Negative Split for Strava

Free, local training analytics on your own Strava runs: rTSS, GAP, zones, intervals, PB curve, recap. Nothing uploaded.

🏃 Strava shows you the run. Negative Split explains it: right on your own activity, profile and training pages, computed entirely in your browser. It adds the deep, honest analytics that usually sit behind Premium (or nowhere), and it never uploads a thing. ✨ No login, no subscription, nothing leaves your browser. 📊 ON EACH ACTIVITY • Negative-split pacing: did you finish faster than you started, split into two halves. • rTSS, Intensity Factor & Normalized Graded Pace (GAP, Minetti model): real training load, hill-fair. • Aerobic decoupling (Pa:HR): did your pace-per-heartbeat drift. • Time in zone + the 80/20 read: how easy vs hard the run really was. • Auto interval detection: finds your reps (warm-up & recovery excluded) and lists each one. • Fitness / Fatigue / Form (CTL/ATL/TSB) trend + training monotony. • Injury-risk read: Acute:Chronic Workload Ratio with the sweet-spot band. • Aerobic trend: Efficiency Factor & decoupling across your recent runs. 🏅 ON YOUR PROFILE • A clean, sortable personal-best list with Riegel-equivalent scoring (which PB is actually your strongest). • Race predictions for 5K/10K/Half/Marathon, fitted to your own PB curve: honest about the marathon. • Pace-duration curve + Critical Velocity (CV) and D′. 🗓️ A FREE YEAR IN SPORT • A private, local recap: totals, sport split, a daily-activity heatmap, monthly volume and season bests, with a downloadable share card. Built from your own history, nothing uploaded. ✍️ WHEN YOU EDIT A RUN • A suggested title and description from the detected workout (e.g. "6x6' @4:12→4:00"): copy it if you like it; it never changes your fields. 🔒 HONEST BY DESIGN ✅ 100% in your browser: your activity data is never uploaded, never sent anywhere. ✅ No login, no account, no subscription. ✅ No official Strava API, no AI on your data: every number is transparent, deterministic sports-science math. ✅ One named site permission (strava.com), never broad web access. ℹ️ Negative Split is an independent project. It is not affiliated with, endorsed by, or sponsored by Strava, Inc. Strava is a trademark of Strava, Inc. 📈 By Ownward: honest, local-first browser tools. https://ownward.hu