https://ferrabelle.com/articles Notes on lifting, cycles and keeping your data on your phone, by Chris Ayers, the developer of Ferrabelle. en-us https://ferrabelle.com/articles/lifting-and-your-cycle-what-the-research-says https://ferrabelle.com/articles/lifting-and-your-cycle-what-the-research-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. Sun, 04 Oct 2026 00:00:00 GMT lifting cycle research https://ferrabelle.com/articles/menstrual-cycle-phases-explained https://ferrabelle.com/articles/menstrual-cycle-phases-explained 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. Sun, 04 Oct 2026 00:00:00 GMT cycle basics https://ferrabelle.com/articles/why-ferrabelle-keeps-data-on-your-phone https://ferrabelle.com/articles/why-ferrabelle-keeps-data-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. Sun, 04 Oct 2026 00:00:00 GMT privacy app https://ferrabelle.com/articles/lifting-on-your-period https://ferrabelle.com/articles/lifting-on-your-period 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. Sun, 04 Oct 2026 00:00:00 GMT lifting cycle period https://ferrabelle.com/articles/health-connect-setup https://ferrabelle.com/articles/health-connect-setup 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. Sun, 04 Oct 2026 00:00:00 GMT how-to health connect app https://ferrabelle.com/articles/why-i-built-ferrabelle https://ferrabelle.com/articles/why-i-built-ferrabelle 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. Sun, 04 Oct 2026 00:00:00 GMT app maker accuracy https://ferrabelle.com/articles/normal-menstrual-cycle-length https://ferrabelle.com/articles/normal-menstrual-cycle-length 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. Sun, 04 Oct 2026 00:00:00 GMT cycle basics https://ferrabelle.com/articles/follicular-phase-strength-training https://ferrabelle.com/articles/follicular-phase-strength-training 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. Sun, 04 Oct 2026 00:00:00 GMT lifting cycle research https://ferrabelle.com/articles/pms-and-training https://ferrabelle.com/articles/pms-and-training 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. Sun, 04 Oct 2026 00:00:00 GMT cycle symptoms lifting https://ferrabelle.com/articles/what-is-the-fe-score https://ferrabelle.com/articles/what-is-the-fe-score 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. Sun, 04 Oct 2026 00:00:00 GMT fe score app research https://ferrabelle.com/articles/lifting-on-birth-control https://ferrabelle.com/articles/lifting-on-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. Sun, 04 Oct 2026 00:00:00 GMT lifting birth control research https://ferrabelle.com/articles/on-device-ai-assistant https://ferrabelle.com/articles/on-device-ai-assistant 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. Sun, 04 Oct 2026 00:00:00 GMT privacy ai app https://ferrabelle.com/articles/cycle-based-training-plans https://ferrabelle.com/articles/cycle-based-training-plans 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. Sun, 04 Oct 2026 00:00:00 GMT lifting cycle research https://ferrabelle.com/articles/why-no-subscription https://ferrabelle.com/articles/why-no-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. Sun, 04 Oct 2026 00:00:00 GMT pricing privacy app https://ferrabelle.com/articles/luteal-phase-training https://ferrabelle.com/articles/luteal-phase-training 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. Sun, 04 Oct 2026 00:00:00 GMT training cycle phases research https://ferrabelle.com/articles/irregular-periods-when-to-see-a-doctor https://ferrabelle.com/articles/irregular-periods-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. Sun, 04 Oct 2026 00:00:00 GMT cycle health when to see a doctor https://ferrabelle.com/articles/sleep-resting-heart-rate-menstrual-cycle https://ferrabelle.com/articles/sleep-resting-heart-rate-menstrual-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. Sun, 04 Oct 2026 00:00:00 GMT recovery wearables research https://ferrabelle.com/articles/how-period-predictions-work https://ferrabelle.com/articles/how-period-predictions-work 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. Sun, 04 Oct 2026 00:00:00 GMT predictions accuracy how it works https://ferrabelle.com/articles/lifting-through-perimenopause https://ferrabelle.com/articles/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. Sun, 04 Oct 2026 00:00:00 GMT perimenopause training research https://ferrabelle.com/articles/how-to-track-your-cycle https://ferrabelle.com/articles/how-to-track-your-cycle 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. Sun, 04 Oct 2026 00:00:00 GMT tracking habits how it works https://ferrabelle.com/articles/ferrabelle-en-espanol https://ferrabelle.com/articles/ferrabelle-en-espanol 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. Sun, 04 Oct 2026 00:00:00 GMT español settings how it works