• PNF and Movement
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• v.9 no.1
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• pp.21-29
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• 2011

Purpose : The purpose of this study was to assess the effects of the lower extremity muscle activity on bridging exercise according to the knee joint angle. Methods : Twenty-five healthy adults volunteered to participate in this study. Subjects were required to complete following four bridging exercises; knee joint flexion $120^{\circ}$, $90^{\circ}$, $60^{\circ}$, $45^{\circ}$. Surface electromyography from selected lower extremity muscles was normalized to maximum voluntary isometric contraction. Muscle activity was measured by QEMG-4 system (LXM 3204, Laxtha Korea). A repeated measures of one-way ANOVA was used to determine the influence of bridging exercise on muscle activity for each muscle and descriptive statistics was used to determine muscle ratio. Results : The biceps femoris of all bridging exercises showed significantly(p<.05). The vastus medialis and lateralis of all bridging exercises showed significant excepted $120^{\circ}$(p<.05). The rectus femoris of all bridging exercises showed no significant. Median of vastus medialis/rectus femoris ratio of $120^{\circ}$ was 2.03, $90^{\circ}$ was 2.16, $60^{\circ}$ was 2.67, $45^{\circ}$ was 4.10. Median of vastus lateralis/rectus femoris ratio of $120^{\circ}$ was 1.70, $90^{\circ}$ was 1.70, $60^{\circ}$ was 2.08, $45^{\circ}$ was 2.58. Median of vastus medialis/vastus lateralis ratio of $120^{\circ}$ was 1.26, $90^{\circ}$ was 1.50, $60^{\circ}$ was 1.52, $45^{\circ}$ was 1.47. Conclusion : Angular motion decreasing with knee joint flexion made increase biceps femoris and vastus medialis activation. This result will be use knee joint stabilizing exercises during bridging or unstable surface training and biceps femoris strength training.

• Korean Journal of Applied Biomechanics
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• v.29 no.2
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• pp.79-88
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• 2019

Objective: The aim of this study was to determine the peak torques of the knee and ankle joint and local stability of the lower extremity's joints, and muscle activation patterns of the lower extremity's muscles between fallers and non-fallers in the elderly women during walking. Method: Four elderly women (age: $74.5{\pm}5.2yrs.$; height: $152.1{\pm}5.6cm$; mass: $55.3{\pm}5.4kg$; preference walking speed: $1.19{\pm}0.06m/s$) who experienced falls within six months since experiment had been conducted (falls group) and thirty-six subjects ($74.2{\pm}3.09yrs.$; height: $153.6{\pm}4.9cm$; mass: $56.7{\pm}6.4kg$; preference walking speed: $1.24{\pm}0.10m/s$) who had no experience in falls (non-falls group) within this periods participated in this study. They were measured torque peaks of the knee and ankle joint using a Human Norm and while they were walking on a treadmill at their natural pace, kinematic variables and EMG signals were collected with using a 3-D motion capture system and a wireless EMG system, respectively. Lyapunov Exponent (LyE) was determined to observe the dynamic local stability of the lower extremity's joints, and muscles activation and their co-contraction index were also analysed from EMG signals. Hypotheses between falls and non-falls group were tested using paired t-test and Mann-Whitey. Level of significance was set at p<.05. Results: Local dynamic stability in the adduction-abduction movement of the knee joint was significantly lower in falling group than non-falling group (p<.05). Conclusion: In conclusion, muscles which act on the abduction-adduction movement of the knee joint need to be strengthened to prevent from potential falls during walking. However, a small number of samples for fallers make it difficult to generalize the results of this study.

• Journal of The Korean Society of Integrative Medicine
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• v.3 no.2
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• pp.47-54
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• 2015

Purpose: This study was to investigate the effects of lumbar stabilization exercise and lower extremity strengthening program on pain, lower extremity muscle in patients with chronic low back pain. Method: The subject were randomly divided two groups. 15 people who were conducted lower extremity exercises and lumbar stabilization exercises called the combined exercise group and other(15 people) who were only conducted lower extremity exercise group. The assessment tools were the pain level and the led muscle power. Exercise was conducted for eight weeks. Result: Pain of the combined exercise group showed significant differences in the change in pain level(p<.05). The leg muscle power showed significant differences within group which hip flexor, extensor muscles and abductor muscles. there were significant differences within combined exercise group (p<.05). But the knee joint in each group showed a significant difference within group (p<.05). Conclusion: This study suggest that the lumbar stabilization exercises and lower extremity exercises showed more efficient results in the pain levels and leg muscles power than only the lower extremity exercise for patients with lumbar instability.

• Physical Therapy Rehabilitation Science
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• v.11 no.4
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• pp.517-525
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• 2022

Objective: The rehabilitation protocols for functional recovery have been emphasized after total knee arthroplasty, and Pilates is in the spotlight as a safe and easily modified exercise method. The purpose of this study was to investigate the effects of mat Pilates exercise on lower extremity function, postural balance, and walking in the individuals with total knee arthroplasty. Design: One group pretest-posttest design. Methods: Eighteen older women with unilateral total knee arthroplasty was recruited in the study. The subjects were evaluated on lower extremity function, postural balance, and walking before and after mat Pilates exercise. All subject performed one hour mat Pilates exercise, 3 times a week for 8 weeks. Mat Pilates exercises were focused on core stability and lower extremity strengthening and, more dynamic movements were added to increase the difficulty of movements every two weeks. The lower extremity function was measured using the Western Ontario and McMaster Osteoarthritis Index (WOMAC), knee joint position sense, and five times sit-to-stand test. Postural balance was assessed by single leg stance test, functional reach test, and timed up and go test. Walking was measured by OptoGait system to temporospatial parameter. Results: The lower extremity function, postural balance, and walking were significantly improved after mat Pilates exercise, except for five times sit-to-stand test (p<0.05). Conclusions: This study demonstrated that the mat Pilates exercise was a useful method to improve lower extremity function, postural balance, and walking in the older women with unilateral total knee arthroplasty.

• Journal of the Korean Society of Physical Medicine
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• v.2 no.2
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• pp.101-112
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• 2007

Purpose : The purpose of this study was to evaluate influence of sacroiliac joint mobilization on lower extremity muscle strength. Methods : The subjects were consisted of thirty patients who had Leg length inequality(LLI) of more than 10mm(16 females. 14 males) from 21 to 41 years of age(mean aged 24.87). All subjects randomly assigned to sacroiliac joint mobilization group(n=15), control group(n=15). sacroiliac joint mobilization group received sacroiliac joint mobilization about 10 minutes for 3 times per week during 4 weeks period. Control group not received intervention during 4 weeks period. The tape measure method(TMM) was used to measure functional Leg length inequality. Biodex System 3 Pro was used to measure strength of Knee extension & flexion. All measurements of each subjects were measured at pre-test, 2weeks post-test and 4weeks post-test. Results : 1. The LLI of sacroiliac joint mobilization group was significantly reduced according to within treatment period(p<.05), most significantly reduced between pre-test and post-test(p<.05). sacroiliac joint mobilization group significantly more reduced than control group(p<.05). 2. The knee extension strength of sacroiliac joint mobilization group was significantly increased according to within treatment period(p<.05), most significantly increased between pre-test and post-test(p<.05). sacroiliac joint mobilization group significantly more increased than control group(p<.05). 3. The knee flexion strength of sacroiliac joint mobilization group was significantly increased according to within treatment period(p<.05), most significantly increased between pre-test and post-test(p<.05). sacroiliac joint mobilization group significantly more increased than control group(p<.05). Conclusion : sacroiliac joint mobilization can reduce LLI and increased lower extremity muscle strength.

• The Journal of Korean Physical Therapy
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• v.14 no.4
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• pp.323-330
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• 2002

This study purposes at applying knee joint taping to preventing muscle fatigue. Twenty six subjects between the ages of 20s and 30s were randomly sampled among healthy males, with an average age of 26yr(range, 22 to 31yr). None of the subjects had a recent or remote history of significant lower extremity injury, No subjects had a history of central nervous system equilibrium problems. To develop muscle fatigue, Isokinetic exercise, which is a repetition of flexion and extension knee joint to $180^{\circ}$/sec, was performed 50 times per person. During the exercise, change of proprioception were measured by applying taping on both knee joints. Analysis has carried out by means of one-way ANOVA with repeated measures and independent t-test at the significance level of $\alpha$=0.05 to detect statistic significance. The results of this study were as follows: First, it was found that the generation of lower extremity muscle fatigue significant affects on proprioception (p < 0.05). Second, the application of taping to knee joint after the generation of lower extremity muscle fatigue significant affect proprioception (p < 0.05). Third, while continual exercise after the generation of muscle fatigue, taping group was significant differences in proprioceptive loss than non-taping group(p < 0.05).

• Korean Journal of Applied Biomechanics
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• v.26 no.4
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• pp.433-441
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• 2016

Objective: The purpose of this study was to understand the injury mechanism and to provide quantitative data to use in prevention or posture correction training by conducting kinematic and kinetic analyses of risk factors of lower extremity joint injury depending on the change of direction at different angles after a landing motion. Method: This study included 11 men in their twenties (age: $24.6{\pm}1.7years$, height: $176.6{\pm}4.4cm$, weight: $71.3{\pm}8.0kg$) who were right-leg dominant. By using seven infrared cameras (Oqus 300, Qualisys, Sweden), one force platform (AMTI, USA), and an accelerometer (Noraxon, USA), single-leg drop landing was performed at a height of 30 cm. The joint range of motion (ROM) of the lower extremity, peak joint moment, peak joint power, peak vertical ground reaction force (GRF), and peak vertical acceleration were measured. For statistical analysis, one-way repeated-measures analysis of variance was conducted at a significance level of ${\alpha}$ <.05. Results: Ankle and knee joint ROM in the sagittal plane significantly differed, respectively (F = 3.145, p = .024; F = 14.183, p = .000), depending on the change of direction. However, no significant differences were observed in the ROM of ankle and knee joint in the transverse plane. Significant differences in peak joint moment were also observed but no statistically significant differences were found in negative joint power between the conditions. Peak vertical GRF was high in landing (LAD) and after landing, left $45^{\circ}$ cutting (LLC), with a significant difference (F = 9.363, p = .000). The peak vertical acceleration was relatively high in LAD and LLC compared with other conditions, but the difference was not significant. Conclusion: We conclude that moving in the left direction may expose athletes to greater injury risk in terms of joint kinetics than moving in the right direction. However, further investigation of joint injury mechanisms in sports would be required to confirm these findings.

• Journal of the Ergonomics Society of Korea
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• v.13 no.2
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• pp.65-79
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• 1994

A biomechanical model of lower extremity in seated postures was developed to assess muscular activities of lower extremity involved in a variety of foot pedal operations. The model incorporated four rigid body segments with the twenty-four muscles to represent lower extremity. This study deals with quasi-static movement to investigate dymanic movement effect in seated foot operation. It is found that optimization method which has been used for modeling the articulated body segments does not predict the forces generated from biarticular muscles and antagonistic muscles reasonably. So, the revised nonlinear optimization scheme was employed to consider the synergistic effects of biarticular muscles and the antagonistic muscle effects from the stabilization of the joint. For the model validation, three male subjects performen the experiments in which EMG activities of the nine lower extremity muscles were measured. Predicted muscle forces were compared with the corresponding EMG amplitudes and it showed no statistical difference. For the selection of optimal seated posture, a physiological meaningful criterion for muscular load sharing developed.

• Archives of Reconstructive Microsurgery
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• v.8 no.2
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• pp.120-129
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• 1999

There were many difficulties in the treatment of extensive, massive, and composite defect in the lower extremity until early 1980's. Recently, microscopic reconstruction of wide soft tissue defect is popularized. But, the combined flap, which requires wide coverage of lower extremity after soft tissue sarcoma excision or traffic accident, is still challenging to the orthopaedic surgeons. We experienced 12 cases of combined scapular and latissimus dorsi flap from 1983 to 1997 in the lower extremity reconstruction of soft tissue defect with satisfactory result. There were no serious donor site complications such as functional disturbance of shoulder joint.

• Korean Journal of Applied Biomechanics
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• v.22 no.1
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• pp.9-16
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• 2012

The purpose of this study was to compare and analyze muscle function and EMG of the trunk and the lower extremity in short and long distance athletes and in order to determine difference in peak torque per unit weight, muscle power per unit weight, endurance ratio, and %MVIC classified by muscle. For that purpose, isokinetic muscle function tests for waist, knee, and ankle joints and EMG measurements for the trunk and the lower extremity muscle with running motion were conducted for 7 short and long distance high school athletes respectively. The study over muscle function of waist, knee, and ankle joints indicates that peak torque per unit weight of short distance athletes is higher than that of long distance athletes in extension and flexion of waist joint, plantar flexion of right ankle joint, and dorsi flexion of left ankle joint. In case of the muscle power per unit weight of short distance athletes is also higher than long distance athletes in waist, knee, and ankle joints. No difference in endurance ratio of waist, knee, and ankle joints between the two groups was founded. The results of the test over EMG of the trunk and the lower extremity show that %MVIC of erector spinae, rectus femoris, vastus medialis, vastus lateralis, and tibialis anterior is higher than that of long distance athletes in support phase. The above results proved to be the same in flight phase except for %MVIC of medial gastrocnemius. In other words, %MVIC of medial gastrocnemius for short distance athletes turned out to be higher than that of long distance athletes in flight phase.