• The Journal of Korean Physical Therapy
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• 제26권1호
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• pp.9-14
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• 2014

Purpose: The purpose of this study was to investigate how different knee alignments (genu varum and genu valgum) affected activations of quadriceps muscles with measurements of onset-time differences between vastus medialis and vastus lateralis during isometric contractions at both 30 and 60 degree knee flexion. Methods: Fifty-two adults (20 genu varum, 12 genu valgum, and 20 control) were enrolled in this study. Subjects with over 4cm distance between knee medial epicondyles were assigned to Genu varum, while subjects with over 4cm distance between ankles medial malleolus were considered as genu valgum group. Surface EMG was used to measure onset time of both vastus medialis and vastus lateralis during isometric contraction at 30 and 60 degree knee flexion. Results: The onset time of vastus lateralis was delayed in genu varum group, and that of vastus medialis was delayed in genu valgum group at both 30 and 60 degree knee flexions. Moreover, onset time difference at $30^{\circ}$ knee flexion between muscles was larger in genu valgum group than genu varum group. Conclusion: Subjects with genu varum or valgum activated quadriceps muscles with different orders pending on flexion degrees. Therefore, when quadriceps training program were planned to prevent pain or deformities, the findings that quadriceps were activated with different orders affected by knee alignments and joint degree at which trainings were performed, must be considered. If the selective training programs of quadriceps femoris are planned to prevent pain or deformities due to poor knee alignments, these should consider the subject's knee alignment condition.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.246-249
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• 2004

The purpose of this study was to investigate the characteristics between EMG timing of muscle contraction and motor impairment in chronic hemiplegic stroke patients. Delay time and co-contraction of 4 patients who had stroke less than 3 years were measured during isometric wrist flexion and extension along the 3 seconds beep signal. Onset and offset of muscle contraction were significantly delayed on the more affected sides than control sides. Offset was significantly delayed than the onset on the affected sides in wrist flexion. Also, recruitment of antagonist was larger than agonist on the affected sides. Co-contraction ratio on the affected side was significantly smaller than control sides in wrist flexion. In affected sides, Fugl-Meyer motor assessment(FMA) shows the correlation of onset delay in wrist flexion and extension. However, co-contraction ratio correlated with FMA in wrist flexion. EMG assessment is likely to be useful outcome measure and provide insights into mechanism for motor recovery in stroke patients.

• The Journal of Korean Physical Therapy
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• 제35권2호
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• pp.53-57
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• 2023

Purpose: The purpose of this study was to compare the changes in the muscle activation of the quadriceps muscle (rectus femoris, vastus lateralis, vastus medialis) during the stand-to-sit (StandTS) movement according to the plantar flexion angle of the ankle joint. Methods: A total of 22 healthy young females participated in this study. During the StandTS under the three conditions (plantarflexion angle 0°, 20°, and 45° of the ankle), electromyography (EMG) data (% maximum voluntary iso¬metric contraction) of the rectus femoris, vastus lateralis, and vastus medialis were recorded using a wireless surface EMG system. Results: There was a significant difference in the muscle activation of rectus femoris, vastus lateralis, and vastus medialis according to the plantar flexion angle (0°, 20°, and 45°) of the ankle. The muscle activation of the quadriceps was the highest at a 45° angle of plantarflexion and the lowest at 0°. One-way repeated ANOVA was used to analyze the muscle activation data of the lower extremity muscles according to the angle of the ankle joint. Conclusion: Based on the results of our study, it was confirmed that the muscle activity of the quadriceps can be increased even in the StandTS movement, which involves the eccentric contraction of the quadriceps muscle. This suggests that maintaining a plantar flexion posture for a long time, say by wearing high-heeled shoes, can quickly cause muscle fatigue in the lower-limb muscles, which can cause a decrease in balance ability leading to falls.

• The Journal of Korean Physical Therapy
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• 제16권3호
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• pp.86-96
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• 2004

A clinical study about painful manifestation on lumbar with regard to movement change of trunk The purpose of this study is to present the basis of low back pain therapy which is close examined of back muscle that is the main reason for that case of back pain when trunk rotation, flexion and extension. Therefore this study, which is based on literature review and clinical experience, has tried to figure out that back pain which is considered to be significant for the most increasing time, posture, motion, painful area, involved muscle have any influence on trunk rotation, flexion and extension This study has done with the patients in oriental rehabilitation clinic, K-oriental hospital, from Jan, 2003 to Dec, 2003. Total cases were 145(male:$39\%$-52 patients, female:$64.1\%$-93 patients) those who complained lumbosacral pain with radiating that makes patient unable to bending or extending the trunk. And they were surveyed retrospect way, checking the medical record and that of therapist. Results are as followings. 1. For sprain patient, $34.5\%$ complained pain on extension, and among them, the most remarkably, patients who did right rotation extension pattern were $20\%$. Herniated disc patient shows greater limit on flexion when trunk moves bending route, but right rotation with extension pattern shows the most limitation on flexion-extension according to the rotation of trunk 2. Cases of morning back pain($60.5\%$) showed high value on right rotation extension pattern($18.6\%$), right rotation flexion pattern($16.3\%$) but did not show big difference on left flexion and extension pattern 3. Patients those who complain pain on sitting position showed highest value each left, right $14.6\%$ of left and right rotation extension pattern 4. Among extension painful patient, there showed highest value of each $32.5\%$ on right rotation extension pattern, and $20.0\%$ on right rotation flexion pattern. 5. Tenderness distribution of quadratus lumborum showed $34.5\%$ on right rotation extension pattern, $20.7\%$ on left rotation extension pattern, and that of iliopsoas muscle at right rotation flexion pattern showed right muscle $20.0\%$, left $50.0\%$ Derived from the results of survey above, for sprain and HIVD patient showed greatest pain on right rotation pattern, for pain plus patient on right rotation extension among those who has extreme pain on sitting in the morning described tenderness on right quadratus lumborum, and those who complain pain on left rotation extension described tenderness on left lumborum the most Decisively, it is possible to figure out the problem muscle that involved when I found the time, position, motion that aggravating and painful area. Therefore this study would be expected to be able to be a useful clinical materials on diagnosis and therapy of low back pain.

• 대한물리치료과학회지
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• 제24권3호
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• pp.56-63
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• 2017

Purpose: This study aimed to investigate the effects of sitting posture on cervical flexion angle and pain during smart phone use. Method: This research was performed on 10 adult female students who use smart phones regularly, Each of the two groups of participants used the provided smart phone for 20 minutes while maintaining the given default posture. The evaluation order was randomly selected and the two groups were photographed twice before and after the experiment and were asked to answer if they felt pain during or after the experiment. Result: First, both upright sitting position and vertebra bent position pre and post experiment readings showed significant statistical difference (p<.05). And it is shown to be a factor that induces pain around the neck via increase in neck flexion angle. Second, although there were no significant statistical difference between the pre and post experiment readings of the upright sitting position results and the vertebra bent position results, the vertebra bent position readings showed bigger changes to the neck flexion angle then the upright sitting position readings. Third, all participants from both groups claimed pain in all the tested postures of smart phone usage. Conclusion: Smart phone usage for an extended amount of time in all body postures may prove to have a negative effect making the "optimal" smart phone usage position as a controlled time with neck stretches included in between short sessions.

• 대한통합의학회지
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• 제11권3호
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• pp.91-98
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• 2023

Purpose : The purpose of this study was to investigate the effect of the posture holding band on muscle activity of the rectus femoris, medial vastus, and vastus lateralis muscles and weight distribution during squat exercise. Methods : This study was conducted with 30 healthy adult men and women in their 20s, and all subjects were randomly assigned to the experimental group and the control group. Squat exercise was performed for 6 weeks. The experimental group received squat exercise while wearing a posture holding band, and the control group applied without wearing a posture holding band. Muscle activity of the quadriceps femoris (rectus femoris, vastus medialis, and vastus lateralis) and weight distribution (knee flexion 0 °, 30 °, 60 °, and 90 °) was measured. Results : According to the results of this study, all three muscles showed a main effect on time and group, and a significant interaction was shown only in the vastus lateralis. In addition, the value of the weight distribution difference according to the knee flexion angle did not show a main effect according to time and group at 30 ° of knee flexion, but showed an interaction. Conclusion : It was confirmed that the application of the posture holding band during squat exercise increased the muscle activity of the quadriceps muscle, and showed greater changes in the vastus lateralis muscle. In addition, it was confirmed that the difference in weight distribution was reduced in the knee flexion, and in particular, a greater change was shown in reducing the difference in weight distribution in the knee flexion of 30 °. Therefore, it is considered that the effect of the exercise can be further enhanced if the unnecessary movement of the trunk is controlled by using equipment such as a posture holding band during squat exercise.

• 한국운동역학회지
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• 제33권1호
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• pp.1-9
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• 2023

Objective: This study identifies the difference among the heights of a chair's backrest (High, Mid, No), the biomechanical changes chair users undergo over time, and the variables that can measure musculoskeletal disorders, eventually providing information on the appropriate type of backrest. Method: Eleven healthy subjects in their 20s and 30s who had no experience with musculoskeletal disorders or surgical operations within the last 6 months participated in this study. Computer typing tasks were randomly designated and performed according to the type of chair backrest, and evaluation was performed for Flexion-Relaxation Ratio (FRR) analysis after the computer typing tasks. This study used eight infrared cameras (sampling rate: 100 Hz) and nine-channel electromyography (sampling rate: 1,000 Hz). ANOVA with repeated measures was conducted to verify the results, with the statistical significance level being α = .05. Results: Although there was no significant difference in craniovertebral angle (CVA), this study showed time and interaction effects depending on the height of the backrest (p<.05). When working without the backrest, the head-spine angle was lower compared to the chairs with backrest, based on the computer work. As for the head angle, the higher the back of the chair was, the less the head flexion and the body angle became, whereas the body flexion became less when there was a backrest. In addition, the body flexion increased over time in all types of backrests (p<.05). The muscle activity of the upper body tended to be high in the high backrest chair. On the other hand, a lower muscle activity was found with a low backrest. Conclusion: These results show that a chair is more ergonomic when the body angle is correctly set without bending and when it is supported by a low backrest. Accordingly, this study determines that the backrest affects shoulder and neck musculoskeletal disorders during typing and that medium-height backrest chairs can help prevent musculoskeletal disorders, contrary to the expectation that high-backrest chairs are preferable.

• 한국전문물리치료학회지
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• 제11권3호
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• pp.19-24
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• 2004

The purposes of this study were to analyze gait patterns of patients with chronic lumboscaral radiculopathy and to investigate gait parameters which can reflect a functional deficit in relation to the level of lumbosacral radiculopathy. The study population consisted of 25 patients of chronic lumbosacral radiculopathy and 25 healthy control subjects. Conventional physical examinations and three-dimensional gait analyses were performed on all participants. The data were analyzed using an independent sample t-test. The results were as follows: (1) In the patients' group, cadence, walking velocity, stride length and double support time were less than in the control group (p<.05). (2) In the patients' group, maximum flexion of hip, maximum flexion of loading response, maximum flexion of swing phase on the knee and maximum plantar flexion of pre-swing were less than the control group (p<.05). Using three-dimensional gait analysis, we could identify specific gait parameters to reflect a functional deficit related to the level of lumbosacral radiculopathy.

• 대한의용생체공학회:의공학회지
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• 제22권4호
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• pp.359-368
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• 2001

A new knee-ankle-foot-orthosis(KAFO) which uses an automatically-controlled electromechanical wrap spring clutch for the knee joint was developed in the present study. It was found that the output voltage from the foot switches of the developed KAFO was proportionally increased with respect to the applied load. The output voltage from the infrared sensor also decreased as the knee flexion angle increased. The knee joint system for the new KAFO weighs only 780g lighter than any other commercially available developed system. In addition, the solenoid reduces the reaction time for the automatic control of the knee joint. The static torque of the clutch was measured for three persons, and it satisfied the normal knee extension moment during the pre-swing. Three-dimensional gait analyses for three different gait patterns (normal gait, locked-knee gait, controlled-knee gait) from five normal subjects were conducted. Controlled-knee gait showed the maximum knee flexion angle of 40.56$\pm9.55^{\circ}$ and the maximum knee flexion moment of 0.20$\pm$0.07Nm/kg at similar periods in the normal gait. Our KAFO system satisfies both stability during stance phase and free knee flexion during the swing phase at the proper period during the gait cycle. Therefore, our KAFO system would be very useful in various low extremity orthotic applications.

• 한국컴퓨터정보학회:학술대회논문집
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• 한국컴퓨터정보학회 2018년도 제57차 동계학술대회논문집 26권1호
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• pp.55-56
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• 2018

Subjects will flex and extend their knees in a prone posture while keeping the pelvis in a neutral state after having straightened the knees and hip. The angle of the manual measurement of an average person when bent is between $110^{\circ}{\sim}135^{\circ}$. If the person complains of pain at the time of flexion, it signifies the presence of abnormality in the knee joints and muscles. The number and proportion of the patients were measured through this experiment.