Workout Volume, Density and RPE, Explained

Volume: how much load did you log?

In a weight-and-repetition log, volume load is the sum of weight multiplied by completed reps. It describes the external load recorded across your sets. It is a way to summarise the entries, rather than a direct measurement of muscle growth or workout quality.

Consistency matters. If you change how you enter dumbbell weights, or mix different machines under one exercise name, the total may change without representing a comparable workout. Bodyweight and assisted movements also need context: a recorded external load cannot capture every part of their difficulty.

Maximus shows volume in its progress dashboard. In the app’s current period comparison, the volume figure represents an average per logged workout for the selected period, while the overall total is shown separately. Read the label and period before comparing numbers.

Density: load over time

Load density adds the session’s duration to the picture. Maximus calculates a workout’s load density as logged volume divided by workout duration in minutes, displayed in kg/min or lb/min. Its period view averages the available workout density values.

Using the illustrative 960 kg session above, a 30-minute duration would give 32 kg/min. The same volume logged over 40 minutes would give 24 kg/min. The arithmetic is straightforward, but the interpretation depends on what you did during that time.

A longer warm-up, a different exercise selection or leaving a session timer running can affect density. A higher number does not automatically mean a better session, and it is not a reason to rush your rest. Compare like with like and use the metric to understand your records.

Work, rest and time under tension

Time under tension, or TUT, records the time spent performing a set. It is separate from the number of repetitions: two sets with the same rep count can take different amounts of time. Keeping both gives you another way to describe the session.

Maximus uses logged TUT and total workout duration to calculate its time-based work percentage. The work-to-rest display expresses that relationship in a more readable form. Because the calculation depends on what was timed, incomplete set timing or a session left running can change the result.

That remainder is not a laboratory measurement of recovery. It can include equipment changes, setup time and other pauses as well as deliberate rest. Treat it as a view of your recorded session rhythm.

RPE: how did it feel?

RPE stands for rating of perceived exertion. It adds your perception of difficulty to the external record of weight, reps and time. Maximus includes an effort rating so that the session history can reflect more than the load alone.

There are different RPE scales and ways of using them. One resistance-training approach links effort to estimated repetitions in reserve: how many more reps someone believes they could complete. A 2016 review by Helms and colleagues explains this approach. It should not be confused with an objective measurement or assumed to match every app’s effort scale.

For your log, use the scale presented by the app consistently and remember that the rating is subjective. The value is context: the same recorded load may feel different on different days. It does not explain the cause of that difference by itself.

Read the metrics together

Start with the original session rather than the direction of an arrow. Check which exercises you performed, whether the weights and reps were entered correctly and whether the timing covers the intended session. Then use the summary to ask more precise questions.

• Volume changed: did you log different exercises, sets or reps?
• Density changed: was the session longer, or did the amount of recorded work change?
• Work-to-rest changed: did the timing include the same parts of both sessions?
• Effort changed: how did this session feel compared with a similar one?

Muscle-group strength goals and body measurements are another view of your history. They are not interchangeable with session volume, and photo-based estimates can vary with how an image is captured. Keep the source of each number in mind.

If your entries are still inconsistent, begin with our guide to keeping a workout log. Clear records make every metric easier to interpret.

Metric descriptions were checked against the Maximus iOS source, including StatsView and the workout data models, on 19 September 2026. Calculations and labels may change in later app versions.