title: Handgrip strength does not represent an appropriate measure to evaluate changes in muscle strength during an exercise intervention program in frail older people.
abstract: BACKGROUND
  Although handgrip strength is considered a strong predictor of negative health outcomes, it is unclear whether handgrip strength represents a useful measure to evaluate changes in muscle strength following resistance-type exercise training in older people. We assessed whether measuring handgrip strength provides proper insight in the efficacy of resistance-type exercise training to increase muscle mass, strength, and physical performance in frail older people.
  
  
  METHODS
  Prefrail and frail older people (≥ 65 y) were either conducting a 24-week resistance-type exercise training or no exercise training. Before, during, and after the intervention, handgrip strength (JAMAR), lean body mass (DXA), leg strength (1-RM), and physical performance (SPPB) were assessed.
  
  
  RESULTS
  Handgrip strength correlated with appendicular lean mass (r = 0.68; p < .001) and leg strength (r = 0.67; p < .001). After 24 weeks of whole body resistance-type exercise training, leg extension strength improved significantly better when compared with the control group (57 ± 2-78 ± 3 kg vs 57 ± 3-65 ± 3 kg: p < .001). Moreover, physical performance improved significantly more in the exercise group (8.0 ± 0.4-9.3 ± 0.4 points) when compared with the control group (8.3 ± 0.4-8.9 ± 0.4 points: p < .05). These positive changes were not accompanied with any significant changes in handgrip strength (26.3 ± 1.2-27.6 ± 1.2 kg in the exercise group vs 26.6 ± 1.2-26.3 ± 1.3 kg in the control group: p = .71).
  
  
  CONCLUSIONS
  Although handgrip strength strongly correlates with muscle mass and leg strength in frail older people, handgrip strength does not provide a valid means to evaluate the efficacy of exercise intervention programs to increase muscle mass or strength in an older population.
authors.affiliation: Top Institute Food and Nutrition, Wageningen, Netherlands.
authors.forename: Michael
authors.initials: M
authors.lastname: Tieland
authors.forename: Lex B
authors.initials: LB
authors.lastname: Verdijk
authors.forename: Lisette C P G M
authors.initials: LC
authors.lastname: de Groot
authors.forename: Luc J C
authors.initials: LJ
authors.lastname: van Loon
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015930:Diet Records; D005260:Female; D016330:Frail Elderly; D015577:Geriatric Assessment / Q000379:methods*; D018737:Hand Strength; D006801:Humans; D057194:Intention to Treat Analysis; D007866:Leg; D008297:Male; D024510:Muscle Development; D053580:Muscle Strength; D010349:Patient Compliance; D010352:Patient Dropouts; D011597:Psychomotor Performance; D055070:Resistance Training; D055948:Sarcopenia / Q000628:therapy*