title: Measuring grip strength in older adults: comparing the grip-ball with the Jamar dynamometer.
abstract: OBJECTIVE
  Decreased grip strength is a predictor of adverse outcomes in older adults. A Grip-ball was developed that can be used for home-based self-monitoring of grip strength to detect decline at an early stage. The purpose of this study was to evaluate the reliability and validity of measurements obtained with the Grip-ball in older adults.
  
  
  METHODS
  Forty nursing home patients and 59 community-dwelling older adults 60 years or older were invited to participate in this study. Grip strength in both hands was measured 3 consecutive times during a single visit using the Grip-ball and the Jamar dynamometer. Test-retest reliability was described using intraclass correlation coefficients. Concurrent validity was evaluated by calculating Pearson correlations between the mean Grip-ball and Jamar dynamometer measurements and between the highest measurements out of 3 trials. Known-groups validity was studied using t tests.
  
  
  RESULTS
  Eighty eight participants (33 men) with a mean age of 75 (SD = 6.8) years were included. Intraclass correlation coefficients for the Grip-ball were 0.97 and 0.96 for the left and right hands, respectively (P < .001), and those for the Jamar dynamometer were 0.97 and 0.98 for the left and right hands, respectively (P < .001). Pearson correlations between the mean scores of the Grip-ball and the Jamar dynamometer were 0.71 (P < .001) and 0.76 (P < .001) for the left and right hands, respectively. Pearson correlations between the highest scores out of 3 trials were 0.69 (P < .001) and 0.78 (P < .001) for the left and right hands, respectively. The t tests revealed that both the Grip-ball and the Jamar dynamometer detected grip strength differences between men and women but not between nursing home patients and community-dwelling older adults. Grip-ball measurements did not confirm higher grip strength of the dominant hand whereas the Jamar dynamometer did.
  
  
  CONCLUSIONS
  The Grip-ball provides reliable grip strength estimates in older adults. Correlations found between the Grip-ball and Jamar dynamometer measurements suggest acceptable concurrent validity. The Grip-ball seems capable of detecting "larger" grip strength differences but might have difficulty detecting "smaller" differences that were detected by the Jamar dynamometer. The Grip-ball could be used in practice to enable home-based self-monitoring of grip strength in older adults. However, for implementation of the Grip-ball as a screening and monitoring device in practice, it is important to gain insight into intersession reliability during home-based use of the Grip-ball and clinical relevance of changes in grip strength.
authors.affiliation: 1Department of Health Services Research, School for Public Health and Primary Care (CAPHRI), Maastricht University, Maastricht, the Netherlands. 2Research Center Technology and Care, Zuyd University of Applied Sciences, Heerlen, the Netherlands. 3Institute Charles Delaunay, Université de Technologie de Troyes, Troyes, France.
authors.forename: Joan
authors.initials: J
authors.lastname: Vermeulen
authors.forename: Jacques C L
authors.initials: JC
authors.lastname: Neyens
authors.forename: Marieke D
authors.initials: MD
authors.lastname: Spreeuwenberg
authors.forename: Erik
authors.initials: E
authors.lastname: van Rossum
authors.forename: David J
authors.initials: DJ
authors.lastname: Hewson
authors.forename: Luc P
authors.initials: LP
authors.lastname: de Witte
mesh_terms: D000368:Aged; D005260:Female; D015577:Geriatric Assessment / Q000379:methods; D018737:Hand Strength / Q000502:physiology; D006801:Humans; D008297:Male; D053581:Muscle Strength Dynamometer; D015203:Reproducibility of Results