Table of Contents

Locator Record

Title: Muscle Strength (MSX_B )
Contact Number: 1-866-441-NCHS
Years of Content: 2001 - 2002
First Published: January, 2004
Revised: NA
Access Constraints: None
Use Constraints: None
Geographic Coverage: National
Subject:Muscle Strength
Record Source: NHANES 2001 - 2002
Survey Methodology: NHANES 2001 - 2002 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

The loss of muscle mass, muscular strength, and power with age has important health and functional consequences. These changes predispose elderly people to falls and functional limitations. Numerous studies suggest that functional limitations are causally linked to disability. In NHANES, an observed timed 20-foot walk and 8 foot walk (instituted in January 2001) will assess physical limitations. Measuring the isokinetic strength of the knee extensors (quadriceps) will assess muscle strength.

Eligible Sample

The measured walk and isokinetic strength testing will be completed on Survey Participants (SPs) 50 years of age and older.

SPs who had a 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 are excluded from the muscle strength exam. SPs 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

A Kin Com MP dynamometer manufactured by Chattanooga Group, Inc ,Chattanooga, TN was used to evaluate knee extensor strength. The outcome measurement is the peak force (Newton) of the quadriceps at one speed (60 degrees/second). Two measured walk test track were set up in the MEC for the measured walk component. A 20 feet long test track area including in it an 8 feet marking was set up in a corridor of the MEC.

Six muscle strength measurements are obtained: three warm-up/ learning measurements and three outcome measurements.

The 8 and 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:

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.

For further details regarding the quality control procedures, analysts should consult the NHANES Muscle Strength Procedures Manual.

Data Processing and Editing

Although six muscle strength trials are preformed only the highest peak force is reported in the data file. The following algorithm was used: For each SP who had > 4 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 - Timed walk & muscle strength time (sec)

Variable Name:
MSAEXLEN
SAS Label:
Timed walk & muscle strength time (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 2429 Range of Values 2293 2293
. Missing 0 2293

MSAEXSTS - Timed walk and muscle strength status

Variable Name:
MSAEXSTS
SAS Label:
Timed walk and muscle strength status
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 1560 1560
2 Partial 469 2029
3 Not done 264 2293
. Missing 0 2293

MSAEXCMT - Timed walk and muscle strength comments

Variable Name:
MSAEXCMT
SAS Label:
Timed walk and muscle strength comments
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
1 Safety exclusion 234 234
2 SP refusal 40 274
3 No time 17 291
4 Physical limitation 219 510
5 Communication problem 8 518
6 Equipment failure 23 541
7 SP ill/emergency 14 555
40 Unable to follow protocol 3 558
56 Came late/left early 106 664
72 Error (technician/software/supply) 2 666
99 Other, specify 67 733
. Missing 1560 2293

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 12 12
2 Myocardial infarction (or"heart attack") in the past six weeks 8 20
3 Told by dr had aneurysm in the brain or had a stroke 102 122
4 Have severe neck or back pain today 38 160
5 Difficult in bending or straightening right knee 69 229
6 Had right knee or right hip replacement 64 293
. Missing 2000 2293

MSDCWUA - Can SP walk unassisted?

Variable Name:
MSDCWUA
SAS Label:
Can SP walk unassisted?
English Text:
Can SP walk unassisted?
Target:
Both males and females 50 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1 Yes 2027 2027
2 No 21 2048
. Missing 245 2293

MSXW20TM - Time to complete 20 ft walk:

Variable Name:
MSXW20TM
SAS Label:
Time to complete 20 ft walk:
English Text:
Time to complete 20 ft walk (in seconds):
Target:
Both males and females 50 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1.64 to 42.38 Range of Values 2027 2027
. Missing 266 2293

MSXW08TM - Time to complete 8 ft walk:

Variable Name:
MSXW08TM
SAS Label:
Time to complete 8 ft walk:
English Text:
Time to complete 8 ft walk (in seconds):
Target:
Both males and females 50 YEARS - 150 YEARS
Code or Value Value Description Count Cumulative Skip to Item
1.32 to 17.45 Range of Values 2027 2027
. Missing 266 2293

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 10 10
2 No 2036 2046
. Missing 247 2293

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 1944 1944
2 Cane 73 2017
3 Walker 18 2035
4 Other 11 2046
. Missing 247 2293

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 19.78 Range of Values 1542 1542
. Missing 751 2293

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 151 Range of Values 1542 1542
. Missing 751 2293

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
21 to 43 Range of Values 1542 1542
. Missing 751 2293

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
1 to 34 Range of Values 1537 1537
. Missing 756 2293

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
-5.75 to 68.25 Range of Values 1542 1542
. Missing 751 2293

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
46 to 805 Range of Values 1542 1542
. Missing 751 2293

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 1542 1542
. Missing 751 2293

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
46 to 658.7 Range of Values 1542 1542
. Missing 751 2293

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 1542 1542
. Missing 751 2293