Body weight
Daily, weekly, or as-you-please. Two-way HealthKit sync — log it in flexRep or your scale, it lands in both. The chart shows daily points and a moving-average line; daily noise stays visible, the trend stays legible.
Body
What you weigh
What you weigh
is part of what you lift.
A 405 squat at 180 is not a 405 squat at 240. The strongest version of any lifter is the version their body is built for that month — and the only way to see that, honestly, is to track the body alongside the bar.
flexRep's body tab is built for the lifter who already knows that scale weight is noisy, body fat percentage is noisier, and the only thing worth reading is the trend.
Four signals. One trend.
Each entry is short and obvious to log. Each chart is built to show the slope, not the spike.
Body fat percentage
Logged manually or pulled from HealthKit. We show the number you entered and the trend across weeks — not a confident estimate from a phone camera. The signal is the slope, not the point.
Tape measurements
Neck, shoulders, chest, arm, waist, hip, thigh, calf. Log what you care about; the rest stays out of your way. Each measurement has its own line, plotted against weight, so recomp shows up the way it actually shows up: as divergence.
Progress photos
Front, side, back, in the lighting you actually train in. Stored locally and synced only through your private iCloud zone. No cloud upload to a third party. No automatic analysis. Photos exist for the same reason mirrors do — to see the work.
The bar and the body are one dataset.
Body metrics aren't a separate hobby — they're context the strength data needs to mean anything.
Relative strength is a real metric.
A 405 squat at 180 is not a 405 squat at 240. Body weight matters for every per-pound calculation flexRep does — strength-to-bodyweight ratios, e1RM trends across a recomp, weekly volume in the context of size.
Recomp is invisible without it.
Eight weeks of "the scale didn't move" can hide three pounds of muscle and three pounds of fat. The combination of bodyweight stable + waist down + arm up tells the story the scale alone won't.
Volume scales with size.
Hypertrophy landmarks are usually written per muscle, not per body weight. But a 150-pound lifter and a 240-pound lifter need different total volumes to produce the same stimulus. Tracking body weight lets the volume charts adjust honestly.
Charts read at a glance, hold up to scrutiny.
Each chart in the body tab is built around one principle: show the noise, but make the signal louder. No flattering the data.
Chart
What you actually see
Weight × time
Daily logged weight as small dots; a moving-average line on top so the trend reads cleanly past day-to-day noise. The axis crops to your range; we don't draw 0–500 lb when you've been 175–185 for a year.
Bodyfat % × time
Same shape, separate axis. The line is the signal; the dots are reminders that any single reading is mostly hydration.
Measurement × bodyweight
A scatter of, say, arm circumference against body weight. Recomp lives in the upper-left quadrant: arms up, weight flat. The chart lets you see it without having to do the math.
Strength-per-pound
Your e1RM on any lift, divided by your body weight on that date. The most honest cross-recomp progress metric we know how to draw.
HealthKit, both ways
Log it once. Land it everywhere.
Body weight syncs in both directions with Apple Health. Step on a smart scale that writes to Health; flexRep picks it up. Log a weight in flexRep; Health picks it up. Body fat percentage syncs the same way.
Per-set workout metadata writes to Health too — so when your watch closes a ring after a heavy day, the ring it closed was earned with real volume, not an estimate.
Especially the photos.
Body data is sensitive. The privacy posture is firmer here than anywhere else in the app, and we'd rather over-explain it than leave you guessing.
Photos stay local.
Every photo lives in the app sandbox and your private iCloud zone. No third-party cloud, no machine-learning pipeline, no "your photo was analyzed by." If you ever delete the app, the photos go with it (export them first if you want to keep them).
Body metrics never leave your device unencrypted.
iCloud sync uses Apple's end-to-end-encrypted CloudKit zones. The flexRep team does not have, and cannot fetch, a copy of your weight history.
Display privacy is a setting.
Hide body weight from the Lock Screen. Hide it from the Watch face. Hide it from the home tab. The data stays; the surfacing is on a per-place dial.
Three things body data is not.
Lifters with miles under the bar know this already. Newer lifters deserve to know it too.
Body fat from a calliper is noise.
So is body fat from a smart scale, a DEXA on a different machine, or your own visual estimate. Every method drifts. Use one method, use it consistently, and read the trend — not the point estimate.
A pound is a pound is a pound.
Your scale, on a good day, is accurate to about ±0.2 lb. We store full precision and round only for display. Don't read meaning into the third digit.
Tape measurements are pose-dependent.
Same arm, same morning, different shoulder position — 0.4 cm of difference is easy. Log them in the same posture every time, or accept the drift and watch the slope.
In the export
Body data ships with body data.
Every body log — weight, fat %, measurement, photo — exports alongside your training data. Roll a recomp spreadsheet. Run a regression of arm circumference against bench e1RM. Hand the JSON to a coach. Pipe it into the AI of your choice with a clear question. It moves with you.
Track the body. Read the slope.
The numbers will move. The trend is what tells you which direction.