How Pendio works

App and web

Pendio is an iPhone app first. It reads your workouts from Strava or Apple Health and analyses them on the phone — terrain, training load, descent load, climbs, and how ready you are for your next race. Your workouts never leave the phone.

pendio.app is the same account on a bigger screen, made for preparing races. It holds what you type — races, courses, fueling settings, race plans — and nothing computed from your workouts.

Getting started

1. Sign in at pendio.app/app with your email, Continue with Google, Sign in with Apple or Connect with Strava. With email, Pendio sends you a 6-digit code; there is no password. The same email finds the same account whichever way you sign in, and a Strava account can add an email under Account. No account yet? Signing in creates one.
2. Find your season and courses. Everything you already set up in the app is there. Distances and heights follow the unit you chose in the app (metric or imperial).
3. Change something here, see it on your phone. The app picks up your edits the next time you open it, and the reverse.

The page works in any up-to-date browser. It's made for a computer or tablet, but works on a phone too.

Season

The season is your list of races, soonest first, with the date and a countdown on each one.

Add a race

Press Add race at the top. A date is enough to put a race on the season (without a name it shows as Untitled race). Add the distance, climb (D+) and descent (D−) to get the taper, recovery and spacing hints below — a race without a distance gets none of them. On trail, descent matters most, because downhill muscle damage takes the longest to recover from. Effort override replaces Pendio's effort estimate (in TSS) if you know better. For terrain, fueling and a race plan, import the race's GPX instead.

A, B and C

A Peak race

Your goal. The season is built around it and you arrive fresh after a full taper. Your nearest A-race is what the app's form projection aims at.

B Secondary

A result you want without reshaping the season. Training eases for a few days before it — a mini-taper from a couple of days for a short race up to about a week for a big mountain one — then it counts as load.

C Training race

Run through it: no taper, full training right up to it. It still counts as load, and a short one can sharpen you.

The timeline

The list itself is the timeline. A line runs from Today through your races, and between two entries it says how many days apart they are. The wider grey stretch is your next A-race's taper: the gap where it begins names its first day (taper starts Thu 3 Dec (16 days)), so a race sitting on the wide stretch falls inside it. The taper needs the A-race's distance (or an effort override); without one the line stays thin all the way.

Under each race

↺ ~9 days to recover

Roughly how long the race's fatigue lingers: a part from the effort and a part from muscle damage — the descent, or on a flatter course the distance itself.

~4-day mini-taper

B races only: the days of easier training before it.

⚡ opener — sharpens the A-race

Short, light, little descent and close to the A-race: a useful sharpener, not a conflict.

⚠ lands in your A-race taper

The race falls inside the taper window.

⚠ recovery reaches the A-race taper

It sits before the taper, but its recovery runs into it.

▤ stacked with another race

Its recovery overlaps another race's.

≈ before a number

The race has no course, so its taper and recovery come from distance, climb and descent only. A race with a course uses the full terrain model.

The phone also scales these estimates by how the race compares with your usual training. The web never sees your training, so its figures can differ a little from the phone's. They're a guide for spacing races, not a medical clearance.

Edit, remove, undo

Click a race to open it — a race with a course opens its course page, a date-only race its edit sheet. The ⋯ menu next to each race:

• A race with a course — Open course, Edit race, Rename (the course and its race together) and Remove from season: the race leaves the season and the course goes back under Saved courses with its GPX and plan. To delete the course itself, use the ⋯ menu under Saved courses.
• A date-only race — Edit race (rename it there too) and Delete race.

A removal or deletion can be undone for five seconds from the bar at the bottom of the page.

Courses

Import a GPX

Press Import GPX and choose the course file from the race's website. Pendio reads it in your browser and shows the distance, D+, D− and the profile before you save.

• Name — filled in from the file when it has one.
• Sport — run or ride. It sets the elevation smoothing and the energy model.
• Race date — with a date the course goes straight into your season with the priority you pick; leave it blank to keep it as a saved course.
• Goal time, carb rate, gel size — optional, the same choices as the Fueling card (Auto or 60–120 g/h; 25 or 40 g); you can change them later on the course page.

A very large recorded track (over 1.5 MB compressed) is stored as plain track points, exactly as the app does it, so both analyse the same file. A course still over 1.5 MB after that is too large to keep in your account, and a file over 64 MB is refused before it's read.

From a race page

Every race course page has Add to Pendio. It opens the app on an iPhone with Pendio, or this page anywhere else, with the course ready to add: Pendio's distance, D+ and D− next to the organiser's, the profile and the race day. Add downloads the organiser's own file from their site, in your browser or on your phone, and checks it against the SHA-256 the race page printed. The course is named after the race and its edition, kept as track points only, and comes with the organiser's aid stations and cut-offs as a race plan you can edit.

• Already added — the same file twice is one course: Add opens the one you have.
• A new file — when the organiser replaces their file, the page offers it as a second course; the one you have, and its race plan, stay as they are.
• Kilometres — the file's. Organisers' distances ran 1–2 % longer than their own files on every course Pendio has measured, so aid stations are placed by the organiser's kilometre scaled to the file.

Pendio never stores or sends a copy of the organiser's file: your device fetches it from the organiser, as their download link would.

Saved courses

Courses that aren't on your calendar. Add to season puts one on as an A race four weeks out and opens the race sheet so you can set the real date and priority. Deleting a course also deletes its race plan; once that has synced, the GPX is gone for good.

The course page

Click a course — or a race that has one — to open its page. It's the app's race screen on a big screen.

Distance, D+ and D−

Read from the GPX with the same method as the app, so the numbers match the phone to the metre.

Elevation

The profile with the hardest climb and hardest descent marked. Click either row — or the shaded stretch — to zoom the profile to it; ✕ zooms back out. More climbs & descents lists the rest.

D+ per 10 km

The climbing in each 10 km (or 10 mi) slice, the biggest one highlighted, and one line on where it sits: front-loaded, or the slice with the biggest block.

Terrain

How much of the course climbs, runs flat and descends; below it, the 13 grade bands as a coloured strip and, under Distance in each grade band, the distance and share in each.

Race day

Switch it on to put the course in your season as an A race four weeks out, then set the real date and priority. The recovery estimate and (for a B race) the mini-taper appear here. Race-day form and readiness are computed on your phone from your workouts.

Fueling and Plan

Below — see Fueling and Race plan.

Section for your watch

Under the elevation profile: a GPX of part of the course — see Sections for your watch.

Click the pencil next to the name to rename the course (and its race).

Fueling

Type a target time and Pendio sizes the whole day. The target is one value for the course: fueling, the race plan and the app all use it.

Carbs

Your hourly rate for the first three hours, then about 4 % less each hour (never below 70 %), because the gut tires. The total and the number of gels come from that.

Carb rate

Auto picks 60, 90 or 100 g/h from how hard the target is for you — for a run that needs the threshold pace you typed in the app's Settings, for a ride your FTP; without it, 90 g/h. Or choose 60, 90, 100, 110 or 120 g/h yourself. From 90 g/h a note reminds you to practise that rate in training — the gut needs it.

Gel size

25 g or 40 g of carbs per gel.

Energy

The kilocalories the course costs at your weight, priced grade by grade (a ride's figure is an estimate). It needs the weight you typed in the app's Settings — weight from Apple Health never leaves your phone. With a threshold pace or FTP typed there too, it also shows how hard the target is as an intensity factor (IF).

Cumulative carbs and timeline

The curve shows the plan building up over the race; ticks mark the big climb where fueling is hard and the long descent where eating is easy. Races over three hours get an hour-by-hour timeline — grams per hour, where you'll be, and a tip when a big climb or descent falls in that hour.

Target time, carb rate and gel size are saved to the course, so the app's fueling card shows the same plan.

The race plan

Race plan

The race plan turns a course into a race-day schedule: where the aid stations are, when you plan to reach each one, how much time you have on every cut-off, how many gels to eat on each leg, and how many to bring from the start and to pack in each drop bag. It sits on the course page, under Fueling. You build it on the web; your phone shows it.

Step by step

1. Set your target time. In the Fueling card, type the finish time you're aiming for as hours:minutes. The plan shares it out over the course.
2. Set the start. The date (filled in from the race date when the course has one), the time, and the race's UTC offset — +02:00 for a summer race in the Alps, for example. The start needs both the date and the time; with only one, a red line says what's missing. Every arrival then gets a clock time, and cut-offs can be given as clock times.
3. Add the waypoints. The list runs from Start to Finish. Copy the aid stations from the race's website: pick the kind, type the distance, press Add. Or press Place on profile and click the elevation chart where the point goes. Drag a marker along the profile to move it.
4. Fill in each waypoint. A name, the minutes you plan to stop, the cut-off if the race has one, the supplies you'll find there (for example water, gels, soup) and notes for you or your crew.
5. Set the finish time limit. The Finish row at the end of the list takes the race's overall time limit and notes for the finish.
6. Optional: fatigue drift and night factor. Add them if you expect to slow down late in the race or in the dark — see below.
7. Check the legs, then save the PDF. Read the arrival times and cut-off margins in the legs table, then press Save PDF.

Everything saves when you leave a field and syncs to your account. Each course has its own plan.

Waypoint kinds

How the split times are worked out

Pendio doesn't guess how fast you'll be. It takes the finish time you typed and shares it out over the course so that you'd hold one even effort from start to finish. Three steps:

1. Stops come off first. The stops at every waypoint are added up and taken off the target. What's left is your moving time.
2. Every leg becomes flat kilometres. Each leg is converted to the distance you could cover on the flat in the same time at the same effort — the grade-adjusted pace (GAP) model the app uses everywhere. A steep climb is worth far more than its length; a runnable descent a little less; a very steep descent more again, because braking costs time too.
3. The moving time is shared by flat kilometres. Each leg gets the same share of the moving time as its share of the flat kilometres. So the grade-adjusted pace — your effort — is the same on every leg, and the real pace follows the ground.

An example

A short 24.1 km demo course — ↑1,399 m ↓1,336 m — with a 3:12 target and three waypoints. The stops (1 + 4 + 3 minutes) come off first: 3:12 − 0:08 = 3:04 of moving time.

eq-km is the flat-kilometre figure — tick Show flat km above the plan's legs table to see it there. Share is only here, to show the sum.

Arrival times follow: Klingenstock at 1:05, Fronalpstock at 1:50 (1:05 + the 1-minute stop + 43:49), Morschach at 2:33, the finish at 3:12. With an 08:00 start those are 09:05, 09:50, 10:33 and 11:12.

Several waypoints at the same spot share one leg end: their stops add up and the tightest cut-off counts. A waypoint on the start or finish line adds no leg — it's listed with the start or the finish.

Cut-offs

Every waypoint has a cut-off field. Leave it empty where the race has no cut-off — that leg shows “–”. Where it has one, pick the form the race publishes it in:

The Finish row's cut-off is the race's overall time limit. Switching a cut-off from one form to the other keeps the same moment — 6:30 after a 05:00 start becomes 11:30.

The table then shows your margin. +1:24 means you're planned to arrive 1 hour 24 minutes before the cut-off. −0:14 in red means the plan misses it: lower the target time, shorten the stops before it, or rethink the race.

Each cut-off keeps the form you gave it. Move the start time and a clock-time cut-off stays at its time on its race day (15:30 stays 15:30), while an after-start cut-off stays the same time after the gun. In the legs table and on the pace card, an after-start cut-off reads 6:30 after start once the plan has a start time.

Fatigue drift and night factor

Both are optional and off by default. Neither changes your finish time — they change how it's shared out. To keep the target, the rest of the race gets a little quicker.

Fatigue drift

“x %/h after n h”: from hour n on, you move x % slower for every hour that passes. With 2 %/h after 3 h, you're 2 % slower four hours in, 4 % at five hours, 14 % at ten.

Night factor

Slows you while the race-local clock is inside the night window (21:00–06:00 unless you change it). × 1.15 means every kilometre in the dark takes 15 % longer. It needs a start time, so the plan knows when it gets dark.

Use them when you know your own pattern from past races. Left off, the plan is the even-effort plan above.

Carbs and gels per leg

Carbs come from the Fueling card: your hourly rate, full for three hours and then tapered by about 4 % an hour. Each leg's carbs are what you eat from reaching the previous station to reaching this one — food taken at a station counts toward the next leg. The legs add up exactly to the Fueling card's total.

The carbs become whole gels of your gel size. Eat is how many to eat on the way to a stop. They are rounded up as the race goes — by every stop you have eaten at least the carbs planned so far — so the legs add up to the race's total and never more than one gel over.

Bring and pack follow your drop bags. Without one, you bring every gel from the start and the table says how many you still carry after each stop. With drop bags, you bring enough to reach the first one, and each drop bag holds enough to reach the next one — or the finish. A line above the table lists it all for packing: Gels: bring 11 from the start · 8 in the drop bag at Vielha (38.0 km) · 25 in all. A drop bag on the start line or the finish line refills nothing.

Aid stations that hand out gels, and crew points, don't count as refills — the plan only counts on what you put in a drop bag yourself. If you know an aid station stocks your gels, mark a drop bag there too.

Reading the legs table

One row per stop, read left to right: where it is and what it is, the leg that leads to it, how long that takes, when you get there, the cut-off, and the gels. Each cell has a main figure and a smaller line under it. The line above the table gives the effort — the grade-adjusted pace (GAP) you hold on every leg.

Waypoint

Its name; under it, in bold, what kind of stop it is (Aid station, Drop bag, Water…), then the distance from the start and the stop you plan there. A waypoint without a name shows its kind as the name. The first row is the start line.

Leg

The leg's length; under it, its climb and descent from the course profile — together they can come to a few metres less than the course's headline figures.

Moving

Planned moving time on the leg; under it, the planned pace. With fatigue drift or the night factor on, the GAP is shown per leg too, because it then changes.

Arrive

With a start time: the race-local clock (+1d is the next day) and, under it, the race time since the start. Without one, the race time only.

Cut-off

The barrier in the form you gave it — a clock time, or after start — and under it your margin: +1:24 ahead, or −0:14 late in red. Empty where there's no cut-off.

Gels

eat 4: the gels to eat on the way to this stop; under it, their carbs in grams and the gels you still carry when you leave — or, at a drop bag, bag 8: the gels to pack in it. On the start row: the gels to bring and how far they take you.

Show flat km

Adds a column with each leg's flat-equivalent distance (eq-km) — the figure the split times are shared out by.

The pace card

Save PDF — at the top of the Plan card — appears once the plan has a target time and at least one waypoint (a finish time limit counts). It downloads the pace card as a PDF straight away: print it, keep it on your phone, or send it to your crew. On your iPhone, the Plan card's Pace card PDF button makes the same card — see below.

The card reads like the legs table: one row per stop — waypoint (distance from the start, stop), leg (distance, climb and descent), moving time and pace, arrival (clock and race time), cut-off and margin (in red when the plan misses it), and the gels (eaten on the leg, then carried on or packed in the drop bag). Each waypoint says in bold what kind of stop it is, so an aid station, a drop bag and a water point read apart on paper too. Above the table: the target, distance, climb, descent, start, the effort and the packing line — the gels to bring from the start and to put in each drop bag; under it, every waypoint's supplies and notes, the finish's included. A long plan runs onto more pages, each numbered.

The PDF uses the standard PDF fonts, so names with accents print as typed; letters outside the Latin alphabet (Greek, Cyrillic, Chinese…) print as “?” on the web's PDF. ⌘P on the course page prints the same card.

On your phone

Your phone shows the plan read-only on the race's screen, under Fueling: every waypoint with its kind (an icon and its name), its arrival time (and clock time when there's a start time), its cut-off and margin, the gels to eat on the way and to pack in each drop bag, the finish time limit, and markers on the profile. To change it, edit it here — the phone picks it up the next time you open the app.

The Plan card's Pace card PDF button makes the same pace card on the phone and opens the share sheet: save it to Files, print it, AirDrop it or send it to your crew.

The phone uses the same target time and the same pacing, so the times match. The carbs per leg can differ by a few grams, because the phone may pick its Auto carb rate from figures that never leave it.

Good to know

• Up to 60 waypoints per plan, the finish row included; notes up to 400 characters.
• Waypoints snap to the course's profile, about 240 points along it — every 100 m on a 24 km course, every 420 m on 100 km. The table shows where each one actually sits.
• Rides get waypoints and cut-offs, but no split times yet.
• Delete plan removes only the plan. Deleting the course removes the plan too.
• A course saved by an old version of Pendio may need importing again before it can be planned.

The course page

Sections for your watch

A piece of the course, for your watch. Training on part of a race — the first 35 km, the big climb, the leg between two aid stations — and want that part on your watch as a course? Under the elevation profile on the course page (and on the race's screen in the app), Section for your watch cuts it out of the course's own GPX. Times come from your target time, never from a prediction; the race's km signs can sit a few hundred metres from the file's kilometres.

1. Pick the stretch. Drag the two handles on the profile, type the start and end, or use a preset: First …, Last … or Between waypoints when the course has a race plan. With Snap to aid stations on, an end within 250 m of a waypoint jumps onto it.
2. Choose the direction. Reverse runs it the other way; Out and back turns at the far end and comes back to the start.
3. Download the GPX. Import it into Garmin Connect (Training → Courses → Import) or your watch's app, and send it to the watch.

The cut

The course file's own track points between the two marks, with one point placed exactly on each mark. Nothing is resampled or smoothed, so the watch follows the race's line. The file is the same, byte for byte, from the website and from the app.

Aid stations

The race plan's waypoints inside the section come along as course points on the track, with their kind and cut-off.

Time and fuel

The time between the plan's arrival times at your target time, stops inside included, then carbs and gels for that time from the course's fueling settings. No plan or no target time, no time; the plan's times follow the race direction, so a reversed or out-and-back section shows none.

Kilometres

Distances are the file's. The race's km signs and your watch can read a few hundred metres apart; aid stations sit where your race plan puts them.

Nothing is saved or sent: the file is made in your browser (or on your iPhone) and leaves only when you download or share it. No map is shown, so the course's coordinates go to no map service — the start and end coordinates have a Copy button instead.

Training on your phone

These are the numbers the iPhone app shows about your training. The app explains each one the first time it appears, then keeps the explanation behind the ⓘ next to it and in Settings → How Pendio works, in the same words as here. The numbers themselves exist only on your phone: they're computed from your workouts, which never leave it.

Workouts

Grade-adjusted pace (GAP)

Your pace, adjusted for the hill. The flat-ground pace for the same effort: faster than your watch pace on climbs, about equal on the flat. A fit to Strava's heart-rate-based GAP (2017)

Descent Load Index (DLI)

How much downhill pounding a session carried. Steeper counts more: 1 km at −10 % is 1.0, at −20 % it's 4.0. The units are Pendio's own, so the weekly trend is what matters. Pendio · descent distance × (grade ÷ 10 %)²

Training Stress Score (TSS)

One number for how hard a session was. It grows with time and intensity; 100 is about one hour at your threshold. Runs are scored from grade-adjusted pace, rides from power. Coggan's TSS · rTSS for runs, hrTSS against threshold HR

Heart-rate cost

What your pace cost your heart. Heart-rate load divided by pace load for the same run. Around your usual, the pace cost what it normally does; higher, it cost more heart rate. Pendio's two load scores, after Firstbeat's idea

Aerobic decoupling

Did heart rate drift away from your pace? The second half of a steady run against the first. Under about 5 %, heart rate and pace stayed together. Pa:HR and Pw:HR decoupling, after Friel

Interval detection

Structured work, found on its own. When a run alternates clearly between fast reps and recoveries, the reps are counted and timed. Steady runs show no structure. Pendio · two-speed split of grade-adjusted pace

Trends

Fitness, fatigue and form (CTL, ATL, TSB)

Your fitness, fatigue and form. Fitness is your 6-week load average, fatigue the last week's. Form is fitness minus fatigue: positive when you're fresh. Banister's impulse-response model, as Coggan's PMC

Acute:chronic workload ratio

This week against the last four, by terrain. Your 7-day load against your 28-day load, for total load, descent load and run climbing. Descent can spike while the total stays calm. Gabbett's acute:chronic ratio, one per terrain lane

Recovery markers

How your body is taking the load. Overnight HRV, resting heart rate and sleep from Apple Health, each against your own usual range. Against your own baseline · Apple Health

Best efforts and records

Your best efforts, recent against all time. For each duration, your best average — grade-adjusted pace on runs, power on rides — over the last 90 days against all time. Strava's best-effort convention for records

Climbs

Climb matching

The same hill, recognised every time. Run or ride a climb twice and its efforts are grouped, so your times on it line up side by side. No segments to set up. Matched by route · categories by Strava's rule

Race

Course terrain

The course, read like a workout. Gain and loss, the grade bands and the hardest climb and descent, measured the same way as your workouts. Pendio's gradient engine · 13 grade bands

Readiness

Your recent training next to the race. Your last weeks against the course's distance, climbing and terrain, as a 0–100 heuristic. It describes the gap; it isn't a forecast. Pendio · a heuristic, not a prediction

Fueling plan

Carbs per hour, from the course's energy cost. Your target time and the terrain's energy cost become carbs per hour and gels, eased off after the third hour. Minetti's energy cost of running on slopes

Course sections

A piece of the course, for your watch. Cut from the course's own GPX between the two marks, aid stations included. Times come from your target time, never from a prediction; the race's km signs can sit a few hundred metres from the file's kilometres. Pendio · the course file's own points; aid stations from your race plan

Courses from race pages

The organiser's course, in your account. Your phone fetched the organiser's own file from their site; Pendio checked it is the file its page measured. Kilometres are the file's: organisers' distances ran 1–2 % longer on every course Pendio has measured. The organiser's file and page; Pendio's engine

Sync and devices

On the Race page, the line next to the title says where things stand: Syncing…, Synced 10:42, or Offline — your edits wait here and sync when you're back. The page syncs when it opens, when you return to the tab, when the connection comes back, and a couple of seconds after each edit. If the same thing is changed in two places, the most recent change wins.

Sign-in

The Account page lists your ways in: Email, Google, Sign in with Apple and Strava. Add an email (a code confirms it) or Google there; Apple and Strava are added in the app.

Signed in on

The list at the bottom of the page shows your phone and browser sessions.

Sign out

Signs this browser out and removes its copy of your plan. Nothing is lost: it's in your account.

Sign out everywhere

Ends every session — phones and browsers — including this one.

Delete your account

Here: Account → Delete account…. In the app: Settings → your name at the top (the Account screen) → Delete account…, which also erases the phone's copy.

Your data

Your workouts, their GPS tracks and heart rate, and everything Pendio computes from them stay on your iPhone. Your account holds what you type: races, courses (the GPX of the route), fueling settings, race plans and the settings you enter in the app. The web shows only those, and what it works out from them — never readiness, predictions or training load from your workouts. The privacy policy has the details.

Questions or ideas? Write to hello@pendio.app.