• Korean Journal of Applied Biomechanics
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• v.19 no.2
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• pp.245-255
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• 2009

The purpose of this study is to analyzed the coordination of lower limb of elderly women who experienced a fall to present basic information for sports science and to deal with the factors that make elderly women fall more effectively. Twenty elderly women were divided into two groups of 10. The mechanisms of balancing lower limb during walk and differences were compared and analyzed using motion analysis and electromyography. The findings of this study are as follows. The first, walking patterns of these women were unstable as their hip joints did not provide sufficient support because of aging. Second, the left and right knee joints showed different walking patterns. The third, the motions of ankle joints became abnormal with increased age. As for the activation of major lower limb muscles, rectus fermois muscle and biceps fermois muscle contracted more to prevent the bending of knees and moved forward while anterior tibial muscle and inner gastrocnemius muscle were demanded highly during walk and the rate of plantar flexion was reduced.

• Korean Journal of Applied Biomechanics
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• v.17 no.1
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• pp.111-119
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• 2007

The purpose of this study was to investigate muscle activity and gait pattern in lower limb depending on the outsole of heel rockers. Fifteen healthy men volunteered for this experiment. Each subject performed totally three trails with two pairs of different heel rocker shoes and a pair of normal running shoes at speed of 1.33m/s for 1 minute during walking on a treadmill. Kinematic data gathered in 100Hz was recorded and analyzed by using the 3D motion capture system to measure the trunk tilt and joint angle of the right lower limb. And the lower extremity muscle activities were simultaneously recorded in 1000Hz and assessed by using EMG. The statistical analysis was the one-way ANOVA with the repeated measures to compare among the three kinds of shoes. The level of statistical significance for all tests was 0.05. Joint angle of lower limb was showed statistically significant different in MST(hip joint), LHS(ankle joint), and RTO(knee and ankle joint). Muscle activity of rectus femoris and biceps femoris was statistically increased in both heel rocker shoes during gait cycle on treadmill. The maximum peak time of tibialis anterior in the negative heel rocker showed the delay of approximately 23.8%time than normal shoes. Gait pattern variability of the negative heel rocker was increased in the first half of the stance phase and the variability of the positive heel rocker was increased in the terminal stance phase. In Conclusion, stability was decreased in between joints of lower limb on positive heel rocker than negative heel rocker. This study found that there were different joint angle, muscle activity, gait pattern and coordinate system of the lower limb in each kind of shoes. These unstability affected the lower extremity and the whole body. A further study has to be continued with study of rehabilitation and exercise for a long-term.

• Journal of Mechanical Science and Technology
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• v.19 no.spc1
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• pp.371-376
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• 2005

Relative contributions of lower extremity joints on the support moment were investigated in this study. Three-dimensional gait analyses were performed in normal walking and in unexpected step-down walking. For both gait studies, inverse dynamics were performed to obtain each joint moment of the lower extremity, which was applied to the forward dynamics simulation to determine the contributions on the support moment at different phases of walking. The forward dynamic simulation results showed that, in normal walking, the ankle plantar flexors contributed significantly during single-limb-support. However, the ankle plantar flexors, knee extensors and hip extensors worked together during double-limb-support. In unexpected step-down walking, the important contributors on the support of the body during single-limb-support were not only ankle plantar flexors but also knee extensors. This study, analyzing the relative contributions of the lower limb joint moments for the body support, would be helpful to understand different unexpected walking conditions and compensatory mechanisms for various pathological gaits.

• Korean Journal of Applied Biomechanics
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• v.23 no.1
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• pp.63-76
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• 2013

The purpose of this study was to investigate the effects of knee joint muscle fatigue and overweight on the angular displacement and moments of the lower limb joints during landing. Written informed consent forms, which were approved by the human subject research and review committee at Dong-A University, were provided to all subjects. The subjects who participated in this study were divided into 2 groups: a normal weight group and an overweight group, consisting of 15 young women each. The knee joint muscle fatigue during landing was found to increase the dynamic stability by minimizing the movements of the coronal and horizontal planes and maintaining a more neutral position to protect the knee. The effect of body weight during landing was better in the normal weight group than in the overweight group, with the lower limbs performing their shock-absorbing function in an efficient manner through increased sagittal movement. Therefore, accumulated fatigue of knee joint muscles or overweight may be highly correlated with the increase in the incidence of injury during landing after jumping, descending stairs, and downhill walking.

• Journal of Biomedical Engineering Research
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• v.31 no.3
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• pp.217-226
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• 2010

The lower limb orthosis with a pneumatic rubber actuator, which is intended for the assistance and the enhancement of muscular activities of lower limbs was developed in this study. Compared to other knee extension assistive devices being developed by other researchers, our device is designed especially for the elderly people and intended only for slight assistance so that the subjects can keep their muscular strength. For the effectiveness of system, muscular activities of major muscles in lower limbs during sit-to-stand (STS) and squat motion were measured and analyzed. Subjects were performed the STS and squat motion with and without lower limb orthosis. We made comparison muscular activities between with and without lower limb orthosis. Lower limb orthosis was controlled using muscular stiffness force feedback that is controlled by muscular activities of the measured muscle from force sensor. For analysis of muscular activities, electromyography of the subjects was measured during STS and squat motion, and these were measured using MP 150(BIOPAC Systems, Inc.). Muscles of interest were rectus femoris(RF), vastus lateralis(VL), vastus medialis(VM) and vastus intermedius(VI) muscles in lower limbs of the right side. A biodex dynamometer was used to measure the maximal concentric isokinetic strength of the knee extensors of wearing and not wearing orthosis on right side. The test were performed using the concentric isokinetic mode of test with the velocity set at 60°/s for muscles around the knee joints. The experimental result showed that muscular activities in lower limbs wearing orthosis using muscular stiffness force of a vastus medialis muscle was reduced and knee extension torque of an knee joint wearing lower limb orthosis was increased. With this, we confirmed the effectiveness of the developed lower limb orthosis.

• Journal of the Korean Society of Physical Medicine
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• v.12 no.3
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• pp.93-98
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• 2017

PURPOSE: This study investigated the activities of lower limb muscles according to the angle of a medio-lateral ramp while walking to promote awareness of the risks associated with a medio-lateral ramp. METHODS: This study was conducted on 20 healthy male adults. The muscle activities of the vastus medialis oblique (VMO), vastus lateralis oblique (VLO), tibialis anterior (TA) and peroneus longus (PL) were measured while the subjects were walking on a 3 m medio-lateral ramp. Five angles (flat, $2^{\circ}$, $5^{\circ}$, $10^{\circ}$, and $15^{\circ}$) were selected for the angle conditions of the experiment on a medio-lateral ramp. The activities were measured during the stance phase only in the middle cycle of a three-cycle walking experiment. The mean value obtained from the three walking tests was used for the analysis. RESULTS: Results showed that walking on a mediolateral ramp required more muscle activities than walking on a flat surface, through which balanced walking was achieved. CONCLUSION: Walking on a medio-lateral ramp requires proper muscle activation and control, without which the risks of injury to the joints of the lower limbs and falls are likely to increase. Therefore, special attention should be given to older people and the disabled under the condition of traversing a ramp.

• Journal of Korean Medicine for Obesity Research
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• v.4 no.1
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• pp.201-211
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• 2004

The treatment of obesity is increasingly becoming important to effective medical treatment, especially in case involving a degradation of the lower joints. A recent case placed two osteoarthritic obese patients who underwent arthroscopic surgery in a regiment of herbal diet. Alter 3-5 months of receiving this oriental treatment, the patients not only lost weight, but also showed significant reduction of joint inflammation and pain. It is true that obese patients with lower limb or osteoarthritis who have undergone normal obesity treatment regularly for 5 years or more will find the treatment becomes less effective over times. However, for patients suffering from lower limb pain or osteoarthristis, oriental obesity treatment, on the whole was effective in decreasing five key areas(5D). For this reason, it is necessary for oriental medicine to be given further study and consideration as an effective treatment of obesity.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.268-273
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• 2000

Velocity-dependent increase in tonic stretch reflexes is one of the prominent characteristics of spasticity. It is very important to evaluate spasticity objectively and quantitatively before and after treatment for physicians. An accurate quantitative biomechanical evaluation for the spasticity which is caused by the disorder of central nervous system is made in this study. A sudden leg dropper which is designed to generate objective testing environment at every trial gives very effective environment for the test. Kinematic data are archived by the 3-dimensional motion analysis system($Elite^{(R)}$, B.T.S., Italy). Kinematic data are angle and angular velocity of lower limb joints, and length and lengthening velocity of lower limb muscle. A program is also developed to analyze the kinematic data of lower limb, contraction and relaxation length of muscles, and dynamic EMG data at the same tim. To evaluate spasticity quantitatively, total 31 parameters extracted from goniogram, EMG and muscle model are analyzed. Statistical analysis are made for bilateral correlations for all parameters. The described instrumentation and parameters to make quantitative and objective evaluation of spasticity shows good results.

• Journal of International Academy of Physical Therapy Research
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• v.2 no.1
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• pp.222-228
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• 2011

With comparison of maximum vertical reaction force and lower limb on drop landing between normal and flat foot group, this study is to provide fundamental data of the prevention of injury and the treatment of exercise which are frequently occurred on flat foot group's drop landing. The surface electrodes were sticked on lateral gastrocnemius muscle, medial gastrocnemius muscle, tibialis anterior and the drop landing on a force plate of 40cm was performed with a normal group who had no musculoskeletal disease and a flat foot group of 9 people who had feet examinations. Vertical reaction force were significantly statistically different between two groups(p<.001). Muscle activity of lower limbs in all three parts were not statistically different but showed high tendency on average in the flat foot group. The flat foot group had difficulties in diversification of impact burden and high muscle activity. Therefore, it was suggested that muscular strengthening of knee joints and plantar flexions of foot joints which were highly affected in impact absorption will be required.

• Korean Journal of Applied Biomechanics
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• v.25 no.2
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• pp.141-147
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• 2015

Objective : This study aimed to understand how increased heart rates at the time of drop landing during a step test would affect biomechanical variables of the lower extremity limbs. Background : Ballet performers do more than 200 landings in a daily training. This training raises the heart rate and the fatigability of the lower extremity limbs. Ballet performance high heart rate can trigger lower extremity limb injury. Method : We instructed eight female ballet dancers with no instability in their ankle joints(mean ${\pm}$ SD: age, $20.7{\pm}0.7yr$; body mass index, $19.5{\pm}1.2kg/m^2$, career duration, $8.7{\pm}2.0yr$) to perform the drop landing under the following conditions: rest, 60% heart rate reserve (HRR) and 80% HRR. Results : First, the study confirmed that the increased heart rates of the female ballet dancers did not affect the working ranges of the knee joints during drop landing but only increased angular speeds, which was considered a negative shock-absorption strategy. Second, 80% HRR, which was increased through the step tests, led to severe fatigue among the female ballet dancers, which made them unable to perform a lower extremity limb-neutral position. Hence, their drop landing was unstable, with increased introversion and extroversion moments. Third, we observed that the increasing 80% HRR failed to help the dancers effectively control ground reaction forces but improved the muscular activities of the rectus femoris and vastus medialis oblique muscles. Fourth, the increasing heart rates were positively related to the muscular activities of the vastus medialis oblique and rectus femoris muscles, and the extroversion and introversion moments. Conclusion/Application : Our results prove that increased HRR during a step test negatively affects the biomechanical variables of the lower extremity limbs at the time of drop landing.