• Physical Therapy Korea
• /
• v.28 no.3
• /
• pp.168-176
• /
• 2021

Background: The foot is a complex body structure that plays an important role in static and dynamic situations. Previous studies have reported that altered foot posture might affect knee joint strength and postural stability, however their relationship still remains unclear. Objects: The purpose of this study was to identify whether pronated foot posture has an influence on knee isokinetic strength and static and dynamic postural stability. Methods: Forty healthy young males aged 18 to 26 years were included. Foot posture was evaluated using the Foot Posture Index-6 (FPI-6), and the subjects were divided into two groups according to their FPI-6 scores: a neutral foot group (n = 20, FPI-6 score 0 to +5) and a pronated foot group (n = 20, FPI-6 score +6 or more). Biodex Systems 3 isokinetic dynamometer was used to evaluate knee isokinetic strength and hamstring to quadriceps ratio at three angular velocities: 60°/sec, 90°/sec, and 180°/sec. The static and dynamic postural stability in a single-leg stance under the eyes-open and eyes-closed conditions were measured with a Biodex Balance System. Results: There were no significant differences between the groups in knee isokinetic strength and static postural stability (p > 0.05), but there was a significant difference in the medial-lateral stability index (MLSI) for dynamic postural stability under the eyes-closed condition (p = 0.022). The FPI-6 scores correlated significantly only with the dynamic overall stability index (OSI) and the MLSI (OSI: R = 0.344, p = 0.030; MLSI: R = 0.409, p = 0.009) under the eyesclosed condition. Conclusion: Participants with pronated foot had poorer medial-lateral dynamic stability under an eyes-closed condition than those without, and FPI-6 scores were moderately positively correlated with dynamic OSI and dynamic MLSI under the eyes-closed condition. These results suggest that pronated foot posture could induce a change in postural stability, but not in knee isokinetic strength.

• Journal of Advanced Technology Convergence
• /
• v.1 no.1
• /
• pp.33-42
• /
• 2022

The flexors and extensors of the knee joint are essential for maintaining body stability. The purpose of this study was to investigate the correlation between the isokinetic parameters of the knee flexor and extensor muscles and the function of the lower extremity muscles. Twenty-two healthy adults participated in this study. The time to peak torque (TTP), acceleration time (AT), and peak torque (PT) of the knee flexor and extensor muscles were measured. A 20m sprint, Sargent jump, one leg hop test, and side shuffle were measured to evaluate lower extremity function. The correlation between each variable was analyzed using Pearson correlation coefficient. PT of the knee flexor showed a significant correlation with single leg hops and 6M hops in a single leg. PT of knee extensors was found to be significantly correlated with Sargent jumps and triple hops. Based on the results of this study, we suggest that the strength of the knee flexor and extensor muscles has the potential to be used to predict lower extremity function.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.18 no.1
• /
• pp.45-52
• /
• 2023

The power generation method using expensive diesel has operation problems such as high cost diesel generator and a lack of reserved power due to increase of power demand in some islands, requiring expansion of power generation facilities. To solve this problems, it is necessary to improve the efficiency of power generation facilities through an ORC(Organic Rankin Cycle) system application that uses waste heat as a heat source. Therefore, localized application technology of price competitive and highly reliable ORC power generation system is needed, and optimization technology of generators is having great effect, so this study performed two generator designs to get a high-efficiency generator with an optimized 30kW output. The comparison of simulation data for two designed models showed that a generator with SPM factor of 46.2% had an efficiency of 92.1% and a power ouput of about 23.2kW based on 12,000rpm, a generator with SPM factor of 44.46%, had a power output of 27.9kW and efficiency of 93.6% based on above rpm. For the verification of improved design model with SPM factor of 44.46%, the prototype test system with 110kW motor dynamometer was installed and got to the efficiency of 92.08% with conditions of the rated capacity 25kW at 12,000rpm, the test results of prototype generator showed the validity of generator design.

• Journal of Korea Entertainment Industry Association
• /
• v.13 no.7
• /
• pp.497-503
• /
• 2019

The purpose of this study was to investigate the effect of self care training program on motor function of upper limb and self-efficacy in chronic stroke patients. This study selected 20 chronic stroke patients in local community men. The subjects carried out self care training program be composed of task oriented training for 40 minutes, 4 times per week for 6 weeks. Manual function test(MFT), digital grip dynamometer, self-efficacy scale were used to evaluate motor function of upper limb and self-efficacy during pre and post intervention. In MFT and hand grip force test, the post outcome were significantly increase than the pre outcome(p<.05). In self-efficacy evaluation, the post outcome of was significantly improve than the pre outcome(p<.05). The result of this study show that the self care training program be composed of task oriented training may be appropriate for improving the motor function of upper limb and self-efficacy in chronic stroke patients. This will enable the application of self care training program in rehabilitation therapy of chronic stroke patients and it will help guide the selection of the therapist as one therapeutic basis

• Journal of Life Science
• /
• v.20 no.4
• /
• pp.549-554
• /
• 2010

Increased external rotation and decreased internal rotation have been noted to occur progressively in the throwing shoulders of baseball pitchers. The purpose of this study was to provide descriptive data for terminal range eccentric antagonist/concentric agonist shoulder muscle strength in collegiate baseball pitchers with humeral head retroversion diagnosed through MRI. The dominant and non-dominant shoulders of 9 asymptomatic baseball pitchers were tested through a range of 20 degrees of external rotation to 90 degrees of internal rotation using the Biodex system 3 isokinetic dynamometer at speeds of $90^{\circ}/s$ and $180^{\circ}/s$. Differences between the dominant and non-dominant shoulders were assessed using the paired samples t-test. Total range of motion, measured at $90^{\circ}$ of glenohumeral abduction, was $180.1^{\circ}$ for dominant shoulders and $183.7^{\circ}$ for non-dominant shoulders. Humeral head retroversion measured $47.6{\pm}6.1^{\circ}$ in dominant and $37.8{\pm}5.3^{\circ}$ in non-dominant extremities. The mean internal rotator concentric contraction (IR-Con) showed a significant difference compared to $31.5{\pm}5.1$ (Nm) in dominant and $38.7{\pm}5.2$ (Nm) in non-dominant shoulders at $180^{\circ}/s$ (p<0.05). The mean external rotator eccentric contraction (ER-Ecc) showed a significant difference compared to $20.3{\pm}4.7$ (Nm) in dominant and $25.1{\pm}3.7$ (Nm) in non-dominant shoulders at $90^{\circ}/s$ (p<0.05). There is a pattern of increased external rotation and decreased internal rotation in the dominant extremity that significantly correlates with an increase in humeral retroversion.

• Journal of the Korean Society of Clothing and Textiles
• /
• v.26 no.1
• /
• pp.74-82
• /
• 2002

The present study is aimed to investigate the effect of the safety hat on the balance of body temperature by observation of the physiological response under hot working environment. The experiment was carried out in a climate chamber of 3$0^{\circ}C$, 50%RH for 70 minutes. To compare the two kinds of safety hat, 5 healthy male subjects worn safety hat without hole (called 'without hole') or safety hat with hole (called 'with hole') according to a randomized cross-over design. The main results of this study are as fellows: Rectal temperature and heart rate were significantly lower level in 'with hole'than in 'without hole'. The mean skin temperature was significantly higher in 'without hole'than in 'with hole'. Blood pressure were significantly low in 'with hole'. Sweat rate which was measured by weight loss before and after experiment was higher in 'without hole'. In subjective ratings, subjects replied more hot, more uncomfortable and more wet, they felt more fatigue in condition of 'without hole'. Work ability which was measured by a grip strength dynamometer was higher in 'with hole'. Safety hat which can be used for safety of the brain in work place is meaningful device of behavioral thermoregulatory response under the hot working environment. The safety hat which is designed for proper ventilation and hygiene can maintain the homeostasis of body temperature by releasing body temperature efficiently.

• Journal of the Korean Society of Safety
• /
• v.10 no.3
• /
• pp.81-95
• /
• 1995

Now, safety assurance in construction sites should be accomplished by its own organization rather than control of the code or government. It is believed that the safety assurance can be considerably improved by a lecture or an education using the existing theories or literatures up to now, but it is thought that fundamental safety assurance we not able to be accomplished without developing safety devices '||'&'||' equipment or taking fundamental measures, based on the result analyzed from workers behaviors. There are various behaviors of the workers showed in construction site, but only tests for hammerusing works such as form, re-bar, stone workers directly related to the grip strength are mainly performed, investigated and measured here for the study. The above works are similar to power grip, 7th picture on seven items which are categorized for hand grip types(Ammermin 1956 ; Jones ; Kobrick 1958). Measurements of grip strength are commonly taken in anthropometric surveys. They are easy to administer but unfortunately it is rather dubious whether they yield any data that are of interest to the engineer. Very fewer controls of tools are grasped and squeesed studies showed very little overall correlation between grip strength and other measures of bodily strength (Laubach, Kromer, and Thordsen 1972), but hammer-using work which is practically progressed in construction site are mainly influenced with grip strength. According to the investigation on work measurement, it is shown that 77% of form worker are using hammer to be related to grip strength. In this study, it is particularly noticed that wearing safety gloves in construction site is required for workers safety but 20% difference between grip strength with safety gloves and without ones are commonly neglected in the site(Fig. 1). Nevertheless, safety operation with consideration of the above 20% difference is not considered in the construction site. Factors of age, kinds of work, working time, with or without safety gloves are in vestigated '||'&'||' collected at the sites for this study. Test, not at each working hour but at 14 : 00 when the almost all of the workers think the most tired, resulting from the questionaires, also when it is shown on the research report has been performed and compared for main kinds of works : form '||'&'||' re-bar work. Tests were performed with both left SE rightand of the workers simultaneously in construction site using Rand Dynamometer(Model 78010, Lafayette Instrument Co., Indiana, U.S.A) by reading grip strength on the gauge while they are pulling, and then by interviewing on their ages, works, experiences and etc., directly. The above tests have been performed for the dates of 15th march-26th May '95 with consideration of site condition. And even if various factors of ambient temperature on the testing date, working condition, individual worker's habit and worker's condition of the previous ate are concerned with the study. Those are considered as constants in this study. Samples are formwork 53, rebar 62, electrician 5, plumber 4, welding 1 from D construction Co., Ltd, ; formwork 12, re-bar 5, electrician 2, from S construction Co., Ltd, , formwork 78, re-bar 18, plumber 31, electrician 13, labor 48, plumber 31, plasterer 15, concrete placer 6, water proof worker 3, maisony 5 from B construction Co., Ltd. As In the previously mentioned, main aspect to be investigated in this study will be from '||'&'||' re-bar work because grip strength will be directly applied to these two kinds of works ; form '||'&'||' re-bar work, eventhough there are total 405 samples taken. It is thought that a frequency of accident occurrence will be mainly two work postures "looking up '||'&'||' looking down" to be mainly sorted, but this factor is not clarified in this study because It will be needed a lot of work more. Tests has been done at possible large scale of horizontally work-extended sites within one hour in order to prevent or decrease errors '||'&'||' discrepancies from time lag of the test. Additionally, the statistical package computer program SPSS PC＋has been used for the study.