• Journal of the Ergonomics Society of Korea
• /
• v.30 no.3
• /
• pp.381-387
• /
• 2011

Objective: The aim of this study was to investigate the maximal grip strength for the combinations of resting time and trial and to provide guideline of resting time for the maximum gripping task associated with the number of trials. Background: Despite many previous researches for the maximal grip strength, few studies have considered the effect of both trials and rest time on the maximum grip strength. Methods: A total of thirty subjects participated in the study. The average of maximum grip strength was measured using JAMAR hydraulic hand dynamometer. The testing position was same as the position recommended by the American Society of Hand Therapists. The between-subject experimental design has been conducted in this study. Trials(1~20 trials) and rest time(2, 3, and 4min) were considered as independent variables, and the maximum grip strength was considered as dependent variable, respectively, in this study. Results: According to the result of the number of trials, the maximal grip strength decreased gradually as the number of trials increased. The ANOVA result showed that the main effect was significant for both resting time(p<.0001) and trial(p<.0001), and the interaction was significant(p<0.0086). Conclusions: The maximal grip strength decreased gradually as the number of trials increased. Thus, basic guideline of resting time was suggested for the number of trials of maximal grip strength tests in this study.

• Journal of Korean Society of Industrial and Systems Engineering
• /
• v.25 no.4
• /
• pp.46-53
• /
• 2002

Push-pull strength has been found to be associated with various work factors such as height, distance, repetition, duration, posture and individual factors. Therefore, this study was performed to investigate the effect of various work factors on push-pull strength and muscle recruitment pattern. Work factors were consisted of grip height(elbow, shoulder), grip distance(100%, 50%, and 25% of maximum grip distance) and shoulder angle(neutral($90^{\cire}$), and abduction($45^{\cire}$, $0^{\cire}$)) during sitting work. The results showed that the normalized strength and EMG value were higher at the elbow height than the shoulder height, and increased with grip distance and shoulder adduction. The results of ANOVA showed that there was significant difference on muscle recruitment patterns among the task conditions. Therefore, it is necessary to consider work factors as well as strength to prevent workers from work-related injuries.

• Journal of International Academy of Physical Therapy Research
• /
• v.4 no.1
• /
• pp.532-538
• /
• 2013

The purpose of this study is to analyze the grip strength by the girth of upper arm and forearm and their muscle activities by duration of grip strength. The subjects were consisted of 20 healthy adults(10 males & 10 females) who had no medical history of neurological and surgical problems with their arms. Girth of upper arm/ forearm and maximum grip strength for 4sec and 30sec were measured. Muscle activity was by wireless electrode EMG system. Co-relation of girth of upper arm/ forearm was significantly high. Upper arm's muscle activity performed for 4sec and 30sec was significantly high. In this study. It suggests that training of upper arm should be performed with the training of grip strength because both of upper arm and forearm affected grip strength.

• Journal of Korean Society of Occupational and Environmental Hygiene
• /
• v.25 no.4
• /
• pp.554-565
• /
• 2015

Objectives: The purpose of this study was to measure estheticians' grip and pinch strength in the hand parts and identify related factors according to general characteristics. Methods: A Jamar dynamometer was used to measure grip strength and a Jamar pinch gauge was used to measure tip, palmar and lateral pinch strength. General data were collected through a questionnaire survey among 116 estheticians from 31 skin care centers and spas. Results: The subjects' mean grip strength was 23.95 kgf for the right hand and 23.42 kgf for the left hand with the dominant right hand recording slightly higher mean grip strength. Their mean pinch strength was the highest with lateral pinch(right 4.89 kgf, left 4.69 kgf), which was followed by palmar pinch(right 3.77 kgf, left 3.88 kgf) and tip pinch(right 2.29 kgf, left 2.25 kgf), in that order. Conclusions: The grip and pinch strength of the hand parts was high when estheticians' commonly used both hands for massage instead of just one. The use of both hands is recommended to protect the hand parts during massage.

• Journal of the Ergonomics Society of Korea
• /
• v.32 no.6
• /
• pp.503-509
• /
• 2013

Objective: The purpose of this study is to analyze the individual finger force between dominant hand and non-dominant hand and to investigate an effect of the individual finger on the total grip strength depending on dominant hand and non-dominant hand. Background: Many studies on the ratio of the grip force between dominant hand and non-dominant hand has been researched. While a 10% rule which is a ratio of the grip force between dominant hand and non-dominant hand has been applied in most studies, studies on the rate of the individual finger force between dominant hand and non-dominant hand have been insufficiently researched. Method: The experiment was preceded with 17 subjects (male, mean 25.8 ages). The individual finger force and total grip strength were measured using pliers being able to change the grip span from 45 to 80mm. Results: The difference of total grip strength between dominant hand and non-dominant hand is following 10% rule. However, the difference of individual finger force between dominant hand and non-dominant hand are not same as the difference of total grip strength. Especially in the case of grip span with 50mm, the differences between total grip strength, index finger, middle finger, ring finger, and little finger were $9.87{\pm}14.80%$, $8.95{\pm}37.17%$, $13.71{\pm}28.27%$, $6.77{\pm}24.35%$, $39.29{\pm}42.46%$, respectively, with p=0.018 of statistical significance. Additionally, the results of regression analysis in 50 and 60mm of grip span showed that the difference in ring finger affected the most to the total grip strength; and the effects followed in order of index finger, middle finger, and little finger. Conclusion: Our study suggests that an effect of individual finger and grip span of pliers have to be considered when explaining the difference of the total grip strength between dominant hand and non-dominant hand. Application: This result is expected to be used for designing ergonomic hand tool.

• The Korean Journal of Community Living Science
• /
• v.25 no.1
• /
• pp.29-37
• /
• 2014

This study examines whether regular exercise moderates the relationship between hand grip strength and cognitive function in older adults. Older adults 65 and over from the third wave of the Korean Longitudinal Study of Ageing Data were analyzed. A moderated multiple regression analysis was conducted to assess the moderating effects of regular exercise on the relationship between hand grip strength and cognitive function. According to the results, regular exercise moderated the effects of hand grip strength on cognitive function, suggesting that regular exercise should be promoted for older adults to reduce unfavorable effects of a decrease in hand grip strength on cognitive function.

• Journal of the Ergonomics Society of Korea
• /
• v.32 no.6
• /
• pp.511-516
• /
• 2013

Objective: The objective of this study is designing an optimal hand tool through maximum grip force study accordance to the hand grip span. Background: In order to prevent musculoskeletal diseases, studies on hand tool design are proceeding based on grip strength, finger force, and contribution of individual finger force on total grip strength. However, experimental apparatus using a tool that is actually used in work place was almost non-existent. Method: 19 males were participated in an experiment. Using the load cell inserted real plier, finger force, grip strength, and subjective discomfort rate of both hands (dominant and non-dominant) were measured in 5 different hand grip span(45mm, 50mm, 60mm, 70mm, and 80mm). Results: There was significant difference(p<0.001) of total grip strength, individual finger force and subjective discomfort rating according to various hand grip span(45, 50, 60, 70, and 80mm). Also, statistically significant different(p<0.001) was shown between the dominant hand and non-dominant hand. In addition, individual finger force in maximum grip was in order of middle finger, ring finger, index finger, and little finger. Conclusion: Optimal grip span of pliers that exerting maximum grip strength is 50~60mm. Application: This finding is expected to be used for designing proper pliers.

• Archives of Plastic Surgery
• /
• v.40 no.1
• /
• pp.52-56
• /
• 2013

Background Measuring grip and pinch strength is an important part of hand injury evaluation. Currently, there are no standardized values of normal grip and pinch strength among the Korean population, and lack of such data prevents objective evaluation of post-surgical recovery in strength. This study was designed to establish the normal values of grip and pinch strength among the healthy Korean population and to identify any dependent variables affecting grip and pinch strength. Methods A cross-sectional study was carried out. The inclusion criterion was being a healthy Korean person without a previous history of hand trauma. The grip strength was measured using a Jamar dynamometer. Pulp and key pinch strength were measured with a hydraulic pinch gauge. Intra-individual and inter-individual variations in these variables were analyzed in a standardized statistical manner. Results There were a total of 336 healthy participants between 13 and 77 years of age. As would be expected in any given population, the mean grip and pinch strength was greater in the right hand than the left. Male participants (137) showed mean strengths greater than female participants (199) when adjusted for age. Among the male participants, anthropometric variables correlated positively with grip strength, but no such correlations were identifiable in female participants in a statistically significant way. Conclusions Objective measurements of hand strength are an important component of hand injury evaluation, and population-specific normative data are essential for clinical and research purposes. This study reports updated normative hand strengths of the South Korean population in the 21st century.

• PNF and Movement
• /
• v.16 no.1
• /
• pp.85-92
• /
• 2018

Purpose: We sought to examine whether using the rhythmic stabilization (RS) technique before proprioceptive neuromuscular facilitation (PNF) wrist taping affected pain and grip strength in patients with wrist pain to provide a basis for the application of PNF taping. Methods: The study consisted of 41 badminton enthusiasts (aged 20-40 years) who reported discomfort and pain due to overuse of their wrists. The subjects were randomly assigned to an experimental group (n=20) or a control group (n=21). In the experimental group, PNF wrist taping was applied after application of the PNF RS technique, and PNF wrist taping was applied after stretching in the control group. The tape was applied five times a week for 3 weeks. Pain was measured using the visual analog scale (VAS). Grip strength was measured using a dynamometer. The paired t-test was performed to compare grip strength and pain within the groups before and after the intervention. Covariance analysis was conducted to compare differences between the experimental group and control group. The level of significance was set as ${\alpha}=0.05$. Results: Within-group changes in grip strength and VAS were significantly different in the control group and experimental group (p<0.01). Grip strength and VAS showed more improvement in the experimental group than in the control group (p<0.01). Conclusion: PNF wrist taping after stretching and the PNF RS technique both significantly reduced pain and improved grip strength in club badminton players with wrist pain. These improvements were significantly greater in the experimental group in which the PNF RS technique was applied. The results suggest that PNF may be considered useful to improve grip strength and reduce wrist pain.

• The Journal of Korean Academy of Orthopedic Manual Physical Therapy
• /
• v.17 no.1
• /
• pp.24-28
• /
• 2011

Background: The purpose of this study is to make a grip strength checker to make people measure their grip strength easily, based on standardized grip strength checker chart. Method: In this study, we measured right hand grip strength of 80 women residents of Deajeon (women in their 30s to 60s, 20 in each) 2 times per day for 5days in same conditions from 20th of November 2010 to 24th of November. it was measured by Jamar Hydraculic Hand Dynamometer made lately to compare with the current measuring equipment. No matter how big their hands are, their hands were fixed at second level. Measured as they sit on a chair and let their shoulders gathered and not be rotated, let their arms be 90 degree, wrist and forearm be at the middle for the first time, and took another after they took a rest, and measured the average of the two. Result: There was not a meaningful difference between the current measuring equipment and the equipment made lately (p>.05). Conclusion: It is thought that the equipment made lately can be believed. In addition, we want people to realize their own grip strength easily by this study.