Ageing erodes physiological safety margins towards the thresholds for impaired mobility
Why build strength in midlife if you are not weak yet?
The finding
Lower-limb explosive power declines with age towards thresholds for impaired functional mobility. Good midlife strength may keep people above the threshold of disability for longer.
- Authors
- Young A; Rantanen T, et al.; Buchner DM, et al.
- Published
- Philosophical Transactions of the Royal Society B 352(1363):1837–43 · 1997
- Evidence
- Read in the primary source; numbers checked.
- Source
- doi.org/10.1098/rstb.1997.0169
How it was studied
Young: a narrative review of ageing and physiological function. Supporting studies: Rantanen 1999 (Honolulu Heart Program) and Buchner 1996 (409 adults aged 60–96).
The numbers
Rantanen and colleagues, who followed 6,089 men for 25 years, describe midlife strength as giving "a greater safety margin above the threshold of disability".
Buchner and colleagues found a non-linear link between leg strength and gait speed: in stronger people strength was unrelated to gait speed, in weaker people it was related. Small changes in capacity matter a lot near the threshold and little above it.
What it does not show
Young is a narrative review; Rantanen is men only and about grip. None of these sets a numeric target for any test in the app.
What Longstanding does with it
This is the reasoning behind a line rather than a pass mark: the aim is to stay far enough above the threshold that the decline of the last decade does not cross it.