title: Does upper limb coordination predict walking speed in older adults? A cross-sectional study.
abstract: OBJECTIVE
  Walking speed is a measure of physical function in older adults. Older adults are sometimes nonambulatory, however, and proxy measures for walking speed may be indicated. Since limb coordination tests can be conducted in non-weight-bearing positions, they may provide that capability. The purpose of this study was to examine the relationship between timed limb coordination and preferred and maximum walking speed, controlling for other known determinants of walking speed.
  
  
  METHODS
  A total of 84 healthy adults (60 women and 24 men) older than 60 years participated. Preferred and maximum walking speed were measured during 10-Meter Walk Tests. Upper limb coordination performance was measured during a timed 5-repetition finger-to-nose test. Other variables measured included isometric knee extension strength, cognition (Montreal Cognitive Assessment), limits of stability (Functional Reach Test), the number of comorbidities (Functional Comorbidity Index), age, height, and sex. Multiple regression and partial correlation analyses (α = .05) were used to identify which variables predicted preferred and maximum walking speed, controlling for all other variables.
  
  
  RESULTS
  Participants' mean preferred walking speed was 129 (24) cm·s⁻¹, and mean maximum walking speed was 176 (37) cm·s⁻¹. Finger-to-nose coordination performance, 4.8 (1.3) seconds, correlated negatively with preferred (r = -0.403) and maximum (r = -0.429) walking speed. Those bivariate correlation coefficients, however, were attenuated by other variables in the regression models (partial r = -0.031, P = .786, and partial r = -0.075, P = .513, for preferred and maximum walking speed, respectively). Variance in age, comorbidities, functional reach, knee extension strength, and height accounted for 55.4% of the variance in preferred walking speed. Variance in knee extension strength, cognition, functional reach, age, and comorbidities accounted for 63.5% of the variance in maximum walking speed. After removing knee extension strength and functional reach from the models--those variables that may be difficult or contraindicated to measure in some patient populations--finger-to-nose coordination was not a statistically significant predictor of preferred walking speed. Variance in age, comorbidities, cognition, height, and finger-to-nose coordination accounted for 55.9% of the variance in maximum walking speed. The change in R² attributed to finger-to-nose coordination performance, however, was only 2.9%.
  
  
  CONCLUSIONS
  While knee extension strength, functional reach, comorbidities, and age were most predictive of walking speed, after removing knee extension strength and functional reach from the regression models, finger-to-nose coordination remained a potentially modifiable marker of neuromuscular control that only weakly predicted maximum walking speed in older adults.
  
  
  CONCLUSIONS
  The timed finger-to-nose test would not appear to be a valid proxy for walking speed when weight-bearing clinical examination procedures are contraindicated.
authors.affiliation: Program in Physical Therapy, Department of Physical Medicine & Rehabilitation, Mayo Clinic College of Medicine, Rochester, Minnesota.
authors.forename: John H
authors.initials: JH
authors.lastname: Hollman
authors.forename: Katherine C
authors.initials: KC
authors.lastname: Beed
authors.forename: Ryan J
authors.initials: RJ
authors.lastname: Buus
authors.forename: Kenzie L
authors.initials: KL
authors.lastname: Schleicher
authors.forename: Desiree J
authors.initials: DJ
authors.lastname: Lanzino
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001132:Arm / Q000502:physiology*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009536:Niacinamide / Q000031:analogs & derivatives; D010879:Piperazines; D011597:Psychomotor Performance / Q000502:physiology*; D016059:Range of Motion, Articular / Q000502:physiology; D016138:Walking / Q000502:physiology*
chemical_list: C523280:AD 101; D010879:Piperazines; D009536:Niacinamide