Capacity 03 · Maintain Function
Signal · ALMI
The muscle you carry into aging.
ALMI measures the lean mass in your arms and legs, normalized to height. It is the clearest readout of skeletal muscle reserve — and skeletal muscle is the organ of metabolic health, glucose disposal, strength, and independence into the later decades.
The ranges that matter
Three bands. One direction.
What matters most is the direction over time under the same conditions — is the number trending toward the Fit band, or drifting away from it?
Fit / Optimal
M ≥ 8.0 · W ≥ 6.0
Strong reserve. Meets or exceeds the threshold protective against sarcopenia. A wide margin into aging.
Well
M 7.0 – 8.0 · W 5.5 – 6.0
Adequate for now, narrow margin into aging. Worth actively building — muscle does not come back easily past 50.
Sick / At Risk
M < 7.0 · W < 5.5 (severe M<6.0, W<4.5)
Low relative muscle mass. Sarcopenia threshold. Function, insulin sensitivity, and injury resilience are at risk.
What it reveals
Muscle is the organ of healthy aging.
Skeletal muscle is not just what moves you. It is where most glucose is disposed of, where most amino acids are stored, and where the reserve lives that you draw on when you are sick, injured, or old.
After about age 30, humans lose muscle and strength slowly unless they actively work against it. The decline accelerates after 60. Sarcopenia — clinically low muscle mass — doesn't announce itself. It reveals itself when someone falls and can't recover.
ALMI normalizes the muscle in your arms and legs to your height, which makes it comparable across people. A higher ALMI at 40 predicts better function at 70 — not because you'll always have that muscle, but because the curve starts higher and declines from there.
This sits in Maintain Function because muscle reserve is the single most modifiable determinant of how well you live into the later decades. Everything you build now becomes the margin you draw on later.
On the floor
If you are in your forties or fifties and ALMI is in the 'Well' band, treat that as an opportunity, not a reassurance. The cheapest muscle to build is the muscle you build now — and the reserve compounds for the next thirty years.
What moves it
Work the system, not the number.
First levers
- Resistance training 2–4 sessions per week, progressively loaded.
- Protein at 0.7–1.0 g per pound of target weight, spread across meals.
- Train the big compound patterns — squat, hinge, press, pull, carry.
- Prioritize recovery quality; muscle is built between sessions.
Second levers
- Creatine monohydrate supports strength and mass in trained adults.
- Manage overtraining; chronic excess catabolizes lean tissue.
- Vitamin D sufficiency supports muscle function and recovery.
- Re-scan every 6–12 months. Protect the trajectory.
Why it sits with "Maintain Function"
ALMI is one of four Maintain Function markers. Read with
BMD,
Grip Strength, and
Body Fat %, it reveals whether function and reserve are holding.
Go deeper
Coaching and education only. Not medical diagnosis or treatment. Excerpts welcome with attribution to metabolicradar.com.