Built for the engine.
Runs, rides, rows and race simulations, every number from the client's own tests and logs.
Example
Training and racing
Ada KowalZones
- Zone 1slower than 5:14/km
- Zone 24:37 to 5:14/km
- Zone 34:18 to 4:35/km
- Zone 44:01 to 4:15/km
- Zone 5a3:56 to 4:03/km
- Zone 5b3:39 to 3:54/km
- Zone 5cfaster than 3:39/km
Last test: 30-minute run test, 2026-10-11: 7.4 km in 30 min: threshold pace 4:03/km, threshold heart rate 176
This week
Running 8.2 km in 35:00, rowing 2 km in 8:00
Running: 6, 6.5, 7, 7, 7.4, 8.2 km a week, oldest first
“30 minute test done: 7.4 km, and 176 for the last 20.”
What is Fenlio for HYROX and endurance training?
Fenlio for HYROX and endurance training is coaching software run by Fen, an agent that works from each client's own numbers. Sessions carry intervals, EMOMs, AMRAPs, pace, heart-rate zones and watts, and the client's player runs the clock. Zones come from their own run, power and row tests, never their age. Stations show the race standard for their HYROX division, simulations log every split, and Fen plans a race block counted back from race day for you to approve.
Write it your way.
Example
Engine and threshold
Threshold run (main): Run 3 x 10 min, rest 2 min, at threshold effort Intervals 8 rounds of 40s on / 20s off: Rowing 250m, pace 1:52/500m, 24 spm SkiErg 15 cal EMOM 12 min: Wall balls 15 Run 200m Easy ride (main): Cycling 1 x 45 min, HR zone 2
Threshold run
- Run3 x 10 min, rest 2 minthreshold effort
Intervals, 8 rounds of 40 s on, 20 s off
- Rowing250 mpace 1:52 per 500 m, 24 strokes a minute
- SkiErg15 cal
EMOM 12 min
- Wall balls15
- Run200 m
Easy ride
- Cycling45 minheart-rate zone 2
What Fen does
Target split times from her own simulation.
Her latest time for every run and station and her transitions, scaled evenly to the goal time you set. Nothing comes from anyone else's times.
- Timed sessions
- Intervals, EMOMs, AMRAPs, For time and Freestyle, with a pace, heart-rate zone, watts or stroke rate on any line. The client's player runs the clock and beeps at each change.
- Zones from their own tests
- A 30-minute run test, a 20- or 30-minute power test, a 5k row. Their pace, heart rate, power and split zones come from it, and a line at threshold effort becomes their own pace, watts or split. A 2k row gives its split and watts.
- Race standard and simulations
- Each station shows the race standard for the client's division beside what they do today, scaled for training. Full and half race simulations log a split for every run and station.
- Target splits and race blocks
- Splits for their goal time from their own latest simulation. Fen builds a race block counted back from race day, and nothing starts until you approve it.
- Training and racing, on their record
- Their race, their zones, their last test and this week's distance and time by sport, on their record. A test their player logged waits for your press before it sets their zones.
Example
Results
Ada Kowal, goal time 1:25:00Simulation, 2026-10-04: 1:27:44, against simulation, 2026-09-13: 1:31:21
| Split | Time | Against before | Target |
|---|---|---|---|
| Run 1 | 5:12 | -0:13 | 5:02 |
| SkiErg | 4:28 | -0:13 | 4:20 |
| Run 2 | 5:18 | -0:12 | 5:08 |
| Sled Push | 3:25 | -0:09 | 3:19 |
| Run 3 | 5:25 | -0:09 | 5:15 |
| Sled Pull | 4:52 | -0:13 | 4:43 |
| Run 4 | 5:30 | -0:11 | 5:20 |
| Burpee Broad Jumps | 5:18 | -0:13 | 5:08 |
| Run 5 | 5:35 | -0:14 | 5:25 |
| Rowing | 4:36 | -0:08 | 4:27 |
| Run 6 | 5:38 | -0:14 | 5:27 |
| Farmers Carry | 2:08 | -0:03 | 2:04 |
| Run 7 | 5:42 | -0:13 | 5:31 |
| Sandbag Lunges | 5:22 | -0:14 | 5:12 |
| Run 8 | 5:50 | -0:16 | 5:39 |
| Wall Balls | 6:25 | -0:17 | 6:13 |
| Transitions | 7:00 | -0:25 | 6:47 |
| Finish | 1:27:44 | -3:37 | 1:25:00 |
Target splits
Their latest time for each split and their transitions add up to 1:27:44. Each is 3.1% faster for a 1:25:00 finish. Runs at 5:21 each.
Their best splits add up to 1:20:44, before transitions.
“My goal for race day is 1:25:00.”
Training zones from their own tests
- 30-minute run testJoe Friel's 30-minute test: threshold pace is the average pace of the whole 30 minutes, threshold heart rate the average of the last 20
- 20-minute power testThe 20-minute test: FTP is 0.95 times the average power (Borszcz et al. 2020)
- 30-minute power testJoe Friel's 30-minute test: FTP is the average power of the whole 30 minutes
- 5k row testConcept2's pace guide: each band is seconds per 500 m added to 5k pace
- Max heart rateConcept2: use the highest heart rate recorded as the maximum
- Resting heart rateMeasured at rest; with a measured max it gives the heart rate reserve (Karvonen)
Endurance sessions ready to add
- Easy runHeart-rate zone 2, 40 min to start, the length is yours
- Long runHeart-rate zone 2, 75 min to start, the length is yours
- Threshold run3 x 10 min at their threshold pace (blocks of 10 to 30 min), 2 min rest to start
- Recovery rideAt their recovery power, 30 min to start, the length is yours
- Endurance rideAt their easy power, 90 min to start, the length is yours
- Tempo rideAt their tempo power, 40 min to start, the length is yours
- Threshold ride2 x 20 min at their threshold power (blocks of 10 to 30 min), 5 min rest to start
- VO2max ride5 x 4 min at their VO2max power (intervals of 3 to 8 min), 4 min rest to start
- Easy row12 km at their UT2 split
- Threshold row3 x 2000 m at their AT split, 6 min rest
A HYROX training plan, counted back from race day.
Fen builds each client's race block from their own program and logs, up to 16 weeks, with both halves of the race at race weight. Nothing starts until you approve it.
Questions
- How are a client's training zones worked out?
- From their own tests. A 30-minute run test gives threshold pace and heart rate, a 20- or 30-minute power test gives FTP, and a 5k row gives row splits, each zone table with its source. With no test there are no zones: Fenlio names the test to log and never estimates from age.
- How are HYROX target split times worked out?
- From the client's own latest time for each run and station, plus their transitions, scaled evenly so the whole adds up to the goal time you set. If a split is missing, Fen asks for a simulation first, and a goal far from their own times is declined.
- Who decides on the race block?
- You do. Fen builds it counted back from race day, up to 16 weeks, with their strength work and both halves of the race at race weight. Nothing is saved or started until you approve it.
- Which races can a client train for?
- HYROX, running, triathlon, rowing, cycling and other races, each with the name you give it. Divisions, station standards, simulations, splits and race blocks are for HYROX races.
- Is Fenlio affiliated with HYROX?
- No. Fenlio is independent software for coaches who train clients for HYROX and endurance races. HYROX is named only to say which race a client trains for.
HYROX is a trademark of its owner. Fenlio is independent software and is not affiliated with HYROX.
Race day, counted back.
Fen keeps up with every client's tests, splits and weeks between sessions.