Table of Contents

Locator Record

Title: NHANES/NNYFS Combined Sample 2012 - Muscle Strength/Grip Test (C_MGX )
Contact Number: 1-866-441-NCHS
Years of Content: 2012
First Published: December, 2014
Revised: NA
Access Constraints: RDC Only
Use Constraints: RDC Only
Geographic Coverage: National
Subject: Muscle strength/grip test component measured the isometric grip strength for participants aged 6 to 15 years, using a handgrip dynamometer
Record Source: NHANES/NNYFS 2012
Survey Methodology: This is a stratified multistage probability sample of the non-institutionalized population aged 3 to 15 years in the U.S. from NHANES 2012 and NNYFS 2012.
Medium: NHANES Web site; SAS transport files

Component Description

This file provides data from the muscle strength/grip test component for the combined samples from NHANES 2012 and the NHANES National Youth Fitness Survey (NNYFS).

The muscle strength/grip test component measured 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.

This dataset can only be accessed through the NCHS Research Data Center (RDC). Instructions for requesting use of these data are available at the RDC website (http://www.cdc.gov/rdc/).

Eligible Sample

NNYFS and NHANES 2012 participants aged 6-15 years, who did not meet any of the exclusion criteria, were eligible for this component.

Participants were excluded from this component if a doctor had ever said they should not participate in sports or other activities because of a health condition or they should only do sports or other physical activities recommended by a doctor. Participants were excluded 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 his/her 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 this NHANES 2012 and NNYFS combined sample, less than 0.2% of the participants were tested in a seated position.

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

Detailed descriptions of the protocol are provided in the Muscle Strength/Grip Test Procedure Manual available on the NHANES (http://www.cdc.gov/nchs/data/nhanes/nhanes_11_12/Muscle_Strength_Proc_Manual.pdf) and NNYFS websites (http://www.cdc.gov/nchs/nnyfs/manuals.htm).

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 analysis of the combined NHANES and NNYFS muscle strength/grip test data must be conducted using the appropriate survey design variables, sample weights, and the basic demographic variables. Please refer to the NNYFS Analytic Guidelines for further details on the use of sample weights and other analytic issues

References

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 - 15 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 - 15 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Completed test on both hands 2048 2048
2 Completed test on only one hand 15 2063
3 Did not perform test 61 2124
. Missing 0 2124

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 - 15 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 23 23
2 No 2034 2057
7 Refused 0 2057
9 Don't know 2 2059
. Missing 65 2124

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 - 15 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 9 9
2 No 2046 2055
7 Refused 0 2055
9 Don't know 2 2057
. Missing 67 2124

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 - 15 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Right-handed 1796 1796
2 Left-handed 219 2015
3 Use both hands equally 48 2063
7 Refused 0 2063
9 Don't know 0 2063
. Missing 61 2124

MGD90DG - 90 degree angle with index finger

Variable Name:
MGD90DG
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 - 15 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 2053 2053
2 No 10 2063
. Missing 61 2124

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 - 15 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Right 1024 1024
2 Left 1039 2063
. Missing 61 2124

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 - 15 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Right 1043 1043
2 Left 1020 2063
. Missing 61 2124

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 - 15 YEARS
Code or Value Value Description Count Cumulative Skip to Item
5 to 55 Range of Values 2063 2063
. Missing 61 2124

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 - 15 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Maximal 2002 2002
2 Questionable 61 2063
. Missing 61 2124

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 - 15 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 53.9 Range of Values 2047 2047
. Missing 77 2124

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 - 15 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Maximal 2004 2004
2 Questionable 43 2047
. Missing 77 2124

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 - 15 YEARS
Code or Value Value Description Count Cumulative Skip to Item
5.1 to 56.7 Range of Values 2062 2062
. Missing 62 2124

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 - 15 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Maximal 2014 2014
2 Questionable 48 2062
. Missing 62 2124

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 - 15 YEARS
Code or Value Value Description Count Cumulative Skip to Item
5 to 53.1 Range of Values 2048 2048
. Missing 76 2124

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 - 15 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Maximal 1999 1999
2 Questionable 49 2048
. Missing 76 2124

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 - 15 YEARS
Code or Value Value Description Count Cumulative Skip to Item
5 to 60.2 Range of Values 2063 2063
. Missing 61 2124

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 - 15 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Maximal 2020 2020
2 Questionable 43 2063
. Missing 61 2124

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 - 15 YEARS
Code or Value Value Description Count Cumulative Skip to Item
5.1 to 53.3 Range of Values 2048 2048
. Missing 76 2124

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 - 15 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Maximal 1992 1992
2 Questionable 56 2048
. Missing 76 2124

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 - 15 YEARS
Code or Value Value Description Count Cumulative Skip to Item
11.4 to 108.7 Range of Values 2048 2048
. Missing 76 2124