Journal of Biosciences and Medicines, 2014, 2, 14-18
Published Online November 2014 in SciRes. http://www.scirp.org/journal/jbm
http://dx.doi.org/10.4236/jbm.2014.29003
How to cite this paper: Dong, R.W., Guo, Q. and Wang, J.Z. (2014) Optimal Cutoffs of Grip Strength for Definition as Weak-
ness in the Elderly. Journal of Biosciences and Medicines, 2, 14-18. http://dx.doi.org/10.4236/jbm.2014.29003
Optimal Cutoffs of Grip Strength for
Definition as Weakness in the Elderly
Renwei Dong, Qi Guo, Jiazhong Wang
Department of Rehabilitation and Sports Medicine, Tianjin Medical University, Tian jin, China
Received Oc tob er 2014
Abstract
Objective: To indentify Optimal cutoffs of grip strength for definition as weakness in the
elderly. Methods: Our study population comprised 1317 subjects (mean ± SD age: 67.6 ± 6.0 years;
44.3% men) from the Hangu area of Tianjin, China . Data collection includes general physical ex-
amin at ion , biochemical indicators and questionnaire. Mobility limitation was defined as a 4-m
walking speed < 0.8 m/s and grip strength represents muscle strength. According to the ROC curve
model, the cut-off point of grip strength was calculated, when mobility limitation was selected as
the target variables. Results: According to the results of ROC curve, In man, grip strength is lower
than 32.45 kg, the strength is weaker, Sensitivity is 79.7% and Specificity is 64.9%, the AUC is
0.764 (p < 0.0 01); In women, grip strength is lower than 18.20 kg, the strength is weaker, Sensitiv-
ity is 53.3% and Specificity is78.1%, the AUC is 0.703 (p < 0.001). Conclusions: Cut points for
weakness derived from this large, diverse sample of older adults may be useful to identify popula-
tions who may benefit from interventions to improve muscle strength and function.
Keywords
Cutoffs, Elderly People, Grip Strength, Weakne ss
1. Introduction
Muscle weakness is related to poor physical performance and incident mobility limitations among older adults
[1]. Weakness is considered a key element of frailty [2] and, increasingly, of sarcopenia [3]. Although the asso-
ciation between weakness and functional limitations strong, there is no consensus regarding a cut point for iden-
tification of risk for functional problems. In order to identify population subgroups in whom weakness is a po-
tential contributor to functional limitations, it is necessary to determine what constitutes a clinically relevant de-
gree of weakness.
2. Participants and Meth o d
2.1. Participants
Our study population comprised residents of the Hangu area of Tianjin, China, aged ≥ 60 y, who joined the na-
tional free physical examination program. All subjects were invited to participate in a comprehensive geriatric

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15
assessment, with the exception of those with a disability that affected the basic activities of daily living, and
factors, which influenced grip strength level, such as stroke、cancer and hand injury, and those who could not
carry out performance-based assessments. The final study population comprised 1317 subjects (mean ± SD age:
67.6 ± 6.0 years; 44.3% men), after those with data deficiencies (n = 92) were excluded.
2.2. 4-m Speed Measurement [4]
Participants were instructed to stand with both feet touching the starting line and to begin walking at their usual
pace after a verbal command was given. The time between activation of the first and the second photocell was
measured and the average speed of two walks was recorded.
2.3. Definition of Mobility Limitation
Walking speed was assessed by trained nurses, where participants were requested to walk 2.4 or 6 meters a
self-selected speed [5]. The length of the walk was determined by asking the participants how fast they normally
walk. Subjects who rated themselves as fast or normal walkers did the longer walk and slow or very slow
self-rated walkers did the shorter walk. At home visits, the shorter walk was always conducted due to space re-
strictions. For the analyses, the walking speed reflects the time from whichever walk was performed by the par-
ticipant. Subjects who were unable to walk without personal support received the worst possible score, i.e. 0 m/s.
Mobilit y limitation was defined as a walking speed, 0.8 m/s because it may reflect underlying disease [6] [7].
2.4. Statistical Analyses
Data with a normal distribution are expressed as the mean ± SD, whereas data with an abnormal distribution are
expressed as the median, with the 25% - 75% inter quartile range given in parentheses. Categorical variables are
expressed as proportions. Receiver operating characteristic (ROC) curve analysis was performed to determine
the optimal grip strength cut-off values, with the presence of mobility limitation as outcome variable. The ROC
curve was agraph of sensitivity plotted against (1-specificity) overall possible diagnostic cut-off values. The op-
timal cut-off values were obtained from the maximal Youden’s Index, calculated as (sensitivity + specificity –1)
and the best combination of sensitivity and specificity.
3. Results
3.1. General Characteristics of the Study Population
The clinical characteristics of the study participants are presented in Ta ble 1. The cross-sectional analyses in-
cluded data on 1317 participants (596men and 721 women; mean ± SD age: 67.6 ± 6.0 year s). In terms of fitness,
male grip strength coefficient and 4-m walking speed is superior to female. Compared to men, women are more
likely to have mobility limitation (men 13.3%, women 18.7%). The percentage of at least 1 CDR in men and
wo m e n , respectively, were 57.0% and 72.1%, The percentage of at least 2 CDR and 3 CDR in women is both
higher than in men.
Figure 1 provides plots of the association between maximum grip strength and gait speed in men and women,
Visual inspection of the LOESS curves provided little evidence of a clear threshold effect of strength on conti-
nuous gait speed.
3.2. The Optimal Cut-Off Point of Grip Strength and the Area under the Curve (AUC) for
Reflecting Mobility Limitation
The optimal cut-off point of grip strength and the area under the curve (AUC) for reflecting mobility li mitation
are presented in Table 2. According to the results of ROC curve, In man, grip strength is lower than 32.45 kg,
the strength is weaker, Sensitivity is 79.7% and Specificity is 64.9%, the AUC is 0.764 (p < 0.0 01 ) ; In women,
grip strength is lower than 18.20 kg, the strength is weaker, Sensitivity is 53.3% and Specificity is 78.1%, the
AUC is 0.703 (p < 0.001).
4. Discussion
With age increased, muscle strength may decline in general. Muscle weakness is considered a key element of

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Table 1. General characteristics of the study population.
Men Women To ta l
n 596 721 1317
Age 68 ± 7 66 ± 6 67 ± 6
Height, cm 170.4 ± 6.3 157.6 ± 6.5 163.4 ± 9.0
Weight, kg 72.9 ± 10.1 63 ± 11 67.5 ± 11.9
sitting time, h 4.0 ± 2.4 4.5 ± 2.6 4.3 ± 2.54
IPAQ, MET 2772 (1386, 6888) 2373 (1386, 5446) 2772 (1386, 5838)
BMI, kg/m2 24.9 ± 3.7 25.2 ± 4.1 25.1 ± 3.9
Somking status, n (%)
None 198 (33.2) 421 (58.4) 619 (47.0)
current 244 (40.9) 213 (29.5) 457 (34.7)
Ex-smoker 148 (24.8) 76 (10.5) 224 (17.0)
Drinking status, n (%)
None 193 (32.4) 654 (90.7) 203 (15.4)
Current 146 (24.5) 10 (1.4) 185 (14.0)
Occasiona lly 115 (19.3) 39 (5.4) 122 (9.3)
Ex-drinking 136 (22.8) 7 (1.0) 790 (60.0)
physial performance
grip strength, kg 34.5 ± 7.5 21.1 ± 5.2 27.2 ± 9.2
4m-walking speed, m/s 1.03 ± 0.21 0.95 ± 0.19 0.98 ± 0.2
grip strength 1.39 ± 3.12 0.85 ± 0.24 1.08 ± 0.39
Blood sampale
TG, mmol/L 1.23 (0.86, 1.72) 1.48 (1.12, 2.06) 1.38 (1.0, 1.89)
TC, mmol/L 4.58 (3.99, 5.13) 5.11 (4.52, 5.85) 4.87 (4.28, 5.61)
GLU, mmol/L 5.38 (4.98, 5.96) 5.41 (4.96, 6.09) 5.39 (4.97, 6.03)
SBP, m mHg 126 ± 12 126 ± 13 126 ± 13
DBP, m mHg 79 ± 6 79 ± 6 79 ± 6
FALL, n (%)
Yes 68 (33.1) 144 (39.8) 212 (36.8)
No 399 (66.9) 434 (60.2) 833 (63.2)
Disease hi s t o r y
Diabetes mellitus, n (%)
Yes 63 (10.6) 130 (18.0) 193 (14.7)
No 527 (88.4) 588 (81.6) 1115 (84.7)
Hypertention, n (%)
Yes 241 (40.4) 388 (53.8) 629 (47.8)

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Conti n ue d
No 346 (58.1) 326 (45.2) 672 (51.0)
Hyperlipidemia, n (% )
Yes 172 (28.9) 303 (42.0) 475 (36.1)
No 419 (70.3) 414 (57.4) 833 (63.2)
Hepatopathy, n (%)
Yes 19 (3.2) 28 (3.9) 47 (3.6)
No 434 (72.8) 557 (77.3) 99 (75.2)
Nephropathy , n (%)
Yes 15 (2.5) 12 (1.7) 27 (2.1)
No 437 (73.3) 571 (79.2) 1008 (76.5)
Limitation, n (%)
Yes 79 (13.3) 135 (18.7) 214 (16.2)
No 517 (86.7) 586 (81.3) 1103 (83.8)
BMI: Body Mass Index; SBP: Systolic blood pressure; SDP: Diastolic blood pressure.
(a) (b)
Figure 1. The association between grip strength and gait speed in men and women. (a) Men (n = 596); (b) Women (n = 721).
frailty [2] and, increasingly, of sarcopenia. The decrease in muscle mass and strength in the elderly has been as-
sociated with multiple adverse events, such as physical disability, quality of life, the rate of patient’s hospitaliza-
tion and mortality [8] [9]. Maximum grip strength can well reflect systemic muscle strength.
Mobility activity can better reflect health status and physical function in elderly, 4 m walking speed at ordi-
nary speed is a simple and effective way, which can better evaluate mobility activity well. In general, 4-m
walking speed is lower than 0.8 m/s is considered to have mobility limitation in the older population. Previous
study showed that it had significant correlation between muscle strength and walking speed in the elderly, which
is consistent with us, therefore, mobility limitation was selected as the target variables in this study. In man, grip
strength is lower than 32.45 kg, the strength is weaker, In women, grip strength is lower than 18.20 kg, the
strength is weaker. However, one cro ss -sectional study about test-retest reliability and cutoff for subjective
weakness of using the hands in heavy tasks, Optimum cutoff values of grip strength were 28.5 and 18.5 kg for

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18
Table 2. AUC and cut-Off point of grip strength in the subjects.
AUC (95%CI) p-value Cut-off Sensitivity (%) Specificity (%)
Men
0.764 (0.708, 0.821) <0.001 32.45 7 9.7 64.9
Women
0.703 (0.655, 0.721) <0.001 18.20 53.3 78.1
men and women, respectively [10]. This is mainly because the target variables is different, the ability to perform
heavy tasks, such as heavy housework or lifting and carrying an 11-kg object was selected as the target variables
in previous study, while mobility limitation was selected as the target variables in this study.
Our study has several limitations. First, it was a cross-sectional study, and thus we could not conclude wheth-
er muscle strength decline led to increased rate of mobility limitation. Therefore, further study should be under-
taken to elucidate this relationship; Second, as the assessments were performed in a public facility, participants
were more likely to be active and healthy. The level of grip strength is higher in people generally. Therefore, our
results might not be fully representative of the general elderly population.
In summary, when considering muscle weakness in elderly, grip strength in men and women is lower than
32.45 kg and 18.20. Cutpoints for weakness derived from this large, diverse sample of older adults may be use-
ful to identify populations who may benefit from interventions to improve muscle strength and function.
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