Muscle strength can better differentiate between gradations of functional performance than muscle quality in healthy 50-70y women.
Peter Francis, William McCormack, Clodagh Toomey and 2 others
PMID 28709586WHAT IT FOUND
In healthy women aged 50 to 70, knee extensor strength was a better marker of functional performance than strength per unit of muscle tissue.
Lower limb strength testing may be a practical way to identify those with poorer walking and chair-rise ability.
Key findings
01Knee extensor strength explained 36% of the variation in extended gait speed, compared with 16% for muscle quality.
02Women in the highest knee extensor strength tertile had mean gait speed 2.6 m/s, compared with 2.1 m/s in the lowest tertile.
03Upper leg lean tissue mass was not associated with functional performance.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
The sample was small, convenience based, and included only healthy women aged 50 to 70 from a university community. The study looked at people at one time point, and the authors note survival bias, meaning the women who were healthy enough to take part may have influenced the results. It did not assess cognitive function, menopause stage, habitual physical activity, cardiorespiratory capacity, or muscle oxidative capacity. Maximal gait speed allowed walking, jogging, or running, so the chosen mode may have over or underestimated speed. DXA was used to estimate lean tissue mass, and the authors note DXA may underestimate age-related change in skeletal mass. The tertile analyses used only 42 to 43 women per group.
Declared interests
The authors declare no conflicts of interest.
The easy way to misread this
Do not read this as evidence that knee extensor strength caused better function or that strength training will improve walking and chair-rise performance. The study was cross-sectional and included only healthy women aged 50 to 70 recruited from a university community.