To take body measurements you can compare over time, wrap a soft tape around the same seven sites at the same landmarks, on the same side, with the same tension, at the same time of day — and repeat each one until two readings agree. The app then does the comparison for you: first reading versus last reading inside a 30-day, 90-day or one-year window, in centimetres and as a percentage. The measuring is the part only you can get right.
The seven sites and where the tape goes
Zyra Workouts stores seven girths, all in centimetres, one entry per day per site (a second save that day overwrites the first). These are the sites and the landmarks that are easiest to find again next month:
| Site (app key) | Where the tape goes | Position |
|---|---|---|
Neck (neck) | Just below the larynx, tape level | Head neutral, looking straight ahead |
Chest (chest) | Around the fullest part, under the arms, tape level | Arms down, normal breath out |
Waist (waist) | At navel height, tape level all the way round | Relaxed, end of a normal breath out — never drawn in |
Hips (hips) | Around the widest point of the hips and glutes | Feet together |
Arm (arm) | Around the thickest point of the upper arm | Flexed or relaxed — choose once |
Thigh (thigh) | Around the thickest point of the upper thigh, a hand's width below the crease | Standing, weight even |
Calf (calf) | Around the thickest point of the calf | Standing, weight even |
You do not have to track all seven. The app lets you hide any metric; hidden ones vanish from the entry form, the lists and the compare screen while their history is kept. Fewer sites, measured well, beat all seven measured in a hurry.
A note on the waist, which is the most common site people choose: gut contents alone can move it by a few centimetres between morning and evening, so it is the one site where "before eating, first thing" is close to mandatory if you want the numbers to compare.
Same side, same tension
Tape measurements are reliable when they are repeatable, and repeatability comes from holding five things constant.
- The landmark. The tape placed a couple of centimetres higher or lower on a thigh reads differently. Use a landmark you can find again — navel, a mole, a fixed distance from a bony point — and write it down if you might forget.
- The side. Arms, thighs and calves differ left to right. The app stores one value per site, so choose a side and stay with it.
- The tension. Snug, not compressing. A spring-loaded tape applies the same pull every time and removes the guesswork.
- Flexed or relaxed. Both are valid; mixing them is not. A flexed arm can read centimetres larger than a relaxed one.
- The conditions. Same time of day, before eating, and not on a limb that is visibly swollen from yesterday's training.
Then repeat. Take each site twice. If the two readings match, log it. If they differ, take a third and average the two closest — 86.5, 87.0, 86.3 becomes (86.5 + 86.3) / 2 = 86.4 cm. A realistic target for your own repeatability is two readings within 0.5 cm on the neck, arm, thigh and calf, and within 1 cm on the chest, waist and hips. If you cannot get there yet, that is a technique problem worth fixing before trusting the trend.
In plain terms: the tape does not need to be perfectly placed; it needs to be placed the same way every time.
Comparing over 30 and 90 days
The compare screen in Zyra Workouts does one simple, explicit calculation per site. For a chosen window — 30 days, 90 days, 1 year or all time — it takes the readings that fall inside the window (a 30-day window covers today and the 29 days before it), and reports:
delta = last − first (cm) pct = delta / first × 100 (signed)
A site needs at least two readings inside the window to appear; otherwise the screen says there is not enough data rather than inventing a row. So if you measure every two weeks, the 30-day view compares readings two to four weeks apart, and the 90-day view compares ones up to three months apart.
Two consequences follow. First, the comparison is only as good as the first and last readings — which is why the repeat-and-average habit above matters more than measuring often. Second, cadence sets what you can see:
| Cadence | 30-day compare shows | 90-day compare shows |
|---|---|---|
| Weekly | 3–4 weeks apart | ~12 weeks apart |
| Every 2 weeks | 2–4 weeks apart | ~10–12 weeks apart |
| Monthly | Often "not enough data" | 2–3 months apart |
Day-to-day differences of about a centimetre are ordinary and mostly reflect timing, tape placement and swelling after training. Measuring every two to four weeks, under the same conditions, gives a comparison in which a change of a centimetre or two means something. That is the check that pairs with the scale in why the scale doesn't match the mirror.
The short version
Seven sites, in centimetres: neck, chest, waist, hips, arm, thigh, calf. Same landmark, same side, same tension, same flexed-or-relaxed choice, same morning conditions; measure twice and average when the readings disagree. The app compares the first and last reading inside a 30-day, 90-day or one-year window in cm and percent, and needs two readings in the window to say anything. Every two to four weeks is enough. It is a training and nutrition progress tool, nothing more. Educational overview only — not medical advice.