title: Strength and muscle mass loss with aging process. Age and strength loss.
abstract: BACKGROUND
  aging process is associated with changes in muscle mass and strength with decline of muscle strength after the 30(th) life year. The aim of this study was to investigate these changes in muscle mass and strength.
  
  
  METHODS
  for this analysis 26 participants were subdivided in two groups. Group 1 comprises participants aged <40 years (n=14), group 2 those >40 years (n=12). We assessed anthropometrics, range of motions, leg circumferences and isometric strength values of the knee joints.
  
  
  RESULTS
  besides comparable anthropometrics, circumferences and strength were higher in group 1 than in group 2. Circumference of upper leg (20 cm above knee articular space) showed for right leg a trend to a significant (median: 54.45 cm (1(st) quartile: 49.35/3(rd) quartile: 57.78) vs 49.80 cm (49.50/50.75), p=0.0526) and for left leg a significant 54.30 cm (49.28/58.13) vs 49.50 cm (48.00/52.53), p=0.0356) larger circumference in group 1. Isometric strength was in 60° knee flexion significantly higher in group 1 than in group 2 for right (729.88N (561.47/862.13) vs 456.92N (304.67/560.12), p=0.00448) and left leg (702.49N (581.36/983.87) vs 528.49N (332.95/648.58), p=0.0234).
  
  
  CONCLUSIONS
  aging process leads to distinct muscle mass and strength loss. Muscle strength declines from people aged <40 years to those >40 years between 16.6% and 40.9%.
authors.affiliation: Centrum Thrombosis and Haemostasis, University Medical Center Mainz of Johannes Gutenberg-University Mainz, Mainz, Germany ; Department of Medicine 2, University Medical Center Mainz of Johannes Gutenberg-University Mainz, Mainz, Germany.
authors.forename: Karsten
authors.initials: K
authors.lastname: Keller
authors.affiliation: Department for orthopedics, trauma surgery and hand surgery, Klinikum Osnabrück, Osnabrück, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Engelhardt
keywords: age; aging; isometric; muscle; sarcopenia; strength