• PNF and Movement
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• v.20 no.1
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• pp.115-123
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• 2022

Purpose: The aim of this study was to investigate the effects of sit-to-stand training with various foot positions combined with visual feedback on muscle onset time and balance in stroke patients. Methods: Thirty stroke patients were randomly assigned into three standing groups: one with a symmetrical foot position (SSF; n = 10), one with an asymmetrical foot position with the affected foot at the rear (SAF; n = 10), and one with visual feedback and an asymmetrical foot position (SVAF; n = 10). Sit-to-stand training with different foot positions was performed for 30 minutes a day, 5 times a week, for a total of 4 weeks. The effects on muscle onset time and balance were assessed. Results: In a comparison of the onset time of muscle contraction, the onset time of the affected side tibialis anterior and less-affected side gastrocnemius muscle and tibialis anterior was significantly shortened in the SAVF group. And onset time of the less-affected side tibialis anterior was shortened in the SAF group. There was a significant difference in the result of functional reach testing in the SVAF group. Conclusion: VRG was effective in improving muscle activity and balance in elderly women aged 65 and older. In this study, sit-to-stand training with visual feedback and asymmetrical foot position showed significant functional improvement.

• The Journal of Korean Physical Therapy
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• v.26 no.6
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• pp.449-452
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• 2014

Purpose: The purpose of this study was to analyze the coordination between trunk flexion and lower limb extension contributing to vertical propulsion during sit-to-stand (STS) at different chair heights in the elderly. Methods: Ten elderly subjects were asked to stand up at their natural speed from different chair heights : (1) $90^{\circ}$ knee flexion; (2) $100^{\circ}$ knee flexion; (3) $110^{\circ}$ knee flexion; and (4) $120^{\circ}$ knee flexion. A standard chair without a backrest or armrests was used in this study. To remove inertial effects of upper limb movements, subjects were asked to stand up from a chair with their arms crossed at the chest. Mean of results of three trials were used in the analysis at different knee flexion angles. Distances moved by the shoulder for compensatory trunk movement was recorded by motion analysis and vertical force was recorded under foot using force plates. Distances moved by the shoulder and vertical ground reaction force measurements were analyzed using repeated ANOVA. Results: Distances moved by the shoulder significantly decreased with higher chair (p<0.05). Vertical forces were not significant difference on chair heights (p>0.05), but results of pairwise comparisons for vertical force revealed significant difference between $90^{\circ}$ knee flexion and $120^{\circ}$ knee flexion (p<0.05). Conclusion: Trunk movement is probably used as a compensatory mechanism at low chair heights to increase lift-off from sitting by the elderly.

• Physical Therapy Korea
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• v.19 no.2
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• pp.29-38
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• 2012

This study aimed to identify the asymmetry observed in the electromyography (EMG) activity patterns of selected trunk and thigh muscles between the affected and unaffected sides during the sit-to-stand movement in ambulatory patients with post-stroke hemiparesis. This study included 20 patients with post-stroke hemiparesis. The differences between stroke fast walkers (${\geq}8m/s$, 11 subjects) and stroke slow walkers (<8 m/s, 9 subjects) were compared. The activation magnitude and onset time of the multifidus, lumbar erector spinae, hamstrings, and quadriceps during the sit-to-stand movement were recorded through surface EMG. Moreover, the EMG activation magnitude and onset time ratios of each bilateral corresponding muscle from the trunk and leg were measured by dividing the relevant values of the unaffected side by those of the affected side. In all the subjects, the activation magnitudes of the multifidus, hamstring, and quadriceps on the affected side significantly decreased compared to those on the unaffected side (p<.05). The onset time of muscle activity in the affected side was markedly delayed for the multifidus and quadriceps during the task (p<.05). The activation magnitude ratios of the quadriceps were markedly decreased in the stroke slow walkers as compared to those in the stroke fast walkers. These findings indicate that the asymmetry in the multifidus, hamstring, and quadriceps muscle activation patterns in patients with post-stroke hemiparesis may be due to the excessive muscle activation in the unaffected side to compensate for the weakened muscle activity in the affected side. Our findings may provide researchers and clinicians with information that can be useful in rehabilitation therapy.

• Journal of Biomedical Engineering Research
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• v.16 no.2
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• pp.217-222
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• 1995

We propose some applications of image processing techniques to extract quantitative measurements by using a camera system developed in Korea university and Catholic Medical School. From now on the system will be called as KCMOTION. The purpose of this study is to provide basic kinematic and kinetic data for the analysis of human movements and to find the clinical usefulness and reliability of the proposed motion analysis system. Two tests, sit-to-stand (STS) movements and pendulum test, are conducted by the system. The aims of the tests are to identify variability and reliability of KCMOTION to give some quantitative comparisons to the other systems. The result of STS movement are compared to the LOCUS IIID motion analyzer by the ratio of maximum flexion movement per body weight to the actual maximum flexion extension torque per body weight. That result in 29 % and 33 % for hip and knee joint, respectively in KCMOTION and 27 % and 30 % in LOCUS IIID System. The results of the pendulum movements are compared to that of using Cybex and Electrogoniometer with relaxation index, amplitude ratio, swing number and swing time. The results of relaxation index and amplitude ratio of the KCMOTION are between those of the Cybex and Electrogoniometer. We also observed that the KCMOTION detect more natural movement, from the results of swing number and time.

• Physical Therapy Korea
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• v.21 no.4
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• pp.49-55
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• 2014

Excessive lumbar flexion during sit-to-stand (STS) is a risk factor for lower back pain. Postural taping can prevent unwanted flexion of the lumbar spine. This study aimed to demonstrate the effect of taping the lower back on the lumbopelvic region and hip joint kinematics during STS. Sixteen healthy subjects participated. All subjects performed the STS with and without taping of the lower back. A three-dimensional motion analysis system was used to measure the kinematics of the lumbar spine, pelvis, and hip joint during STS. The angle of the peak lumbar flexion, pelvic anterior tilting, and hip flexion and angular displacement of the lumbar spine between starting position and maximal lumbar flexion were collected. Paired t-tests, or Wilcoxon's rank-sum test for non-parametric distribution, were used to assess differences in the measurements with and without taping. A p-value <.05 was taken to indicate a significant difference. Significant differences were observed in the angle of the peak lumbar flexion, pelvic anterior tilting, hip flexion and angular displacement of the lumbar spine (p<.05). Taping was associated with a significant decrease in the angle of peak lumbar flexion and angular displacement of the lumbar spine between the starting position and maximal lumbar spine flexion. In addition, the peak angle of pelvic anterior tilting and hip flexion were significantly increased with taping. The findings of this study suggest that taping the lower back can decrease excessive lumbar flexion, and increase the pelvic anterior tilting and hip flexion motion during STS.

• Journal of The Korean Society of Integrative Medicine
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• v.6 no.1
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• pp.7-14
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• 2018

Purpose : The purpose of this study was to confirm changes in the muscle activity of the quadriceps femoris with changes in the ankle and hip joint angles during the transition from sitting to standing. Method : Twenty-five healthy 20-30-year-old women participated in the study. The subjects performed standing-up movements in four positions: standard posture (hip = $90^{\circ}$/ankle = $0^{\circ}$); posture on a decline board (hip > $90^{\circ}$/ankle < $0^{\circ}$), posture on a footboard (hip > $90^{\circ}$/ankle = $0^{\circ}$); and posture on a decline board with a higher chair (hip = $90^{\circ}$/ankle < $0^{\circ}$). Then, the muscle activities of the rectus femoris, vastus medialis and vastus lateralis were measured using surface electromyography. Result : The muscle activities of the rectus femoris, vastus medialis and vastus lateralis in the footboard application were statistically significantly higher than in the application of the decline board with a higher chair. Conclusion : This study confirms that the flexion of the hip joint has a greater effect than the plantar flexion of the ankle joint on the muscle activity of the quadriceps during a sit-to-stand movement.

• Journal of Biomedical Engineering Research
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• v.29 no.6
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• pp.484-492
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• 2008

Sit to stand(STS) movement is one of the most common activity in daily life. In addition, Korean traditionally stand up from various sitting heights in one's daily life compared to other foreigners. As Korea enter rapidly to the aging society, needs of the elderly's independent life are increasing. Therefore the importance of research about the analysis of elderly's activity in daily life is rapidly increasing. In this study, we analyzed joint movements and changes of muscle length during STS(sit-to-stand) at various sitting heights(table seat, bath seat, bottom) in the Korean elderly's daily life by using the motion analysis and musculoskeletal modeling. Ten Korean elderly and young were participated in this experiment. Three heights of sitting posture which could represent typical sitting in Korean daily life were chosen as table seat(42cm), bath seat(21cm) and bottom(0cm). As the results, the elderly showed both smaller knee/hip flexion and larger trunk flexion relatively in comparison to the young during table seat STS. The elderly also showed larger dorsiflexion and smaller ROM of knee, hip, trunk compared to the young during bath seat STS. Additionally, the elderly showed larger plantarflexion, hip flexion, smaller knee flexion and trunk flexion during the first half of bottom STS and larger knee flexion, hip flexion and trunk flexion during the second half of bottom STS. In addition, we could know contraction and relaxation characters of major muscles in lower limb during various STS through the analysis of changes in muscle length by musculoskeltal modeling.

• Korean Journal of Applied Biomechanics
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• v.18 no.2
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• pp.59-64
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• 2008

D. W. KANG, J. S. CHOI, and G. R. TACK, A Study on Real-Time Sports Activity Classification & Monitoring Using a Tri-axial Accelerometer. Korean Jouranl of Sport Biomechanics, Vol. 18, No. 2, pp. 59-64, 2008. This study was conducted to study the real-time sports activity classification and monitoring using single waist mounted tri-axial accelerometer. This monitoring system detects events of sports activities such as walking, running, cycling, transitions between movements, resting and emergency event of falls. Accelerometer module was developed small and easily attachable on waist using wireless communication system which does not constrain sports activities. The sensor signal was transferred to PC and each movement pattern was classified using the developed algorithm in real-time environment. To evaluate proposed algorithm, experiment was performed with several sports activities such as walking, running, cycling movement for 100sec each and falls, transition movements(sit to stand, lie to stand, stand to sit, lie to sit, stand to lie and sit to lie) for 20 times each with 5 healthy subjects. The results showed that successful detection rate of the system for all activities was 95.4%. In this study, through sports activity monitoring. it was possible to classify accurate sports activities and to notify emergency event such as falls. For further study, the accurate energy consumption algorithm for each sports activity is under development.

• Journal of the Ergonomics Society of Korea
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• v.35 no.6
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• pp.493-501
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• 2016

Objective: This study analyzes the effect of angle conditions of rehabilitation equipment used for supporting hemiplegic patients on their rehabilitation training for standing action. The study was performed by adjusting the rear angle of seat inclination through a motion analysis. Background: Owing to a loss of muscle rigidity and degradation of muscle control ability, hemiplegic stroke patients suffer from asymmetrical posture, abnormal body balance, and degraded balance abilities due to poor weight-shifting capacity. The ability to shift and maintain one's weight is extremely essential for mobility, which plays an important role in our daily life. Thus, to improve patients' ability to maintain weight evenly and move normally, they need to undergo orthostatic and ambulatory training. Method: Using a motion analysis system, knee movements on both hemiplegic side and non-hemiplegic side were measured and analyzed in five angles ($0^{\circ}$, $10^{\circ}$, $30^{\circ}$, $50^{\circ}$, $70^{\circ}$) while supported by the sit-to-stand rehabilitation equipment. Results: The knee movements on both sides increased as the angle increased in angle support interval to support a hemiplegic patient's standing up position. In standing up interval, a hemiplegic patient's knee movement deviations on both sides decreased, and the movement differences between hemiplegic and non-hemiplegic legs also decreased as the angle increased. Conclusion: The results of this study showed that the rehabilitation effectiveness increases as the angle increases, leading to a balanced standing posture through the decrease of movement difference between hemiplegic and non-hemiplegic sides and an improved standing up ability through the increase of knee movement on both sides. However, angles higher than $50^{\circ}$ didn't provide a significant effect. Therefore, a support angle under $50^{\circ}$ was proposed in this study. Application: The results of this study are expected to be applicable to the design of sit-to-stand support equipment to improve the effectiveness of the rehabilitation process of hemiplegic patients.

• Physical Therapy Rehabilitation Science
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• v.5 no.2
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• pp.63-69
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• 2016

Objective: To evaluate the effects of sit-to-stand (STS) imagery group training (IGT) on STS movement and balance performance for chronic hemiparetic stroke. Design: Randomized controlled trial. Methods: A total of 30 people with chronic hemiparetic stroke (15 for STS-IGT group and 15 for control) were recruited in this study. The STS-IGT group participated in a videotape-based STS-IGT for 30 minutes a day, five days a week for six weeks, while the control group watched a documentary on television for the same period. The STS-IGT focused on a five-stage protocol. Specifically, external imagery was used during the four phases of the STS movement from the seat of the chair to standing up. All of the participants also participated in a regular rehabilitation program. STS movement and balance performance were assessed using three clinical measures. Results: After training, time to perform the 5-repetition STS test significantly increased in the STS-IGT group (change value, $4.0{\pm}2.0$ sec) compared with the control group (change value, $0.9{\pm}0.7$ sec) (p<0.05). There was a greater improvement in Berg balance scale scores in the STS-IGT group (change value, $0.2{\pm}4.1$ points) compared with the control group (change value, $0.3{\pm}0.9$ points) (p<0.05). There was a greater improvement in Timed Up and Go scores in the STS-IGT group (change value, $2.6{\pm}1.5$ sec) compared with the control group (change value, $0.9{\pm}1.0$ sec) (p<0.05). Conclusions: STS-IGT can be considered as a useful option for restoration of STS movement and balance performance for individuals with chronic hemiparetic stroke who are unable to fully participate in physical activities.