From One Finish Line to the Next: Using the Riegel Model to Plan Smart Pacing
We use a simple power-law to bridge the gap between two distances so we can plan with confidence. The idea is straightforward: your current performance anchors reality; the training factor adjusts how that performance scales as the distance changes. With a few careful inputs, we turn a personal best or recent race into a practical pacing plan for the next challenge.
Why a power-law works for racing
As distance grows, time rises faster than linearly—fatigue and fueling play bigger roles, and efficiency shifts with pace. A power-law captures that curvature without demanding lab data. It isn’t perfect, but it is consistent, which is the key to making good decisions across training blocks and courses.
Choosing a sensible training factor
The exponent k encodes how your fitness scales. Runners with strong endurance often sit on the low side (≈1.03–1.05), while speed-leaning profiles may live higher (≈1.07–1.10). We tune k with experience: if predictions for longer races are too fast, raise it slightly; if they’re conservative, lower it. Keep notes—your value tends to remain stable across a season with similar training volume.
Turning predictions into workouts
Once we have a target pace, we build repeatable workouts around it. For a 10K, cruise intervals at or just slower than race pace teach rhythm without excessive strain. For a half or marathon, long runs at portions of goal pace—layered with fueling practice—teach economy and gut readiness. The prediction isn’t a promise; it’s a north star for the next few weeks.
Course, conditions, and realism
A flat, cool course behaves differently from a rolling route in the sun. We consider elevation, surface, wind exposure, and congestion. If conditions look hot or hilly, we nudge the pace modestly. It’s better to finish strong than to chase a number that the day won’t allow.
Fueling and long-distance pacing
Beyond the half marathon, fueling and hydration dominate outcomes. Even pacing assumes a steady energy supply; under-fueling turns even plans into positive splits. We practice gel timing, electrolyte intake, and bottle handling in training so race day feels familiar. A small plan beats a big guess.
Adapting the model to you
The best projection is the one you iterate. After each key effort, compare predicted and actual results. Adjust k by a hundredth or two. Over a season, your personal factor will settle—and your pacing calls will become uncannily accurate.
Putting it all together
We anchor predictions in what we’ve already done, layer in what the course and weather demand, and keep the plan honest with recent workouts. The goal is not to be perfect; it’s to be prepared. With a clear target pace and simple split plan, race mornings feel calmer—and finishes, more satisfying.