title: Reproducibility and relationship of single-joint strength vs multi-joint strength and power in aging individuals.
abstract: BACKGROUND
  Reliable and sensitive muscle strength/power assessments are essential when evaluating age-related and/or training-induced changes in maximal strength and power.
  
  
  OBJECTIVE
  To investigate the reproducibility and inter-relationship of single-joint isokinetic/isometric leg muscle strength vs multi-joint mechanical muscle function during counter-movement jump (CMJ) in moderately trained aging individuals (age 72.3+/-6.6).
  
  
  RESULTS
  The within-subject coefficient of variation (CV(w-s)) for the single-joint test showed good reproducibility (<10%) for quadriceps and hamstring strength (except for hamstring isometric). Plantar flexion demonstrated good to moderate reproducibility (CV(w-s) range: 10.4-17.2%). Excellent to good CV(w-s) (<10%) was observed for all concentric CMJ parameters, except for plantar flexor mean work (CV(w-s)=13%). Eccentric CMJ parameters demonstrated good to moderate reproducibility (CV(w-s) range: 8.1-18.2%). Isokinetic and isometric quadriceps, hamstring and plantar flexor single-joint strength measurements were found to correlate with several CMJ parameters.
  
  
  CONCLUSIONS
  Single-joint and multi-joint strength and power assessment tests of the lower limbs appear to be reproducible in aging individuals. Furthermore, associations between single-joint strength and multi-joint CMJ power and force variables exist. To evaluate functional capacity in elderly people further investigations must be carried out to identify specific power/strength parameters that are most tightly linked to functional performance.
authors.affiliation: Centre of Applied and Clinical Exercise Sciences, Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense M, Denmark. ahlarsen@health.sku.dk
authors.forename: A
authors.initials: A
authors.lastname: Holsgaard Larsen
authors.forename: P
authors.initials: P
authors.lastname: Caserotti
authors.forename: L
authors.initials: L
authors.lastname: Puggaard
authors.forename: P
authors.initials: P
authors.lastname: Aagaard
mesh_terms: D000375:Aging / Q000502:physiology*; D000704:Analysis of Variance; D005260:Female; D006801:Humans; D007537:Isometric Contraction / Q000502:physiology; D007866:Leg / Q000502:physiology*; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000502:physiology*; D015203:Reproducibility of Results