Compare Yourself to Yourself

Most training platforms compare your results with those of other people. They tell you how your VO2 Max ranks against other users, where your pace falls within your age group, or how your recovery compares to the broader population. While these comparisons can provide useful context, they do not answer a more important question:

Are you actually improving?

For long-term training, what matters most is not your ranking among others, but how you are changing relative to your past self. This is the first core principle of Treadmill HIIT Evaluator: Compare Yourself to Yourself.

To make this possible, a reliable basis for comparison must first be established. If the structure of every workout is completely different, any comparison quickly loses its meaning. Running for 20 minutes today and 40 minutes tomorrow, completing 6 intervals in one session and 12 in the next, or constantly switching between different training protocols makes it impossible to determine whether any observed changes are the result of improved fitness or simply different workout designs.

For this reason, Treadmill HIIT Evaluator encourages users to establish a relatively consistent treadmill HIIT protocol. Speed, incline, and intensity can certainly be adjusted to match individual fitness levels, but the overall workout structure should remain as consistent as possible. Only when measurements are taken under similar conditions can long-term trends become truly comparable.

After the first training session is completed, we do not immediately compare the results with those of other users. Instead, we convert Day 1 into a personal baseline. This baseline does not represent excellence, an average level, or a target to achieve. It simply records the user's actual starting point. Every future evaluation is built upon this personal baseline.

To support this approach, we introduced two core metrics: PCS (Progress Comparison Score) and SQS (Session Quality Score).

PCS is designed to measure long-term progress. SQS is designed to evaluate the quality of an individual workout. Although they serve different purposes, both are grounded in the same principle: personal history.

Within the PCS framework, the Day 1 baseline is assigned a score of 60. This number has no special meaning in itself. It is not a passing grade, nor is it intended to represent an average performance level. Its purpose is simply to provide a fixed reference point. Every future workout is evaluated relative to this baseline. As training capacity improves, PCS gradually rises above 60. If performance declines, PCS falls below 60.

As a result, the same PCS score can represent very different things for different individuals. Two users may both achieve a PCS of 75, yet arrive there through entirely different training journeys. PCS is not about ranking. It is about change. It answers a single question:

How has today's version of you changed compared with Day 1?

While long-term trends are important, we also need a way to understand the quality of an individual workout. This is where SQS comes in.

SQS is not intended to measure progress. Instead, it evaluates whether a workout achieved its intended training quality. To do this, several key characteristics of the heart-rate curve are converted into scoring dimensions.

Peak Score (PS) is used to represent training intensity. It uses the age-adjusted theoretical maximum heart rate as a reference point and maps actual workout intensity into a standardized scoring system. Workouts that achieve more effective intensity levels receive higher scores.

Peak Width Score (PWS) is used to represent workout cycle structure. It is anchored to a theoretical minimum effective training cycle and evaluates whether the rhythm of the workout aligns with the characteristics of effective HIIT training.

In addition to intensity and cycle structure, we also evaluate heart-rate waveform quality. PS Ratio is primarily designed to identify abnormal or low-quality heart-rate patterns. Its purpose is not to reward ideal waveforms, but rather to penalize patterns that deviate significantly from the intended training model. Examples include insufficient peaks, inadequate recovery, or distorted heart-rate curves.

PWS Ratio uses a segmented scoring approach. Rather than pursuing a single optimal value, different score ranges are assigned to different intervals. The goal is to encourage effective training while discouraging users from optimizing for a single metric at the expense of overall workout quality.

By combining PCS and SQS, we can observe both long-term trends and individual workout quality. Evaluation no longer depends on population averages. Instead, it is anchored in the user's own training history. The focus shifts away from how fast someone else ran today and toward a more meaningful question:

Are you moving forward compared with your past self?

That is the essence of Compare Yourself to Yourself.

Once we can reliably observe change over time, the next question naturally follows: if we know whether we are progressing, plateauing, or declining, how should we adjust the next workout?

That is the topic of our next article:

Make Small Adjustments.