• The Journal of Korean Physical Therapy
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• v.36 no.3
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• pp.103-109
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• 2024

Purpose: The performance of a task is influenced by the perception of its demands and the development of a response according to the movement pattern. This study aims to compare the change in kinetic variables and quadriceps muscle activity according to demands on angular velocity. Methods: Thirty-eight participants performed knee extensions at self-selective angular velocities of slow, moderate, and fast. Angular velocity, kinetic variables, and muscle activity (vastus medialis, vastus lateralis, and rectus femoris) were measured using a dynamometer and surface electromyography. kinetic variables and muscle activity of the knee extensors at three self-selected angular velocities were compared and correlations between the variables were analyzed. Results: There were significant differences in muscle activity and kinetic variables among angular velocities (p<0.001). Self-selective angular velocity was positively correlated with muscle activities and kinetic variables (p<0.001). The power in fast was 40 times higher than that in slow velocity. Conclusion: The simultaneous increase in angular velocity and force output was based on increased effort. The highest power was indicated for the fastest movement. We discovered that muscle activity and torque increased at a similar rate for increasing demands on angular velocity. The individual's most appropriate pattern would have been applied at the movement of self-selective angular velocity, and fast movement is considered to have the highest efficiency.

• The Journal of Korean Physical Therapy
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• v.27 no.2
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• pp.89-95
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• 2015

Purpose: The purpose of this study is to determine the effects of visual information on movement time and each angular velocity of trunk and lower extremity joints while healthy adults are in sitting and squat motion. Methods: Participants consisted of 20 healthy male and female adults; movement time and each angular velocity of trunk, pelvis, hip, knee and ankle of sitting and squat motion according to common vision, visual task and visual block were analyzed using a three dimensional motion analysis system. Results: Each angular velocity of the trunk, pelvis, hip, knee and ankle in phase 2 of the sitting showed significant difference according to the types of visual information (p<0.05). Movement time and each angular velocity of pelvis and hip in phase 2 of squat motion showed significant difference according to the types of visual information (p<0.05). According to the common vision, each angular velocity of knee and ankle in phase 1 was significantly fast in sitting (p<0.05). According to the common vision, each angular velocity of trunk, pelvis, hip, knee, and ankle in phase 2 was significantly fast in sitting (p<0.05). Conclusion: Visual information affects the angular velocity of the motion in a simple action such as sitting, and that in more complicated squat motion affects both the angular velocity and the movement time. In addition, according to the common vision, visual task and visual block, as angular velocities of all joints were faster in sitting than squat motion.

• Journal of Biomedical Engineering Research
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• v.30 no.2
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• pp.142-146
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• 2009

The purpose of this study is to investigate the angular velocity of forearm pronation/supination movement in Parkinson's disease patients, as a quantitative measure of the bradykinesia. Thirteen Parkinson's disease patients ($64{\pm}11.0$ yrs, male:6, female:7) participated in the experiments. The subjects' both right and left forearms were scored by a rater according to rapid alternating movement of hands category in the UPDRS (unified Parkinson's disease rating scale) and the angular velocity of forearm pronation/supination was measured at the same time. As analysis parameters, RMS (root mean square) angular velocity and RMS angle were used. The parameters showed negative correlation with the clinical score (RMS angular velocity: r= - 0.914, RMS angle: r= -0.749). The RMS angular velocity of all clinical scales were significantly different one another except for the non significant difference between those of scale 3 and 4. RMS angle of scale 0 was significantly different from those of scale 2, 3, 4 and that of scale 1 was significantly different from those of scale 3 and 4. This suggests that RMS angular velocity can be used for a quantitative measure of bradykinesia in motor examination.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.3
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• pp.674-677
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• 2010

The purpose of this study was to analyze bradykinesia of forearm movement in patients with Parkinson's disease (PD) as compared to those of normal subjects. A gyrosensor was selected for the measurement of forearm movement, because it can provide angular velocity signal which is free from the gravitational artifact and also because it can be conveniently used during clinical test of bradykinesia. Forty PD patients (age: $65.7\pm11.1$ yrs, H&Y stage:$2.3\pm0.5$), 14 age-matched elderly subjects ($65\pm3.9$ yrs) and 17 healthy young subjects ($24\pm2.1$ yrs) participated in this study. Angular velocity during forearm movement of pronation/supination was measured in both arms. Suggested quantitative measures of bradykinesia were root-mean-squared (RMS) angular velocity, RMS angle, peak power and total power which were derived from the angular velocity. ANOVA showed that all measures were significantly different among three groups (p<0.001). Subsequent post-hoc test revealed that all measures in PD patients were significantly smaller than in healthy elderly and healthy young subjects (p<0.05). This results suggest that PD patients can be differentiated from normal subjects using suggested measures.

• Korean Journal of Applied Biomechanics
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• v.21 no.1
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• pp.39-46
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• 2011

The purpose of this study was to examine differences between players who bend the left elbow and those who stretch it during the forward swing from BST to BC in a 2-handed backhand stroke among outstanding high school tennis players, and to assess the detailed 3D rotational kinematic characteristics of the shoulder and the hip. Statistically significant differences were observed between groups in the longitudinal axis rotation angle of the shoulder and the angle between the shoulder and the arm at BST, and in the side to side movement of the shoulder, the up and down movement of the hip, the side tilt angular velocity of the shoulder, the side tilt angular velocity of the hip, and the front tilt angular velocity of the hip at BC. The difference in the longitudinal axis rotation angle of the shoulder between the 2 groups suggests a difference in the flexibility of the joint in the shoulder arm racquet system. The longitudinal axis rotation angular velocity of the shoulder reached its peak at 75 % of the duration of the analyzed segment and then decreased little by little until BC. This time is considered the stage for increasing the angular velocity of the upper arm, the forearm, the hand and then the racquet, which are more distal segments than the shoulder.

• Korean Security Journal
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• no.31
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• pp.187-207
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• 2012

The purpose of this study was to analyze the punching movement at the horseback riding stance, one of the basic movements in Taekwondo, with 3D images and further the kinetic variables such as time, velocity, angle, angular velocity, and angular acceleration according to the types. It also aimed to examine the characteristics of each type and suggest instructional methods for the right punching movement. For those purposes, three members from the College Taekwondo Poomse Demonstration Squad were put to the test. The research findings led to the following conclusions: 1. Performance Time of the Punching Movement : In Section 1, Type 1 and 2 recorded $0.24{\pm}0.07s$ and $0.42{\pm}0.08s$, respectively, for the punching movement at the horseback riding stance. While Type 1 took less performance time in the punching movement, Type 2 took less time for take back according to each section's percentage in the total performance time. 2. Variables of Linear Velocity and Linear Acceleration : Each type recorded different linear velocity for each aspect, but the highest linear velocity represented the moment of impact for each type. Type 2 recorded the highest linear velocity in Aspect 4, which was the moment of impact. 3. Variable of Joint Angle : There were no big outer differences in the joint angle during the punching movement between Type 1 in the aspect of impact and Type 2, but the individuals assumed dynamic positions in the punching movement of Type 2 with more diverse changes to the joint angle. 4. Variables of Angular Velocity and Angular Acceleration During the punching movement of Type 1, the Aspect 3 in the moment of impact recorded angular velocity of $0.79{\pm}0.02deg/s$, $0.91{\pm}0.04deg/s$, and $5.24{\pm}0.09deg/s$ at the pelvis, shoulder, and wrist respectively. During the punching movement of Type 2, the Aspect 3 in the moment of impact recorded angular velocity of $1.32{\pm}0.03deg/s$, $0.21{\pm}0.03deg/s$, and $4.98{\pm}0.08deg/$ at the shoulder, wrist, and pelvis, respectively. In the Aspect 3 in the moment of impact in Type 2, the angular acceleration at the right wrist joint was $176.24{\pm}1.11deg/s^2$, which was bigger than that in the moment of impact in Type 1.

• Korean Journal of Applied Biomechanics
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• v.15 no.4
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• pp.105-115
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• 2005

Recently among several tennis techniques forehand stroke has been greatly changed in the aspect of spin, grip and stance. The most fundamental factor among the three factors is the stance which consists of open, square and closed stance. The purpose of this study was to investigate the relations between the segments of the body, the three dimensional anatomical angle according to open, close, and square stance patterns during forehand stroke in tennis. For the movement analysis three dimensional cinematographical method(APAS) was used and for the calculation of the kinematic variables a self developed program was used with the LabVIEW 6.1 graphical programming(Johnson, 1999) program. By using Eular's equations the three dimensional anatomical Cardan angles of the joint and racket head angle were defined. In conclusion, the first hypothesis, "In three dimensional maximum linear velocity of racket head would be significant difference among the stance patterns during forehand stroke in tennis" was rejected. The second hypothesis, "In three dimensional anatomical angular displacement of trunk would be significant difference among the stance patterns during forehand stroke in tennis" was rejected and the result showed that the internal-external rotation showed most important role among the three dimensional anatomical angular displacement of trunk The third hypothesis, "In three dimensional anatomical angular displacement of upperlimb would be significant difference among the stance patterns during forehand stroke in tennis" was rejected and the result showed that The three dimensional anatomical angular displacement of shoulder joint showed most important role in forehand stroke. Flexion-extension and internal-external rotation the open stance showed the largest angular displacement and is follwed by square stance and closed stance. The fourth hypothesis, "In three dimensional anatomical angular velocity of upperlimb would be significant difference among the stance patterns during forehand stroke in tennis" was rejected and the result showed that X-axis angular velocity and Z-axis angular velocity the square stance showed the largest angular velocity of the trunk and X-axis angular velocity and Y-axis angular velocity the closed stance showed the largest angular velocity of the shoulder joint.

• Journal of Biomedical Engineering Research
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• v.31 no.3
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• pp.240-244
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• 2010

The purpose of this study is to compare finger tapping (FT) movement of patients with Parkinson's disease (PD) with normal subjects. A gyrosensor system was used for the measurement of FT movement, because it provides angular velocity free from the gravitational artifact and it can be used during clinical FT test listed in unified PD rating scale (UPDRS). Forty PD patients (age: 65.7 ${\pm}$ 11.1 yrs, H&Y stage:2.3 ${\pm}$ 0.5), 14 age-matched elderly subjects (65${\pm}$3.9 yrs) and 17 healthy young subjects (24${\pm}$2.1yrs) participated in this study. Angular velocity of finger tapping movement was measured in both right and left index finger. As quantitative measures, root-mean-squared (RMS) angular velocity, RMS angle, peak power and total power were used. ANOVA showed that all measures were significantly different among three groups (p<0.001) in all quantitative measures. Post-hoc test revealed that all quantitative measures except peak power in patients with PD were significantly smaller than in both healthy elderly and young subjects (p<0.01). This suggests that the measures developed in this study can distinguish patients with PD from normal subjects.

• Journal of Biomedical Engineering Research
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• v.33 no.1
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• pp.47-52
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• 2012

The purpose of this study is to investigate whether medication and deep brain stimulation (DBS) have differential effects on the speed and amplitude of bradykinesia in patients with Parkinson's disease (PD). Five PD patients with implanted DBS electrodes (age: $60.6{\pm}7.4yrs$, H&Y stage: $3.1{\pm}0.2$) participated in this study. FT (finger tapping) movement was measured using a gyrosensor system in four treatment conditions: Med (Medication)-off/DBS-off, Med-off/DBS-on, Med-on/DBS-off and Med-on/DBS-on. Quantitative measures representing average speed and amplitude of FT movement included root-mean-squared (RMS) angular velocity and RMS angle. One-way repeated measures ANOVA showed that RMS angular velocity of Med-on/DBS-on was significantly greater than those of Med-off/DBS-off and Med-off/DBS-on (p < 0.01) whereas RMS angle was not different among conditions (p = 0.06). Two way repeated measures ANOVA showed that only medication improved RMS angular velocity (p < 0.01), whereas both medication and DBS had no significant effect on RMS angle (p > 0.02). Effect size of RMS angular velocity was greater than that of RMS angle in both medication and DBS. This suggests that medication and DBS have differential effects on FT bradykinesia and velocity and amplitude impairments may be associated with different functional aspects in PD.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.11
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• pp.2114-2118
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• 2010

The purpose of this study was to analyze bradykinesia of toe tapping movement in patients with Parkinson's disease (PD) as compared to those of normal subjects. 39 PD patients (age: $65.5{\pm}11.2$ yrs, H&Y stage:$2.3{\pm}0.5$), 14 eldelry subjects with comparable mean age ($65.0{\pm}3.9$ yrs) and 17 healthy young subjects ($24.1{\pm}2.1$ yrs) participated in this study. Angular velocity during repetitive toe tapping movement was measured in both feet using a gyro sensor system. Suggested quantitative measures of bradykinesia were root-mean-squared (RMS) angular velocity, RMS angle, peak power and total power which were derived from the angular velocity signal. ANOVA showed that all measures were significantly different among three groups (p<0.001). Subsequent post-hoc test revealed that all measures in PD patients were significantly smaller than in healthy elderly and healthy young subjects (p<0.02). All measures were significantly correlated with UPDRS scores(r=-0.689~-0.825). These results suggest that the developed system can be used as quantitative measures of the lower limb bradykinesia in PD patients.