Table of Contents

Locator Record

Title: Muscular Strength (MSX )
Contact Number: 1-866-441-NCHS
Years of Content: 1999 - 2000
First Published: June, 2002
Revised: NA
Access Constraints: None
Use Constraints: None
Geographic Coverage: National
Subject:muscle strength, physical functioning
Record Source: NHANES 1999 - 2000
Survey Methodology: NHANES 1999 - 2000 is a stratified multistage probability sample of the civilian non-institutionalized population of the U.S.
Medium: NHANES Web site; SAS transport files

Component Description

An observed timed 20-foot walk was used to assess functional limitations.
Muscle strength was assessed by measuring the isokinetic strength of the knee extensors (quadriceps).

Eligible Sample

Target Sample and Exclusion Criteria

Examinees 50 years of age and older were eligible for this component.

Examinees who had a history of myocardial infarction within the past six weeks, chest or abdominal surgery within the past three weeks, knee surgery or knee replacement surgery, severe back pain, a history of brain aneurysm or stroke were excluded from the muscle strength exam. Examinees who are not able to walk alone without holding onto someone are excluded from the timed walk. The use of a walker or cane is permitted for the timed walk.

Protocol and Procedure

Data Collection Methods

A Kin Com MP dynamometer manufactured by Chattanooga Group, Inc.,
Chattanooga, TN was used to evaluate knee extensor strength. measurement is peak torque (Newton/meters) of the quadriceps at one speed The outcome
(60 degrees/second). A measured walk test track was set up in the MEC for the measured walk component. A 20 feet long test track area was set up in a corridor of the MEC. Adhesive tape strips on the floor indicated the start and stop points for the measured walk component.

Examination Protocol

Six muscle strength measurements are obtained: three warm-up/ learning measurements and three test measurements for the muscle strength component record.
The 20-foot walk was timed using a hand-held stopwatch. The examinee is asked to walk at their usual pace. Start and stop times are defined as follows:

START TIME: When the survey participant’s first foot touches the floor across the start line.

STOP TIME: When the survey participant’s foot touches the floor across the finish line.

Staff

Certified health technicians conduct the examinations. All health technicians receive intensive training on the NHANES examination protocols.

Quality Assurance & Quality Control

The quality control procedures include site visits with expert consultants and NCHS and contractor staff; implementation of a continuous quality assurance plan that includes a procedural checklist; and continuous data review to identify systematic error. The NHANES Quality Control Manual includes a more detailed description of the quality control procedures that were implemented for both components.

Data Processing and Editing

Although six muscle strength trials are preformed only the highest peak forced is reported in the data file. The following algorithm was used: For examinee who had 4 or more trials, select one peak force from trials 4-6. If fewer than 4 trials were completed, select the highest peak force from the trials that were completed.

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 50 YEARS - 150 YEARS

MSAEXLEN - length of a MEC exam (sec)

Variable Name:
MSAEXLEN
SAS Label:
length of a MEC exam (sec)
English Text:
Timed walk & muscle strength time (sec)
Target:
Both males and females 50 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 2884 Range of Values 2156 2156
. Missing 0 2156

MSAEXSTS - Status of a MEC exam

Variable Name:
MSAEXSTS
SAS Label:
Status of a MEC exam
English Text:
Timed walk and muscle strength status
Target:
Both males and females 50 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Complete 1481 1481
2 Partial 461 1942
3 Not done 214 2156
. Missing 0 2156

MSAEXCMT - Comment code for an exam

Variable Name:
MSAEXCMT
SAS Label:
Comment code for an exam
English Text:
Timed walk and muscle strength comments
Target:
Both males and females 50 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 None 1 1
1 Safety exclusion 135 136
2 SP refusal 26 162
3 No time 9 171
4 Physical limitation 126 297
5 Communication problem 5 302
6 Equipment failure 36 338
7 SP ill/emergency 11 349
14 Interrupted 1 350
56 Came late/left early 80 430
99 Other, specify 18 448
. Missing 1708 2156

MSDEXCLU - Exclusion criteria for muscle strength

Variable Name:
MSDEXCLU
SAS Label:
Exclusion criteria for muscle strength
English Text:
Exclusion criteria for muscle strength
Target:
Both males and females 50 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Chest/abdomen surgery past three weeks 10 10
2 Myocardial infarction (or"heart attack") in the past six weeks 3 13
3 Told by dr had aneurysm in the brain or had a stroke 99 112
4 Have severe neck or back pain today 88 200
5 Difficult in bending or straightening right knee 25 225
6 Had right knee or right hip replacement 32 257
. Missing 1899 2156

MSXWTIME - Time to complete 20 ft walk (seconds)

Variable Name:
MSXWTIME
SAS Label:
Time to complete 20 ft walk (seconds)
English Text:
Time to complete 20 ft walk (seconds)
Target:
Both males and females 50 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 to 61.2 Range of Values 1933 1933
. Missing 223 2156

MSXWPAIN - Pain reported on walking:

Variable Name:
MSXWPAIN
SAS Label:
Pain reported on walking:
English Text:
Pain reported on walking:
Target:
Both males and females 50 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 11 11
2 No 1933 1944
. Missing 212 2156

MSAWDEV - Type of device used:

Variable Name:
MSAWDEV
SAS Label:
Type of device used:
English Text:
Type of device used:
Target:
Both males and females 50 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 None 1878 1878
2 Cane 52 1930
3 Walker 9 1939
4 Other 6 1945
. Missing 211 2156

MSDPTIME - Time to peak force in seconds

Variable Name:
MSDPTIME
SAS Label:
Time to peak force in seconds
English Text:
Time to peak force in seconds
Target:
Both males and females 50 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 9.2 Range of Values 1500 1500
. Missing 656 2156

MSDPFANG - Angle of peak force (degrees)

Variable Name:
MSDPFANG
SAS Label:
Angle of peak force (degrees)
English Text:
Angle of peak force (degrees)
Target:
Both males and females 50 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
89.5 to 150.5 Range of Values 1500 1500
. Missing 656 2156

MSXARML - Arm length cm

Variable Name:
MSXARML
SAS Label:
Arm length cm
English Text:
Arm length cm
Target:
Both males and females 50 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
2 to 90 Range of Values 1500 1500
. Missing 656 2156

MSXGRAV - Gravity Correction in Lb

Variable Name:
MSXGRAV
SAS Label:
Gravity Correction in Lb
English Text:
Gravity Correction in Lb
Target:
Both males and females 50 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
0 to 46 Range of Values 1480 1480
. Missing 676 2156

MSDPFVEL - Peak force velocity degree/seconds

Variable Name:
MSDPFVEL
SAS Label:
Peak force velocity degree/seconds
English Text:
Peak force velocity degree/seconds
Target:
Both males and females 50 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
-5.25 to 65.5 Range of Values 1500 1500
. Missing 656 2156

MSDPF - Peak force (Newtons)

Variable Name:
MSDPF
SAS Label:
Peak force (Newtons)
English Text:
Peak force (Newtons)
Target:
Both males and females 50 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
77 to 825 Range of Values 1500 1500
. Missing 656 2156

MSDNTR - Number of trials

Variable Name:
MSDNTR
SAS Label:
Number of trials
English Text:
Number of trials
Target:
Both males and females 50 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 to 6 Range of Values 1500 1500
. Missing 656 2156

MSDAPF - Average peak force (Newtons)

Variable Name:
MSDAPF
SAS Label:
Average peak force (Newtons)
English Text:
Average peak force (Newtons)
Target:
Both males and females 50 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
69.3 to 696.8 Range of Values 1498 1498
. Missing 658 2156

MSDPFTR - The selected peak force trial

Variable Name:
MSDPFTR
SAS Label:
The selected peak force trial
English Text:
The selected peak force trial
Target:
Both males and females 50 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 to 6 Range of Values 1500 1500
. Missing 656 2156