Abstract

Background: There are frequent stops, jumps and sprints in basketball, and the front foot often lands in the process. The forefoot landing mode will change the direction of the ankle joint at the first touch of the ground, and affect the joint load distribution and energy absorption of the lower limbs.Ankle flexion accompanied by valgus during landing may increase the risk of ankle sprain. Functional insoles can regulate the biomechanics of the lower limbs through material selection and structural design.However, research on basketball insoles mainly focusses on the performance of specific sports tasks, while the design of the biomechanical characteristics related to injury caused by the landing of the forefoot has received little attention.It is still a challenge to strike a balance between targeted protection and affordability and affordability.

Objective: This study aims to develop a checkered structure insole with functional zoning design.It provides effective protection for male college students who have not received professional basketball training at an economical price, but are used to using the front sole landing mode in basketball running and jumping tasks.Through the landing buffer stage of three-step basket and emergency jump action, the proposed insoles are compared with the standard insoles.This study will examine its immediate impact on the biomechanics and subjective comfort of lower limb joints.The research results are not only expected to provide a basis for basketball injury prevention strategies, but also support the development of functional insoles with targeted biomechanical characteristics and widely available.

Methods: The experiment will recruit male college students who havn’t receiver professional basketball training from Guangzhou Sports College.The screening criteria include: in the landing process of the three-step basket and emergency stop jump movements, it is customary to adopt the front sole landing mode, and there has been no musculoskeletal injury in the past six months.G*Power software will be used to calculate the a priori sample volume, assuming that the effect amount is 0.8, the statistical efficacy is 0.80, and the significance level is 0.05.

This study will combine literature review, questionnaire evaluation, experimental testing and statistical analysis.Functional insoles will be made of thermoplastic polyurethane (TPU) foam through additive manufacturing technology, and functionally divided according to the distribution of sole pressure.The front foot and arch area will adopt a face-centred cubic (FCC) lattice structure to provide impact cushioning and arch support.The heel area adopts a body-centred cubic (BCC) lattice structure to provide a flexible cushioning effect.

The heel area adopts a body-centred cubic (BCC) lattice structure to provide a flexible cushioning effect.Vicon three-dimensional infrared motion capture system and AMTI force platform will collect kinematic and dynamic data synchronously.Under each insole condition, multiple successful experimental data will be collected for each task, and the subjective comfort will be evaluated using the visual analogue scale (VAS).Paired sample t-test will be carried out in SPSS to compare the differences in impact load, joint kinematics, joint torque and subjective comfort under two insole conditions. The statistical significance level is set to p < 0.05.

Results: Compared with standard insoles, it is expected that functional insoles will cause the following changes in the biomechanics of the lower limbs during the landing of the forefoot.In terms of dynamics, it is expected that the peak vertical ground reaction force and maximum load rate will be reduced.The FCC lattice area at the front foot is expected to weaken the high-frequency impact load in the early stage of landing.The BCC lattice area at the heel is expected to improve the stress distribution in the later stage of landing.In terms of kineology, the flexion angle of the hip and knee joints at the first touch of the ground is expected to increase.The flexion and inward angle of the ankle joint are expected to decrease.The duration of ankle flexion and inversion at the same time is expected to be shortened.Compared with standard insoles, the visual simulation score (VAS) of functional insoles is expected to be higher in terms of cushioning effect, support and overall comfort.

Conclusions: By integrating the high support and energy absorption capacity of the FCC lattice in the forefoot and arch area, and combining the flexible buffering characteristics of the BCC lattice in the heel area, this functionally zoning lattice structure insole is expected to reduce the peak vertical ground reaction force and maximum load rate when the forefoot lands.In addition, it is expected that the insole can also increase the flexion angle of the hip and knee joint at the first touch of the ground, reduce the angle of ankle flexion and inflexion, and improve the user's subjective feeling of cushioning, support and overall comfort.The use of thermoplastic polyurethane (TPU) and additive manufacturing technology may provide a feasible solution for both protective performance and economy, so as to promote the widespread popularisation of professional sports aids.The results of this study are expected to provide an experimental basis for the design of functional insoles for basketball and guide the development of evidence-based injury and disease prevention equipment for amateur players.