09/02/2026
Quick question for anyone over 40 — when did you last leave the ground on purpose?
Because a box jump isn't a party trick. It's a stress test for the thing that ages first.
Most people assume aging takes strength. It doesn't — not first. It takes power: force x speed. Strength declines roughly 1–2% a year past midlife. Power declines about twice as fast.
The reason is fibre-specific. Type II "fast-twitch" fibres — the ones that fire hard and fast — atrophy earlier and more severely than the slow-twitch fibres that carry a walk or a bike ride. Add the motor units that drop out with age, and you don't just get weaker. You get slower to produce force.
That quality is called rate of force development, and it's what decides whether you catch yourself on a stumble or go down. It's also the quality nobody trains.
Steady-state cardio won't defend it. Neither will a leg press moved slowly. Fast-twitch fibres respond to speed and intent — loaded slowly, they stay quiet.
Which is why jumps are programmed into my clients' training in their 40s, 50s and 60s. Scaled to the person. A step-up. A low box. A hard med-ball throw. The height was never the point. The speed is.
Train for function, not just fitness.
📍 Body In Fushion — private one-on-one training and longevity, Edmonton
Book a session: bodyinfushion.com or call 780-242-6846
