Comparison

kaizen | Adaptive Run Training vs Subintervals

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

kaizen | Adaptive Run Training

This app uses your running history to calculate your current fitness and set dynamic weekly distance targets. It offers personalized training guidance to help you achieve your running goals, whether for a specific race or general improvement. The app provides race predictions and flexible training plans that adapt to your schedule.

Highlights
  • Data-driven training partner
  • Dynamic weekly distance targets
  • Personalized fitness calculations
  • Race predictions for various distances
  • Flexible training plans
  • Build consistency and improve fitness
Features
Read full description

kaizen is load-based run training for committed runners, starting with the running you have already done. Connect Strava, Garmin or Apple Health so kaizen can analyse your training and race history. See how your fitness is developing, what shape you are in now and what your training suggests is possible. kaizen then connects that picture with your goal and timeline to map the weekly training load needed ahead. kaizen does not process or store location data. Train toward a 5K, 10K, half marathon or marathon—or set a rate of improvement without an upcoming race. CHOOSE HOW YOU TRAIN Use a suggested training structure or build the week yourself: • Even Spread for a calm, repeatable weekly rhythm • 1 Long, 1 Hard to anchor the week around one longer run and one harder effort • Build Your Own for complete control over the week Choose structured workouts, plan your runs and see how each session contributes to your weekly target. ADAPT AS YOU GO Move or edit sessions when the week changes. Every completed run recalculates both your current fitness and the training load needed ahead. HOW LOAD WORKS Equal distances do not always represent equal training. kaizen uses distance, pace and elevation—along with supported cross-training minutes—to understand the load created by different activities. This keeps the bigger picture consistent while giving you control over how the work gets done. Start with a seven-day free trial. Terms: https://runkaizen.com/terms Privacy: https://runkaizen.com/privacy

About

Subintervals

Visualize your training data with detailed displays and interactive graphs. Customize your analysis and sync seamlessly with intervals.icu for up-to-the-minute insights into activities, events, and performance metrics.

Highlights
  • Detailed activity and event visualization
  • Interactive performance graphs
  • Seamless intervals.icu sync
  • Customizable data analysis
  • Actionable training insights
Features
Read full description

Elevate Your Training with Subintervals Subintervals transforms your intervals.icu data into actionable insights. This app brings your training activities, events, and performance metrics to life through detailed displays and interactive graphs. Customise and control your data for a tailored analysis, and seamlessly sync with intervals.icu for up-to-the-minute information. Key Features: - Detailed visualisation of activities and events. - Dynamic, interactive graphs for performance tracking. - Effortless sync with intervals.icu. Please note that it is an independent application developed by an enthusiast keen on providing a complementary tool to the official platform.

Screenshots

kaizen | Adaptive Run Training4 screens
Subintervals4 screens

Verdict

The call

The clearest difference is review sentiment: Subintervals at 100% against kaizen | Adaptive Run Training's 59%. Subintervals also leads on monetization model (free with in-app purchases vs subscription) and rating (5.0 vs 4.8). kaizen | Adaptive Run Training's advantage is ratings volume (28 vs 2). On price, update cadence, ads and in-app purchases there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. kaizen | Adaptive Run Training sells 15 in-app purchases, starting at $12.99 per month and Subintervals sells 4 one-off in-app purchases. Whichever you choose, the download price is not the number that matters.

ReceptionRating · Positive reviews · Number of ratings

Subintervals holds the better App Store score, 5.0 against 4.8. That said, the two scores are not equally well evidenced: kaizen | Adaptive Run Training has 28 ratings behind it against 2, so its average is the more settled of the two. Written reviews point the same way: 59% of kaizen | Adaptive Run Training's written reviews are positive against 100% of Subintervals's.

UpkeepUpdate frequency

kaizen | Adaptive Run Training ships an update every 10 days, Subintervals weekly. The most recent releases landed on October 10, 2026 and September 29, 2026 respectively.

Scorecard5 real differences · 5 level
kaizen | Adaptive Run Training versus Subintervals: the parameters behind the verdict, then further details
Parameterkaizen | Adaptive Run TrainingSubintervals
PriceFreeFree
Rating4.8 (28 ratings)5.0 (2 ratings) — better
Positive reviews58.6% of reviews100.0% of reviews — better
Number of ratings28 — better2
Update frequencyEvery 10 daysWeekly — better
AdsNoNo
In-app purchasesYesYes
MonetizationSubscriptionFree with in-app purchases — better
DevicesiPhoneiPhone, iPad, iPod — better
Requires iOS16.415.1 — better
Further details — not scored
Size81 MB95 MB
Age rating4+4+
DeveloperRun Kaizen LTDInaki Arroyo Nebreda

Customer experience

kaizen | Adaptive Run Training

All ratings28 ratings
Positive92.9%
Neutral0.0%
Negative7.1%
Written reviews87 reviews
Positive58.6%
Neutral13.8%
Negative27.6%

Subintervals

All ratings2 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews2 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

Bugs and requests

kaizen | Adaptive Run Training

Reported bugs

25 issues
  • Setup process crashes or loops
  • App crashes frequently
  • Mileage calculations are incorrect
  • Planned mileage doesn't add up correctly
  • App doesn't get past the first step
Show 20 more
  • Race prediction screen freezes
  • App doesn't work at all
  • Data imports incorrectly (mileage/pace)
  • Issues with unit conversion (miles/kilometers)
  • Subscription charge without reminder
  • Weekly targets change based on paces
  • Only shows one week ahead
  • Can't get past prediction screen
  • Stuck on loading stage
  • Imported Strava data is wonky
  • Race predictor only gives marathon distance prediction
  • Training days logged as previous day
  • Cannot control subscription
  • Inconsistent distance recommendations
  • Records disappear and reappear
  • Improve prediction section hides event selection
  • Week planning tool shows wrong paces
  • Marathon goal always defaults to 2:00:00
  • Can't consistently log in
  • App is immature and has bugs

Requested features

9 requests
  • Allow editing of runs
  • More personalization in training plans
  • Ability to start the training week on different days
  • Consider elevation in training calculations
  • Add more workout suggestions and paces
Show 4 more
  • Predict times for distances other than marathon
  • FAQ and tutorials for better understanding
  • Ability to plan runs in decimals
  • Integration with other platforms beyond Strava

Subintervals

Not enough reviews yet to summarise bugs or requests.

In-app purchases

15 purchases

kaizen | Adaptive Run Training

Subscriptions15
  • Subscription1 Month trial$12.991 Month
  • Subscription$12.991 Month
  • Monthly Subscription7 Days trial$14.991 Month
Show 12 more
  • Monthly Subscription14 Days trial$14.991 Month
  • Subscription$14.991 Month
  • Subscription$19.993 Months
  • Subscription$24.993 Months
  • Quarterly Subscription14 Days trial$34.993 Months
  • Quarterly Subscription7 Days trial$34.993 Months
  • Subscription$49.991 Year
  • Subscription$69.991 Year
  • Annual Subscription7 Days trial$89.991 Year
  • Annual Subscription14 Days trial$89.991 Year
  • Subscription1 Month trial$89.991 Year
  • Subscription2 Months trial$89.991 Year
4 purchases

Subintervals

One-time4
  • Coffee$3.99
  • Lunch$11.99
  • Big Thanks$17.99
Show 1 more
  • Sponsor$44.99

Questions

Is kaizen | Adaptive Run Training free?
kaizen | Adaptive Run Training is free to download, with in-app purchases available.
Is Subintervals free?
Subintervals is free to download, with in-app purchases available.
Which has better reviews, kaizen | Adaptive Run Training or Subintervals?
Subintervals is rated higher. kaizen | Adaptive Run Training averages 4.8 out of 5 from 28 ratings, while Subintervals averages 5.0 from 2 ratings.
Do kaizen | Adaptive Run Training or Subintervals have ads?
Neither kaizen | Adaptive Run Training nor Subintervals shows ads.
Which is updated more often, kaizen | Adaptive Run Training or Subintervals?
kaizen | Adaptive Run Training ships an update every 10 days, and Subintervals weekly. Most recently, kaizen | Adaptive Run Training was updated on October 10, 2026 and Subintervals on September 29, 2026.

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