Is stair climb power a clinically relevant measure of leg power impairments in at-risk older adults?
OBJECTIVE
To test the clinical relevance of the stair climb power test (SCPT) as a measure of leg power impairments in mobility-limited older adults.


METHODS
Cross-sectional analysis of baseline data from participants within a randomized controlled trial.


METHODS
Rehabilitation research gym.


METHODS
Community-dwelling older adults (N=138; mean age, 75.4 y) with mobility limitations as defined by the Short Physical Performance Battery (SPPB).


METHODS
Not applicable.


METHODS
Leg power measures included the SCPT and double leg press power measured at 40% (DLP40) and 70% (DLP70) of the 1 repetition maximum. Mobility performance tests included the SPPB and its 3 components: gait speed, chair stand time, and standing balance.


RESULTS
Stair climb power per kilogram (SCP/kg) had correlations of moderate strength (r=.47, r=.52) with DLP40/kg and DLP70/kg, respectively. All 3 leg power measures correlated with each of the mobility performance measures with the exception of DLP40/kg (r=.11, P=.27) and DLP70/kg (r=.11, P=.18) with standing balance. Magnitudes of association, as described by the Pearson correlation coefficient, did not differ substantively among the separate power measures as they related to SPPB performance overall. Separate adjusted multivariate models evaluating the relationship between leg power and SPPB performance were all statistically significant and described equivalent amounts of the total variance (R(2)) in SPPB performance (SCP/kg, R(2)=.30; DLP40, R(2)=.32; DLP70, R(2)=.31). Analyses of the components of the SPPB show that the SCPT had stronger associations than the other leg power impairment measures with models predicting chair stand (SCP/kg, R(2)=.25; DLP40, R(2)=.12; DLP70, R(2)=.13), whereas both types of leg press power testing had stronger associations with models predicting gait speed (SCP/kg, R(2)=.16; DLP40, R(2)=.34; DLP70, R(2)=.34). Stair climb power was the only power measure that was a significant component of models predicting standing balance (SCP/kg R(2)=.20).


CONCLUSIONS
The SCPT is a clinically relevant measure of leg power impairments. It is associated with more complex modes of testing leg power impairments and is meaningfully associated with mobility performance, making it suitable for clinical settings in which impairment-mobility relationships are of interest.
Bean
Jonathan F
JF
Department of PM&R, Harvard Medical School, Boston, MA, USA. jfbean@partners.org
Kiely
Dan K
DK
LaRose
Sharon
S
Alian
Joda
J
Frontera
Walter R
WR
D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D005080:Exercise Test; D005260:Female; D005684:Gait / Q000502:physiology; D006801:Humans; D035002:Lower Extremity; D008297:Male; D051346:Mobility Limitation; D018482:Muscle, Skeletal / Q000503:physiopathology; D004856:Postural Balance; D016032:Randomized Controlled Trials as Topic; D012111:Residence Characteristics; D012307:Risk Factors; D013647:Task Performance and Analysis