Lifting, cycles and your data.
Notes on lifting, cycles and keeping your data on your phone. Written by Chris, the developer of Ferrabelle.
-
Lifting through your cycle: what the research actually says
The biggest reviews on strength training and the menstrual cycle find trivial to small effects and low-quality evidence. Here is the honest scorecard.
Read the article -
The four phases of a menstrual cycle, in plain words
What happens in each phase of the menstrual cycle, why day 14 is an average and not a rule, and which half of the cycle moves around the most.
Read the article -
Why your cycle data stays on your phone
Why I built Ferrabelle with no account and no server, what local-only means in practice, and how you can check it yourself on your own phone.
Read the article -
Lifting on your period: what changes and what does not
Training during your period is fine for most people. The measured drop in performance is trivial, and symptoms are the real variable. What the research found.
Read the article -
How to connect Health Connect to Ferrabelle (and what it reads)
A step-by-step guide to Health Connect on Android: where it lives on your phone, how to allow each data type, what Ferrabelle reads, and how to turn it off.
Read the article -
Why I built Ferrabelle, and how it works under the hood
The story behind a cycle tracking app for women who lift, told by its developer, and what is under the hood: a phone-only engine and a test you can rerun.
Read the article -
How long is a normal menstrual cycle?
21 to 35 days is the usual adult range, 28 is only the average, and some change from month to month is normal. What the guidance and the big datasets show.
Read the article -
Training in the follicular phase: is it really your strong window?
What three reviews found about strength in the follicular phase, why the barbell evidence is the thinnest, and how to use the window as a nudge, not a rule.
Read the article -
PMS and training: working with the week before your period
PMS by the clinical definition, how common symptoms are in women who train, why regular exercise is on the self-help list, and when it is time to see a doctor.
Read the article -
The Fe Score: what goes into the number
Chris explains the Fe Score: five weighted inputs, four bands, why it shows its math, and the honest catch about how much weight cycle phase gets.
Read the article -
Lifting on hormonal birth control
Two meta-analyses on the pill and lifting found no meaningful effect on performance or gains. What they cover, what they miss, and what the app's mode does.
Read the article -
AI on your phone: how Ferrabelle's on-device assistant works
What on-device means in Ferrabelle: Gemma or your phone's built-in AI answers on the phone, the assistant is off by default, and predictions never use AI.
Read the article -
Should you plan your training blocks around your cycle?
The evidence for and against planning training blocks by cycle phase, from a narrative review to a 2026 lifting study, and why the app's forecast bends to you.
Read the article -
Why Ferrabelle Pro is a one-time purchase, not a subscription
Ferrabelle is free, with a USD 9.99 one-time Pro unlock. Chris explains why an app with no server and no account has no monthly bill to pass on to you.
Read the article -
Training in the luteal phase without writing the week off
What the research says about lifting in the second half of your cycle: a higher resting heart rate, rougher late days, and no reason to stop.
Read the article -
Irregular periods: what counts, and when to see a doctor
What doctors mean by irregular periods, the common causes ACOG and the NHS list, and their own lists of reasons to book an appointment.
Read the article -
Sleep and resting heart rate across your cycle
Resting heart rate has a measurable cycle pattern, lowest on period days and highest mid-luteal. Sleep is less clear. How to read your own numbers.
Read the article -
How Ferrabelle predicts your next period (and how I check it)
Where the starting assumptions come from, how the app learns your cycle, and the published test: a 1-day median error on a public dataset, weak spots included.
Read the article -
Lifting through perimenopause
Women lose muscle across the menopause transition, activity helps hold on to it, and lifting still builds strength. What the studies found.
Read the article -
What to log, and a tracking habit you can keep
Why doctors ask for your last period date, what is worth logging each day (dates, flow, symptoms, sleep, how training felt) and how to keep it short.
Read the article -
Ferrabelle en español: a note for Spanish speakers
The app speaks Spanish. How to switch the language, what is translated and what is not, and where to find reliable Spanish-language health information.
Read the article