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.

The lumbrical muscles contribute to the intrinsic plus position, that is simultaneous metacarpophalangeal (MCP) flexion and interphalangeal (IP) extension. The strength of the lumbrical muscles is necessary for normal hand function. However, there is no objective and efficient method of strength measurement for the lumbrical muscles. In addition, previous studies have not investigated the measurement of the cross-sectional area (CSA) of the lumbrical muscles using ultrasonography (US) and the relationship between lumbrical muscle strength in the intrinsic plus position and the CSA. Therefore, the purpose of this study was to identify the measurement method of the CSA of the lumbrical muscles using US and to examine the relationship between maximal isometric strength and the CSA of lumbrical muscles. Nine healthy males participated in this study. Maximal isometric strength of the second, third, and fourth lumbrical muscles was assessed using a tensiometer in the intrinsic plus position which isolated MCP flexion and IP extension. The CSA of the lumbrical muscles was measured with an US. The US probe was applied on the palmar aspect of the metacarpal head with a transverse view of the hand in resting position. There was no significant difference between maximal isometric strength of the lumbrical muscles, but the fourth lumbrical muscle was stronger than the others. The CSA of the lumbrical muscles was significantly different and the fourth lumbrical muscle was significantly larger than the second lumbrical muscle. There was moderate to good correlation between maximal isometric strength and the CSA of the lumbrical muscles. Therefore, we conclude that maximal isometric strength of the lumbrical muscles was positively correlated to the CSA of the lumbrical muscle in each finger, while the measurement of the CSA of the lumbrical muscles, using US protocol in this study, was useful for measuring the CSA of the lumbrical muscles.

In using both hands, everyone dominantly use one hand and it is called left-handedness or right-handedness person. Measurements of grip and pinch strength provide objective indexes to represent functional integrity of the upper extremity. This study was conducted for thirty female college students(19 right-handedness and 11 lefthandedness). For assessment of the type of handedness, questionnaire was used; for grip strength, Jamar dynamometer was used; for pinch strength, Jamar pinch gauge was used. In right handedness, the grip and pinch strength of the dominant right hand was significantly higher than those of the non-dominant hand. In addition, regular exercises were shown to give influences on reduction of strength gaps between dominant and non-dominant hands. In both groups of left and right handedness, the grip and pinch strength of the dominant hand were significantly higher than those of the non-dominant hand, and regular exercises were shown to give influences on reduction of strength gaps between dominant and non-dominant hand.

Grip strength is an objective indicator for evaluating the functional movement of upper extremities. Therapists have been using it for a long time as an excellent barometer for evaluating the therapy process, therapeutic effects and prognosis of patients with injuries in upper extremities. This study investigated the effects of extensor pattern position and elastic taping of non-dominant hand on the grip strength of dominant hand among general adults. The subjects of this study were 23 males and 7 females from physical therapy departments of 3 Universities located in Busan who agreed to participate in the experiment and the resultant data were analyzed using SPSS version 12.0. The results of the study were as follows. First, there was a significant difference between the grip strength of dominant hand when the non-dominant hand was at the neutral position and that when the non-dominant hand was at the extensor pattern position and both hands were at the maximum strength simultaneously (Bonferroni-corrected p<.001). Second, there was a significant difference between the grip strength of dominant hand when the non-dominant hand was at the neutral position and that when the elastic taping of non-dominant hand was applied (Bonferroni-corrected p<.001). Third, there was no significant difference between the grip strength of dominant hand when the non-dominant hand was at the extensor pattern position and both hands were at the maximum strength simultaneously and that when the elastic taping of non-dominant hand was applied. The irradiation effects through the extensor pattern position of non-dominant hand and application of the elastic taping to non-dominant hand showed significant results in improving the maximum grip strength of dominant hand. This finding could be suggested as the probability for the indirect treatment of the upper extremities of hemiplegia and orthopedic patients due to the long-term fixing of upper extremities.

The purpose of this study is to find the standard value of hand width, of grip strength and of pinch strength by age, sex, and by left hand and right hand and also to find how the general characteristics influences grip strength and pinch strength. Martin Vigorimeter (List No. 17-27-01) was used for measuring grip strength, and the pinch gauge (0∼30 lbs) of B&L engineering for measuring pinch strength. The subjects of this study are the children at the age of three to seven years, who attending the babies' play room, kindergarten and the primary school in Seoul and the Kyungki province area. They all were normally developed without any significant neurology problem. wo hundred girls and two hundred boys were partifipated in this study. They were divided into ten subgroups according to the age of six month interval. Each group consisted of forty children of twenty boys and twenty girls. Analysis of data presents the technical statistics upon the hand width of right and left hand and the grip strength and pinch strength according to the age and sex. Multiple regression analysis using mixed liner model was operated in order to find how the general characteristics (of the age, sex, and side of hand) influence hand width, grip strength, and pinch strength individually. Also, we calculated the correlation among hand width, grip strength and pinch strength under the condition of controlling general characteristics; and to find correlation between the right hand and the left hand of the age and sex, we carried out paired t-test and came to the conclusion as follows: 1.　Hand width is significantly increased with the increase of age (p<0.01). The increase of hand width according to age, boy is wider than that of girl significantly (p<0.01), and the right hand is wider than that of the left hand significantly (p<0.01). 2.　Grip strength is significantly increased as the age and hand width increased (p<0.01). The increase of grip strength according to the age, boy is stronger than that of girl significantly (p<0.01), and grip strength of the right hand is stronger than that of the left hand(p<0.01). 3.　Three-jaw pinch strength is increased as the age, hand width and grip strength are increased(p<0.01). But there is no significant difference of three-jaw pinch strength according to sex and the side of hand(p>0.05). 4.　Tip pinch strength is significantly increased as the age and grip strength are increased(p<0.05). The increase of tip pinch strength according to the age, boy is stronger than that of girl significantly (p<0.05), but there is no significant difference between the right hand and the left hand(p>0.05). 5.　Lateral pinch strength is significantly increased as the age and grip strength are increased(p<0.01). But the increase of lateral pinch strength, there is no significant difference according to the hand width, sex and the side of hand(p>0.05). 6.　The test of correlation among hand width, grip strength and pinch strength showed the correlation between grip strength and pinch strength was stronger than the correlation between hand width and pinch strength(0.3<r<0.7). There was strong correlation between each pinch strength(0.3<r<0.7). Above all, the correlation of three-jaw pinch strength and tip pinch strength was strongest(0.7<r<1.0). 7.　The test of hand width according to the age and sex, and the difference between the right hand and the left hand in grip strength and pinch strength showed that there was significant difference against all the test of hand width, of grip strength, and of pinch strength in the age group from seven years and six months to seven years and eleven months than the age group under six years, specially in girls group(p<0.05).