title: A novel protocol to test age-related decreases in sit-to-stand movement abilities in healthy subjects.
abstract: BACKGROUND
  The development of simple approaches to quantitatively estimate functional motor performance in a wide range of ages is crucial for early detection of locomotive syndrome (LS). Sit-to-stand (STS) movements from a chair are important in activities of daily living (ADL), although such tasks are the most mechanically demanding among all ADL. Here, we propose a novel test to score STS abilities to estimate individual functional motor status and investigated age-related changes in STS scores as a method to evaluate reduction in performance.
  
  
  METHODS
  A total of 606 healthy subjects (average age, 48.4 years; age range, 20-87 years) without neuromusculoskeletal disorders participated in the study. We designed a test to score STS abilities, based on STS determinant variables, including seat height, foot positioning, and both-leg- or one-leg-standing tasks. STS scores ranged from 0 to 14 points, depending on the difficulty or mechanical demands of the STS task. We evaluated the STS score of the subjects divided into seven 10-year age groups.
  
  
  RESULTS
  A significant and negative correlation was observed between STS scores and subject age (men: r = -0.65, P < 0.001; women: r = -0.62, P < 0.001). The proportion of subjects able to stand on one leg from a chair seat height of 100% of knee height decreased with age from 100% for both men and women aged 20-29 years to 0.0% and 7.1% for men and women aged 80-87 years, respectively. A large variation in STS scores was observed for subjects aged >60 years. There was a negative linear correlation between mean STS score per age group and mean age (men: R(2) = 0.93, slope = -0.10, intercept = 16.63 points; women: R(2) = 0.92, slope = -0.08, intercept = 14.76 points).
  
  
  CONCLUSIONS
  The ability to perform STS was negatively correlated with age among healthy subjects aged 20-87 years. For subjects aged >60 years, STS abilities decreased, but within-group variability increased. This test was useful to identify the deterioration of functional motor performance and prevent early LS.
authors.affiliation: Organization for Promotion of Tenure Track, University of Miyazaki, 1-1 Gakuen-kibanadai-nishi, Miyazaki, 889-2192, Japan. Electronic address: g.yamako@cc.miyazaki-u.ac.jp.
authors.forename: Go
authors.initials: G
authors.lastname: Yamako
authors.affiliation: Department of Mechanical Design Systems, Faculty of Engineering, University of Miyazaki, Miyazaki, 889-2192, Japan.
authors.forename: Gang
authors.initials: G
authors.lastname: Deng
authors.affiliation: Department of Medicine of Sensory and Motor Organs, Division of Orthopedic Surgery, Faculty of Medicine, University of Miyazaki, Miyazaki, 889-1692, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Totoribe
authors.affiliation: Department of Medicine of Sensory and Motor Organs, Division of Orthopedic Surgery, Faculty of Medicine, University of Miyazaki, Miyazaki, 889-1692, Japan.
authors.forename: Etsuo
authors.initials: E
authors.lastname: Chosa
mesh_terms: D000203:Activities of Daily Living; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002985:Clinical Protocols; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D008875:Middle Aged; D051346:Mobility Limitation; D009043:Motor Activity / Q000502:physiology*; D011187:Posture; D015203:Reproducibility of Results; D018570:Risk Assessment; D055815:Young Adult