Myeong-Soo Kang ¹, Jong-Hyun Yang ², Jeong Ho Lee ³, Siddhartha Bikram Panday ⁴, Kitae Kim ¹, Je-Heon Moon ¹, Do-Hoon Koo ¹

Affiliations
1 Department of Physical Education, Seoul National University, KR
2 Korea Institute for Curriculum and Evaluation, KR
3 K2 Korea Co. Ltd, KR
4 Seoul National University, KR

Abstract

Objectives: The purpose of the study was to quantify lower limb foot kinematics, Center Of Mass (COM) and Center Of Pressure (COP) across three different surface terrain. Methods/Statistical Analysis: Thirty-one female walked over 7 m walkway at self-selected speed on three different surface terrain randomly A) Levelled surface, B) Soft urethane mat, C) Destabilising rock surface. A total of 8 infrared motion capture cameras and pressure measurement system were used to record the participant’s gait. As a statistical measure, one-way repeated measure ANOVA with Bonferroni post hoc test was used to observe differences across three surface terrains. Findings: The effect of surface condition on decreased speed and shorter stride length was observed. The difference was much larger on uneven surface condition with ankle externally rotated and shorter cop trajectory than even and control surface terrain. Surface characteristics imposed a greater challenge for maintaining dynamic balance by the control system which presumably changed the gait pattern for reducing the risk of fall. Application/Improvements: When designing footwear for outdoor, manufacturers should consider on the mechanism of the ankle joint which is prone to external rotation during destabilizing conditions. Thus, braces, lacing technique as well as outsole should be designed accordingly to reduce the risk of being injured.

Keywords

Footwear Science, Kinematics, Gait Analysis, Surface Terrain.

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Jong-Hyun Yang ¹, Do-Hoon Koo ², Insik Shin ²

Affiliations
1 Korea Institute for Curriculum and Evaluation, Seoul, KR
2 Department of Physical Education, Seoul National University, Seoul, KR

Abstract

Objectives: The purpose of this study was to analyze the differences in posture during push-off phase between an actual speed skating condition and on slide-board, and provide the basis for improvement of slide-boards. Methods/Statistical Analysis: Nine speed skaters participated in the experiment. To obtain kinematic data in these two conditions, two methods were taken under consideration for the recording motion. The push-off phase was defined as the time period from the left toe contact on the ice surface to the right toe off which was normalized to 100 data points. Univariate analysis of variance was used to test if the differences between two groups with changing time frame in the whole push-off phase are significant. Findings: The results show that the distance between the two feet on the slide board was much longer, while the angle of rotation of both feet was much smaller in the entire push-off phase. Also, there was no significant difference in hip angle between two situations. The knee angle was significantly higher at the early stage of push - off, and the ankle angle was higher at the end of the push - off phase during the slide board training than the actual skate situation. In conclusion, design constraints limits the space on the slideboard which effects the kinematic parameters and made the distance between the left and right foot more distant, as well as smaller rotations of the push off foot. Current slideboards prefer hip-bending exercises, but they do not help with stretching exercises on the knees and ankles. Application/Improvements: Therefore, the structural design of the slide board can be improved by allowing the skater to perform forward propulsion, but not propel the knee or ankle explosively in the medial-lateral direction at the end of the push-off phase.

Keywords

Posture, Push-Off, Skating, Slide-Board.

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