Table of Contents

Component Description

The muscle strength/grip test component measured the isometric grip strength using a handgrip dynamometer. The goals of this component were to provide: 1) nationally representative data on muscle strength; 2) prevalence estimates of children with poor muscle strength; and 3) data to study the association between muscle strength and other health conditions and risk factors, such as obesity, physical activity and dietary patterns.

 

Eligible Sample

Participants aged 6 years and older, who did not meet any of the exclusion criteria, were eligible for this component.

Participants were excluded from this component if they were unable to hold the dynamometer with both hands (e.g., missing both arms, both hands, thumbs on both hands, or paralyzed in both hands). Participants who were able to grip the dynamometer with one hand still performed the component. Participants who had surgery on either hand or wrist in the last three months were not tested on that particular hand.

 

Protocol and Procedure

In this component, muscle strength was measured through a grip test using a handgrip dynamometer. A trained examiner explained and demonstrated the protocol to the participant. The examiner then adjusted the grip size of the dynamometer to the participant’s hand size and asked the participant to squeeze the dynamometer for a practice trial. The practice trial was to determine if the procedure was understood by the participant and the grip size properly adjusted.

After the practice, the participant was asked to use one of the hands to squeeze the dynamometer as hard as possible, exhaling while squeezing to avoid build-up of intra-thoracic pressure. The test was then repeated for the other hand. Each hand was tested three times, alternating hands between trials with a 60-second rest between measurements on the same hand.

The grip test was performed in the standing position unless the participant was physically limited. In 2011-2012, among those who were tested, less than 0.2% of the participants younger than 20 years old were tested in a seated position. Therefore information on testing position was not released for participants younger than 20 years due to disclosure concern. Researchers who are interested can access this information through the NCHS Research Data Center. Information on testing position for participants 20 years and older is included in the present dataset.

Prior conditions may affect a person’s grip strength; therefore, we collected data on whether the participant has ever had surgery on his/her hands or wrists for arthritis or carpal tunnel syndrome. In 2011-2012, among those who were tested, less than 0.1% of the participants younger than 20 years old reported ever had hand/wrist surgery for arthritis or carpal tunnel syndrome. Due to potential disclosure risk, this prior surgery information is only released for participants 20 years and over in the present dataset. Information on younger participants is only available through the Research Data Center.

The participant was randomly assigned to start the test with his/her dominant or non-dominant hand. The practice trial was usually proformed with the opposite hand that was assigned to be tested first, unless the participant was physically limited and only had one hand that was eligible for the test.

Detailed descriptions of the protocol are provided in the NHANES Muscle Strength/Grip Test Procedure Manual available on the NHANES website.

 

Quality Assurance & Quality Control

Examiners were regularly monitored by NCHS staff and field supervisors. Retraining sessions were conducted periodically with the examiners to reinforce the proper protocols and techniques. Inspection, calibration, and maintenance of the equipment and supplies were performed on a regular basis.

As part of on-going quality control practices, all data were reviewed systematically for logical or operational inconsistencies and examiner errors.

 

Data Processing and Editing

During the data processing, edits were made to ensure the logical consistency and analytic usefulness of the data. Extreme values were reviewed and cross-checked with other available data.

Grip test status code (MGDEXSTS):
This derived variable indicates the following for each participant:

      1 = Completed test on both hands - the participant performed the test on both hands.

      2 = Completed test on only one hand - due to physical limitations, the participant only performed test on one of the hands.

      3 = Did not perform test - Grip test did not take place due to various reasons (such as no time, arrived late/left early, refusal, illness, emergency, or equipment failure).


Combined grip strength (MGDCGSZ):
The combined grip strength was calculated as the sum of the largest reading from each hand, and expressed in kilogram. This variable was not calculated for participants who only performed the test on one hand.

 

Analytic Notes

The NHANES examination sample weights should be used to analyze the muscle strength/grip test data. Please refer to the NHANES Analytic Guidelines and the on-line NHANES Tutorial for further details on the use of sample weights and other analytic issues.

 

Codebook and Frequencies

SEQN - Respondent sequence number

Variable Name:
SEQN
SAS Label:
Respondent sequence number
English Text:
Respondent sequence number.
Target:
Both males and females 6 YEARS - 150 YEARS

MGDEXSTS - Grip test status

Variable Name:
MGDEXSTS
SAS Label:
Grip test status
English Text:
Grip test status
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Completed test on both hands 7064 7064
2 Completed test on only one hand 113 7177
3 Did not perform test 644 7821
. Missing 0 7821

MGD050 - Ever had surgery on hands or wrists

Variable Name:
MGD050
SAS Label:
Ever had surgery on hands or wrists
English Text:
Have you ever had surgery on your hands or wrists for arthritis or carpal tunnel syndrome?
Target:
Both males and females 20 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 158 158
2 No 4620 4778
7 Refused 3 4781
9 Don't know 2 4783
. Missing 3038 7821

MGD060 - Which hand or wrist had surgery

Variable Name:
MGD060
SAS Label:
Which hand or wrist had surgery
English Text:
Which hand or wrist was the surgery on?
Target:
Both males and females 20 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Right hand/wrist 60 60
2 Left hand/wrist 36 96
3 Both hands/wrists 62 158
7 Refused 0 158
9 Don't know 0 158
. Missing 7663 7821

MGQ070 - Recent pain/aching/stiffness-right hand

Variable Name:
MGQ070
SAS Label:
Recent pain/aching/stiffness-right hand
English Text:
Have you had any pain, aching or stiffness in your right hand in the past 7 days?
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 812 812
2 No 6313 7125
7 Refused 1 7126
9 Don't know 4 7130
. Missing 691 7821

MGQ080 - Cause of recent pain in right hand

Variable Name:
MGQ080
SAS Label:
Cause of recent pain in right hand
English Text:
Is the pain, aching or stiffness in your right hand caused by arthritis, tendonitis, or carpal tunnel syndrome?
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 437 437
2 No 157 594
7 Refused 0 594
9 Don't know 218 812
. Missing 7009 7821

MGQ090 - Pain in right hand gotten worse recently

Variable Name:
MGQ090
SAS Label:
Pain in right hand gotten worse recently
English Text:
Has the pain, aching or stiffness in your right hand gotten worse in the past 7 days?
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 77 77
2 No 735 812
7 Refused 0 812
9 Don't know 0 812
. Missing 7009 7821

MGQ100 - Recent pain/aching/stiffness-left hand

Variable Name:
MGQ100
SAS Label:
Recent pain/aching/stiffness-left hand
English Text:
Have you had any pain, aching or stiffness in your left hand in the past 7 days?
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 675 675
2 No 6451 7126
7 Refused 2 7128
9 Don't know 3 7131
. Missing 690 7821

MGQ110 - Cause of recent pain in left hand

Variable Name:
MGQ110
SAS Label:
Cause of recent pain in left hand
English Text:
Is the pain, aching or stiffness in your left hand caused by arthritis, tendonitis, or carpal tunnel syndrome?
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 385 385
2 No 136 521
7 Refused 0 521
9 Don't know 154 675
. Missing 7146 7821

MGQ120 - Pain in left hand gotten worse recently

Variable Name:
MGQ120
SAS Label:
Pain in left hand gotten worse recently
English Text:
Has the pain, aching or stiffness in your left hand gotten worse in the past 7 days?
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 76 76
2 No 598 674
7 Refused 0 674
9 Don't know 1 675
. Missing 7146 7821

MGD130 - Dominant hand

Variable Name:
MGD130
SAS Label:
Dominant hand
English Text:
Are you right-handed, left-handed, or do you use both hands equally?
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Right-handed 6320 6320
2 Left-handed 617 6937
3 Use both hands equally 240 7177
7 Refused 0 7177
9 Don't know 0 7177
. Missing 644 7821

MGQ90DG - 90 degree angle with index finger

Variable Name:
MGQ90DG
SAS Label:
90 degree angle with index finger
English Text:
Was the participant able to achieve a 90 degree angle with the index finger on the eligible hand(s)?
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 7122 7122
2 No - Not right hand 29 7151
3 No - Not left hand 14 7165
4 No - Not either hand 12 7177
. Missing 644 7821

MGDSEAT - Testing position

Variable Name:
MGDSEAT
SAS Label:
Testing position
English Text:
Testing position
Target:
Both males and females 20 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Standing 4611 4611
2 Seated 172 4783
. Missing 3038 7821

MGAPHAND - Hand assigned for practice trial

Variable Name:
MGAPHAND
SAS Label:
Hand assigned for practice trial
English Text:
The hand assigned for the practice trial
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Right 3563 3563
2 Left 3614 7177
. Missing 644 7821

MGATHAND - Begin the test with this hand.

Variable Name:
MGATHAND
SAS Label:
Begin the test with this hand.
English Text:
Begin the test with this hand.
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Right 3614 3614
2 Left 3563 7177
. Missing 644 7821

MGXH1T1 - Grip strength (kg), hand 1, test 1

Variable Name:
MGXH1T1
SAS Label:
Grip strength (kg), hand 1, test 1
English Text:
Grip strength (kg), hand 1, test 1
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
5 to 79.2 Range of Values 7170 7170
. Missing 651 7821

MGXH1T1E - Grip strength, hand 1, test 1 effort

Variable Name:
MGXH1T1E
SAS Label:
Grip strength, hand 1, test 1 effort
English Text:
Whether the participant exerted a maximal or questionable effort during the test 1 on hand 1, as assessed by the technician.
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Maximal 6911 6911
2 Questionable 259 7170
. Missing 651 7821

MGXH2T1 - Grip strength (kg), hand 2, test 1

Variable Name:
MGXH2T1
SAS Label:
Grip strength (kg), hand 2, test 1
English Text:
Grip strength (kg), hand 2, test 1
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 77.3 Range of Values 7071 7071
. Missing 750 7821

MGXH2T1E - Grip strength, hand 2, test 1 effort

Variable Name:
MGXH2T1E
SAS Label:
Grip strength, hand 2, test 1 effort
English Text:
Whether the participant exerted a maximal or questionable effort during the test 1 on hand 2, as assessed by the technician.
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Maximal 6892 6892
2 Questionable 179 7071
. Missing 750 7821

MGXH1T2 - Grip strength (kg), hand 1, test 2

Variable Name:
MGXH1T2
SAS Label:
Grip strength (kg), hand 1, test 2
English Text:
Grip strength (kg), hand 1, test 2
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
5.2 to 83.7 Range of Values 7161 7161
. Missing 660 7821

MGXH1T2E - Grip strength, hand 1, test 2 effort

Variable Name:
MGXH1T2E
SAS Label:
Grip strength, hand 1, test 2 effort
English Text:
Whether the participant exerted a maximal or questionable effort during the test 2 on hand 1, as assessed by the technician.
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Maximal 7050 7050
2 Questionable 111 7161
. Missing 660 7821

MGXH2T2 - Grip strength (kg), hand 2, test 2

Variable Name:
MGXH2T2
SAS Label:
Grip strength (kg), hand 2, test 2
English Text:
Grip strength (kg), hand 2, test 2
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
5 to 83.8 Range of Values 7066 7066
. Missing 755 7821

MGXH2T2E - Grip strength, hand 2, test 2 effort

Variable Name:
MGXH2T2E
SAS Label:
Grip strength, hand 2, test 2 effort
English Text:
Whether the participant exerted a maximal or questionable effort during the test 2 on hand 2, as assessed by the technician.
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Maximal 6955 6955
2 Questionable 111 7066
. Missing 755 7821

MGXH1T3 - Grip strength (kg), hand 1, test 3

Variable Name:
MGXH1T3
SAS Label:
Grip strength (kg), hand 1, test 3
English Text:
Grip strength (kg), hand 1, test 3
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
5 to 85.8 Range of Values 7159 7159
. Missing 662 7821

MGXH1T3E - Grip strength, hand 1, test 3 effort

Variable Name:
MGXH1T3E
SAS Label:
Grip strength, hand 1, test 3 effort
English Text:
Whether the participant exerted a maximal or questionable effort during the test 3 on hand 1, as assessed by the technician.
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Maximal 7055 7055
2 Questionable 104 7159
. Missing 662 7821

MGXH2T3 - Grip strength (kg), hand 2, test 3

Variable Name:
MGXH2T3
SAS Label:
Grip strength (kg), hand 2, test 3
English Text:
Grip strength (kg), hand 2, test 3
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
5.1 to 82.9 Range of Values 7059 7059
. Missing 762 7821

MGXH2T3E - Grip strength, hand 2, test 3 effort

Variable Name:
MGXH2T3E
SAS Label:
Grip strength, hand 2, test 3 effort
English Text:
Whether the participant exerted a maximal or questionable effort during the test 3 on hand 2, as assessed by the technician.
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Maximal 6943 6943
2 Questionable 116 7059
. Missing 762 7821

MGDCGSZ - Combined grip strength (kg)

Variable Name:
MGDCGSZ
SAS Label:
Combined grip strength (kg)
English Text:
Combined grip strength (kg): the sum of the largest reading from each hand.
Target:
Both males and females 6 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
11.4 to 169.6 Range of Values 7064 7064
. Missing 757 7821