• Korean Journal of Applied Biomechanics
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• v.27 no.2
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• pp.141-147
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• 2017

Objective: We obtained force-displacement curves for countermovement jumps of multiple heights and examined the effect of an arm swing on changes in vertical jumping strategy. Countermovement jumps with hands on hips (Condition 1) and with an arm swing (Condition 2) were evaluated to investigate the mechanical effect of the arm movement on standing vertical jumps. We hypothesized that the ground reaction force (GRF) and/or center of mass (CoM) motion resulting from the countermovement action would significantly change depending on the use of an arm swing. Method: Eight healthy young subjects jumped straight up to five different levels ranging from approximately 10% (~25 cm) to 35% (~55 cm) of their body heights. Each subject performed five sets of jumps to five randomly ordered vertical elevations in each condition. For comparison of the two jumping strategies, the characteristics of the boundary point on the force-displacement curve, corresponding to the vertical GRF and the CoM displacement at the end of the countermovement action, were investigated to understand the role of arm movement. Results: Based on the comparison between the two conditions (with and without an arm swing), the subjects were grouped into type A and type B depending on the change observed in the boundary point across the five different jump heights. For both types (type A and type B) of vertical jumps, the initial vertical force at the start of push-off significantly changed when the subjects employed arm movement. Conclusion: The findings may imply that the jumping strategy does change with the inclusion of an arm swing, predominantly to modulate the vertical force advantage (i.e., the difference between the vertical force at the start of push-off and the body weight).

• Korean Journal of Applied Biomechanics
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• v.24 no.3
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• pp.295-300
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• 2014

The purpose of this study was to investigate the effects on jump performance and balance in soccer player with functional ankle instability of difference of neuromuscular training. In 33 male college soccer player with functional ankle instability subjects of this study randomization, combined training group (group I, n=11), balance training group (group II, n=11) and control group (group III, n=11) that included in the plyometric training and balance training was classified group. The intervention was conducted three times a week for 8 weeks. Before and after intervention, measured in surface area ellipse and countermovement jump and countermovement jump with arm swing. Showed a significant improvement in postural control and jump performance from the combined training group and balance training group compared to the control group. Showed a significant improvement in countermovement jump from the combined training group compared to the balance training group. Combined training and balance training showed the increased jump performance and postural control in soccer player with functional ankle instability.

• Korean Journal of Applied Biomechanics
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• v.16 no.4
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• pp.153-164
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• 2006

This thesis is focused on kinematical and kinematical analysis of each types(Type #1 : use both swing of arm and reaction of knee, Type #2 : Use only swing of arm, not reaction of knee, type #3 : Neither use of swing of arm nor reaction of knee) of vertical jumps according to gender of High School Students. The subjects of this study is High School Student's male and female, 5 each, for analyzation of actions 3D image analyzing and GRF machines were used. To identify the differences of analyzed variables, an independent T-test on gender, an One-way ANOVA on types were used. Summery of the results are stated below. first of all, female students showed differences on Hip Joint angle and Joint Velocity from male students on Kimentic Variable. So training on hip joint force of flection and extension of female students is needed. Both male and female students showed relatively bigger result of arm's Angular Momentum than thigh's Angular Momentum on Type #1. This is regarded of faster Joint Velocity of Arm. Bigger result of female students of arm's contribution on Type #1 than male students can be said as Female student's weaker hip joint's angular muscle force than male student's, so the dependency of arm is heavier than male students. In Kinetic variable, GRF showed bigger result on male students than female students. So female students need to enhance joint's torque to increase GRF than male students. On vertical Impulse, high numeric data of last two reaction of tiptoe of vertical GRF and antero-posterior GRF helped increasing impulse by extending action time of force.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
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• v.22 no.1
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• pp.43-49
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• 2016

Background: The purpose of this study was to investigate the effects on balance and Jump performance in soccer player with functional ankle instability of Movement with mobilization (MWM) and taping. Methods: In 30 male college soccer player with functional ankle instability subjects of this study randomization, fibular reposition taping (FRT) group (n=10), kinesio taping (KT) group (n=10), control group (n=10) that included in the MWM and taping was classified group.Before and after intervention, measured in surface area ellipse and countermovement jump with arm swing. Results: Showed a significant balance and jump performance from the FRT group and KT group compared to the control group. Showed a significant improvement in balance from the FRT group compared to the KT group. Conclusions: MMW and taping showed the increased balance and Jump performance in soccer player with functional ankle instability.