Biomechanical Analysis Of Lower Limbs During Soccer Related Movements With Different Studded Soccer Shoes

Objective: Soccer is one of the world's most popular sports.The biomechanical factors relevant to success in the game of soccer are those which relate to the technical performance of skills,to the equipment used and to the causative mechanisms of injury.Soccer players greatly rely on the design of their footwear to enable optimum performance.The purpose of this study was to testing for difference in performance and injury risks between three different outsole configuration soccer shoes.Methods: A total of 14 experienced soccer players participated in the tests.Participants were asked to complete tasks of straight-ahead running and 45° left sidestep cutting respectively at the speed of 4.5±0.2m/s.They selected soccer shoes with soft ground design(SG),artificial ground design(AG)and turf cleats(TF)randomly.During 45° cut.The 8-camera Vicon motion analysis system(Oxford Metrics Ltd.,Oxford,UK)was used to capture participant's lower limb kinematics.A Kistler force platform was synchronized to collect the ground reaction force.The in-shoe plantar pressure measurement system(Novel Pedar System,Germany)was used to measure the pressure and force exerted on the insole pressure sensors.The SPSS 17.0 software(SPSS Inc.,Chicago,IL,USA)was used for statistical analysis.The Post Hoc Multiple Comparisons and LSD(least significance difference)of ANOVA(analysis of variance)were taken for data analysis,the significance level was set at 0.05.Results: During 45° cut,SG showed greater peak knee flexion angles and peak knee abduction angles than TF.During cutting movement.SG and AG showed significantly higher VALR compared with TF.SG showed significantly lower peak horizontal ground reaction force(PHF)and average required traction ratio compared with other conditions.During stance phase of 45° left sidestep cutting,Peak pressure and force-time integral of TF in the heel region was significantly smaller than AG and SG.SG showed significantly greater peak pressure and forcetime integral than AG and TF in medial forefoot(MFF).Conclusions and Implications: Greater knee flexion angle may help to absorb higher impact force,but may incur more energy cost,which in turn may predispose players to fatigue.Higher peak knee abduction angles of SG may increase the knee joint loads and strain on the ACL.Higher VALR of SG may resulted in Achilles tendinitis,calluses observed in plantar skin or even tibia stress fracture.Higher average traction ratio of SG may offer a performance benefit,however higher utilized traction might lead to risk of slip resistance and foot fixation which might increase the load of lower limbs.Excessive pressure of SG and an accumulative effect in a small area may result in calluses observed in plantar skin,forefoot pain or even metatarsal stress fracture.Advised that professional soccer players should select SG soccer shoes on natural turf to improve traction and performance.Sub-elite and amateur players would better select firm ground design(FG)and AG to avoid non-contact injuries.