• Journal of The Korean Society of Integrative Medicine
• /
• v.4 no.4
• /
• pp.67-75
• /
• 2016

Purpose: The purpose of this study was to compare Hip-Knee-Ankle(HKA) angle and muscle activation ratio between vastus medialis(VM), rectus femoris(RF), and vastus lateralis (VL), and by this, to examine their relationship. It is aimed to explore how the activation ratio among the muscles involved in patellofemoral kinetics would vary in relation with the frontal alignment of the lower extremity. Subjects and Methods: 26 healthy subjects were recruited for the study. The HKA angles were measured with radiograph. The VM, RF, VL muscle activation level were measured by surface electromyography while each participant performed 4 different types of movement (isometric knee extension, squat, ambulation, step-up) and VM/RF, VM/VL, RF/VL ratios were calculated. Pearson correlation was used to estimate the relationship between the HKA angle and the muscle ratio. Results: There was significant moderate correlation between HKA angle and VM: RF on the left side during ambulation (p<0.05). Moderate correlations were also observed during step-up and squat with less significance (p<0.1). Conclusion: The frontal alignment of the knee measured by the HKA angle was conditionally associated with muscle activation ratio between VM and RF (VM:RF); On the left, during ambulation, step-up, and squat, the more valgus knee tended to correlate with the more VM muscle activation ratio, which is expected to induce more stabilizing effect to the patella and its tracking. It suggests that the frontal alignement measured by the HKA-angle can affect PF kinetics. It also indicates a possibility that increase in valgus alignment of the knee, by the HKA measurement, may not act unfavorably to generate PFP.

• Korean Journal of Applied Biomechanics
• /
• v.27 no.3
• /
• pp.171-179
• /
• 2017

Objective: The purpose of this study was to perform a kinematic and kinetic analysis of double-under jump rope technique according to skill level and sex. Method: Participants comprised a skilled group of 16 (9 males, 7 females), and an unskilled group of 16 with 6 months or less of experience (9 males, 7 females). Five consecutive double-under successes were regarded as 1 trial, and all participants were asked to complete 3 successful trials. The data for these 3 trials were averaged and analyzed after collecting the stable third jump in each trial. The variables used in the analysis included phase duration, total duration, flight time, vertical toe height, stance width, vertical center of mass displacement, and right lower limb ankle, knee, and hip joint angles in the sagittal plane during all events. Results: The skilled group had a shorter phase and total duration and a shorter flight time than the unskilled group. The vertical center of mass displacement and ankle dorsiflexion angle were significantly smaller in the skilled group. The male group had a shorter phase duration than the female group. The vertical toe height was greater, the stance width was smaller, and the ankle and hip flexion angles were smaller in the male group. Conclusion: Variables that can be used to distinguish between skill levels are phase and total duration, flight time, vertical center of mass displacement, and ankle dorsiflexion angle. Differences between sexes in double-under jump rope technique may be related to lower limb flexion angle control.

• The Journal of Korean Physical Therapy
• /
• v.21 no.1
• /
• pp.89-96
• /
• 2009

Purpose: The purpose of this study was to determine the effect of modified golf swing training on gait characteristic in hemiplegic patient through Kwon 3D motion analysis system. Methods: This study has performed single subject design from September to October 2008. The subject had left hemiplegia due to CVA in December 2003. He has treated Bobath approach twice a week. In order to increase ankle dorsiflexion and knee flexion, the subject has applied modified golf swing training on the basis of Bobath approach. The measurement of gait characteristic was taken by Kwon 3D motion analysis system. Results: The results were as follows : 1) Walking velocity was increased 0.62m/sec than before the training. 2) Step length was increased 0.09m than before the training. 3) Left ankle and hip angle were increased, but left knee angle was decreased. Conclusion: It could be concluded that the activity modified golf swing training in walking pattern contributed to improve the movement quality and speed of gait.

• Korean Journal of Applied Biomechanics
• /
• v.18 no.1
• /
• pp.1-10
• /
• 2008

This study analyzed the rear foot angle of the supporting leg and the anatomical rotation angle of the kicking angle in soccer instep kick and drew conclusions as follows. When the supporting leg was landing on the ground, the valgus angle of the ankle joint reached the maximum peak, and plantar flexion was slightly different in the timing of the maximum peak between the two groups. The flexion angle of the rear foot was statistically significantly different between the two groups, and the movement of the crus on the landing of the supporting foot did not show a statistically significant difference between the groups. The crus leaned backward most before the impact, and the side to side gradient of the crus on impact was $22^{\circ}$. The flexion/extension of the hip joint of the kicking leg reached the maximum peak when the supporting foot was landing on the ground, and at the moment, the maximum extension angle of the hip joint was over $30^{\circ}$. The flexion angle of the knee joint of the kicking leg was largest after landing. While the maximum plantar flexion angle and maximum valgus angle of the ankle joint were not significantly different between the two groups, the maximum external rotation angle was significantly different.

• Journal of rehabilitation welfare engineering & assistive technology
• /
• v.10 no.1
• /
• pp.37-45
• /
• 2016

The purpose of this study was to assess the intra-rater, inter-rater and test-retest reliability and validity of frontal plane lower extremity alignment estimated from a rasterstereographic method using ABW-Mapper. Eighteen subjects participated in this study. The S angle (stereographic angle-frontal plane lower extremity alignment estimated from a rasterstereographic method) in standing was measured throughout the two sessions with one week interval by two different readers. In the first session, a reader measured S angle twice per subject with a short break in-between. The Q-angle (quadriceps angle) was measured using a standard goniometer from a photography taken through digital camera with the participant standing in the same position as in the S angle measurement. The HKA(hip-knee-ankle) angle was measured from a computer based digital radiograph with the computerized measurement software. Reliability was tested using intraclass correlation coefficients(ICC). Validity was tested using a Pearson's correlation coefficient. Excellent intra-rater(ICC=0.956~0.974), inter-rater(ICC=0.962), test-retest reliability (ICC=0.945) were demonstrated. There were strong negative correlations between S angle and Q-angle (r=-0.739), and between S angle and HKA angle (r=-0.702). Therefore, the S angle measured using a rasterstereographic mapper may be used to as a preliminary or supplementary tool to evaluate and study LE alignment in the frontal plane in relation to HKA angle or Q-angle.

• Physical Therapy Rehabilitation Science
• /
• v.6 no.1
• /
• pp.7-13
• /
• 2017

Objective: The aim of this study was to investigate the inter-rater and intra-rater reliability of rehabilitative ultrasound imaging (RUSI) for measurement of muscle thickness with changes in angles of the gluteus maximus (GM) at rest and during contraction. Design: Cross-sectional study. Methods: Twenty-two healthy men volunteered for this study. GM muscle images were obtained in the resting position and during prone hip extension with knee flexion at hip abduction angles of $0^{\circ}$ and $30^{\circ}$, respectively. Two examiners randomly measured the thickness of the GM twice in three different positions. The first position was a comfortable prone position. The second position was prone hip extension with knee flexion (PHEKF) to $90^{\circ}$. The third position was achieved by hanging a 1-kg weight on the ankle of the lifted leg during PHEKF with the angle of the lifted leg the same as the second position. Intra-class correlation coefficients (ICCs), standard error measurements, and minimal detectable changes were used to estimate reliability. Results: The intra-rater reliability ICCs (95% confidence interval) of the GM were >0.870, indicating good reliability. Inter-rater reliability ICCs ranged from 0.668 to 0.913. The reliability of measurements of muscle thickness at each position was similar to the reliability of the angle change. Differences in muscle thickness and ratios for each position with $0^{\circ}$ and $30^{\circ}$ of hip abduction were not statistically significant. Conclusions: In the present study, the intra-rater reliability of muscle thickness measurements of the GM was good, and the inter-rater reliability was moderate to good. Reliable RUSI measurements of wide and large muscles, such as the GM muscle at rest and during contraction, are feasible. Further investigation is required to establish the reproducibility of the protocols presented in this study.

• Korean Journal of Applied Biomechanics
• /
• v.21 no.5
• /
• pp.511-520
• /
• 2011

The purpose of this study was to provide scientific information to track and field coaches and athletes through the analyses of the biomechanics characteristics of the top 4 sprinters in the men's 100 m final in the IAAF World Championships Daegu 2011. Twelve video cameras (Sony, Japan) were used to capture the mid portion of the race (40 m - 70 m) with a sampling frequency of 60Hz. Biomechanical variables including the right ankle, knee and hip angles, the trunk angle, and the velocity of center of mass (COM) in the running direction, were calculated with the Kwon 3D program (Visol, Korea). Correlation coefficients between the COM velocity and each variables were calculated using Matlab 2008a (MathWorks, USA) at an alpha level of 0.05. The findings indicated that Yohan Blake (JAM) showed greater range of motion at the ankle and hip. Walter Dix(USA) showed greater knee and trunk movement, and Kim Collins (SKN) showed more dorsi-flexed and extended trunk angles during the race. Finally, Christophe Lemaitre (FRA) showed more plantar-flexed ankle with a less trunk motion, throughout the analyzed race.

• Korean Journal of Applied Biomechanics
• /
• v.19 no.4
• /
• pp.637-645
• /
• 2009

The purpose of this study was to investigate the biomechanical alterations in the punching motion of 10 elderly women after 12 weeks of taekwonaerobics training. Seven infrared cameras(Qualisys MCU-240) and 2 force platforms(Kistler-9286AA) were used to acquire raw data. The results were as follows. First, the minimum joint angles of the lower limbs had a statistically significant difference between both the dorsiflexion/plantar flexion(1eft, $p=0.001^*$) and the inversion/eversion(both, $p=0.009^*$, $p=0.04^*$) from the ankle angle. There were differences in abduction/adduction(left, $p=0.04^*$) from the knee angle, as well as internal/external rotation(both, $p=0.07^*$, $p=0.02^*$) from the hip angle. Second, the maximum resultant joint moments of the lower limbs had statistically significant differences in the inversion/eversion moment from the ankle joint(both, $p=0.05^*$, $p=0.05^*$), the abduction/adduction moment(left, $p=0.08^*$) from the knee joint, and the internal/external rotation moment(right, $p=0.09^*$) from the hip joint. Third, the maximum resultant joint powers of the lower limbs had a statistically significant difference both in flexion/extension joint powers(both, $p=0.05^*$, $p=0.01^*$) and in abduction/adduction(both, $p=0.02^*$, $p=0.00^*$) from the hip joint, as well as abduction/adduction(left, $p=0.00^*$) from the knee joint, In conclusion, the elderly women were somewhat changed after 12 weeks of taekwonaerobics training.

• Korean Journal of Applied Biomechanics
• /
• v.12 no.2
• /
• pp.143-157
• /
• 2002

This study was to analyze the kinematic variables when the subjects performing Uchi-mata(inner thigh reaping throw) by Kumi-kata types((How to grasp A or B?) and two different opponent's height in Judo. Kinematic variables were temporal, posture. Data analysis was collective comparison of two-way ANOVA, t-test by type A&B and two different opponent's height. There were significant difference of Kumi-kata types(p<.05) in the time elapsed on Kake phase(KP : throwing phase) and hip, knee, ankle-angle of the attacking foot in the 1st stage of KP and knee, ankle-angle of the attacking foot and hip, knee ankle-angle of the supporting foot in the 2nd stage of KP. There were significant difference of two opponent's(p<.05) in the time elapsed on KP and hip-angle of the supporting foot in 1st stage of KP. Therefore, the interaction effect(p<.05) were in the time elapsed on KP and hip-angle of the supporting foot in the 2nd stage of KP. So, It could be suggested that Judoka hold on the part-behind neck lapel(type A) at the sleeve with the other of Judogi jacked when opponent's height was short. Because the time elapsed on KP of type B was not so fast as type A(p<.05) during performed Uchi-mata, and also the bigger hip-angle of the supporting foot in the 2nd stage of KP grew, the faster the time elapsed on KP became.

• Journal of the Korean Applied Science and Technology
• /
• v.40 no.4
• /
• pp.642-649
• /
• 2023

The purpose of this study was to analyze the effects of knee joint injury experiences of judo players on kinematic factors and center of pressure factors during uchimata. Among right-handed male college judo players specializing in uchimata, 13 people who had a knee joint injury experience(age, 20.69.1±0.75 years; height, 172.85±4.81 cm; body mass, 74.92±5.51 kg; and career, 8.92±0.95 years) and 13 people who did not have a knee joint injury experience(age, 21.08.1±0.76 years; height, 172.54±6.32 cm; body mass, 76.62±9.09 kg; and career, 9.46±0.94 years) within the last 2 years were divided into two groups and participated as subjects. The two groups were evaluated for differences in ankle, knee, and hip joint angle variables, COP range, and velocity components during uchimata. As a result of the study, the EIG group showed smaller values in the knee joint flexion angle at E3 and the hip joint extension angle at E4 during uchimata than the NIG group. In addition, the EIG group showed lower values in the range of motion of the COP and forward movement velocity of the COP in the one-leg support phase than the NIG group.