Most runners reach a plateau around month four or five of consistent training. The pace feels stuck, sessions feel harder than they should, and there is no clear signal whether to push harder or back off. Usually the problem is not fitness. It is invisible training load: the runner has been collecting GPS data without the analytical layer that tells them whether load is building productively or accumulating fatigue faster than it can be cleared.
The solution is not a more expensive watch. It is an app that turns raw session data into a coherent picture of training stress over time.
What a serious runner needs from an app
GPS and pace are table stakes. The features that separate a training tool from a basic fitness tracker:
- Training load per session (TSS or equivalent): a single number quantifying how stressful each run was, so a 45-minute tempo and a 90-minute easy long run are directly comparable and cumulative over days and weeks
- Heart rate zone distribution: not just average heart rate, but time spent in each zone, confirming whether an easy day actually stayed in Zone 2 rather than drifting into Zone 3
- Performance Management Chart (PMC): CTL (fitness), ATL (fatigue), and TSB (form) tracked over weeks and months; the tool that shows whether training is building fitness or accumulating uncleared fatigue
- Apple Health integration: pulling HRV, VO2 max, resting heart rate, and sleep data from wearables already in use
- Programme scheduling: assigning sessions to specific days and tracking compliance across a full training block
Apps that cover two or three of these are common. Apps that provide all five for free are not.
How the main options compare
| App | GPS and zones | TSS / training load | PMC | Apple Watch | Free |
|---|---|---|---|---|---|
| Strava | Excellent | Paywalled | Paywalled | Yes | Partial |
| Nike Run Club | Good | None | None | Yes | Yes |
| TrainingPeaks | Excellent | Yes | Yes | Yes | No, from £13.99/month |
| Garmin Connect | Excellent (Garmin only) | Yes | Yes | No | Yes, Garmin only |
| PROTR | Good | Full | Full | Full | Yes |
Strava is the strongest free platform for GPS tracking and community. Route logging, segment comparisons, and a large social network of runners and cyclists are genuinely well-built. Training load, the PMC, and structured plan tools are paywalled at £8.99/month. For GPS and social features the free tier is solid; for analytical training tools, it stops there.
Nike Run Club is fully free, with audio-guided runs and coaching plans for 5K through marathon. The limitation is data depth: no training load calculation, no PMC, and heart rate data shows only an average rather than zone breakdown. It is a plan-following tool, not a training analysis one.
TrainingPeaks is the reference standard for serious endurance athletes. Professional coaches use it, and its PMC and TSS tools are best-in-class. Meaningful use starts at the premium subscription, making it expensive relative to what most recreational athletes actually need.
Garmin Connect is a genuinely good free option for Garmin owners. Training load, recovery time estimation, and PMC are all available without payment. The limitation is hardware lock-in: it requires a Garmin watch and does not integrate with Apple Watch or Apple Health in any meaningful way.
The athlete who runs and lifts
A significant share of recreational runners incorporate strength training. Three sessions of running plus two or three sessions in the gym is a common weekly pattern for athletes focused on injury prevention or performance. For these athletes, most endurance apps are blind to half of their training: strength sessions are logged as generic activity with no stress calculation.
This matters because recovery capacity is shared across modalities. A heavy lower-body session on Tuesday affects the quality of Wednesday's threshold run. An app that cannot see the Tuesday session cannot give an accurate read on fatigue or TSB heading into the rest of the week.
How PROTR works for endurance athletes
PROTR is free. All training load analytics, the full PMC, and heart rate zone tools are available at no cost with no subscription required.
GPS sessions log via Apple Watch in real time, capturing heart rate zones, lap splits, and pace. TSS is calculated automatically from threshold data for running, cycling, and swimming, then fed directly into the PMC.
Apple Health sync reads VO2 max, HRV, sleep, and resting heart rate without manual entry. FTP and threshold pace are inferred from Apple Health history on first connection, so the PMC is populated from day one.
Strength sessions contribute to the same training load calculation as runs, so ATL reflects total weekly stress rather than endurance load alone.
[Download PROTR free on the App Store](https://apps.apple.com/app/id6760012262)
What to check before committing to an app
Log a full training week in any app before deciding it works. The things worth checking:
- Heart rate zone distribution visible after each session, not just average HR
- Training load calculated automatically, without manual data entry after each run
- Strength sessions appearing in the same training load chart as endurance sessions
- Previous session data visible during a new session, so pace and effort targets are grounded in recent history
An app that requires manual calculation to produce useful information is not practical at real training volume. The data that changes daily decisions needs to surface in under ten seconds after a session ends, not after opening a spreadsheet.