Can you keep expressing quality as the game gets longer?

What Sustain is

Sustain is your engine: the ability to repeat quality efforts, resist fatigue, and recover between plays, games, and training days. It's the capacity that decides whether the athlete who shows up in the first five minutes is the same one who shows up in the last five.

We test it in three groups:

• Aerobic capacity — the base engine. It powers recovery between every sprint, shift, and rep, not just distance running.
• Anaerobic repeatability — can you sprint, recover for twenty seconds, and sprint again at nearly the same speed? Games are made of exactly this.
• Muscular endurance — how long your strength lasts. Push-ups and pull-ups live here: not how strong you are once, but how long you can stay strong.

The part most training skips

Watch any youth game and you'll see it: the athlete who was electric early, invisible late. Nothing “went wrong” — their engine just couldn't fund their talent for four quarters.

Here's what makes Sustain interesting to test: fatigue doesn't only make you slower. It makes you lower quality — sloppier cuts, longer ground contacts, later reactions. So an athlete's Sustain scores tell us something their highlight reel can't: how much of their athleticism survives when it matters most. And because every other quality we test degrades under fatigue, Sustain quietly protects all of them.

How we measure sustain

One honest note on how we run these: engine testing is demanding, so we schedule it deliberately — often on its own day, always after readiness checks — because a tired test is a wasted test.

What develops it

Aerobic base building, interval work, repeat-sprint training, and muscular-endurance progressions — dosed to your sport's actual demands. A soccer midfielder, a lineman, and a point guard don't need the same engine. Your map tells us which one to build.