APEX PWR  |  Lessons in Longevity

You Booked a DEXA and a VO2 Max. Here Is What They Still Cannot Tell You.

Almost everyone who walks in here for testing arrives with the same two names already in their head. A DEXA scan and a VO2 max. They have read about both, a friend got one, and the underlying motive is nearly always identical even when the words differ.

People want to know whether they are aging well. They want to know whether the next thirty years are going to look like the last ten, and they want a number that tells them before it becomes obvious.

Those two tests are excellent, and we run a lot of them. They also leave a specific gap, and this article is about what sits in it.

What Each of the Famous Two Actually Answers

Here is the gap in one sentence. Two people can have the same lean mass on a DEXA report, within a pound, and one of them can get off the floor holding a toddler while the other needs an arm of the sofa.

The Three Qualities Worth Measuring As You Age

There is reasonable agreement in the aging and performance literature about which physical qualities carry the most weight after about 40, and they separate cleanly into three.

1. Power, which is force produced quickly

Strength is how much you can move. Power is how fast you can produce force. They are trained differently and they decline differently, and the research on aging reports that power declines earlier and more rapidly than maximal strength, and relates more closely to functional performance.

Think about what that means practically. Standing up from a low chair is a power task. Climbing a flight of stairs at a normal cadence is a power task. Catching yourself when your foot clips a kerb is almost entirely a power task, because maximal strength has no time to show up inside a quarter of a second.

How we test it. Two force plates, measuring the force each leg puts into the ground thousands of times per second. A countermovement jump for people who can jump, and a sit-to-stand test for people who cannot or should not. The sit-to-stand version is the quietly important one, because it works for almost anybody at almost any level and still produces a real number rather than a stopwatch impression.

2. Strength, measured where it is cheapest and where it matters most

Grip strength is the famous one. We wrote about it at length in a separate article on grip strength and what it predicts, including the 139,691 person PURE study in which each five kilogram reduction in grip strength was associated with roughly a 16 percent higher risk of death from any cause. If that is new to you, read that one next.

The piece we did not cover there is knee extension. A handheld dynamometer gives a hard number for how much force the muscles on the front of the thigh can produce, each side separately. That matters for two reasons. It is the primary engine for standing, climbing and controlling a descent, and it is the measure that most reliably exposes a weak side that has been quietly compensated for since an old injury you have stopped thinking about.

How we test it. Handheld dynamometry for grip and knee extension, left and right scored independently against reference ranges.

3. Balance and movement capacity

This is the one people skip, and the research on it is the most startling in this article.

A study published in the British Journal of Sports Medicine in 2022 asked 1,702 adults aged 51 to 75 to stand on one leg for ten seconds. Not a long hold. Ten seconds, no support.

One in five, in a group whose average age was 61. People who in every other respect were going about ordinary lives.

The usual caution applies and it is worth stating clearly: this is an observed association in a cohort study, and failing a balance test does not cause anything. Balance is a composite output of the inner ear, vision, joint position sense, ankle and hip strength, and the nervous system that coordinates them, so a poor score is a signal that something upstream is worth examining rather than a verdict in itself.

How we test it. Quiet standing and single leg stance on the plates, which produce a measurement of postural sway rather than a pass or fail. Then walking assessment and a timed up and go, which measures the full sequence of rising from a chair, walking three metres, turning, returning and sitting back down.

The Fourth Thing, Which Is Not a Quality at All

Asymmetry runs underneath all three.

Most people load one side harder than the other without any awareness of it, often as a leftover from an injury that resolved a decade ago. A single whole body number hides this completely, because the strong side quietly covers for the weak one and the total still looks fine.

Two plates see each leg separately. A dynamometer scores each hand and each knee separately. That is how a 23 percent difference between legs shows up on a report instead of showing up as a torn hamstring on a ski trip.

Why the Second Measurement Is Worth More Than the First

One reading tells you where you sit against people your age, which is mildly interesting and occasionally reassuring in a way that is not useful.

Two readings, a year or two apart, tell you your rate of change. A woman at the fiftieth percentile for lower body power at 52 who is still at the fiftieth at 56 is in an entirely different position from one who was at the eightieth and has arrived at the fiftieth, even though their reports on the day look identical. One of them is losing something quickly and has time to do something about it. Nothing on a single report distinguishes them.

This is the same argument we make about bone density and body composition, and it is the reason we would rather test you at 45 than impress you at 70.

What This Looks Like at APEX

All of it sits inside one session, the Longevity Performance Assessment. Power on the plates, strength on the dynamometer, balance and gait measured rather than eyeballed, and asymmetry scored across every bilateral measure.

You leave with two things. A set of numbers scored against reference data and explained to you in person by the person who ran them, and a training plan built from what those numbers say rather than from what a generic program assumes about someone your age.

If you hold DEXA scan pack credits, they spend on this. A credit is a credit, and a good number of people are sitting on unused ones while only ever booking the two tests they already knew the names of.

Frequently Asked Questions