Grip force and pinch grip in an adult population: Reference values and factors associated with grip force

Abstract

To establish reference values of grip force and pinch grip in 10-year age-spans of an adult population, and to explore personal and activity factors associated with grip force.
The study has a cross-sectional design. A total of 566 participants, aged 20-94 years, were recruited from a variety of settings. Grip force and pinch grip in Newtons (N) were measured with the electronic instrument Grippit, while demographic data were obtained by a questionnaire.
In general, males are stronger than females in all age groups, and females in their thirties are equally strong as males in their seventies. In both genders, grip force reaches its maximum in the third decade of life and decreases from the age of 40. Gender is the most important predictor of grip force, with a difference of 216 N (B = 216, p < 0.001) in force between females and males. In the gender-specific regression analyses, age, height, and exercise came out as independent significant predictors of grip force in both females and males.
Grip force increases from the age of 20 and curves at the age of 40. Males are stronger than females in all age groups. Grip force is strongly associated with gender, age, height, and regular exercising.

Full text

Scandinavian Journal of Occupational Therapy. 2011; Early Online, 1–9
ORIGINAL ARTICLE
Grip force and pinch grip in an adult population: Reference values and
factors associated with grip force
TOVE NILSEN
1
, MERETE HERMANN
1
, CAMILLA S. ERIKSEN
1
, HANNE DAGFINRUD
2
,
PETTER MOWINCKEL
2
& INGVILD KJEKEN
2
1
Department of Rheumatology, Diakonhjemmet Hospital, Oslo, Norway, and
2
National Resource Centre for
Rehabilitation in Rheumatology, Diakonhjemmet Hospital, Oslo, Norway
Abstract
Objectives: To establish reference values of grip force and pinch grip in 10-year age-spans of an adult population, and to explore
personal and activity factors associated with grip force. Methods: The study has a cross-sectional design. A total of
566 participants, aged 20–94 years, were recruited from a variety of settings. Grip force and pinch grip in Newtons (N)
were measured with the electronic instrument Grippit, while demographic data were obtained by a questionnaire. Results: In
general, males are stronger than females in all age groups, and females in their thirties are equally strong as males in their
seventies. In both genders, grip force reaches its maximum in the third decade of life and decreases from the age of 40. Gender
is the most important predictor of grip force, with a difference of 216 N (B =216, p<0.001) in force between females and
males. In the gender-specific regression analyses, age, height, and exercise came out as independent significant predictors of
grip force in both females and males. Conclusions: Grip force increases from the age of 20 and curves at the age of 40. Males are
stronger than females in all age groups. Grip force is strongly associated with gender, age, height, and regular exercising.
Key words: Hand function, normative values, occupational therapy
Introduction
Grip force is a parameter of disease and functional
ability in a variety of conditions, such as rheumatic
and neurological diseases (1–9). Previous research has
shown that persons with these chronic diseases, or
who have reduced nutritional status, have reduced
grip force compared with healthy individuals (10).
Studies further indicate that there is a strong corre-
lation between grip force and the ability to perform
daily activities (3,11,12). Measures of grip force are
therefore widely used in functional assessment of
persons with injuries or pathology of the upper
extremities, and are also a frequent outcome measure
in trials evaluating the effectiveness of interventions,
such as occupational therapy.
Occupational therapists often use hand exercises as
a mean to improve grip force. However, numerous
factors have been reported to affect grip force. Gender
and age are well-documented predictors (13–18), and
correlations to height and body mass index have been
found (19). Work and leisure activities are also con-
sidered predictors of grip force, but studies seem to be
inconclusive concerning this influence (13,19–21).
People use a wide variety of grips when performing
daily activities. Transverse volar grip and pinch grip
are among the most frequently used grips (22,23), and
are therefore considered as important parameters of
hand function. In a transverse volar grip, the palmar
side of the hand and fingers, including the thumb, are
clasped around a tool or material. In a pinch grip, the
pulp of thumb and index finger are pressed against an
object or material. While a transverse volar grip is
used when handling larger objects, pinch grip is more
of a precision grip. In the following, the term grip
force is used when referring to transverse volar grip
Correspondence: Tove Nilsen, Department of rheumatology, Diakonhjemmet Hospital, P.O.Box 23 Vinderen, No-0319 Oslo, Norway. Tel: +47 22 45 15 00.
Fax: + 47 22 45 48 50. E-mail: tove.nilsen@diakonsyk.no
(Received 30 June 2010; accepted 17 December 2010)
ISSN 1103-8128 print/ISSN 1651-2014 online 2011 Informa Healthcare
DOI: 10.3109/11038128.2011.553687
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force, while the term hand strength is used when
referring to both grip force and pinch grip or to
general strength in the hand.
A number of devices have been used to measure
grip force (15). The electronic instrument Grippit has
proved to be a reliable and valid instrument for
measuring grip force in healthy individuals as well
as for persons with pathology in the upper extremities
(6,16,18,24). Normal values for grip force measured
with Grippit have been published based on 169
healthy subjects, but once gender and age stratified,
the numbers in each group were small (18). Reference
values for a bigger population have also been collected
(16). However, mean values were not reported, only
the range of values for the different age groups.
Further, reference values for pinch grip measured
by Grippit are not available.
The aims of this study were to establish reference
values of grip force and pinch grip in 10-year age-
spans of a normal adult population, and to explore
personal and activity factors associated with grip force.
Materials and methods
The study has a cross-sectional design and used a
convenience sample. The Regional Ethics Committee
of Southeast Norway was consulted before data were
obtained. As all participants were adults and the data
collected were completely anonymous, they con-
cluded that no formal approval of the study was
needed.
Population
To ensure a representative sample according to age
and socioeconomic background, testing took place at
a wide variety of settings (shopping malls, workplaces,
community centres for the elderly, a sports centre,
and at Diakonhjemmet Hospital) and different geo-
graphical locations in the region of Oslo between
April 2008 and September 2009. A total of 678 volun-
teers ‡20 years were tested. Of these, 112 were
excluded due to the presence of injuries or pathology
that might influence grip force, such as inflammatory
or neurological diseases, heart conditions, or trauma
of the upper extremities. Of the remaining 566
participants there were 315 women and 251 men.
Instrument and testing procedures
Three occupational therapists (TN, MH, and CSE)
recorded the data using two Grippit instruments, one
for measuring grip force and another for measuring
pinch grip (Figure 1). Before commencement of
the study, both instruments were calibrated at
AB Detektor, Gothenburg, Sweden.
In Grippit, force recordings in Newtons (N) are
displayed on the electronic unit every 0.5 seconds
over a period of 10 seconds. The peak and average of
the 20 registrations, as well as the final value (last
recording) were recorded.
All testing was performed according to “Basic test-
ing procedure using Grippit”, except for the position-
ing of the arm when testing pinch grip (18). The
participants performed one trial with each hand.
They tested their right hand first. Often, two persons
were tested at a time. Therefore, approximately half of
the participants tested grip force first, while the other
half tested pinch grip first, dependent on which of the
test instruments was available. When testing grip
force, the participants had the inside of their hand
and all their fingers, including the thumb, pressed
Figure 1. The instrument Grippit, grip force to the left and pinch grip to the right.
2T. Nilsen et al.
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against the testing device. Procedures for positioning
of pinch grip have, to our knowledge, not been devel-
oped. In this study, the arm rest was not used when
testing pinch grip, because it led to an awkward
position of the wrist. Instead the forearm rested
semi-prone on the table, with the shoulder in a slightly
abducted position. The wrist was held in a neutral
position. The strength between the pulp of the thumb
and the index finger was recorded while the remaining
fingers were held in a flexed position.
Questionnaire
The participants completed a questionnaire compris-
ing questions regarding personal factors and activity
level. Gender, age, height (in cm), weight (in kg),
hand dominance, and level of education (£12 years,
>12 years) were categorized as personal factors. Work
status (yes/no), regular exercising (yes/no), and per-
formance of work tasks or leisure activities demanding
moderate to a large amount of hand strength (yes/no)
were categorized as activity-level factors.
Data analysis
The demographic data are presented as mean
(range) for continuous variables and as percentage
for categorical variables. Because of the marked
difference between genders in both grip force and
pinch grip, all analyses were gender specific. Subjects
were divided into groups according to gender and
age-spans (in 10-year intervals, from 20–29 years to
70–79 years, and ‡80 years). The means, standard
deviations (SD), and 95% confidence intervals (CI)
of recorded grip force and pinch grip were calculated
for peak, average, and final values. Power calcula-
tions were based on the mean and SD in each age
group in the ongoing data collection. We continued
to include participants until we reached the number
of participants needed to detect a 20% difference
in mean right-hand grip force and pinch grip,
between a specific age group and any other age
group, with a significance level of 0.05 and power
of 80%. As the variation in strength decreases with
higher age, fewer participants were needed in the
older age groups.
A kernel smoother was applied to show the associ-
ation between hand strength (grip force and pinch
grip, respectively) and age, stratified for gender.
A Pearson correlation analysis was performed to
explore the relationship between grip force and pinch
grip. The associations were interpreted as being high,
moderate, or weak if the correlation was over 0.6,
between 0.3 and 0.6, and less than 0.3, respectively
(25). T-tests were used to compare hand strength of
right vs left hand (paired samples), and between
participants with right- and left-hand dominance
(independent samples).
Multiple regression analysis, backward deletion
method, was used to describe the relationship
between grip force and factors that correlated with
strength.
Correlations between the dependent and indepen-
dent variables, as well as between the independent
variables, were explored. Independent variables with a
correlation to the dependent variable between 0.3 and
0.7 were entered into the model, while variables with
weaker or stronger correlation were dismissed from
the model (26). If two independent variables had a
correlation above 0.7, only one of the variables was
entered into the model. Histograms and scatter-plots
of standardized residuals were checked for normality,
linearity, and homoscedasticity. The dependent
variable used in the models was the mean of the
peak grip force values of the right and left hand.
We chose to use grip force rather than pinch grip
as the dependent variable in the models, because grip
force is most commonly used as an outcome measure
in studies. Values of p£0.05 were considered to be
significant. Data were analysed using the Statistical
Packages for Social Sciences version 14.0 (SPSS Inc.,
Chicago, IL).
Results
Participants
A total of 566 persons were included in the sample.
The majority of the participants were working. Only
10 participants reported being unemployed or receiv-
ing a disability pension, nine participants did not
specify why they were not working, and 131 partici-
pants were retired. Almost two-thirds of the partici-
pants had received higher education. A little more
than half reported that they exercised regularly, while
approximately 30% and 40% of the participants
reported performing work tasks or leisure activities
demanding moderate to a large amount of hand
strength, respectively (Table I).
Grip force
In general, males are significantly stronger than
females in all age groups, and females at their stron-
gest (333 N) are equally as strong as men in their
seventies (340 N). The variation (range) of strength is
larger in the younger age groups, and for males
compared with females. Grip force reaches its max-
imum in the third decade of life for both genders, with
a mean of 567 N (SD 109) for males and 333 N (SD
76) for females, and then decreases (Figure 2,
Tables II and III). In general, the participants are
Hand strength in adults 3
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stronger in their right than in their left hand, but this
difference seems to decrease with higher age. In both
genders the difference between hands is largest in the
thirties, with females being 10.4% stronger in their
right hand than in their left, and males being 7.4%
stronger, respectively. The loss of strength during a
10-second period (the ratio between peak and final
value) increases with higher age, and indicates
reduced endurance for both genders in the older
age groups (see Tables II and III for comparison of
peak and final value measures).
Pinch grip
As regards grip force, males are stronger than females
in their pinch grip, and the range of strength is wider
for younger compared with older participants, and for
males compared with females (Appendixes 1 and 2).
Males are at their strongest in their forties (87 N),
while females are at their strongest in their twenties
(58 N). Both males and females maintain their pinch
grip until the age of 50 (Figure 3, Appendix Tables I
and II). Even though a gradual decline occurs after
turning 50, males in their eighties (60 N) are still
stronger than females at any age.
The relationship between pinch grip in the right
and left hands differs from that of grip force. Both
males and females are stronger in their right than in
their left hand in their twenties and thirties. However,
from the age of 40, this varies between age-spans
(Appendix Tables I and II). Pinch grip endurance
seems to be less dependent on age compared with grip
force. From the age of 30 to 80, the strength reduction
during a 10-second period seems to be fairly constant.
Correlation between grip force and pinch grip
There was a high and positive correlation between
grip force and pinch grip for females (r =0.64,
p<0.001) and a moderate correlation for males
Table I. Demographic data.
Female (n =315) Male (n =251) Total (n =566)
Age, years mean (range) 51.9 (20–94) 47.1 (20–93) 49.8 (20–94)
Height, cm mean (range) 166.3 (143–185) 181.3 (160–198) 173 (143–198)
Weight, kg mean (range) 66.6 (44–110) 85 (60–130) 75 (44–130)
Right handed, % 91 90.9 91
Education >12 years, % 64.3 75.5 69.3
Working yes, % 69.3 78.5 73.4
Work tasks demanding hand strength yes% 31.1 26.2 28.9
Exercising regularly yes, % 52.3 54.5 53.2
Leisure activities demanding hand strength yes% 38.2 42.4 40.2
*Levels of missing data were low for all items.
800
700
600
500
300
400
200
100
0
800
700
600
500
300
400
200
100
0
20 30 40 50 60 70 80 90
Age (years)
20 30 40 50 60 70 80 90
Age (years)
Males
Females
Males
Females
Grip force right hand (Newton)
Grip force left hand (Newton)
Figure 2. Peak values of grip force in the right and left hand, respectively, according to age and gender, shown by a Kernel smoother.
4T. Nilsen et al.
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(r =0.55, p<0.001). The results showed only small
variations when data from the right or left hand were
used, or depending on whether peak, average, or final
values were chosen.
Hand dominance
In this sample, 9% of the females and 9.1% of the
males reported left hand dominance. In general, right-
hand-dominant participants were significantly stron-
ger in their right hand compared with their left hand
(p<0.001), while no difference in grip force was
found between hands in participants who were
left-hand dominant.
For pinch grip, left-hand dominant partici-
pants were significantly stronger in their left hand
compared with their right hand (p=0.009), while no
difference in strength was found between hands in
right-hand-dominant participants.
However, comparison of right-hand-dominant and
left-hand-dominant participants showed no signifi-
cant difference in grip force for either right hand
(p=0.73) or left hand (p=0.43). Also, for pinch
grip, there was no difference in strength when right-
hand-dominant and left-hand-dominant participants
were compared (right hand p=0.61, left hand
p=0.17).
Predictors of grip force
Bivariate analyses showed a high negative correlation
between grip force and age (r =–0.62, p=<0.001) for
males. There was a moderate correlation to work
status (r =0.57, p=<0.001) and height (r =0.32,
Table II. Grip force in females measured in Newtons (N).
Age Number Hand Peak SD 95% CI Average SD 95% CI Final SD 95% CI
20–29 55 R
L
327
297
61
52
310, 343
282, 310
285
254
64
52
268, 302
240, 272
257
232
66
58
239, 275
216, 247
30–39 46 R
L
333
298
76
60
310, 356
280, 316
292
254
75
63
270, 314
235, 272
264
232
75
64
242, 287
213, 251
40–49 39 R
L
315
298
61
58
294, 335
279, 317
272
255
63
61
252, 293
235, 275
253
234
67
59
230, 275
214, 253
50–59 62 R
L
300
284
61
53
284, 315
271, 298
260
244
59
54
245, 275
231, 258
240
224
59
51
225, 255
211, 236
60–69 38 R
L
234
223
51
51
217, 250
207, 240
194
184
45
46
179, 209
169, 199
176
166
44
49
162, 190
149, 181
70–79 31 R
L
197
188
64
64
173, 220
164, 211
161
152
64
56
138, 185
131, 172
144
134
63
49
121, 167
116, 152
80–+40 R
L
145
139
51
51
128, 161
122, 155
114
108
49
46
99, 130
93, 122
100
94
46
45
85, 114
79, 108
Table III. Grip force in males measured in Newtons (N).
Age Number Hand Peak SD 95% CI Average SD 95%CI Final SD 95%CI
20–29 46 R
L
545
509
92
91
517, 572
482, 536
486
454
87
94
460, 512
426, 482
446
416
91
109
419, 473
384, 448
30–39 67 R
L
567
526
109
101
541, 594
501, 550
517
473
113
104
489, 544
447, 498
483
444
116
104
454, 511
419, 469
40–49 36 R
L
548
531
108
109
511, 584
494, 568
497
483
109
111
460, 534
446, 521
467
456
104
108
432, 503
420, 493
50–59 36 R
L
469
466
106
83
433, 505
438, 493
417
408
103
87
382, 452
379, 437
388
380
102
87
353, 422
350, 409
60–69 22 R
L
420
409
135
127
360, 480
353, 465
362
361
133
124
304, 421
306, 416
339
339
128
122
282, 395
284, 393
70–79 20 R
L
340
345
74
67
305, 374
314, 376
298
294
70
65
265, 331
264, 324
272
264
64
70
242, 301
231, 296
80+22 R
L
290
282
91
80
250, 331
246, 317
239
235
86
83
201, 277
192, 272
204
206
90
89
164, 244
167, 245
Hand strength in adults 5
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p=<0.001), and a weak correlation to regular
exercising (r =0.29, p=<0.001), weight (r =0.24,
p=<0.001) and education (r =0.24, p=<0.001).
Also, for females, high correlations were found
between grip force and age (r =–0.7, p=<0.001)
and work status (r =0.65, p=<0.001), while there
were moderate correlations to education (r =0.4,
p=<0.001), height (r =0.39, p=<0.001) and
regular exercising (r =0.31, p=<0.001). The corre-
lations to work tasks demanding hand strength
(r =0.16, p=0.020) and weight (r =0.14,
p=0.015) were weak. There were no significant
correlations between grip force and leisure activities
demanding hand strength for either gender.
The independent variables with correlations
between 0.3 and 0.7 to grip force were entered into
the regression model, and additionally the variable
regular exercising for males. There was a strong
intercorrelation between the independent variables
work status and age (for males 0.77 and for females
0.76). This is not surprising since only 19 of our
participants were out of work, except for those who
were retired. So as not to compromise our results
work status was removed from the model.
A preliminary multiple regression analysis (for the
total sample, data not presented), showed that gender
is the most important predictor of grip force, with a
difference of 216 N (B =216, p<0.001) in strength
between females and males. In the gender-specific
regression analyses, age, height, and exercise came
out as independent significant predictors of grip force
for both genders (Table IV), and the Beta values of
females were in general approximately 70% of those of
males. The regression model explained 56.5% of the
variation in grip force for females, and 45% of the
variation for males.
Discussion
This study demonstrates that in general grip force
increases from the age of 20 and curves at the age of
40. The results further confirm that gender is the
most important predictor of hand strength. Men
are stronger than women in all age groups, and
women at their strongest are equally as strong as
men between 70 and 80 years. As previous studies
report that grip force is an important predictor of
activity performance (3,11,12), one can assume that
180
160
140
120
100
80
60
40
20
0
180
160
140
120
100
80
60
40
20
0
Pinch grip right hand (Newton)
Pinch grip left hand (Newton)
20 30 40 50 60 70 80 90
Age (years)
20 30 40 50 60 70 80 90
Age (years)
Males
Females
Males
Females
Figure 3. Peak values of pinch grip in the right and left hand, respectively, according to age and gender, shown by a Kernel smoother.
Table IV. Factors affecting grip force in females and males.
Females (R
2
=0.565) Males (R
2
=0.45)
Independent variables B 95% CI pB 95% CI p
Age (years) –2.5 –2.9, –2.2 <0.001 –3.7 –4.4, –3<0.001
Height (cm) 3.3 2.3, 4.3 <0.001 4.4 2.6, 6.1 <0.001
Regularly exercising (no =0/yes =1) 21.1 8.3, 34 0.001 31 5.7, 56.3 0.017
Note: Dependent variable is the mean of the peak values in the right and left hand.
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elderly women are more vulnerable than men when it
comes to maintaining function in daily activities, due
to lower hand strength and reduced endurance in
hand grips.
As one of the aims of this study was to analyse the
relationship between strength and activity level,
we decided to keep the variable regular exercising
in the regression model for males, even though the
correlation to grip force was below 0.3. Regular
exercising came out as an independent predictor of
grip force in the multivariate regression models,
together with age and height. Of these three signifi-
cant predictors, exercising is the one that may be
modified. Occupational therapists should therefore
promote exercise and physical activity, and guide
people in finding motivating exercise regimes and
physical activities that can be incorporated into their
daily life. It further seems especially important to
encourage elderly women and people at risk of
reduced hand strength to continue to use their hands
in straining activities and, if necessary, also to perform
hand exercises.
Not surprisingly, there was a strong positive corre-
lation between grip force and pinch grip. Nevertheless,
the difference between genders was larger for pinch
grip compared with grip force, in favour of the males.
One reason for this may be the differences in the
anatomical structures of the carpo-metacarpal joint
of the thumb (CMC1), with a more flexible CMC1
joint in females compared with males (27,28). Pinch
grip involves only two fingers, with the force being
applied in a distant grip between the tips of the fingers,
thus to a large degree depending on a stable thumb. In
contrast, grip force involves all five fingers in a grip with
proximal force application, thereby diminishing the
importance of a stable CMC1 joint.
As in previous studies involving grip force, we
found that left-hand-dominant participants were
equally strong in both hands, while right-hand-
dominant participants were strongest in their domi-
nant hand (13,14,16,29). Concerning pinch grip, the
results were the opposite, with right-hand-dominant
participants being equally strong in both hands and
left-hand-dominant participants being strongest in
their left hand. However, right-hand-dominant and
left-hand-dominant individuals are equally strong.
These findings have the important practical implica-
tion that data in studies involving hand strength in
healthy individuals can be organized according to left
and right hand regardless of hand dominance of the
individual participant.
One important factor when determining reference
values for hand strength is to ensure that the collected
data are from a representative sample. The optimal
design would be to draw a random sample from a
large population. However, in a study using this
method, only 23% of the invited persons were willing
to participate (30). Also, we had to limit the data
collection to the region of Oslo, for practical and
economic reasons. Previous research has shown
that health aspects such as morbidity and life expec-
tancy vary among the different districts of Oslo (31).
To ensure a sample with different socioeconomic
characteristics, we visited different arenas and dis-
tricts of the town, and recruited participants by setting
up a testing station onsite. When demographic data
from this study were compared with data representing
a Norwegian population (32), we found them to
correspond on factors like height, weight, work status,
and exercising. The values in the current study are
also, to a large degree, in line with previously pub-
lished normative Grippit data (18). Further, the
power calculation ensured a sample with enough
participants in each group to detect a 20% difference
in strength between each of the age groups.
Testing of the participants was performed accord-
ing to “Basic testing procedures”as described in the
article where the Grippit instrument was introduced
(18). This implies that the participants performed one
trial with each hand, starting with their right hand.
This may potentially introduce a systematic error, as
there is a risk that participants performed better in the
second testing due to a learning effect. However, this
effect is probably limited, since all participants tested
the instrument prior to the actual trial by briefly
squeezing the handle.
In many studies of grip strength, participants per-
form three trials. It has, however, been found that one
trial is as reliable as three trials, and that multiple trials
may cause fatigue and pain and therefore this is not
necessarily an advantage (16,24,33).
It should be noted that stronger individuals might
be overrepresented in this sample, as several of the
individuals who did not want to participate in the
study gave low hand strength as the reason for declin-
ing. Some authors also emphasize that there are dif-
ferences between nationalities in hand strength, due to
differences in body size and muscle mass (15,21).
Reference values can, therefore, not automatically
be generalized to any given population.
One limitation in this study is the lack of reliability
testing of measures of pinch grip with the Grippit
instrument. In two previously published studies of
persons with neuropathy and muscular dystrophies,
the authors conclude that pinch grip evaluation
should be interpreted with caution (9,34). Our expe-
rience is that it is more difficult to standardize the test
situation for pinch grip than for grip force, because the
armrest leads to a somewhat awkward position of the
wrist. Also, the individual differences are probably
larger when testing pinch grip than when testing grip
force, due to greater variation in positioning of the
Hand strength in adults 7
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fingers while gripping the device. Studies are therefore
needed to test different aspects of reliability of the
Grippit instrument concerning measurements of
pinch grip.
In summary, we found that grip force increases
from the age of 20 and curves at the age of 40.
Men were stronger than women in all age groups,
with men in their seventies being equally as strong
as women in their thirties. In addition to age and
gender, regular exercising is a strong predictor of
grip force.
Declaration of interest: The authors report no
conflicts of interest. The authors alone are responsible
for the content and writing of the paper.
References
1. Aldehag AS, Jonsson H, Ansved T. Effects of a hand training
programme in five patients with myotonic dystrophy type 1.
Occup Ther Int 2005;12:14–27.
2. Alexanderson H, Dastmalchi M, Esbjornsson-Liljedahl M,
Opava CH, Lundberg IE. Benefits of intensive resistance
training in patients with chronic polymyositis or dermatomy-
ositis. Arthritis Rheum 2007;57:768–77.
3. Bjork MA, Thyberg IS, Skogh T, Gerdle BU. Hand function
and activity limitation according to health assessment ques-
tionnaire in patients with rheumatoid arthritis and healthy
referents: 5-year followup of predictors of activity limitation
(The Swedish TIRA Project). J Rheumatol 2007;34:296–302.
4. Bodur H, Yilmaz O, Keskin D. Hand disability and related
variables in patients with rheumatoid arthritis. Rheumatol Int
2005;1–4.
5. Di Monaco M, Di Monaco R, Manca M, Cavanna A. Hand-
grip strength is an independent predictor of distal radius bone
mineral density in postmenopausal women. Clin Rheumatol
2000;19:473–6.
6. Hammer A, Lindmark B. Test–retest intra-rater reliability
of grip force in patients with stroke. J Rehabil Med 2003;
35:189–94.
7. Pettersson K, Wagnsjö T, Huling E. NeuFlex compared with
Sutter prostheses: A blind, prospective, randomised compar-
ison of Silastic metacarpophalangeal joint prostheses. Scand J
Plast Reconstr Surg Hand Surg 2006;40:284–90.
8. Rahman N, Thomas JJ, Rice MS. The relationship between
hand strength and the forces used to access containers by well
elderly persons. Am J Occup Ther 2002;56:78–85.
9. Svensson E, Hager-Ross C. Hand function in Charcot Marie
Tooth: Test retest reliability of some measurements. Clin
Rehabil 2006;20:896–908.
10. Vaz M, Tangam S, Prabhu A, Shetty PS. Maximal voluntary
contraction as a functional indicator of adult chronic under-
nutrition. Br J Nutr 1996;76:9–15.
11. Nordenskiöld UM, Grimby G. Assessments of disability in
women with rheumatoid arthritis in relation to grip force and
pain. Disabil Rehabil 1997;19:13–19.
12. Thyberg I, Hass UA, Nordenskiold U, Gerdle B, Skogh T.
Activity limitation in rheumatoid arthritis correlates with
reduced grip force regardless of sex: The Swedish
TIRA project. Arthritis Rheum 2005;53:886–96.
13. Crosby CA, Wehbè MA, Mawr B. Hand strength: normative
values. J Hand Surg 1994;19A:665–70.
14. Hanten WP, Chen WY, Austin AA, Brooks RE, Carter HC,
Law CA, et al. Maximum grip strength in normal subjects
from 20 to 64 years of age. J Hand Ther 1999;12:193–200.
15. Innes E. Handgrip strength testing: A review of the literature.
Austr Occup Ther J 1999;46:120–40.
16. Massy-Westropp N, Rankin W, Ahern M, Krishnan J,
Hearn TC. Measuring grip strength in normal adults: Refer-
ence ranges and a comparison of electronic and hydraulic
instruments. J Hand Surg [Am] 2004;29:514–19.
17. Mathiowetz V, Kashman N, Volland G, Weber K, Dowe M,
Rogers S. Grip and pinch strength: Normative data for adults.
Arch Phys Med Rehabil 1985;66.
18. Nordenskiöld UM, Grimby G. Grip force in patients with
rheumatoid arthritis and fibromyalgia and in healthy subjects:
A study with the Grippit instrument. Scand J Rheumatol
1993;22:14–19.
19. Günther CM, Bürger A, Rickert M, Crispin A, Schulz CU.
Grip strength in healthy Caucasian adults: Reference values.
J Hand Surg 2008;33A:558–65.
20. Josty IC, Tyler MPH, Shewell PC, Roberts AHN. Grip and
pinch strength variations in different types of workers. J Hand
Surg 1997;22B:266–9.
21. Werle S, Goldhahn J, Drerup S, Simmen BR, Sprott H,
Herren DB. Age- and gender-specific normative data of
grip and pinch strength in a healthy adult Swiss population.
J Hand Surg 2009;34E(1):76–84.
22. Fitinghoff H, Söderback I, Nordemar R. An activity analysis of
hand grips used in housework by female rheumatoid arthritics.
Work 1994;4:128–36.
23. Sollerman C, Ejeskär A. Sollerman hand function test:
A standardised method and its use in tetraplegic patients.
Scand J Plast Reconstr Hand Surg 1995;167–76.
24. Lagerstrom C, Nordgren B. On the reliability and usefulness
of methods for grip strength measurement. Scand J Rehabil
Med 1998;30:113–19.
25. Bland JM, Altman DG. Measuring agreement in
method comparison studies. Stat Methods Med Res 1999;
8:135–60.
26. Pallant J. Multiple regression. SPSS Survival manual.
New York: Open University Press; 2001. p. 134–50.
27. Ouellette EA, Makowski A-L. How men and women are
affected by osteoarthritis of the hand. OTJR 2006;37:
541–8.
28. Neumann DA, Bielefeld T. The carpometacarpal joint of the
thumb: Stability, deformity, and therapeutic intervention.
J Orthop Sports Phys Ther 2003;33:386–99.
29. Petersen P, Petrick M, Connor H, Conklin D. Grip strength
and hand dominance: Challenging the 10% rule. Am J Occup
Ther 1989;43:444–7
30. Sunnerhagen KSS, Hedberg M, Henning G, Cider Å,
Svantesson U. Muscle performance in an urban population
sample of 40- to 79-year-old men and women. Scand J Rehab
Med 2000;32:159–67.
31. Brekke M, Hjortdahl P, Thelle DS, Celius EG, Heldal E,
Joner G, et al. Forskjeller i sykelighet mellom indre øst og ytre
vest i Oslo (Differences in morbidity between a deprived and
affluent area of Oslo). Tidsskr Nor Lægeforen 1998;118:
14–17.
32. Statistics Norway. LevekÅrsundersøkelsen (Survey of Living
Conditions) 2002.
33. Coldham F, Lewis J, Lee H. The reliability of one vs three grip
trials in symptomatic and asymptomatic subjects. J Hand Ther
2006;19:318–27.
34. Aldehag AS, Jonsson H, Littorin S, Ansved T. Reliability of
hand function testing instruments in patients with muscular
dystrophies. Int J Ther Rehabil 2008;15:211–18.
8T. Nilsen et al.
Scand J Occup Ther Downloaded from informahealthcare.com by Diakonhjemmets Sykehus on 04/12/11
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Appendix 1
Pinch grip in females measured in Newtons (N).
Appendix 2
Pinch grip in males measured in Newtons (N).
Age Number Hand Peak SD 95% CI Average SD 95% CI Final SD 95% CI
20–29 55 R
L
58
54
16
13
53, 62
50, 57
46
44
11
11
43, 49
41, 47
41
40
11
10
38, 44
37, 42
30–39 46 R
L
54
52
15
14
50, 59
48, 56
45
43
13
11
41, 48
39, 46
42
39
12
11
38, 45
36, 42
40–49 39 R
L
56
55
13
12
52, 60
51, 59
47
46
11
10
43, 50
42, 49
43
41
10
10
40, 46
38, 44
50–59 62 R
L
49
52
12
10
46, 52
49, 55
42
43
11
9
39, 45
41, 45
39
40
11
8
36, 42
38, 42
60–69 38 R
L
45
44
10
10
42, 49
41, 48
37
36
9
8
34, 40
33, 39
33
32
8
7
31, 36
30, 35
70–79 31 R
L
43
42
13
13
38, 48
37, 47
34
33
11
11
30, 38
29, 37
31
31
10
12
27, 35
27, 36
80–+40 R
L
32
30
14
12
28, 37
26, 34
24
22
11
10
21, 28
19, 26
22
20
10
10
19, 25
16, 23
Age Number Hand Peak SD 95% CI Average SD 95% CI Final SD 95% CI
20–29 46 R
L
80
76
24
10
72, 87
70, 83
67
63
19
15
62, 73
58, 67
62
57
19
15
57, 68
52, 62
30–39 67 R
L
85
84
21
11
80, 90
79, 89
74
72
20
19
69, 79
67, 76
68
66
20
21
63, 72
61, 71
40–49 36 R
L
87
90
23
10
79, 94
83, 97
75
77
20
19
68, 82
71, 84
70
70
20
19
63, 76
63, 76
50–59 36 R
L
78
82
19
8
71, 84
76, 87
66
68
18
17
60, 72
63, 74
61
63
17
17
56, 67
57, 68
60–69 22 R
L
72
76
24
7
61, 82
65, 88
60
63
22
22
50, 70
53, 72
53
57
22
20
43, 63
48, 66
70–79 20 R
L
63
63
9
12
59, 67
57, 69
54
54
9
12
50, 58
48, 59
50
48
12
12
44, 55
43, 54
80–+22 R
L
60
61
16
10
53, 67
53, 70
49
49
14
16
42, 55
42, 55
43
44
17
14
36, 51
37, 49
Hand strength in adults 9
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