 0.001. The calculated actual knee bending moment served as the reference standard. Correlation analysis was conducted to compare the average joint moments and average mechanical work output calculated by OpenSim tools with the mass of body segments and the sarcomere SPM at each time step. RESULTS: The SPM significantly decreased the error in joint rotation moment but did not show a significant reduction in the error in the calculation of mechanical work output at each time step. The SPM demonstrated an advantage in calculating instantaneous power, with a negligible difference compared to real instantaneous power output, and improved the accuracy in computing total mechanical work output by reducing the error rate to 43.1%. CONCLUSION: The results showed that the SPM-based biomechanical algorithm significantly reduced errors in joint rotation moment calculations compared to the traditional Hill-type model in OpenSim, particularly in dynamic contraction conditions. The SPM also exhibited a better transient response, recovering and declining muscle force more quickly. These advantages can be attributed to the SPMs modeling principles, which assume equal time constants for muscle activation and inactivation, resulting in faster muscle force predictions. However, when it comes to the calculation of mechanical work output, both the Hill-type model in OpenSim and the SPM showed no statistically significant difference in error. This aligns with the principles of both models and the studys experimental design. It is worth noting that the complexity of muscle contraction energy output is influenced by factors like action potential frequency, movement type, and muscle activation timing. While the SPM has shown effectiveness in previous experiments, caution should be exercised when applying these results, as the validation data came from insect muscles. In conclusion, the skeletal muscle modeling based on the SPM of sarcomere appears to be a better approach for biomechanical research.
Read CV Yining XuECSS Paris 2023: OP-BM15
INTRODUCTION: To explore the biomechanical mechanisms of anterior cruciate ligament (ACL) injuries during the pre-squat phase of clean and jerk, thus providing a theoretical basis for preventing ACL injuries in weightlifting sports. METHODS: By utilising the German SIMI Motion 10.2 movement analysis system and AnyBody simulation system, an athletes pre-squat clean and jerk with ACL injury during competition was analysed and compared with their normal pre-squat non-injured clean and jerk. The differences in the kinematic and dynamic indicators of lower limb joints under injured and non-injured pre-squat conditions were investigated. RESULTS: Knee joint torque during non-injured clean and jerk was consistently positive (i.e. external rotation) but turned from positive to negative (i.e. from external rotation to internal rotation) during injured clean and jerk, reaching a maximum internal rotation torque of 21.34 Nm at the moment of injury. At every moment, the muscle activation and simulated muscle force of the quadriceps and gastrocnemius during injured clean and jerk were higher than those during non-injured clean and jerk. Conversely, the muscle activation and simulated muscle force of the semitendinosus, semimembranosus, biceps femoris and soleus during non-injured clean and jerk were higher than those during injured clean and jerk. The knee joint rotation angle during injured clean and jerk firstly increased and then declined, peaking at 46.93° at the moment of injury, whereas it gradually increased during non-injured clean and jerk. The proximal tibia on the left side during injured clean and jerk moved forward faster by 0.76 m/s compared with that during non-injured clean and jerk. CONCLUSION: The small muscle activation and simulated muscle force of the hamstring and soleus could not timely and effectively resist the large muscle activation and simulated muscle force of the quadriceps (especially the medial quad) and gastrocnemius, causing the force applied to the ACL to exceed the ultimate load-bearing capacity of the ACL. Kinematic indicators in the athletes injured lift demonstrated certain disparities from those in their non-injured lift. Amongst these indicators, knee internal rotation and tibial anterior translation during the pre-squat phase of weightlifting might be the kinematic characteristics of ACL injuries.
Read CV Houwei ZhuECSS Paris 2023: OP-BM15
INTRODUCTION: The metatarsal bones, integral components of the metapodial complex, play a critical role in the transmission of stress and serve as a pivotal element in the attenuation of axial loads in speed skating. Conventional biomechanical approaches have demonstrated proficiency in characterizing the impact of technical manoeuvers on foot kinetics; however, they fall short in shedding light on the internal mechanical repercussions instigated by variations in biomechanical parameters. This significantly constrains the advancement of principled analysis aimed at enhancing the technical manoeuvers in speed skating. The objective of this investigation was to develop a sophisticated three-dimensional (3D) finite element model (FEM) of the foot in conjunction with a speed skate to examine the mechanical behaviour of the metatarsal and metatarsophalangeal joints under various loading conditions. METHODS: A 3D FEM was reconstructed utilizing data from computed tomography and 3D scanning. The models validity was ascertained through the comparison of FEM-predicted outcomes with in vivo measurement data. The FEM was subjected to push-off angles derived from video analysis of an elite skater, with angles set at 42°, 49°, 56°, 63°, and 70°, respectively. Boundary conditions and loading parameters for the FEM stipulated that the distal ends of the tibia and fibula, along with the associated soft tissues, were fixed. The displacement of the ice surface was constrained in all four cardinal directions. The applied forces included a ground reaction force and an Achilles tendon force, quantified at 640N and 480N respectively, while the frictional force between the ice surface and the skate blade was set at a coefficient of 0.003. RESULTS: The error rates of validation of plantar soft and blade bottom were less than 10%. During the skating propulsion phase, maximal stress is localized at the fifth metatarsal, with the third metatarsal experiencing the least. A decrease in the push-off angle correlates with reduced stress in the first and second metatarsals and increased stress from the third to fifth metatarsals. The most significant stress fluctuations are observed in the first and fifth metatarsals, with changes of 5.229 MPa and 6.379 MPa, respectively. Additionally, the stress at the first and second metatarsophalangeal joints decreases correspondingly, with variations of 0.011 MPa and 0.004 MPa. CONCLUSION: The alteration in the angle of push-off exerts a discernible influence on the mechanical behaviour of the Metatarsal and Metatarsophalangeal Articulations. These findings offer fresh insights into the biomechanics of skating, potentially guiding the design of sports equipment and the refinement of training programs.
Read CV Wang HaichunECSS Paris 2023: OP-BM15