Height estimation using forearm and lower leg lengths in healthy young individuals.
Minami Sato, Atsuya Otsuka, Takayoshi Saito and 1 others
PMID 41700151WHAT IT FOUND
Tape-measuring forearm and lower-leg length together estimated standing height in 81 healthy physical therapy students with an error of ± 4.3 cm.
The equation was reasonably accurate for women and clearly weaker for men.
Key findings
01Adding left forearm and lower-leg length together gave the best prediction of standing height: the equation height = 1.6 × left total length + 67.0 accounted for R² = 0.72 of the variation, with a standard deviation of the error of ± 4.3 cm.
02The approach was far less accurate in men: the male equation accounted for only R² = 0.34 of the variation, and forearm length on its own barely correlated with height in men (0.299 on the left, 0.362 on the right).
03Applying the previously published formula developed for hospitalised older adults to these young students overestimated height, by an average of 0.5 to 1.1 cm depending on the side measured.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
All 81 participants were second-year students in one physical therapy department at one university, so the results may not hold for other ages, occupations or ethnic groups. The estimate was much poorer in men, where the equation accounted for only R² = 0.34 of the variation; the authors say it should be applied to all young men only with caution and that forearm length in men may be distorted by muscle and soft tissue over the bone. The spread of the error was ± 4.3 cm, which the authors say limits use where high precision is needed. Measurements were taken only once, with the authors relying on reliability figures published elsewhere rather than checking repeatability in this sample.
Declared interests
The authors declare no competing interests relevant to the contents of this article. No funding source is stated in the text supplied.
The easy way to misread this
Do not read R² = 0.72 as meaning this formula is accurate for every patient. In the men in this study the equation accounted for only R² = 0.34 of the variation in height, and the authors themselves say it should be used in all young men only with caution.
Summarised by AI from the full paper, without a clinician reviewing it. Check it against the source before it changes what you do. Read it on PubMed →