• Physical Therapy Rehabilitation Science
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• v.10 no.2
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• pp.98-105
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• 2021

Objective: The purpose of this study was to examined the kinematic relationship and differences through the range of motion (ROM), muscle activity, and vertical ground reaction force (VGRF) during forward and backward lunge movements, which are effective in improving muscle strength and balance ability of the lower extremities, and to provide clinical information on more efficient lunge movements. Design: Cross-sectional study Methods: Fifteen adult males who met the selection criteria were tested for their dominant feet.Forward and backward lunges were then performed, and the ROM, muscle activity, and VGRF were measured for kinematic analysis during the lunge movement.The differences betweenthe forward lunge and backward lunge intervention were examined using a paired t-test. Results: A significant increase in the ROM of the knee and ankle was observed during the forward and backward lunges (p<0.05). In addition, in terms of the muscle activity, the peak values of the vastus medialis oblique (VMO) and VGRF also showed a significant increase in the forward lunge compared to the backward lunge (p<0.05). Conclusions: This study showed an increase in VGRF peak value, knee and ankle ROM, and VMO muscle activity during forward lunge. Based on these results, it is considered necessary to apply differently depending on the direction of progress in consideration of the musculoskeletal situation and physical ability during the lunge movement.

• Korean Journal of Applied Biomechanics
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• v.24 no.1
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• pp.85-93
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• 2014

The purpose of this study was to investigate a relationship among Taekwondo, soccer and gymnastic athletes their balance ability and lower extremity muscle strength, muscle endurance and also whether these variables show differences by sports type. For this purpose, 10 Taekwondo athletes, 10 soccer athletes and 10 gymnastic athletes that is a high school in I area were selected and their balance ability, isokinetic muscle strength and muscle endurance were measured by using force platform (AMTI) and isokinetic measurement (HUMAC NORM). Then the following results were obtained by conducting pearson product-moment correlation analysis and one-way ANOVA. In case of both right and left foot one-leg standing with open-eyes, there was a relation between both knee extension maximal muscle strength of Taekwondo, soccer, gymnastic athletes and balance ability, and in case of right foot one-leg standing with open-eyes, there was a relation between that is right plantar flexion and dorsi flexion maximum muscle strength and muscle endurance of Taekwondo, soccer, gymnastic athletes and their balance ability. Furthermore, in case of left dorsi flexion maximum muscle strength, there were significant differences in order of Taekwondo, gymnastics and soccer, and for isokinetic plantar flexion maximum muscle endurance, both right and left showed significant differences in order of Taekwondo, gymnastic and soccer.

• Journal of the Korea Convergence Society
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• v.12 no.8
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• pp.61-66
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• 2021

The purpose of this study was to investigate the relationship between vertical jump and lower extremity muscle strength of elementary school baseball players. This study subjects were conducted with a total of 40 subjects. Vertical jump was measured using a vertical jump gauge, and a hand held dynamometer was used to measure lower extremity muscle strength. For the measurement of lower extremity muscle strength, flexion·extension·adduction·abduction·internal rotaiton·external rotation of both hip joint, flexion·extension of both knee joint, dorsi flexion·plantar flexion of both ankle joint were measured. pearson's correlation analysis was used to analyze the correlation between vertical jump and lower extremity muscle strength. From these results, it was found that the stronger the leg muscles except for the plantar flexion, the higher the vertical jump was, indicating a positive correlation. In future studies, follow-up studies on the relationship between batting ability and vertical jump & lower extremity muscle strength are needed.

• Journal of Korean Physical Therapy Science
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• v.27 no.1
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• pp.9-17
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• 2020

Background: This study aimed to examine the repeatability of hamstring strength during maximal voluntary contractions (MVCs) and to examine the sex difference. Design: Quasi-experiment design. Methods: The study recruited 23 healthy young individuals as participants. Hamstring flexibility was measured before and after MVCs by active knee extension test. Five trials of MVCs were performed, and hip extension forces were measured using a strain gauge during MVCs. Repeatability was confirmed by intraclass correlation coefficient (ICC) and coefficient of variation, and the difference between male and female participants was confirmed by independent samples t-test. Results: The forces measured during MVCs were significantly different between men and women over five trials. We observed the minimum and maximum force production at the first and fifth trial of MVCs in both men and women. Excellent to moderate reliability of the hamstring strength during MVCs was found in men (ICC range, 0.70-0.98) and women (ICC range, 0.66-0.90). There was no significant difference in hamstring flexibility between men and women. Conclusion: In clinical settings, we recommend excluding the first trial of MVCs in both men and women. Additionally, performing at least three trials of MVCs would be useful to improve the reliability of the baseline measures in women.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.5 no.1
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• pp.1-10
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• 2011

Our study is to verify validation of exercise effect that developing exercise and rehabilitation instrument using pneumatic actuators available rehabilitation and healthcare, while at the same time safer and more convenient for the user to select the desired exercise. Shares subject to the usual exercise is conducted in less than a week in the knee extension and flexion at the undergraduate level there is no more than 10 of the 20 patients were female. Subject performed knee exercise 3 set a day with 12times a set using fluid type exercise instrument and pneumatic exercise instrument that build in this study. Experiment has progressed in 4-weeks with 3-days a week. Our exercise load consist of two type. One is active exercise load with developed instrument in our study and the other one is passive exercise load with fluid instrument. Exercise program based on real-time muscle activation patterns and muscle activity before and after exercise by comparing the effects of exercise for rehabilitation has been verified. The results showed that muscular activity is higher in active exercise load than passive load, and improvement of muscle strength more increased too. Equipment more user-centered exercise more effectively exercise may enhance muscle strength was found. This study can adapt rehabilitation program and exercise for patient and weaker. Also our system can provide easily and convenient prescription of rehabilitation for expert related rehabilitation.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.12 no.1
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• pp.53-62
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• 2018

In this study, we developed a smart 1RM system for national health management and physical fitness, which enables quantitative 1RM measurement in various types of exercise using digital pulley technology, and to test the effect on training by using it. We developed the smart 1RM system, which is composed of portable muscle strength measuring device, Bluetooth communication based mobile phone data transmission and circuit diagram, and height adjustable system body. We recruited the 30 participants with 20th aged and divided into training and non-performing groups with 15 participants randomly. The participants performed 5 sets of elbow, lumbar, knee extension / flexion 10 times using smart 1RM system and the experimental period was 3 days a week for a total of 8 weeks. The experimental results showed that the maximum strength of the elbow, lumbar, and knee joints was significantly improved before and after maximal muscle strength training in the training group. Oxygen intakes during 1RM exercise mode showed 10.91% than endurance. To verify the validity of the smart 1RM maximal strength data, the reliability was 0.895 (* p <0.00). This study can be applied to the early rehabilitation treatment of the elderly and rehabilitation patients more quantitatively using the national health care.

• Korean Journal of Applied Biomechanics
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• v.27 no.4
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• pp.247-255
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• 2017

Objective: The purpose of this study was to investigate the maximum core muscle activation angle according to core-strengthening exercises. Method: Twenty-six young female football players (age: $17.84{\pm}0.80years$, height: $163.08{\pm}5.25cm$, weight: $54.96{\pm}7.41kg$) registered in the Korea Football Association from D High School located in Seoul were the subjects of this research. An electromyogram (Noraxon, USA) was used for monitoring the maximum core muscle contraction activity. Results: The angle for the maximum core muscle strength per core exercise and muscle was the smallest for the upper rectus abdominis in the windshield wiper exercise. The angle of the vastus medialis was significantly the largest. The range of angles at which the maximum strength was observed for each core exercise were as follows: 1) abdominal flutter kicks ($11{\sim}40^{\circ}$), 2) leg raises ($21{\sim}34^{\circ}$), 3) scissors ($45{\sim}66^{\circ}$), 4) knee to elbow sit-ups ($42{\sim}64^{\circ}$), 5) reverse crunches ($9{\sim}40^{\circ}$), 6) butt-ups ($24{\sim}32^{\circ}$), 7) V sit-ups ($5{\sim}24^{\circ}$), 8) windshield wipers ($11{\sim}20^{\circ}$), 9) bird dog ($11{\sim}18^{\circ}$), and 10) raised leg plank ($38{\sim}50^{\circ}$). Conclusion: Four kinds of motion could be classified according to the range of angles at which the core muscles were maximally activated. The first group involves the range of motion that gives the maximum muscle strength when the lower extremity and ground angle was between $5^{\circ}$ and $24^{\circ}$, such as the V sit-ups, windshield wipers, and bird dog. The second group comprised the flutter kicks and reverse crunches at an angle between $9^{\circ}$ and $40^{\circ}$. The third group comprised the leg raise and butt-up exercises at an angle between $21^{\circ}$ and $34^{\circ}$. The fourth group included the scissors, knee to elbow sit-ups, and raised leg plank at an angle between $38^{\circ}$ and $66^{\circ}$. These results may be useful as basic data for core movement and core muscle training according to the purpose of exercise.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.1
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• pp.229-238
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• 2013

The aim of this study is to evaluate university canadian paddlers' iso-kinetic muscle function and provide training advices. Eight university paddlers with a 8.5 years career participated in this study. Inbody 720, biodex system III, biodex stabilizer system and THP 2 are used to investigate body component, muscle function(peak torque, average power and work fatigue), agility and dynamic balance. Iso-kinetic muscle function around shoulder, thorax and knee are measured. And then bilateral and unilateral muscle imbalance are calculated at each joint. Results of this study are as follows; University canadian paddlers' BMI average is 24.90 $kg/m^2$ and percent body fat is 12.23%. Reaction time average was 324 msec and balance score at each leg are below 2.0. A3, A4, A5, A6, A8 are needed to train shoulder muscle strength and power. A1, A2, A7, A8 are needed to strengthen shoulder muscle endurance. A2, A5, A8 are needed to train thorax muscle strength and power. A1, A8 are needed to strengthen thorax muscle endurance. Most of paddlers' reciprocal muscle balance ratio on thorax and knee are out of normal range. A2, A3, A4, A8 are needed to train abdominal strength and A3, A5, A6, A7, A8 are needed to train hamstring strength.

• Archives of Orthopedic and Sports Physical Therapy
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• v.14 no.2
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• pp.45-53
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• 2018

Purpose: The purpose of this study was to investigate the effects of muscle activity and muscle strength according to verbal command volume during isokinetic and isometric quadricep exercises. Methods: To measure muscle activity and muscle strength, surface electrodes were attached to the participants, as they sat on a Biodex chair. The isometric exercise was performed three times, with maximum exercise at $30^{\circ}$ bending angle, based on a maximum extension state of the knee at $0^{\circ}$. The average holding time was unified to three seconds. In addition, the isokinetic exercise was performed three times, at $60^{\circ}/sec$. The verbal command ranged between 0∾60 dB and 0∾75 dB. Muscle activity was measured using surface electromyography (4D-MT, Relive, Gimhae, Korea). The Biodex System 4 was used to measure the isometric and isokinetic strength of the nodal line, and 4D-MT was used to measure muscle activity. Results: There were significant improvements in the maximal and relative muscle strengths, when the 0∾ 60 dB and 0∾75 dB verbal commands were applied with isokinetic extension/flexion (p<.05). The isokinetic exercise (0∾75 dB) group showed a significant difference in the vastus medialis oblique muscle activity change (p<.05), while the isometric exercise (0∾75 dB) group showed a significant difference in the rectus femoris muscle activity change (p<.05). Conclusions: Our results reveal that verbal commands effectively improve muscle activity and muscle strength during isokinetic and isometric quadricep exercises.

• The Journal of Korean Physical Therapy
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• v.17 no.1
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• pp.69-79
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• 2005

The purpose of study were to determine the effect of Elastic Band Exercise Based of PNF L/E pattern(EBEBP) on the balance in the elderly people. 24 health elderly women aged 65 to 85 years participated who live in Sun-cheon city Jeon-nam. Participants were divided into exercise(12) and control(12) group to randomized. Exercise participants received strengthening exercise for 30minutes in two times a week for 4weeks while control group continued their normal activities. Exercise used to yellow elastic band which 4 patterns of PNF by 1) hip extension - adduction - external rotation with knee extension, 2) hip extension-abduction-internal rotation with knee extension. 3) hip flexion - adduction - external rotation with knee flexion, 4) hip flexion - abduction - internal rotation with knee flexion. All subjects participated in 3 tests Berg Balance Test(BBT), One-Leg Standing Test(OLST), Functional Reaching Test(FRT). Exercise and control group were tested before and at the end of the test. This collected date were analysed by using paired t-test and independent t-test. The results of this study are as follows; 1. The experimental group was statistically significant difference in balance performance clinical test of BBT(p<0.01), OLST(p<0.01), FRT(p<0.001). 2. The control group was no significant difference in balance performance clinical test of BBT, OLST, FRT(p>0.05). 3. After the exercise, there was significant difference in the BBT(P<0.01), OLST(P<0.05), FRT(P<0.001) between the experimental group and control group in EBEBP. Thus, elastic band exercise based of PNF L/E pattern can result in improved muscle strength and balance in the elderly people. Further studies are required to show long-term effects of exercise training on the elderly people.