title: Relationship between strength, power and balance performance in seniors.
abstract: BACKGROUND
  Deficits in strength, power and balance represent important intrinsic risk factors for falls in seniors.
  
  
  OBJECTIVE
  The purpose of this study was to investigate the relationship between variables of lower extremity muscle strength/power and balance, assessed under various task conditions.
  
  
  METHODS
  Twenty-four healthy and physically active older adults (mean age: 70 ± 5 years) were tested for their isometric strength (i.e. maximal isometric force of the leg extensors) and muscle power (i.e. countermovement jump height and power) as well as for their steady-state (i.e. unperturbed standing, 10-meter walk), proactive (i.e. Timed Up & Go test, Functional Reach Test) and reactive (i.e. perturbed standing) balance. Balance tests were conducted under single (i.e. standing or walking alone) and dual task conditions (i.e. standing or walking plus cognitive and motor interference task).
  
  
  RESULTS
  Significant positive correlations were found between measures of isometric strength and muscle power of the lower extremities (r values ranged between 0.608 and 0.720, p < 0.01). Hardly any significant associations were found between variables of strength, power and balance (i.e. no significant association in 20 out of 21 cases). Additionally, no significant correlations were found between measures of steady-state, proactive and reactive balance or balance tests performed under single and dual task conditions (all p > 0.05).
  
  
  CONCLUSIONS
  The predominately nonsignificant correlations between different types of balance imply that balance performance is task specific in healthy and physically active seniors. Further, strength, power and balance as well as balance under single and dual task conditions seem to be independent of each other and may have to be tested and trained complementarily.
authors.affiliation: Department of Training and Movement Science, University of Potsdam, Potsdam, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Muehlbauer
authors.forename: Carmen
authors.initials: C
authors.lastname: Besemer
authors.forename: Anja
authors.initials: A
authors.lastname: Wehrle
authors.forename: Albert
authors.initials: A
authors.lastname: Gollhofer
authors.forename: Urs
authors.initials: U
authors.lastname: Granacher
mesh_terms: D000058:Accidental Falls / Q000517:prevention & control; D000368:Aged; D000375:Aging / Q000502:physiology*; D001696:Biomechanical Phenomena / Q000502:physiology; D005260:Female; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D007866:Leg; D008297:Male; D053580:Muscle Strength / Q000502:physiology*; D004856:Postural Balance / Q000502:physiology*; D012307:Risk Factors