The preoperative grip strength of a person can be measured using a dynamometer. If the grip strength is below the recommended cut-off level for age and sex, then the person (1) is at high risk for post-operative complications and (2) should have nutritional assessment. The cut-off value was set at 85% of that shown by normal persons of that age and gender. The hand grip strength predicted 74% of complications.
Patient selection: 247 normal volunteers used to derive normal values for age and gender with ages from 16 to 95
Measurement:
(1) Performed using a mechanical dynamometer.
(2) Results reported in kilograms.
(3) The nondominant hand tends to show slightly great strength (Table III, page 21, Webb (1989).
Criteria for serious complication:
(1) post-operative stay > 14 days
(2) death
Quadratic Equations for Normal Grip Strength
female grip strength in kilograms =
= 25.9 + (0.55 * (age in years)) - (0.0077 * ((age in years)^2))
R value: 0.78
male grip strength in kilograms =
= 42.03 + (0.57 * (age in years)) - (0.0073 * ((age in years)^2))
R value: 0.56
from Table II, page 31, Webb et al (1989)
cut-off strength in kilograms =
= (grip strength in kilograms for gender and age) * 0.85
Exponential Equations for Normal Grip Strength
female grip strength in kilograms =
= 3.91 * EXP(-0.012 * (age in years))
R value: 0.74
male grip strength in kilograms =
= 4.12 * EXP(-0.0049 * (age in years))
R value: 0.48
from Table II, page 31, Webb et al (1989)
NOTE: When age values are entered into the exponential equations, unrealistic values are returned. I tried several variations of the equations and could not get reliable results.
Age and Gender Grip Strength Cutoff Values (at 85% of Normal)
age in years |
female grip strength in kilograms |
male grip strength in kilograms |
15 |
28 |
42 |
20 |
29 |
43 |
25 |
30 |
44 |
30 |
30 |
45 |
35 |
30 |
45 |
40 |
30 |
45 |
45 |
30 |
45 |
50 |
29 |
45 |
55 |
28 |
44 |
60 |
27 |
43 |
65 |
25 |
41 |
70 |
23 |
39 |
75 |
20 |
37 |
80 |
18 |
35 |
85 |
15 |
32 |
90 |
11 |
29 |
95 |
8 |
26 |
from Table V, page 32, Webb et al (1989)
Medal Equations for Grip Strength Cutoff Values
from Figure 3, page 32, Webb et al (1989)
female age 15-30 years grip strength in kilograms =
= (-0.01 * ((age in years)^2)) + (0.65 * (age in years)) + 20
female age 30-95 years grip strength in kilograms =
= (-0.00483 * ((age in years)^2)) + (0.25193 * (age in years)) + 27.3632
male age 15-40 years grip strength in kilograms =
= (-0.00752 * ((age in years)^2)) + (0.5805 * (age in years)) + 34.025
male age 40-95 years grip strength in kilograms =
= (-0.004453 * ((age in years)^2)) + (0.2498268 * (age in years)) + 42.665
Specialty: Nutrition, Surgery, general, Surgery, orthopedic