Reliability of isometric trunk moment measurements in healthy persons over 50 years of age.
OBJECTIVE
To determine the short- and long-term test-retest reliability of maximum isometric trunk moment measurements in healthy volunteers over 50 years of age, to compare these results with those from volunteers younger than 50 years, and to test whether volunteers' anticipatory emotional state affects the precision of these measurements.


METHODS
Forty-two older persons (21 females; age range 50-90 years) and 44 younger persons (19 females; age range 18-49 years) performed maximum isometric trunk extensions, flexions, and rotations using dynamometers (DAVID, Fi, David Health Solutions Ltd, Helsinki, Finland). They repeated the tests after 1-2 days (short-term) and at 6 weeks (long-term). Retest-reliability was evaluated for age- and gender-specific subgroups, with assessment of intraclass correlation coefficient (ICC2,1) , standard error of measurement, smallest real difference, and smallest real difference, in percent.


RESULTS
For the elderly group, smallest real difference, in percent values varied up to 33% and were similar to those obtained from young volunteers. Precision of the trunk rotation tests was lower than that of trunk flexion or extension. Retest agreement exceeded 0.75 (ICC2,1) for all tests, with no relevant differences observed between gender- and age-specific subgroups. Neither participants' motivation nor their anticipatory emotions correlated with the individual coefficients of variation of the trunk muscle moment measurements.


CONCLUSIONS
Isometric maximum trunk extension and flexion moment measurements taken from healthy persons > 50 years old are as reliable as those from persons < 50 years old, and can be expected to enable an acceptable level of detection of expected changes in muscle strength parameters as a result of planned exercise interventions.
Karl Landsteiner Institute for Outpatient Rehabilitation Research, Vienna, Austria.
Thomas
T
Kienbacher
Birgit
B
Paul
Richard
R
Habenicht
Christian
C
Starek
Markus
M
Wolf
Josef
J
Kollmitzer
Gerold
G
Ebenbichler
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D005260:Female; D005387:Finland; D064368:Healthy Volunteers; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D009068:Movement / Q000502:physiology; D053580:Muscle Strength / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology*; D016059:Range of Motion, Articular / Q000502:physiology; D012016:Reference Values; D015203:Reproducibility of Results; D019415:Torque; D060726:Torso / Q000502:physiology*; D055815:Young Adult