Best for: Athletes who want maximum training flexibility (outdoors, group rides, Zwift races, free rides) without sacrificing the structure needed to improve.
In this guide: What Magic Buckets is, why Xert trains three systems (Low/High/Peak), how the algorithm works, the two ways to use Magic Buckets, and the most common questions.
Quick Answers
- Magic Buckets helps you hit your daily Low / High / Peak XSS targets—the three “systems” Xert trains.
- The “Magic” is that Xert can calculate interval guidance in real time, second-by-second, based on gets.
- You can use Magic Buckets in real-time (recommended) or generate a structured workout using the same, powerful algorithm.
If you’d rather watch than read, here’s a short YouTube walkthrough where Scott explains and demonstrates Magic Buckets:
What Magic Buckets Is
Most training platforms prescribe training plans by using fixed workouts: “Do these intervals at these watts for these durations, then repeat that X number of times.”
Magic Buckets flips the model:
- Xert recommends your daily strain targets (Low / High / Peak XSS)
- Magic Buckets turns those targets into actionable guidance so you can hit them on any ride
- The guidance adapts dynamically based on your fatigue and what you’ve already done
Key idea: Xert is not about perfectly hitting a wattage on every step. It’s about applying the right dose of strain (XSS) to the right energy systems to drive improvement.
Why Xert Trains Three Systems
Xert models training and fitness across three energy systems because real riding—and real performance—demands more than just training your FTP. If you ever ride or race hard, you need to train more than just your FTP. Xert helps you train several aspects of your fitness:
- Low XSS (Endurance / aerobic strain): builds durability and supports your Threshold system
- High XSS (Hard sustained strain above TP): develops your high-intensity capacity (HIE system)
- Peak XSS (Very short explosive strain): develops sprint/punch power (Peak Power system)
This is why group rides, races, and punchy terrain “feel” different than steady endurance: they draw from different systems.
Magic Buckets helps you hit the right mix without needing to follow a rigid workout script.
What are “Buckets”?
The buckets at the bottom of the real-time data field represent your targets for today: Low, High, and Peak.
As you ride:
- Each bucket fills based on the type of strain you’re accumulating
- Magic Buckets watches how evenly you’re progressing toward the targets
- If one bucket is filling too quickly (or lagging behind), it adjusts guidance so you stay aligned with the intended balance
This is why Magic Buckets works so well for real-world riding: it adapts to whatever happens, then helps you “finish the job.”
How Magic Buckets Works
Every second, Magic Buckets continuously considers:
- your Fitness Signature (TP, HIE, PP)
- your current fatigue (via MPA modeling)
- your daily targets and the XSS you’ve already accumulated
Then it calculates:
- the recommended Target Power (what to push)
- the recommended recovery effort (how easy to go)
- how to do that efficiently while staying aligned with Low/High/Peak targets
This is what makes it “Magic”: it’s not a static workout. It’s a workout that gets built and adjusted as you ride.
Two Ways to Use Magic Buckets
1) Real-time Magic Buckets (Recommended)
This is the signature experience: Magic Buckets runs live and turns any ride into a SMART, adaptive session.
Best for:
- outdoor riding where terrain is unpredictable
- group rides and races (you ride naturally, then top up what you’re missing)
- indoor free rides or Zwift racing where you still want to stay “on plan”
Available on:
- Garmin (Connect IQ)
- Hammerhead Karoo
- Xert EBC (Android) (iOS on our radar)
Related article: Using Magic Buckets in Real Time: Data Field Guide
2) Magic Buckets Workout Generator (Structured Workout)
If you prefer a structured workout with a clear start/finish - or if you’re training on a platform that doesn't support real-time Magic Buckets, use Xert's workout generator instead.
It uses the same algorithm to create a custom structured workout for today’s Low/High/Peak targets. You can preview it and customize settings like:
- max Challenge Level (CL)
- interval duration (work interval length)
Related article: Xert Workout Generator
Challenge Level (CL)
Challenge Level describes how deep into fatigue you are the interval power:
- CL rises as you accumulate fatigue — when you ride above TP
- CL falls as you recover — when you ride below TP
- Higher CL is more time-efficient, but more demanding
- CL applies to high-intensity work (High/Peak targets), not Low-only endurance days
Related article: Challenge Level (CL)
Common Questions (FAQ)
Do I have to do structured workouts to Improve?
No. You can absolutely improve without following rigid, step-by-step workouts. Magic Buckets is designed to turn any ride into purposeful training by guiding you toward the right Low/High/Peak strain targets for the day.
That means you can still ride hard—but instead of “random hard riding,” Magic Buckets helps you apply the right dose of intensity to the systems that matter for your goals, while also reminding you when it’s time to back off so your High/Peak systems can recover and you can keep making improvements.
How does Magic Buckets calculate the interval power and structure?
Magic Buckets uses two main inputs:
- your remaining Low/High/Peak XSS targets (what you still need today), and
- your Fitness Signature (your personal capabilities)
From there, it calculates a work/recovery pattern that fills your buckets as efficiently as possible. In general:
- If you need more Peak strain, the intervals tend to be higher power / more explosive.
- If you need more High strain, the session tends to include more repeated hard efforts.
- If your buckets start filling unevenly (common when free riding in groups or in races), Magic Buckets will adjust the interval targets to bring you back toward the intended balance.
How long do I need to hold my Intervals?
There’s no fixed “hold this for __ seconds” rule. Magic Buckets isn’t a traditional workout with preset interval durations, so the work timer actually counts up while you hold the effort.
You can keep the work effort going as long as it makes sense for the terrain and how you feel—then back off and recover when you need to.
Recovery guidance does include a suggested duration. If you ride near the recommended recovery power for the suggested time, Magic Buckets can let fatigue settle and will reset your Challenge Level down cleanly to the next whole level.
What’s the Difference between Magic Intervals and Magic Endurance?
The mode you see on the data field (Magic Intervals vs. Magic Endurance) depends on your recommended Low/High/Peak XSS targets for the day:
- If your day includes High/Peak targets, you will see Magic Intervals with work & recovery guidance for higher-intensity efforts.
- If your day is mostly Low-only (endurance-focused), you will see Magic Endurance with guidance aimed at steady, low-intensity strain.
Want to change the mode?
You can adjust today’s targets on the Today page by editing the Target XSS values in the Daily Summary. Changing your targets changes what Magic Buckets guides you to do.
Can I do a structured workout using Magic Buckets?
Yes. If you have a scheduled structured workout, Magic Buckets can use that workout’s Low/High/Peak XSS values as the targets for its guidance. In other words, it doesn’t follow the workout step-by-step—instead it guides you to achieve the same overall strain targets using Magic Buckets feature.
This is especially helpful if you prefer Magic Buckets-style guidance, but still want to follow a coach-planned session or are following a training plan from another app or platform.
Do I need to create a Magic Buckets workout to use the data field?
No. You don’t need to create, schedule, or “send” a Magic Buckets workout to use the Magic Buckets data field. Magic Buckets automatically uses:
- your daily recommended Low/High/Peak XSS targets, or
- the targets from a scheduled workout (if one is scheduled for that day)
Can I use Magic Buckets during group rides or races?
Yes—this is one of the best use cases. Ride naturally with the group, then use Magic Buckets guidance to top up what’s missing.
Does Magic Buckets replace my plan?
Magic Buckets is just one way to execute your daily targets. It works with both:
- XATA (daily adaptive recommendations), and
- Forecast AI plans (planned targets in your calendar)
The targets feel too hard / impossible—what should I do?
Most often this is solved by:
- Doing your training at a relatively lower Challenge Level
- If you have relatively large High/Peak XSS targets, allow your MPA to recover by breaking your ride into "sets" — be sure to rehydrate & eat between efforts!
If targets consistently feel unrealistic, your Fitness Signature may be off. Consider reviewing your activities & recent breakthroughs and search for bad data.
Related article: How to Verify Your Fitness Signature — and what to do if it seems wrong
Comments
0 comments
Please sign in to leave a comment.