Adolescents' poor sitting posture is hazardous, and long-term poor sitting posture can lead to elevated incidence of neck pain. This study investigated the biomechanical attributes of the adolescent neck to mitigate the hazards of poor sitting posture and to provide recommendations for adolescent neck health; The C1-T3 images of the cervical region were acquired from the same subject in normal posture as well as in cervical forward flexion posture with a gap between scans of 0.50mm, and the CT images were transformed into DOCM format in Mimics for subsequent 3D modelling. A finite element (FE) model of the C1-T3 normal posture as well as the cervical forward flexion posture was established. In order to investigate the differences between the two models' cervical vertebrae and intervertebral disc stress, the stress and intervertebral disc strain of the two models were compared. A standard cervical spine model and a FE model for cervical forward flexion were created and validated. The range of motion, vertebral body, and intervertebral disc stresses were examined for both models. Comparison with previous literature confirmed the accuracy of the forward flexion model, showing consistent results with the normal cervical spine model. In the forward flexion direction, the model demonstrated increased stresses in the vertebral body, particularly in the anterior side, surpassing those in the normal model. The maximum stress in the vertebral body reached 5.99 MPa, and in the intervertebral disc, it was 1.02 MPa. Overall, stresses in the anterior cervical flexion model exceeded those in the normal model. Poor neck posture leads to more pronounced stress concentration phenomena in the vertebral body, increasing peak pressure in the vertebral body, in addition increasing com-pression on the intervertebral discs, leading to an increased risk of neck pain risk as well as cervical dysplasia, and therefore excessive forward flexion of the cervical spine in adolescents should be avoided.

Research has indicated that modifying shoes' longitudinal bending stiffness (LBS) could potentially influence running biomechanics and performance among amateur runners. Nevertheless, scant attention has been given to adolescent runners in previous studies, leaving the impact of various LBS shoes on distal joint kinematics and muscular mechanics unclear. Given the distinctive musculoskeletal attributes of adolescents, delving into this matter holds significant importance. Thirteen adolescent amateur runners with rear foot strikes were recruited for the study. Each participant performed running tasks along a 10-meter runway at a speed of 3.3±5% m/s while wearing two types of LBS shoes, randomized for each trial. The specific LBS values of the shoes were 2.7 Nm/rad (low) and 8.6 Nm/rad (high). Lower limb joint biomechanical data were collected using a Vicon motion analysis system and AMTI force platform. Lower limb joint kinematics and muscular mechanics were analyzed using Opensim software. Paired t-tests were employed to identify differences in distal joint kinematics and muscular mechanics during stance phases. We found that there was a significant increase in contact time, while the range of motion (ROM) of the metatarsophalangeal (MTP) joint in the sagittal plane significantly decreased in the high LBS shoe condition. Additionally, the impulse of flexor digitorum brevis and flexor hallucis longus significantly increased under the high LBS shoe condition. The results show that high LBS shoes impose a greater load on the distal muscles, potentially elevating the risk of running-related injuries. The low LBS shoes are more suitable for adolescent runners.

Diabetic foot is a common complication in patients with diabetes, which can lead to plantar ulcers and even necessitate amputation. This study aims to utilize finite element analysis to simulate the offloading effects of 3D-printed insoles with various structures on plantar pressure and to explore the use of machine learning in providing optimal plantar pressure offloading solutions for patients with diabetic foot. The results demonstrated that negative Poisson's ratio structured insoles were more effective in reducing plantar pressure (reducing pressure by an average of 39.2%) than barefoot and conventional structures. This was achieved through a unique lateral contraction deformation, which increased the contact area with the foot. The pressure-reducing effect of insoles may be weight-related, suggesting that heavier patients may require stiffer insoles. However, the machine learning algorithm demonstrated a poor fit (only 60.75%) in the task of recommending suitable insoles. In conclusion, this study demonstrated the significant effect of negative Poisson's ratio structured insoles in reducing plantar pressure in diabetic patients, providing new ideas for diabetic foot protection. With the development of data analysis technology in the future, the feasibility and application of personalised insole design will be more promising.

Single-leg landing (SL) imposes substantial mechanical demand on the patellar tendon, with peak patellar tendon force (PPTF) serving as a key metric for characterizing the internal mechanical environment of the tendon. This study integrates 3D modeling with high-resolution in vivo kinematics to quantify the patellar tendon moment arm (PTMA) and the PPTF, examining their biomechanical correlations and neuromuscular features. Minimal sex-related PTMA differences suggest comparable anatomical leverage during knee flexion across both sexes. In both sexes, PPTF was significantly positively correlated with the knee flexion angle at initial contact (IC) and significantly negatively correlated with the knee range of motion (ROM). Muscle network analysis showed lower clustering coefficients in high-frequency versus low-frequency bands. Reduced IC knee flexion and increased ROM attenuate patellar tendon mechanical demand. By incorporating individualized moment-arm analysis, this study provides a biomechanical basis for understanding patellar tendon loading during landing.