Table of Contents

Locator Record

Title: Muscle Strength - Grip Test (Y_MGX )
Contact Number: 1-866-441-NCHS
Years of Content: 2012
First Published: September , 2013
Revised: NA
Access Constraints: None
Use Constraints: None
Geographic Coverage: National
Subject: NNYFS muscle strength/grip test component measured the isometric grip strength for participants aged 6 to 15 years, using a handgrip dynamometer
Record Source: NNYFS 2012
Survey Methodology: NNYFS 2012 is a stratified multistage probability sample of the non-institutionalized population aged 3 to 15 years in the U.S.
Medium: NHANES Web site; SAS transport files

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 6-15 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 do only 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, or 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 this NNYFS 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 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 NNYFS Muscle Strength/Grip Test Procedure Manual available on the NNYFS website at: 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 NNYFS examination sample weights should be used to analyze the muscle strength/grip test data. Please refer to the NNYFS Analytic Guidelines for 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 1206 1206
2 Completed test on only one hand 5 1211
3 Did not perform test 13 1224
. Missing 0 1224

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 8 8
2 No 1201 1209
7 Refused 0 1209
9 Don't know 0 1209
. Missing 15 1224

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 2 2
2 No 1207 1209
7 Refused 0 1209
9 Don't know 0 1209
. Missing 15 1224

MGQ130 - Dominant hand

Variable Name:
MGQ130
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 1045 1045
2 Left-handed 131 1176
3 Use both hands equally 35 1211
7 Refused 0 1211
9 Don't know 0 1211
. Missing 13 1224

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 1207 1207
2 No 4 1211
. Missing 13 1224

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 615 615
2 Left 596 1211
. Missing 13 1224

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 597 597
2 Left 614 1211
. Missing 13 1224

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 1211 1211
. Missing 13 1224

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 1177 1177
2 Questionable 34 1211
. Missing 13 1224

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
5.3 to 53.3 Range of Values 1205 1205
. Missing 19 1224

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 1191 1191
2 Questionable 14 1205
. Missing 19 1224

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 1210 1210
. Missing 14 1224

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 1182 1182
2 Questionable 28 1210
. Missing 14 1224

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 1206 1206
. Missing 18 1224

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 1181 1181
2 Questionable 25 1206
. Missing 18 1224

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
5.3 to 60.2 Range of Values 1211 1211
. Missing 13 1224

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 1189 1189
2 Questionable 22 1211
. Missing 13 1224

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
5.2 to 53.3 Range of Values 1206 1206
. Missing 18 1224

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 1174 1174
2 Questionable 32 1206
. Missing 18 1224

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
11.5 to 108.7 Range of Values 1206 1206
. Missing 18 1224