Lean body mass calculator

Lean body mass (LBM) from height, weight and sex by the Boer, James and Hume formulas, with the implied body fat percentage.

更新于 已验证的示例:4

Accepts 5'11" or 5 ft 11 in
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Lean body mass (Boer)
kg
Lean body mass (Boer): 56.0 kg
小数位数:1;取最近值,等距时取偶数末位
James
56.5kg
Hume
52.8kg
Implied body fat (Boer)
20.0%

About 56 kg of your 70 kg is lean mass by the Boer formula, leaving roughly 20 % as fat; the 3 formulas range from 52.8 to 56.5 kg.

Body composition (Boer)

20%fat
Lean mass56 kgFat mass14 kg
计算方法 S
  1. Inputs in kilograms and centimetres

    w=70 kg,h=175 cmw = 70\ \text{kg},\quad h = 175\ \text{cm}
  2. Boer

    0.407×70+0.267×175−19.2=56.02 kg0.407 \times 70 + 0.267 \times 175 - 19.2 = 56.02\ \text{kg}
  3. James

    1.1×70−128×(70175)2=56.52 kg1.1 \times 70 - 128 \times \left(\frac{70}{175}\right)^2 = 56.52\ \text{kg}
  4. Hume

    0.32810×70+0.33929×175−29.5336=52.81 kg0.32810 \times 70 + 0.33929 \times 175 - 29.5336 = 52.81\ \text{kg}
  5. Implied body fat

    (1−56.0270)×100=20.0%\left(1 - \frac{56.02}{70}\right) \times 100 = 20.0\%

关于Lean body mass calculator

Lean body mass (LBM) is body weight minus fat: muscle, bone, organs, skin and body water. It is estimated here from height, weight and sex with three regression formulas, Boer (1984), James (1976) and Hume (1966). Subtracting the Boer estimate from your weight gives an implied body fat percentage.

Clinicians use LBM to scale some drug doses and fluid volumes, and the Katch-McArdle equation uses it to estimate resting energy needs. For a man weighing 70 kg at 175 cm the three formulas give 52.8 to 56.5 kg, and Boer's 56.0 kg implies about 20 % body fat.

The formulas assume average body composition for a given height and weight, so they cannot see unusual muscle or fat. The James formula peaks and then falls as weight rises, which underestimates lean mass in obesity (Green and Duffull, 2002). A tape or skinfold measurement adds information about your own build.

计算示例

Man, 70 kg, 175 cm

Sex (for the formula)
Male
Weight
70 kg
高度
175 cm
Lean body mass (Boer)
56.0 kg
James
56.5 kg
Hume
52.8 kg
Implied body fat (Boer)
20.0%

核验来源:Python 3.8 decimal: 0.407·70 + 0.267·175 − 19.2; 1.1·70 − 128·(70/175)²; 0.32810·70 + 0.33929·175 − 29.5336

Woman, 60 kg, 165 cm

Sex (for the formula)
Female
Weight
60 kg
高度
165 cm
Lean body mass (Boer)
44.9 kg
James
44.6 kg
Hume
43.4 kg
Implied body fat (Boer)
25.2%

核验来源:Python 3.8 decimal: 0.252·60 + 0.473·165 − 48.3; 1.07·60 − 148·(60/165)²; 0.29569·60 + 0.41813·165 − 43.2933

Obesity: James falls below the others

Sex (for the formula)
Male
Weight
150 kg
高度
175 cm
Lean body mass (Boer)
88.6 kg
James
71.0 kg
Hume
79.1 kg

核验来源:Python 3.8 decimal; James peaks at 1.1·175²/256 = 131.6 kg and declines beyond it (Green & Duffull 2002)

Imperial: 180 lb, 5 ft 10 in woman

Sex (for the formula)
Female
Weight
180 lb
高度
70 in
Lean body mass (Boer)
56.4 kg
James
56.2 kg
Hume
55.2 kg

核验来源:Python 3.8 decimal after 180 lb = 81.6466 kg and 70 in = 177.8 cm

常见问题

Is lean body mass the same as muscle mass?

No. Lean body mass is everything that is not fat: muscle, bone, organs, skin, blood and body water. Skeletal muscle is the largest part but not all of it. In an MRI study of 468 adults, Janssen and colleagues (2000) measured skeletal muscle at 38.4 % of body weight in men and 30.6 % in women, while a man with 20 % body fat has lean mass equal to 80 % of his weight.

How is lean body mass calculated from height and weight?

With a regression formula fitted to measured body composition. Boer's is 0.407 × weight + 0.267 × height − 19.2 for men and 0.252 × weight + 0.473 × height − 48.3 for women, with weight in kg and height in cm. For a 60 kg woman 165 cm tall that gives 44.9 kg, which implies 25.2 % body fat, in the ACE average range for women.

Why does the James formula give low values for heavy people?

Its squared term, 128 × (weight ÷ height)² for men, grows faster than the 1.1 × weight term, so estimated lean mass peaks and then falls as weight rises. At 175 cm the peak for men is at 131.6 kg, and a 150 kg man gets 71.0 kg against Boer's 88.6 kg. Green and Duffull (2002) cautioned against using it as a size descriptor for obese patients.

What is a normal lean body mass percentage?

It is 100 % minus body fat percentage. The American Council on Exercise's average body fat ranges, 18–24 % for men and 25–31 % for women, correspond to lean mass of 76–82 % and 69–75 % of body weight. Athletes sit higher: ACE's athlete ranges of 6–13 % and 14–20 % fat mean 87–94 % and 80–86 % lean mass.

“Lean body mass calculator”有多准确?

准确性取决于输入值和方法的假设。十进制运算使用50位有效数字,但估算、数值方法和源数据的精度可能较低;显示时的舍入并不能消除这些限制。 已按独立来源核验的计算示例:4。 例如,“Man, 70 kg, 175 cm”根据Python 3.8 decimal: 0.407·70 + 0.267·175 − 19.2; 1.1·70 − 128·(70/175)²; 0.32810·70 + 0.33929·175 − 29.5336进行核验。

这种方法出自哪里?

Boer P. Estimated lean body mass as an index for normalization of body fluid volumes in humans. Am J Physiol 1984;247:F632–F636; James WPT. Research on obesity. London: HMSO, 1976 (DHSS/MRC Group report); Hume R. Prediction of lean body mass from height and weight. J Clin Pathol 1966;19:389–391; Green B, Duffull SB. Caution when lean body weight is used as a size descriptor for obese subjects. Clin Pharmacol Ther 2002;72:743–744.

关于此计算器

Boer (M)=0.407w+0.267h−19.2(F)=0.252w+0.473h−48.3James (M)=1.1w−128(wh)2(F)=1.07w−148(wh)2Hume (M)=0.32810w+0.33929h−29.5336(F)=0.29569w+0.41813h−43.2933\begin{aligned}\text{Boer (M)} &= 0.407w + 0.267h - 19.2 & \text{(F)} &= 0.252w + 0.473h - 48.3\\ \text{James (M)} &= 1.1w - 128\left(\tfrac{w}{h}\right)^2 & \text{(F)} &= 1.07w - 148\left(\tfrac{w}{h}\right)^2\\ \text{Hume (M)} &= 0.32810w + 0.33929h - 29.5336 & \text{(F)} &= 0.29569w + 0.41813h - 43.2933\end{aligned}

来源

  1. Boer P. Estimated lean body mass as an index for normalization of body fluid volumes in humans. Am J Physiol 1984;247:F632–F636
  2. James WPT. Research on obesity. London: HMSO, 1976 (DHSS/MRC Group report)
  3. Hume R. Prediction of lean body mass from height and weight. J Clin Pathol 1966;19:389–391
  4. Green B, Duffull SB. Caution when lean body weight is used as a size descriptor for obese subjects. Clin Pharmacol Ther 2002;72:743–744

仅供参考,不构成医疗建议。这些公式描述的是人群,并非您的个人情况;根据结果采取行动前,请咨询医务人员。

已对照来源验证

此计算器包含 4 个已解示例,答案来自独立来源。这些示例会在测试套件中运行,你也可以在此运行验证。

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