The engine, in full.

You calibrate once: enter your bodyweight, run a single high-rep set on each of the main barbell lifts. FormBase estimates your one-rep-max with Brzycki and parks each lift on a tier against the Strength Level standards (Beginner, Novice, Intermediate, Advanced, Elite).

From there the engine writes a multi-week program in your chosen frequency. Every prescribed lift has a rep range. Hit the top of the range across every working set, the program bumps the weight on every future occurrence of that lift. Miss it, the prescription holds. No "feel-based" RPE guessing, no manual adjustments.

Per-muscle progression tracker. The Progress tab shows a Swift Charts line of your estimated 1RM per lift per week for the last 8 to 12 weeks. Trends are honest: up is up, flat is flat. The plateau detector watches for 4-week flat windows and surfaces a recommendation when one shows up.

Synthetic tiers for accessories. Curls, tricep pushdowns, hip thrusts, leg press, pullups don't have published 1RM standards, so FormBase builds tier baselines from each lift's bodyweight-equivalent and its known relationship to the main barbell lifts. Accessory PRs count toward your composite Strength Score, just at a smaller weight than a heavy squat does.

FormBase sets five heart-rate zones from the Karvonen reserve formula (max HR minus resting HR, scaled by percent intensity). That's the floor. The interesting part is what happens after you start logging real runs.

Observed pace at zone. Every Strava-synced run is segmented by HR zone, and the median pace inside each zone is tracked over time. Your "Z2 pace" is no longer "what the formula says easy is," it's "what you actually hold for 20 minutes at 65 percent HR reserve." When the observed value drifts, the zone shifts with you.

Race goal projection. Set a target finish for a 5K, 10K, half, or full marathon. FormBase projects your current finish from your observed Z2 and threshold paces, factors a small race-day boost, and tells you if the target is in reach. Out-of-reach goals get a callout, not a participation trophy. Adjust the target, the projection updates.

Z3 / Z4 observation for Hyrox. The 1 km runs inside a Hyrox race sit at Z3, sometimes Z4. FormBase uses your observed Z3 pace (when available) to estimate the run portion of your projected Hyrox finish. No Strava connection? Falls back to your calibration value.

Your program is a sequence of phase blocks: build, peak, taper, deload, recovery. Each phase has a length in weeks and a defining quality (volume up, intensity up, volume down, intensity down). Race goals re-sequence the phases around your target date. If you don't have a race, the program runs an indefinite build with deloads every 4 to 6 weeks.

Strength and running days interleave inside the week. A typical hybrid layout: lift Mon, easy run Tue, lift Wed, rest Thu, tempo or intervals Fri, long run Sat, optional accessory Sun. The strength program respects your run days (no heavy lower-body the day before a long run) and the run program respects your lift days (no intervals after a hinge-focused session).

Hyrox is the visible flavor of hybrid. If you tell FormBase you're training for a Hyrox race, you get the per-station logger, station personal bests at race spec, and a finish-time projection that combines your station times with your observed Z3 pace. Stations can be logged at custom distances for practice (ski erg at 400m instead of 1000m), and those logs are flagged so they don't poison your race-spec personal bests.

Body flags. Mark a tender knee or a tight shoulder; the next prescribed session that loads the flagged area gets softened. Yellow flag reduces intensity, red flag substitutes the affected movement. Flags clear after 7 days unless you keep them on.