Tell a doctor you want to know your risk of an early death, and the test you’ll get almost never moves fast. It measures how much you can do — how hard you can squeeze, how heavy you can lift. It never asks the question that a decade of data now says matters more: how quickly can you do it?

Muscle power — force multiplied by speed — beats raw strength as a predictor of mortality, and most men over 40 don’t train it at all. They train the slow half, the heavy half, and leave the speed half to waste away.

The Number Strength Hides

Strength and power sound like the same thing. They aren’t, and the difference is the whole point.

  • Strength is the maximum force you can produce, at any speed. A heavy deadlift. A hard handgrip squeeze.
  • Power is force velocity — how fast you can recruit that force. A deadlift moved slowly is strength. A sandbag moved explosively is power.

Why does speed matter for how long you live? Because power declines roughly twice as fast as strength as you age. You lose the speed of force long before you lose the amount of it — and the speed is what gets you off a chair, up a flight of stairs, or braced before a fall. Strength asks “can you lift it.” Power asks “can you move it in time.” The second question is the one that keeps people alive and independent.

The Study That Reframed the Message

The evidence is a 2025 study in Mayo Clinic Proceedings — the CLINIMEX Exercise cohort, following 3,888 men and women aged 46 to 75 for a median of 10.8 years.

Researchers measured both halves — muscle power and muscle strength — and watched who died. The result, adjusted for age, body composition, and multiple health conditions:

  • Relative muscle power in the lowest group predicted nearly six times greater mortality risk in men (hazard ratio 5.88, P < .001) and nearly seven in women (6.90).
  • Relative strength in the lowest group predicted a hazard ratio of 1.62 in men — with a confidence interval that crosses 1 and a P value of .11, meaning it was not a statistically significant predictor in this cohort.

Read that again. In the same people, over the same decade, power was a strong signal and strength barely registered. The men and women carrying the most muscle power outlived the ones who could only squeeze or lift slowly — even when their raw strength looked fine.

That’s the quiet warning for a 40-something man: your strength number can look healthy while your power — the thing that actually predicts the next ten years — is quietly eroding.

How to Train the Speed Half

Power is a trainable quality, and it’s not a matter of going maximal-effort heavy every session. The lever is speed against sub-maximal load, not more weight.

  1. Move lighter loads fast. A classic, trainable dose is ~40–50% of your 1-repetition maximum, moved as explosively as you safely can. You’re not chasing failure; you’re chasing speed of the bar.
  2. Pick the right movements. Power lives in big, fast patterns — a weighted upper-row moved explosively (the exact movement the study measured), loaded jumps, medicine-ball throws, sled pushes. Not slow, grind-out isolation work.
  3. Two or three hard speed sets, fresh. Power is a neurological quality. It’s best trained at the start of a session, when you’re fresh — not as a finisher when you’re already fatigued.
  4. Don’t chase soreness. If you’re wrecked the next day, you trained fatigue, not power. Power sessions feel short and crisp, and they should.

The trap is treating power as “just train heavy.” Heavy forces you to move slow. What you want is the opposite — sub-maximal and fast.

The Decade-Scale Point

A strength-only plan is training half the signal. It builds the muscle that looks right and lifts heavy, but it lets the thing that predicts your lifespan — the speed of force — slip first, quietly, for years.

For a man planning his next decade instead of his next six weeks, the message is simple: train the number that predicts your longevity, and don’t forget the speed half. Strength is the engine; power is how fast you can use it — and the speed is what you’ll miss when you need it most.

If you’ve only been tracking the slow half, start with the other longevity number: grip strength, the mortality signal most lifters ignore. That post covers the amount of force; this one covers the speed of it — train both, and you’ve covered the full signal. If you’re newer to the gym and need a foundation first, start with how to strength-train after 40.

Sources

  • Araújo CGS, Kunutsor SK, et al. Muscle Power Versus Strength as a Predictor of Mortality in Middle-Aged and Older Men and Women. Mayo Clinic Proceedings. 2025;100(8):1319–1331. doi:10.1016/j.mayocp.2025.02.015. — CLINIMEX cohort, n=3,888 (ages 46–75, 67.8% men), median 10.8 years follow-up; lowest vs highest relative power HR 5.88 (men, P<.001) and 6.90 (women); strength HR 1.62 (men, P=.11)/1.71 (women, P=.31), non-significant. Power measured via upper-row movement with a FitroDyne device; strength via handgrip.
  • Mayo Clinic Proceedings editorial: “The Need for Speed: Improving Muscle Power for Longevity.” 2025. — contextual review confirming power as a stronger mortality predictor than strength, and the clinical case for moving power assessment into standard practice.