• 대한인간공학회지
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• 제26권3호
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• pp.59-65
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• 2007

In this study, six grip spans (45mm-65mm) were tested to evaluate the effects of handle grip span and user's hand size on maximum grip strength, individual finger force, and subjective ratings of comfort using a digital dynamometer with individual force sensors. Forty-six males were assigned into three hand size groups according to their hand lengths. Results showed that overall 55mm and 50mm grip spans were the most comfortable sizes and associated with the highest grip strength in the maximum grip force exertions, whereas 65mm grip span was rated as the least comfortable size as well as the lowest grip strength. In the interaction effect of grip span and hand size, small and middle hand sized participants rated the best preference and the least preference grip spans differently with large hand sized participants. With respect to the analysis of individual finger force, the middle finger force was the strongest and the highest contribution to the total finger force, followed by ring, index and little fingers. In addition, it was noted that each finger had a different optimal grip span for exerting maximum force resulting in a bowed contoured shaped handle for two-handle hand tools. Thus, the grip spans for two-handle hand tools might be designed according to the users' hand and finger anthropometrics to maximize performance and subjective perception of comfort.

• 대한의용생체공학회:의공학회지
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• 제34권3호
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• pp.156-162
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• 2013

Moments of inertia of limb segments are essential to calculate parameters related to the segmental rotation. To analyze the human motion accurately and specifically, moments of inertia obtained from the individual are required. In this study, a simple method to determine a subject-specific moment of segmental inertia using a dynamometer is introduced. In order to evaluate the method, one male participated to test for his forearm plus hand on a commercial dynamometer. Three passive speeds, i.e. 240, 270, and $300^{\circ}/s$, were chosen to confirm whether the moment of inertia values at each speed approach to a fixed value. The same procedure was repeated on the day after to evaluate whether the method is reproducible. As the results, there were no significant differences among the speeds and between the days. The value of the moment of the forearm inertia was 0.216 $kg{\cdot}m^2$ that is apparently higher compared to values by previous models. Nonetheless, it seems to be acceptable based on our body mass index analysis using reported subject height and mass in each previous study. According to our results, the developed method could be useful to determine the segmental moment of inertia of an individual, showing no significant differences among the speeds and between the days. Thus, we believe that our results are reliable according to two appropriate evaluation procedures. This finding would be helpful to calculate segmental rotation related parameters of an individual.

• 한국기계가공학회지
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• 제11권1호
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• pp.13-19
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• 2012

In this study, ultrasonic vibration tool designed and made by using FEM analysis. And machining test was carried out in various machining conditions using ultrasonic vibration capable CNC machine. For work material, alumina ceramic ($Al_2O_3$) was used while for tool material diamond electroplated grinding wheel was used. To evaluate ultrasonic vibration effect, grinding test was performed with and without ultrasonic vibration in same machining condition. In ultrasonic mode, ultrasonic vibration of 20kHz was generated by HSK 63 ultrasonic actuator. The two grinding speeds, 1.67m/s and 3.35m/s, were applied. On the other hand, grinding forces were measured by KISTLER dynamometer.

• 한국전문물리치료학회지
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• 제24권4호
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• pp.38-45
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• 2017

Background: To improve muscle flexibility, static stretch is the most common type and is considered safe and effective for improving overall flexibility of muscles. During the stretch, the intensity is more likely to be determined by the degree of an athlete's pain and practitioner's skills rather than quantitative measures of stretch. It is necessary to determine the optimal intensity for the stretch. Objects: The purpose of this study is to explore the relationship between hand held dynamometer (HHD) and verbal rating scale (VRS) in comparison of the effects of continuance time on active (walking) and inactive (sitting) movement after static stretch. Methods: A cross-sectional study was conducted with a sample (n=62) recruited from a university. Participants were randomly assigned to 2 different groups (n=31 for each group) based on participants' positions either remaining in sitting or freely walking around for a series of re-assessments. Data was collected at pre-warm up, pre-stretch, post-stretch, and additional assessments at the time of 3, 6, 9, 12, 15, 20 and 30 minutes after the stretch. Results: Relationship between VRS and HHD scores represents very weak correlation (Spearman's p=-.16, p>.05). Pearson's correlation analysis was conducted following the logarithmic transformation of the two scores. Pearson's correlation after the transformation still showed a very low relationship and a poor linear relationship between the two scores (Pearson's r=-.18, p>.05). Conclusion: The optimal intensity for stretch cannot be solely determined by the subjective pain perception. The objective measurement such as HHD could be used in conjunction with the pain perception.

• 재활복지공학회논문지
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• 제7권1호
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• pp.21-27
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• 2013

수동 휠체어의 추진은 추진 동작의 낮은 효율로 인하여 사용자의 상지 관절에 고통과 부상까지 유발할 수 있다. 이에 따라 수동 휠체어 추진 중에 발생하는 상지 관절의 운동역학적 해석이 필요하다. 본 연구에서는 수동 휠체어 추진 중 상지 관절에 작용하는 토크를 구할 수 있는 2차원 역동역학 모델을 개발하였다. 개발한 모델은 시상면에서 상완, 하완, 손에 해당하는 3개의 체절로 상지를 구성하였고 몸통으로부터 3개의 체절을 회전조인트로 연결한 개방연쇄구조를 갖는다. 역동역학 해는 뉴턴-오일러 방법으로 구하였고 요구되는 입력자료는 실험을 통하여 획득하였다. 수동 휠체어 추진에 필요한 상지 거동의 운동학적 자료는 3차원 동작분석 시스템에서 추출하였고 역동역학 모델의 외력에 해당하는 운동역학적 자료는 브레이크식 다이나모미터에서 추출하였다. 역동역학 모델을 이용한 해석을 통하여 수동 휠체어 추진에 따른 상지 관절의 회전각과 관절 토크를 구하였다. 개발된 모델은 상지 관절에 관한 생체역학적 해석 도구이며 적은 노력으로 3차원 역동역학 모델로 확장하는 토대가 된다.

• 대한물리치료과학회지
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• 제5권4호
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• pp.845-850
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• 1998

The purpose of those study is to estimate grip and hand activity of RA patients and find that the evaluation is very a valuable to the RA patients. The term of the evaluation was from June 25. 1998.. to July 30. 1998 and researched at Hanyang university Rheumatic Hospital. This study researched 100 normal people and 85 RA patients and analyzed the results and averaged those with t-test by Excel data. The results of those study are as follows. 1. The highest percent of those results of the dynamometer, pinch research was the people who are on 40s. 2. The results of all RA patients marked lower than those of normal people. 3. It's difficult to do hard work such as washing, opening can, transferring boxes to the patients. 4. The above research is effective to RA patients.

• Annals of Rehabilitation Medicine
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• 제42권6호
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• pp.822-832
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• 2018

Objective To determine the socio-demographic, psychologic, hematologic, or other relevant factors associated with hand grip strength in Korean farmers. Methods A total of 528 healthy Korean farmers were enrolled. Hand grip strength was measured in both hands using a hydraulic dynamometer. Socio-demographic characteristics were assessed and anthropometric measurements were obtained. Psycho-cognitive measurements such as sleep quality (Pittsburgh Sleep Quality Index) and Go/No-Go test response time were conducted. In addition to physical measurements, serologic parameters including insulin-like growth factor 1 were measured. The factors associated with hand grip strength were analyzed using multiple linear regression analysis after adjusting for age, height, and weight. Results The mean hand grip strength was associated with the Pittsburgh Sleep Quality Index total score (${\beta}=-0.12$, p=0.01), the Go/No-Go test response time (${\beta}=-0.18$, p=0.001), vitamin D (${\beta}=0.12$, p=0.02), and insulin-like growth factor 1 levels (${\beta}=0.1$, p=0.045). In female farmers, hand grip strength was only associated with the Pittsburgh Sleep Quality Index total score (${\beta}=-0.32$, p<0.001). Conclusion The results of this study demonstrate that hand grip strength was associated with sleep quality and attention in Korean farmers.

• Physical Therapy Rehabilitation Science
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• 제13권2호
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• pp.231-239
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• 2024

Objective: This study was conducted to investigate the effect of high-intensity laser therapy(HILT), transcutaneous electrical nerve stimulation(TENS), and ultrasound(US) treatment on pain, grip strength, and hand function in patients who had undergone carpal tunnel syndrome surgery. Design: A randomized controlled trial. Methods: Thirty patients who had undergone carpal tunnel syndrome surgery were randomly assigned to receive either TENS combined with HILT, US combined with HILT, or only HILT as the control group. Treatments were applied around the surgical site, and pre- and post-treatment changes were evaluated. Pain was assessed using NPRS, hand symptoms using CTS-6 and BCTQ-SSS, grip strength with an electronic dynamometer, and hand function using BCTQ-FSS. Treatments were administered seven times over two weeks. Results: The pain and symptoms were significantly reduced(p<0.05) and grip strength and hand function were significantly increased(p<0.05) after treatment compared to before treatment for all subjects. Pain was significantly reduced(p<0.05) and grip strength was significantly increased(p<0.05) in the TESN+HILT group and US+HILT group compared to the Control group. Hand symptoms were significantly reduced(p<0.05) and hand function significantly increased(p<0.05) in the TENS+HILT group compared to the Control group. Conclusions: TENS combined with HILT was found to be more effective than US combined with HILT in reducing pain and symptoms and improving grip strength and hand function in patients following carpal tunnel syndrome surgery. These findings suggest that these treatment modalities can be beneficially applied in clinical practice.

• Physical Therapy Rehabilitation Science
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• 제9권3호
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• pp.171-177
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• 2020

Objective: This study aimed to investigate the upper limb strength, active joint range of motion (AROM), and upper limb function in persons with chronic stroke using virtual reality training in combination with upper limb sensory stimulation. Design: Two-group pretest-posttest design. Methods: 20 subjects were divided into two groups of 10, the sensory motor stimulation and virtual reality training (SMVR) and virtual reality training (VR) groups. The training was conducted for 30 minutes per session, three times a week for 8 weeks.The participants' upper limb strength was measured via the hand-held dynamometer, joint angle AROM was measured via dual inclinometer, function was measured using the Jebson-Taylor hand function test and the manual function test. Results: Significant differences were observed in all groups before and after the training for upper extremity strength, AROM, and function (p<0.05). Between the two groups, the SMVR group showed significant improvement in muscle strength, AROM, and Jebsen-Taylor hand function test scores compared with the VR groups (p<0.05). Conclusions: In this study, we confirmed that sensory stimulation and VR had positive effects on upper extremity strength, AROM, and function of persons with chronic stroke. The results suggest that in the future, VR in combination with sensory stimulation of the upper limb is likely to become an effective method (a rehabilitation training program) to improve the upper limb function of persons with chronic stroke.

• The Journal of Korean Physical Therapy
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• 제19권2호
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• pp.33-39
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• 2007

Purpose: The purpose of this study was to investigate the effect of wrist position on grip strength. A Grip-Strength is measurement of muscle strength in hand. It is evaluated for the motor function and handicap of hand, projection of treatment plan. It is important because correct treatment. Methods: Total 80 college students were participated in this study, who consisted of 40 males and 40 females(age range: $20{\sim}26$). A Grip-Strength Dynamometer was used to measure the grip strength in three wrist position(flexion, extension, neutral position) and two elbow position(supination, pronation). The ANOVA was conducted to determine any significant difference in grip strength between the wrist position and the two elbow position. Results: The results were as follows: 1. The grip strength was affected by wrist position changes. 2. The difference of grip strength according to elbow position Was not significant difference (p>0.01). 3. The grip strength i1l neutral position was strongest among 3 position of wrist (p<0.01). Conclusion: A Grip-Strength was significant difference in wrist position. Pronation position was minimum grip-strength but not significant difference between supination and pronation.