The purpose of this study was to find out reference values for grip strength, tip, key and palmar pinch and then to compare it among male and female between dominant and non dominant hand in 20-40 years of age.
350 healthy population including both male and female of Hubbali and Dharwad participated in this present study. Examining grip strength is an important component of hand rehabilitation. It helps in identifying patient’s limitations, setting goals and focus on finding out the treatment strategies for any hand or upper extremity injuries. Power grip is the result of forceful flexion of all the finger joints with the maximum voluntary force that the subject is able to exert under normal bio kinetic conditions. Grip strength is affected by many factors such as muscle strength, hand dominance, age, state of nutrition, time of day, sensory loss, pain, and restricted range.
The present studies focused on finding the hand grip and pinch strength of healthy individuals and then compare the same with hand dominance. From the previous studies done it is clearly evident that healthy Indian adults exhibit lower grip strength when compared with age and gender match population from countries like USA, Europe and Australia with same level of physical activity and lifestyle. A study done in 2012 has also reported of lower grip strength, pinch strength among Asian countries than European population. One of the reasons for Indian to have less grip strength is their shorter stature and lower BMI when compared with age and gender matched controls across other continents.
There is a hypothesis that grip strength would be highest at 90? of elbow flexion, but a recent study done in 2013 on influence of various elbow position concluded that higher grip strength was recorded in complete elbow extension that is 0? of flexion and lowest at 135? of flexion. The same was also reported by Kuzala et al and Balogun et al. The biomechanical perspective to prove the above mentioned lines might be the length tension relationships of the muscle involved. Flexor Digitorum Superficialis the only primary finger flexor that crosses the elbow joint, therefore the position of elbow might affect the strength performance of the muscle. At 90? of elbow flexion the muscle is placed in a shortened position, it is when the muscle is incapable to generate tension necessary to get a functional contraction.
At highest degree of elbow flexion, the flexor digitorum superficialis is placed at a mechanical disadvantage position (maximum shortened position). Thus the present study chose to opt for a position which generates maximal strength that is shoulder adducted, arm held close to the body and elbow at zero degree of extension, forearm and wrist neutral. This position has allowed more compensations or overflow to occur thus helping in producing greater grip strength. All the participants were tested in standing position because standing position was associated with higher grip strength compared with sitting position due to increase temporal and spatial summation of contracting muscles in standing apart from increase cortical and peripheral arousal. The values provided in the present study particularly focused on participants leading a sedentary lifestyle and low level of physical activity. 350 participants were divided into two age group of 20-29 years and 30-40 years with equal distribution of males and females.
The strength of both dominant and non-dominant hands was examined simultaneously. Later the collected data was analyzed for result. TABLE 1 shows the normal distribution of males and females of both the age groups. TABLE 2 shows dominant hand mean grip strength of males and females of age group 20-29 years. The mean grip strength for dominant hand of males was 34.9±5.7 kg and for females dominant hand was 21.1±3.8 kg.
TABLE 3 shows non dominant hand mean grip strength of males and females of age group 20-29 years. The mean grip strength for non dominant hand of males was 32.6±6.2 kg and for females non dominant hand was 19.1±3.8 kg. TABLE 4 shows dominant hand mean tip strength of males and females of age group 20-29 years .The mean tip strength for dominant hand males was 6.6±1.7 kg and for females dominant hand was 5.05±1.2 kg. TABLE 5 shows non dominant hand mean tip strength of males and females of age group 20-29 years. The mean tip strength for non dominant hand males was 6± 1.6 kg and for females non dominant hand was 4.4± 1.1 kg. TABLE 6 shows dominant hand mean key strength of males and females of age group 20-29 years.
The mean key strength for dominant hand males was 6.7±2.2 kg and for females dominant hand was 5.5±3.3 kg. TABLE 7 shows non dominant hand mean key strength of males and females of age group 20-29 years. The mean key strength for non dominant hand males was 6±2 kg and for females non dominant hand was 4.9±1.2 kg. TABLE 8 shows dominant hand mean palmar strength of males and females of age group 20-29 years.
The mean palmar strength for dominant hand males was 7.9±2.2 kg and for females dominant hand was 6.3±6.6kg. TABLE 9 shows non dominance hand mean palmar strength of males and females of age group 20-29 years. The mean palmar strength for non dominant hand males was 7.3±2 kg and for females non dominant hand was 5.7±1.5 kg. The above tables shows that male dominant hand of age group 20-29 years have more grip strength, tip, key and palmar strength when compared with female dominant hand of same age group. It is also seen that male non dominant hand have higher grip, tip, key and palmar strength when compared with female non dominant hand of same age group. TABLE 10 shows the mean grip strength of dominant hand of males and females of age group 30-40 years.
The mean grip strength for males dominant hand was 32.8±5 kg ; for females dominant hand was 22.2±4.4 kg. TABLE 11 shows the mean grip strength of non dominance hand of males and females of age group 30-40 years. The mean grip strength for males non dominant was 30.5±5.4 kg ; for female non dominant hand was 19.2±4.2 kg. TABLE 12 shows the mean tip strength of dominant hand of males and females of age group 30-40 years. The mean tip strength for males dominant hand was 6.4± 1.3 kg and for females dominant hand was 5.8±1.4 kg.
TABLE 13 shows the mean tip strength of non dominant hand of males and females of age group 30-40 years. The mean tip strength for males non dominant hand was 5.8±1.4 kg and for females non dominant hand was 5.2±1.3 kg. TABLE 14 shows the mean key strength of dominant hand of males and females of age group 30-40 years .The mean tip strength for males dominant hand was 6.4 ±1.7 kg and for female dominant hand was 5.7±1.3 kg. TABLE 15 shows the mean key strength of non dominant hand of males and females of age group 30-40 years. The mean tip strength for males non dominant hand was 5.6±1.7 kg and for females non dominant hand was 5.2±1.1 kg.
TABLE 16 shows the mean palmar strength of dominant hand of males and females of age group 30-40 years. The mean palmar strength for males dominant hand was 7.6 ±1.6 kg and females dominant hand was 6.4 ±1.7 kg. TABLE 17 shows the mean palmar strength of non dominant hand of males and females of age group 30-40 years. The mean palmar strength for males non dominant hand was 6.5±1.7 kg and females non dominant hand was 5.8±1.5 kg. The above tables shows that dominant hand of male of age group 30-40 have more grip, tip, key and palmar strength when compared with dominant hand of female of same age group.
It is also seen that non dominant hand of male have higher grip, tip, key and palmar strength when compared with non dominant hand of female of same age group. From the above data it is confirmed that men showed a higher grip, tip, key and pinch strength when compared with women which is in concordance with findings from previous studies. The reason for this is increased bone mineral density and muscle mass in males when compared to females. Muscle strength is largely determined by muscle girth; muscle with large cross sectional area can generate more force and therefore lift more weight. The male testosterone enlarges muscles so men tend to be stronger than women.
It is also found that testosterone increases type II fibers which are fast fibers with high activity of glycolytic enzymes and a higher propotion of type II fibers in males is consistent with our finding of greater strength in males. And also the males in this study were significantly taller and heavier which contributes to higher grip strength. The influence of height, weight and BMI on grip strength is already studied. Height has a better correlation than weight whereas BMI has a weak correlation. Similarly our study demonstrated a moderate correlation with height and weak correlation with weight and BMI.
The correlation of height with higher grip strength can be explained by speculated relationship between height and length of upper extremity which gives an idea that taller people have a longer upper extremity, which provides a longer lever to hand muscles offering better mechanical advantage to generate greater grip strength. The majority of participants in this study were right hand dominant so the higher grip among men may be due to the preferential use of the dominant hand in daily activities which acts as an endurance training for the muscles of hand. This leads to the difference in muscle mass and also hypertrophy of the muscle in dominant hand as compared to non dominant. The amount and the type of work done by males are more strenuous compared to females, which leads to development of stronger muscles in males than females. Hence all the above mentioned points give an explanation of males having more grip strength when compared to females.
The first study done in India in the year 2013 did not provide any range for normal values of grip and pinch strength and they focused only on grip strength of dominant hand of male versus female subjects. So when the data generated from our present study was compared with the above mentioned study for the dominant hand of age group 18-30 years it was found that the mean grip strength of male and female of our present study was less. ( Present study) Hubbali ; Dharwad Mean strength (Mullerpatan et al.) Mumbai Mean strength Grip(kg) Male 34.9 ± 5.7 Female 21.1 ± 3.8 Male 37.84 ± 7.9 Female 22.12 ± 4.1 The reason for overall less grip strength of both male and female as shown in above table is subjects undergoing any kind of strengthening program for upper limb was excluded from the present study and also labourer class population was not included in this present study. The second study titled,” Study of Hand Grip Strength in Indian Population” done in the year 2016 provided a range for only grip strength in both dominant and non dominant hand of male and female of age group 21 to 80 years. Data generated from the present study shows that the range for grip strength of male dominant hand of age group 20-29 years is 19.5 – 52 kg and male non-dominant hand is 14.8-56.4 kg, whereas in the previous study the range for grip strength of male dominant hand is 31.40 – 32.76 kg and male non-dominant hand is 26.20 – 27.56 kg.
The range for grip strength of female dominant hand of age group 20-29 years is 13.4-32.2 kg and female non-dominant hand is 12.1-32.8 kg whereas in the previous study the range for grip strength of male dominant hand is 23.93-25.11 kg and female non-dominant hand is 19.35-20.69 kg. The range for grip strength of male dominant hand of age group 30-40 years is 21.4-44.2 kg and male non-dominant hand is 14.8-42.2 kg whereas in the previous study the range for grip strength of male dominant hand is 40.92-42.20 kg and female non dominant hand is 35.45-36.55 kg. The range for grip strength of female dominant hand of age group 30-40 years is 13.4-37.8 kg and male non-dominant hand is 14-37.6 kg whereas in previous study the range for grip strength of female dominant hand is 33.23-34.37 kg and female non-dominant hand is 28.46-29.74 kg. Thus the above mentioned range shows that data collected from present study provides a wider range for grip strength for both dominant and non dominant hand of male and female of age group 20-40 years.
The reason for a wider range of values is the small sample size of age group 20-40 years whereas in the last study a sample of 600 of age group 21-80 years was taken. Though the height of 350 participants were measured but the sample from the present study are not height matched only age matched participants were taken into consideration. So, this gives a reason for a wider variance in range of grip and pinch strength. The present study generated normative values of hand grip and pinch strength. These values can be applied specifically to the population of Hubbali and Dharwad.
