PMID- 28797826
OWN - NLM
STAT- MEDLINE
DCOM- 20180604
LR  - 20181113
IS  - 1873-6815 (Electronic)
IS  - 0531-5565 (Print)
IS  - 0531-5565 (Linking)
VI  - 98
DP  - 2017 Nov
TI  - Knee extensor power asymmetry is unrelated to functional mobility of older 
      adults.
PG  - 54-61
LID - S0531-5565(17)30175-4 [pii]
LID - 10.1016/j.exger.2017.08.008 [doi]
AB  - PURPOSE: To determine whether knee extensor power asymmetry limits functional 
      mobility of older adults who possess muscle weakness. METHODS: Knee extensor 
      power was measured in 36 older men and women (76.0+/-7.6yr), for each leg, on an 
      isokinetic dynamometer at 60, 180, and 300degs(-1) and power asymmetry was 
      calculated as the percent difference in power between strong and weak legs, at 
      each isokinetic velocity. 400-m walk, stair ascent, and five-repetition chair 
      rise tests were performed to assess functional mobility. Pearson correlations 
      were used to examine the relationship between weak leg power, strong leg power, 
      power asymmetry, and 400-m walk time, stair ascent time, and chair rise time. 
      Participants were then stratified into low power-high asymmetry (LP-HA), low 
      power-low asymmetry (LP-LA), high power-high asymmetry (HP-HA), and high 
      power-low asymmetry (HP-LA) groups who were compared for functional mobility. 
      RESULTS: Knee extensor power asymmetry was unrelated to 400-m walk time (r=0.16, 
      p=0.180), stair ascent time (r=0.22, p=0.094), or chair rise time (r=0.03, 
      p=0.437), whereas weak and strong leg powers were equally associated with 400-m 
      time (r=-0.62, p<0.001; r=-0.62, p<0.001), stair ascent time (r=-0.55, p<0.001; 
      r=-0.57, p<0.001), and chair rise time (r=-0.28, p=0.048; r=-0.31, p=0.032), 
      respectively. Power asymmetry was lowest at 60degs(-1) (12%), and increased with 
      contraction velocity (p=0.001) to 15% at 180degs(-1) and to 20% at 300degs(-1). 
      LP-HA exhibited 26% slower 400-walk time than HP-LA (p=0.015) and 19% slower than 
      HP-HA (p=0.037). LP-HA had 31% slower stair ascent time than HP-LA (p=0.033). 
      There were no differences in chair rise performance between groups. CONCLUSIONS: 
      Knee extensor power asymmetry was unrelated to 400-m walk, stair ascent, and 
      chair rise performance in older adults. Weak and strong limb powers were equally 
      related to these functional measures, but a leftward shift of the power-mobility 
      curve exists for the weak leg that may hinder clinical assessment if strength or 
      power is measured on a single limb and symmetry is assumed. The greatest degree 
      of knee extensor power asymmetry occurred at the fastest isokinetic velocity, 
      which suggests high-speed muscle contractions may better differentiate laterality 
      of function in older individuals.
CI  - Copyright (c) 2017 Elsevier Inc. All rights reserved.
FAU - LaRoche, Dain P
AU  - LaRoche DP
AD  - Department of Kinesiology, University of New Hampshire, Durham, NH, USA. 
      Electronic address: dain.laroche@unh.edu.
FAU - Villa, Michelle R
AU  - Villa MR
AD  - Department of Kinesiology, University of New Hampshire, Durham, NH, USA.
FAU - Bond, Colin W
AU  - Bond CW
AD  - Department of Kinesiology, University of New Hampshire, Durham, NH, USA.
FAU - Cook, Summer B
AU  - Cook SB
AD  - Department of Kinesiology, University of New Hampshire, Durham, NH, USA.
LA  - eng
GR  - R15 AG040700/AG/NIA NIH HHS/United States
PT  - Journal Article
PT  - Research Support, N.I.H., Extramural
DEP - 20170807
PL  - England
TA  - Exp Gerontol
JT  - Experimental gerontology
JID - 0047061
SB  - IM
MH  - Age Factors
MH  - Aged
MH  - Aged, 80 and over
MH  - *Aging
MH  - Exercise Test
MH  - Female
MH  - Geriatric Assessment
MH  - Humans
MH  - Knee Joint/*physiopathology
MH  - Male
MH  - *Mobility Limitation
MH  - *Muscle Contraction
MH  - *Muscle Strength
MH  - Muscle Strength Dynamometer
MH  - Muscle Weakness/diagnosis/*physiopathology
MH  - Muscle, Skeletal/*physiopathology
MH  - Risk Factors
MH  - *Walking
PMC - PMC5664955
MID - NIHMS900617
OTO - NOTNLM
OT  - Aging
OT  - Imbalance
OT  - Laterality of function
OT  - Lower-extremity function
OT  - Strength
OT  - Symmetry
COIS- Conflicts of Interest: The authors report no conflicts of interest.
EDAT- 2017/08/12 06:00
MHDA- 2018/06/05 06:00
PMCR- 2018/11/01
CRDT- 2017/08/12 06:00
PHST- 2017/02/14 00:00 [received]
PHST- 2017/06/29 00:00 [revised]
PHST- 2017/08/06 00:00 [accepted]
PHST- 2017/08/12 06:00 [pubmed]
PHST- 2018/06/05 06:00 [medline]
PHST- 2017/08/12 06:00 [entrez]
PHST- 2018/11/01 00:00 [pmc-release]
AID - S0531-5565(17)30175-4 [pii]
AID - 10.1016/j.exger.2017.08.008 [doi]
PST - ppublish
SO  - Exp Gerontol. 2017 Nov;98:54-61. doi: 10.1016/j.exger.2017.08.008. Epub 2017 Aug 
      7.