• 한국정밀공학회지
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• 제24권8호통권197호
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• pp.130-137
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• 2007

The optimized prosthetic mass distribution was a controversial problem in the previous studies because they are not supported by empirical evidence. The purpose of the present study was to evaluate the effect of prosthetic mass properties by modeling musculoskeletal system, based on the gait analysis data from two above-knee amputees. The joint torque at hip joint was calculated using inverse dynamic analysis as the mass was changed in knee and foot prosthetic components with the same joint kinematics. The results showed that the peak flexion and abduction torque at the hip joint were 5 Nm and 15 Nm when the mass of the knee component was increased, greater than the peak flexion and abduction torque of the control group at the hip joint, respectively. On the other hand, when the mass of the foot component was increased, the peak flexion and abduction torque at the hip joint were 20 Nm and 15 Nm, greater than the peak flexion and abduction torque of the control, respectively. The hip flexion torque was 4.71-fold greater and 7.92-fold greater than the hip abduction torque for the knee mass increase and the foot mass increase on the average, respectively. Therefore, we could conclude that the effect of foot mass increase was more sensitive than that of knee mass increase for the hip flexion torque. On the contrary, the mass properties of the knee and foot components were not sensitive for the hip abduction torque. In addition, optimized prosthetic mass and appropriate mass distributions were needed to promote efficiency of rehabilitation therapy with consideration of musculoskeletal systems of amputees.

• 대한물리치료과학회지
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• 제9권3호
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• pp.67-75
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• 2002

The purpose of this study was to evaluate the effects of quadriceps femoris flexibility exercise which would improve the degree of knee flexion range of motion, extension torque, and the activities of daily living (ADL) in elderly subjects with degenerative knee arthritis. Fourteen elderly patients (two men and twelve women) with degenerative knee arthritis participated and had a quadriceps femoris flexibility exercise intervention program in this study. The mean age of the patients was 70.00 years for men and 71.16 years for women. This study carried out the experimental study of one group pretest-posttest design, which evaluated the degree of knee flexion range of motion, extension torque, the ADL ability of the patients before and after applying the exercise intervention for five weeks. The results of this study are as follow: 1. The knee flexion ranges of motion of the patients were measured before and after the intervention and the ranges increased significantly both in the left and right knee flexion range of motion (p < 0.05). 2. The peak torque of the knee muscle, the peak torque/body weight, and average power of the patients showed significant increases in both in the left and right knee after applying the intervention (p < 0.05). 3. The intervention produced a significant reduction in pain of the patients (p < 0.05). Their functional activities of ADL improved significantly compared with before the intervention (p < 0.05). It has been shown that the quadriceps femoris flexibility exercise intervention program increased significantly the knee flexion range of motion, and extension torque, as well as an increase in performance of functional activities of ADL of the patients. Thus, the quadriceps femoris flexibility exercise should be considered as one of the therapeutic exercises for the elderly patients with degenerative knee arthritis applied.

• 한국운동역학회지
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• 제31권1호
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• pp.30-36
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• 2021

Objective: The objective of the present study was to analyze the relationship between strength of the lower extremity's joints and their local dynamic stability (LDS) of gait in elderly women. Method: Forty-five elderly women participated in this study. Average age, height, mass, and preference walking speed were 73.5±3.7 years, 153.8±4.8 cm, 56.7±6.4 kg, and 1.2±0.1 m/s, respectively. They were tested torque peak of the knee and ankle joints with a Human Norm and while they were walking on a treadmill at their preference speed for a long while, kinematic data were obtained using six 3-D motion capture cameras. LDS of the lower extremity's joints were calculated in maximum Lyapunov Exponent (LyE). Correlation coefficients between torque of the joints and LyE were obtained using Spearman rank. Level of significance was set at p<.05. Results: Knee flexion torque and its LDS was negatively associated with adduction-abduction and flexion-extension movement (p<.05). In addition, ratio of the knee flexion torque to extension and LDS was negatively related to internal-external rotation. Conclusion: In conclusion, knee flexion strength should preferentially be strengthened to increase LDS of the lower extremity's joints for preventing from small perturbations during walking in elderly women.

• Physical Therapy Rehabilitation Science
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• 제13권2호
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• pp.223-230
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• 2024

Objective: In this study, we compared the key indices of isokinetic tests for knee joint extension and flexion according to the presence or absence of pain in elite athletes with past knee and thigh injuries. Design: Crossed-sectional study Methods: This study was conducted on 33 elite athletes. The elite athletes who participated in this study were divided into a group with pain and a group without pain due to past knee and thigh injuries. The subjects in each group performed an isokinetic muscle strength test for knee joint extension and flexion. After the isokinetic muscle strength test, the main indices of the isokinetic test were compared between the pain group and the non-pain group. Results: In the comparison of the pain group and the non-pain group for 60°/s knee flexion and extension in elite athletes, there was a significant difference only in the torque max average/kg for knee extension. However, there was no statistically significant difference in all other variables. The comparison of the pain group and the non-pain group for 240°/s also showed a significant difference in the torque max average/kg for knee extension, and there was no statistically significant difference in all other variables. Conclusions: In subjects who have experienced previous knee or thigh injuries and have mild pain during strong isokinetic strength tests, torque average/kg is affected, but other strength variables are not affected. Therefore, it would be good to consider this aspect and use it as a basis for testing and training elite athletes.

• 한국전문물리치료학회지
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• 제14권3호
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• pp.23-31
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• 2007

The purpose of this study was to determine the influence of high-heeled shoes on walking of obese women as it was already proven an extrinsic factor of knee osteoarthritis in women with normal weight. In this study the aimed therefore in particular was to utilize high-heeled shoes in proving it's causal influence on knee osteoarthritis by measuring the angle and torque of the knee joint. Fifteen obese women (BMI>25 $kg/m^2$) were measured in their twenties. Each angle and torque of their knee joints during walking on 6.5 cm high-heeled shoes and with a bare feet, were compared with each other and analyzed with a 3D motion analysis system. There was no significant difference in walking speed, cadence and stride length between the two conditions. However, there was a significant increase in a double limb support time and the stance phase when walking on high-heeled shoes as when walking with bare feet. The peak knee flexion angle and peak knee varus torque was higher when walking on high-heeled shoes than with bare feet. On the contrary, the peak knee flexion angle in the swing phase was not statistically different. The prolongation of peak knee varus torque was also proven. There was a significant increase in peak knee varus torque in the initial and last stance phases during walking on high-heeled shoes as compared to walking on bare feet. Through the above results, it was proven that when obese women walked on high-heeled shoes, rather than with bare feet, peak knee flexor and varus torque increased along with the changes of the in knee joint angle. Therefore, the influence of high-heeled shoes might be a significant intrinsic factor in knee osteoarthritis of obese women.

• 운동영양학회지
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• 제24권4호
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• pp.28-33
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• 2020

[Purpose] This study aimed to investigate the effects of branched-chain amino acid (BCAA) supplement on delayed onset muscle soreness (DOMS) by analyzing the maximum muscle strength and indicators of muscle damage. [Methods] Twelve men with majors in physical education were assigned to the BCAA group and placebo group in a double-blinded design, and repeated measurements were conducted. DOMS was induced with an isokinetic exercise. Following BCAA administration, the changes in the knee extension peak torque, flexion peak torque, aspartate aminotransferase (AST), creatine kinase (CK), and lactate dehydrogenase (LDH) concentrations were analyzed. The maximum knee muscle strength was measured at the baseline (pre-D0) following BCAA administration for 5 days before exercise (-D5, -4D, -3D, -2D, -1D). In contrast, the post-treatment measurements (D3) were recorded after BCAA administration for 3 days (post-D0, D1, D2). Blood samples were obtained before (pre-D0), immediately after (post-D0), 24 h (D1), 48 h (D2), and 72 h (D3) after the exercise to analyze the indicators of muscle strength. BCAA was administered twice daily for 8 days (5 days and 3 days before inducing DOMS and during the experimental period, respectively). [Results] There was no difference in the flexion peak torque between the groups. However, the BCAA group showed a significantly higher extension peak torque at D3 (second isokinetic exercise), compared to the placebo group (p<.05). There was no difference in AST changes between the groups. Nonetheless, the CK and LDH were significantly reduced in the BCAA group, compared to the placebo group. There was no correlation between the extension peak torque and flexion peak torque. However, the CK and LDH increased proportionately in DOMS. Moreover, their concentrations significantly increased with a decreasing peak torque (p<.01). [Conclusion] An exercise-induced DOMS results in a decrease in the peak torque and a proportional increase in the CK and LDH concentrations. Moreover, the administration of BCAA inhibits the reduction of the extension peak torque and elevation of CK and LDH concentrations. Therefore, BCAA might be administered as a supplement to maintain the muscle strength and prevent muscle damage during vigorous exercises that may induce DOMS in sports settings.

• Physical Therapy Rehabilitation Science
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• 제12권2호
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• pp.201-205
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• 2023

Objective: Resistance exercise is a necessary element to improve quality of life, and measurement and evaluation of muscle strength provide important information for prescription and management of rehabilitation and exercise programs. This study analyzed the correlation between direct and indirect 1RM for isokinetic maximum torque of the knee joint in order to provide useful information in the field of exercise programs. In addition, the flexion-extension ratio and the difference in left-right deviation were verified. Design: A cross-sectional study Methods: The subjects of this study were 33 healthy adult men and women without medical problems who participated in the health exercise class program at S University in Seoul. The correlation between isokinetic maximum torque and direct and indirect 1RM was analyzed, and a dependent t-test was performed to analyze the flexion-extension ratio and left-right deviation. Results: There was a high correlation between the isokinetic maximum torque and direct and indirect 1RM, and no statistically significant difference was shown between the test methods in the analysis of the flexion-extension ratio and left-right deviation. Conclusions: Isokinetic muscle function measuring equipment is expensive, so it is difficult to use it in local exercise rehabilitation and training sites. Through this study, it was found that direct and indirect 1RM isokinetic maximum torque showed a high correlation, and there was no difference in evaluating muscle function such as flexion-extension ratio and left-right deviation. Therefore, it is considered that the muscle function evaluation using 1RM in general field can be usefully utilized.

• 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.

• The Journal of Korean Physical Therapy
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• 제12권2호
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• pp.145-152
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• 2000

슬관절 자세에 따라 족관절 저측굴곡관의 근력을 비교 분석하기 위하여 건강한 남녀 20명을 대상으로 Cybex 6000을 사용하여 측정한 결과는 다음과 같다. 1. 최대 토오크 값은 양쪽 모두 슬관절 신전상태서 $90^{\circ}$ 굴곡에서보다 높았다. 슬관절 신전상태에 대한 $90^{\circ}$ 굴곡에서의 토오크 값의 비는 운동속도 $30{\circ}/sec$ 와 $90{\circ}/sec$에서 각각 $75.7\%\;85.2\%$였다. 2. 최대 토오크는 $30{\circ}/sec\;90^{\circ}/sec$에서 모두 슬관절 신전상태에서 $90^{\circ}$ 굴곡상태에서보다 운동의 초기에서 나타났으나 유의란 차이는 업었다. 3. 저측룰곡근의 총일량은 굴곡보다 신전상태서 높았다. 슬관절 신전상태 대한 $90^{\circ}$ 굴곡에서의 총일량의 비는 운동속도 $30{\circ}/sec$와$90{\circ}/sec$에서 각각$81\%,\;89\%$였다. 4 저측굴곡근의 근지구력은 슬관절 신전상태와 $90^{\circ}$ 굴곡상태애서 $78.35\%,\;92.70\%$로 굴곡상태에서 높았다. 5. 일률은 $30{\circ}/sec$에서 슬관절 신전에서 높았다. 위 연구 결과는 족관절 손상환자의 물리치료 시에 배 측굴곡근과 저측굴곡근의 근력 비와 더불어 근재교육에 유용한 자료로 사용될 수 있을 것으로 사료된다. 또한 근력증가를 위한 목적으로 운동치료 시 슬관절 신전상태에서의 저측굴곡운동이 더 효율적인 방법이라 생각된다.

• The Journal of Korean Physical Therapy
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• 제11권2호
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• pp.1-4
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• 1999

The purpose of this study was to analyze the changes of the muscle strength and length according to the changes of evaluation postures. Subjects of this study were 13 male and 13 female students. 6 evaluation postures were selected for this study(K90H90, K90H45, K90H0, K70H90, K70H45, K70H0 ; K90=knee $90^{\circ}$ flexion, K70=knee $70^{\circ}$ flexion, H90=hip $90^{\circ}$ fleion, H45=hip $45\circ}$ flexion. H0=hip $0^{\circ}$ ). The peak torque and hamstring muscle length(from fibula head to ischial tuberosity) were measured at each postures. The peak torque level was evaluated by make use of the KIN-COM. The results were as follows : 1. The peak torque in male was significantly increased with changes of hip flexion angle but not in female(($90^{\circ}\;>\;45^{\circ}\;>0^{\circ}$). 2. The hamstring length and peat torque in male and female was significantly changed according to the alteration of evaluation postures.