For years, cyclists have used Training Stress Score (TSS) to track how hard a workout felt. It’s a simple formula based on power, duration, and FTP, giving one number that represents your training load.
TSS has been incredibly useful — but it’s one-dimensional. It tells you how much work you did, not what kind of work it was or how it affected your body.
Two rides can have the same TSS but strain your body in completely different ways. One might be a steady endurance ride, the other a criterium full of explosive surges. Both create fatigue, but they build very different forms of fitness.
That’s where Dimensional Training Load (DTL) comes in.
The Foundation: Your 4DP Athlete Profile
TSS is built around FTP (Functional Threshold Power) — a single benchmark that estimates the hardest effort you can sustain for about an hour. Every watt you produce is measured relative to that number.
Dimensional Training Load (DTL) takes that idea further. Instead of viewing all power through the lens of FTP, it looks at your complete 4DP Athlete Profile, which measures your ability to produce power across four key dimensions:
- Endure (FTP): long, steady aerobic power
- Breakaway (MAP): sustained high-intensity efforts
- Attack (AC): short, near-maximal bursts
- Sprint (NM): peak neuromuscular power
This approach provides a far more accurate reflection of your true training stress for each activity.
For example: Imagine two riders with the same FTP. Rider A can sprint up to 700 watts, Rider B up to 1000. If both hit 700 watts during an interval, TSS sees those efforts as identical. DTL doesn’t — it recognizes that Rider A is pushing their limit while Rider B is still in their comfort zone, and it weights those efforts accordingly.
For a more complete breakdown of how all of these metrics work together, check out our support page.
How DTL Works
DTL doesn’t just look at how much power you produced — it looks at how you produced it. It analyzes the relationship between power, cadence, and duration to understand the physiological strain behind each effort.
Cadence is a key part of that picture. A hard effort at 90 RPM feels and functions very differently from the same wattage at 120 RPM — different muscles, recruitment patterns, and energy systems are at play.
DTL factors in your preferred cadence — the rhythm where your body feels most efficient during moderate efforts. Any time you drift above or below that natural cadence, your body has to work harder to stabilize, adding a layer of strain that traditional metrics ignore.
Every ride is made up of many different efforts — long grinds, short bursts, steady spins. DTL breaks these moments into load contributors and maps each one to the 4DP dimension it stresses.
For example:
- High-cadence drills and sprints feed your Neuromuscular system.
- Long sustained pushes build your Endurance and Breakaway systems.
Each contributor earns its own DTL score based on how much strain it creates. Those scores combine to form your total DTL — a single number representing the full intensity of your ride.
DTL scales naturally with effort: the harder and longer you go, the higher the score.
Why DTL Matters
TSS quantifies how much stress or load you created. DTL shows how that stress was distributed across your fitness dimensions.
Because it measures training stress across multiple power dimensions, DTL doesn’t just capture intensity — it reveals what kind of work you did. It’s the difference between knowing you pushed hard and knowing whether you trained endurance, anaerobic power, or sprint ability.
Viewed over time, DTL becomes even more powerful. As your rides accumulate, patterns start to emerge — you can see whether your training is balanced across systems or if you’re leaning too heavily on one type of effort.
It also connects directly to how your body adapts: endurance builds slowly and lasts, while sprint power comes fast but fades quickly if ignored. By tracking your DTL across weeks and months, you get a clear picture of how your fitness is evolving — not just how tired you are today.
In short, DTL isn’t just more accurate — it’s more meaningful, showing how your training is shaping you over time
What You See in the Wahoo App
When you complete a ride with power and cadence data, the Wahoo app visualizes DTL in several ways:
- Total DTL Score: Your overall training load for the ride, so you can see how demanding it was.
- Relative Training Load Bar Graph: Compare that ride’s DTL to your last 90 days, so you can see if it was easier, harder, or right on target.
- 4DP Load Distribution: Shows how your effort was divided across Endure, Breakaway, Attack, and Sprint — so you can identify which systems you trained most.
- DTL per Hour + Map View: Plots your DTL per hour alongside your ride map, so you can pinpoint where your hardest efforts happened.
Together, these insights help you train with purpose — not just chase numbers.
For a more complete breakdown of how all of these metrics work together, check out our support page.
DTL’s Role in the Bigger Training Picture
Dimensional Training Load isn’t just another number — it’s the foundation of Wahoo’s entire Cycling Fitness Metrics ecosystem.
Because DTL captures your training load with greater accuracy, every other metric that builds on it becomes more precise too. Cycling Trends uses DTL to show how your training focus shifts over time. Training Capacity relies on it to gauge how ready your body is to perform again — and because each 4DP dimension has its own unique fatigue and recovery pattern, that Training Capacity is far more accurate than what traditional models can deliver. Meanwhile, your Fitness Score, the daily reflection of your overall progress, becomes more meaningful when it’s powered by data that understands how you trained, not just how much.
DTL acts as the connective tissue between your workouts and your long-term goals — the data layer that transforms raw effort into insight. It’s what allows Wahoo’s tools to move beyond tracking fatigue and start revealing how your training is shaping you as an athlete.
Getting Started with DTL
DTL is available to Wahoo Premium subscribers in both the Wahoo App and SYSTM. Basic training load information is available to all users, but full dimensional insights require a subscription or active trial.
To get started:
- Complete an Athlete Profile assessment in the Wahoo App to establish your 4DP baseline.
- Record rides with power and cadence data for the most accurate analysis.
- View your DTL breakdown after each ride in the Activity Details page.
- Explore the Training Progress section to see how your DTL evolves over time.
The Bottom Line
Training Stress Score simplified training load into a single number. Dimensional Training Load evolved that concept by recognizing that fitness isn’t one-dimensional. Your training shapes you across multiple systems at different rates.
DTL reveals exactly how each workout contributes to your specific fitness dimensions. That clarity transforms training from guesswork into strategy.
Because understanding what you trained is the first step to training smarter.
