Most endurance athletes fall into the same loop. They figure out race pace, they grind race pace, and they hope that if they repeat it enough times it’ll start to feel easier. Sometimes it works. More often, it just makes you really good at being tired.
A better way to think about performance is this: the goal isn’t to suffer better at race pace. The goal is to make race pace cheaper. More controllable. More repeatable. And that comes down to one thing—your speed reserve.
Speed reserve is simply the gap between what you can do at the top end and what you need to do on race day. The bigger that gap, the calmer your race pace feels. When your ceiling is low, race pace sits uncomfortably close to your limit. Every little surge spikes you. Hills cost more than they should. Late-race fatigue shows up early and refuses to leave. But when your ceiling rises, the same pace becomes manageable. It’s not that the race gets easy—it’s that you stop living on the edge the whole time.
This isn’t just a “5K speed” concept either. Speed reserve matters just as much for Ironman, marathons, 70.3, HYROX, and long-course work because those events punish inefficiency. If your race pace is too close to your ceiling, you spend the entire day paying interest.
Where most athletes get stuck is the middle. The gray zone. Not easy enough to recover, not hard enough to move the needle, just hard enough to feel productive. It looks responsible on paper and feels like “real work” in the moment. But when most of your training lives there, your performance range starts to shrink instead of expand. You get tougher, sure. You get better at suffering. But you don’t necessarily get better at performing.
Building speed reserve means training the full spectrum. Easy training has to be easy. It builds the base, improves durability, and lets you stack volume without breaking down. It’s not flashy, and it doesn’t give you that “I crushed it” feeling—but it’s the part that makes everything else work. Then you need real high-intensity work—the kind that actually raises the ceiling. Short hard intervals, repeats, strides, VO₂-type efforts. That work gives you gears you didn’t have before. It makes submaximal pace less expensive. It’s the difference between hanging on and having options.
And yes, threshold and tempo still matter. They’re just not supposed to dominate. Think of threshold as the bridge between the base and the ceiling: easy work builds the engine, hard work raises the ceiling, and threshold teaches you how to use what you’ve built. Used strategically, it’s powerful. Used obsessively, it becomes a rut.
If you look at how high-level endurance athletes train across sports—running, cycling, rowing, triathlon, skiing—you see the same pattern: a lot of easy work, a smaller amount of very hard work, and less time than most people expect stuck in the moderate zone. Not because it’s trendy, but because it expands the athlete’s usable range and lowers burnout.
On race day, a bigger speed reserve shows up in obvious ways. Pace feels calmer. Hills don’t feel like emergencies. Surges don’t send you into panic mode. You can respond instead of just survive. And late-race fatigue shows up later—or at least you’re not falling apart the first time the course asks a question.
There’s also a mindset shift that comes with it. When you know you’ve trained above race pace—when you know you have gears—you stop racing scared. You don’t live on the red line all day. You execute. You stay patient. You make decisions instead of reacting.
So if you want better performance without burning yourself into the ground, keep your easy days truly easy. Include real high-intensity work to raise your ceiling. Use threshold with purpose, not as a default. Stop trying to make every session feel important. Start thinking in terms of range, not just race specificity.
Because the goal isn’t to get better at suffering at race pace. The goal is to widen the gap between what you can do and what you need to do.
That gap is your edge.