Rurilab isn't magic and it isn't a black box. Its plans rest on three well-established ideas from endurance science. Understanding them makes every recommendation the app gives you easier to trust.
Coined by exercise physiologist Jack Daniels, VDOT is a practical measure of running fitness derived from race or hard-effort performances. Two runners with the same VDOT should train at similar paces, regardless of their raw lab numbers.
Its real power is translation: a VDOT maps directly to your training paces — easy, marathon, threshold, interval and repetition. Rurilab estimates your VDOT from your recent quality runs, so your prescribed paces follow your fitness as it rises and falls, instead of being frozen at sign-up.
Research on endurance athletes keeps landing on the same pattern: the best distribute roughly 80% of running at easy intensity and only about 20% hard. It sounds counterintuitive — run easier to race faster — but easy running builds the aerobic base and lets you absorb the hard sessions that actually drive adaptation.
The most common amateur mistake is the opposite: too many runs in the "moderately hard" middle, which is tiring enough to hurt recovery but not hard enough to spark top-end gains. Rurilab structures weeks around the 80/20 split to keep you on the productive side of that line.
Every session is stress; fitness is the body adapting to stress it can recover from. To keep that balance visible, Rurilab uses the classic impulse-response model popularized as the Performance Management Chart:
This is also how a sensible taper works: hold fitness (CTL) while letting fatigue (ATL) fall, so form (TSB) rises into race day.
Load models describe the training; recovery signals describe how you're handling it. Trends in heart-rate variability (HRV), resting heart rate and sleep help flag when to back off before a number becomes an injury. Rurilab folds these into its daily read on whether to push, cruise, or rest.
Finally, these pieces are sequenced over time — base, build, peak, taper — using Banister-style periodization so hard blocks are followed by absorption, and everything points at your goal race. A plan is a sequence, not a pile of workouts.
Put together — VDOT for paces, 80/20 for intensity, CTL/ATL/TSB for load, recovery signals for readiness, periodization for order — you get a plan that's demanding when you're ready and forgiving when you're not.