Research Of Rocker Angle’s Effect On Human Gait Characteristics

Objective:Rocker angle is a common structure in modern sneakers. By the means of measuring lower extremity biomechanical parameter of different rocker angles during human’s normal walking, the effects of different rocker angles on human gait will be revealed, and according to the change of gait characteristics, to analyse the mechanisms of human’s corresponding motion regulation.Methods:16 male subjects (25.9yrs±1.3yrs,175.6cm±3.8cm,69.3kg±7.7kg, shoe size: 42) participated in this study. Five pairs of testing shoes are modified Warrior Canvas basketball shoes, rocker angles are 0°(0#),5°(1#),7.7°(2#),10.3°(3#) and 15.5°(4#) respectively. Kinematic and kinetic data were acquired by eight-camera high-speed video capture system (Motion Analysis Raptor-4, USA,200Hz) and 3D force platform (Kistler 9281CA, Switzerland, 1000Hz) simultaneously, joint angles and torques of lower limbs are used in the research. Statistical analysis was performed using SPSS for Windows (version 13.0). A P-value less than 0.05(one-way ANOVA) was considered statistically significant.Results:1,The average ground contacting time of foot when wearing 1#,2#,3#,4# are all longer than wearing 0#(left foot, P<0.05. right foot, P<0.01).2,The average left knee flexion angles of subjects when wearing 1#,2#,3# and 4# are all larger than wearing 0# at the time of RHO(right heel off)(P=0.003).3,The average angles of left ankle joint of subjects when wearing 1#,2#,3# and 4# are all larger than wearing 0# at the time of LHO (left heel off) (P=0.000), RHS(right heel strike) (P=0.000) and LTO(left toe off ground) (P=0.023). The average minimum and maximum values of joint angles of ankle of subjects when wearing 1#、2#、3#、4# are all larger than wearing 0#(p=0.000,p=0.135), however, there is no statistical significance of these difference(p=0.476).4,The left plantar flexion angle is smaller when wearing 1#,2#, 3#,4# compared to 0#at the time of RHO(right heel off)(p=0.044).5,The post loading rate of peak force on X axis is larger when wearing 1#,2#,3#,4# compared to 0#(P=0.021).6,The rotation torque of knee joint and the flexion torque of ankle joint is smaller when wearing 1#,2#,3#,4# compared to 0# (P=0.004,P=0.007).Conclusion:1,The increase of rocker angle will extent the ground contacting time of foot.2,The increase of rocker angle will increase the flexion angle of knee joint of swing leg during swing phase.3, The change of the rocker angle affects ankle joint’s starting and ending angles in sagittal plane but not affects ankle joint’s range of motion.4, The increase of rocker angle will decrease the rotation torque of knee joint and the plantar flexion torque of ankle joint at the late phase of stance.