How to Calculate Training Volume: Direct and Indirect Sets

To calculate training volume for a muscle, add its direct working sets to a proportion of its indirect sets. One practical method counts direct sets as 1.0 and indirect sets as 0.5. This captures, for example, the work your triceps do during bench presses alongside their dedicated exercises.

The method is known as fractional counting, and the resulting totals as fractional sets. hitPR calls them Hits. The number helps you spot overlap in your workout plan. On its own, it cannot tell you how much a muscle will grow or how well it has recovered.

What counts as a set for a muscle?

Training volume can mean several things. You can count every set in a session, or multiply sets by reps and weight. To work out how much training a particular muscle group receives, you also need to assign exercises to muscles: ten sets in your plan rarely mean ten sets for every muscle.

Direct sets count towards the muscle that the exercise primarily targets within the system being used. That includes isolation exercises such as biceps curls, but also compound exercises such as bench presses for the chest. Here, “direct” does not mean “isolation exercises only”.

Indirect sets arise when another muscle makes a substantial contribution to the movement and is therefore assigned a secondary role. In this classification, the triceps and front delts fill that role in the barbell bench press. One set can appear in several muscles’ totals even though you performed it only once.

Primary and secondary assignments depend on the specific exercise. Grip, equipment and execution can matter. You should therefore not assume that the assignments for the barbell bench press apply to every pressing exercise.

How the same training can add up to six, ten or fourteen sets

Suppose your weekly plan includes eight working sets of barbell bench presses and six working sets of cable triceps pushdowns. There are three ways to count the triceps work:

You performed the same fourteen sets in every case. The difference comes entirely from how much of that work is credited to the triceps. The fractional calculation is 6 + 8 × 0.5 = 10 weighted triceps sets.

The eight bench press sets contribute eight weighted sets for the chest and four for the front delts. These are separate totals for individual muscles. Adding them together does not produce a new count of sets actually performed, nor a measure of the session’s overall fatigue.

Pulling exercises create similar overlap. With these assignments, eight sets of pull-ups and six sets of barbell curls give you ten weighted biceps sets. Counting only the curls leaves the pull-ups’ contribution out of your planning.

Why give indirect sets half credit?

There is scientific support for using 0.5 as a counting factor. A meta-regression on training volume compared three ways of analysing existing training studies: indirect sets received no credit, half credit or full credit. Of these approaches, fractional counting received the strongest support for the relationship between volume and muscle growth.

The factor was not established experimentally for every muscle and exercise. The authors explicitly describe 0.5 as an approximation; the appropriate contribution may depend on the exercise and training experience, among other things. The study supports a consistent planning tool, not a claim such as “a bench press set produces exactly half the growth stimulus in the triceps”.

This middle option has a practical advantage: it accounts for overlap between exercises without giving every secondary assignment a full set. The calculation also stays transparent. You can see whether a high total comes mainly from direct exercises or from numerous indirect contributions.

The trade-off is simplification. Half a set sounds precise, but individual training effects cannot be quantified that accurately. Two plans with the same weighted set total can still differ considerably in exercise selection and effects.

How reliable are individual muscle assignments?

A useful assignment considers what muscles do during the movement and, where possible, long-term training data. Measurements of electrical muscle activity, known as EMG, can provide clues. However, a higher EMG reading cannot be translated into a corresponding percentage of muscle growth. A review of set counting for multi-joint exercises also discusses this limitation.

The squat illustrates why some involvement alone is not enough to justify an assignment. In a ten-week study involving 17 men, squat training increased the volume of the measured knee extensors, glutes and adductors, among other findings. No corresponding increase was detected in the hamstrings. This was a small study and does not establish that squats can never have an effect there. It does, however, argue against counting squats as comprehensive training for every leg muscle.

Differences can also be hidden within a muscle group. In a twelve-week comparison of leg extensions and leg presses, 17 untrained adults trained each leg with one of the exercises. Overall quadriceps growth was similar, but one part — the rectus femoris — grew more with leg extensions. A single number for the quadriceps does not capture that different distribution.

Use muscle assignments to get an overview of your plan. You still need to assess whether your exercise selection suits a particular training goal. Even a well-supported primary/secondary classification does not provide a precisely measured factor for every exercise.

How to compare Hits with set recommendations

Before applying advice such as “ten sets per muscle per week”, find out how those sets were counted. It would be wrong to assume that research always counts direct sets only. The 2019 review already describes analyses in which lat pulldowns and curls each count as a full set for the elbow flexors. Its authors also recommended full credit at the time to stay consistent with the available evidence.

The direction of the difference depends on the comparison. Fractional totals are higher than direct-only totals when indirect sets contribute. They are lower than totals that give those same indirect sets full credit. Switching counting methods does not change the training you performed.

Check three things before applying a recommendation to your plan:

• Muscle assignments: Which exercises were counted towards the muscle in question?
• Weighting: Do indirect sets count as 0, 0.5 or 1?
• Time period: Does the number describe a session, a week or an average across a longer plan?

Without that information, the recommendation remains a rough guide. A blanket conversion such as “ten sets in the research equal fifteen Hits” would not be justified. For help choosing your own volume, see the article on sets per muscle group per week.

What Hits mean in hitPR

In hitPR, an included set contributes 1.0 Hit to a primary muscle and 0.5 Hits to a secondary muscle. This makes overlap visible even when you build your plan around exercises rather than individual muscles. The muscle map and muscle-volume figures help you see how that work is distributed.

The examples below match the verified default assignments in the exercise library as of October 2026. Each included set contributes 1.0 to its primary muscle and 0.5 to each secondary muscle listed:

The example with eight bench press sets and six cable pushdown sets therefore gives you ten triceps Hits. Four squat sets contribute four quadriceps Hits and two each for the glutes and adductors. This squat variation does not receive hamstring Hits. That describes the stored counting rule; the absence of an entry does not mean the muscle is completely inactive.

The calculation follows defined rules. In the verified version, the plan calculation includes repetition-based sets with 1 to 35 reps. Warm-up sets and exercises measured by time or distance do not contribute to that muscle set total. These limits describe the app’s calculation. They do not imply, for example, that a set can no longer provide a training stimulus from the 36th rep onwards.

The figures in a plan describe intended volume, so a weekly average is not the same as a single session. When assessing your own training week, you also need to consider what you actually completed. If you have edited an exercise’s muscle assignments yourself, your display may differ from these defaults.

When an assignment in the library is improved, the muscle volume recalculated from it may change too. That does not mean the plan contains more or fewer sets performed. The new number distributes the same training volume differently between muscles. Comparisons across such a change therefore require a look at the exercises and their assignments.

How the number can help you plan your training

Its main value is bringing direct and indirect work together. In the triceps example, the six cable sets account for only part of the weekly work. Before adding more direct sets, you can consider how much pressing your plan already includes and how you are progressing with it.

Set quality matters too. How close you take a set to muscular failure influences its effect. A meta-regression on proximity to failure found greater muscle growth on average when sets ended closer to failure. The exact relationship remained uncertain because effort levels were estimated. A weighted set total alone cannot capture these differences. The article on effective sets explains how to assess demanding working sets.

A consistent counting method is particularly useful for monitoring progress. If your exercises, execution and effort stay similar, it is easier to relate changes in set count to your development. Consider your training performance and whether you have recovered enough by the next session. A stronger colour on the muscle map is not, by itself, a reason to add sets.

The calculation cannot make exercise-selection decisions for you either. Two indirect sets mathematically equal one direct set, but that does not make exercises freely interchangeable. The movement you choose still matters, particularly when targeting a specific part of a muscle.

Conclusion

Fractional counting shows how different exercises contribute to a muscle’s training. Adding direct sets to half the indirect sets gives you a transparent basis for assessing your plan and changes to it. Compare recommendations that use the same counting method, and assess your progress alongside the training you actually perform. This keeps the number useful for planning without implying more precision than it can offer.

Sources

• Pelland, J. C. et al. (2026; online 2025). The Resistance Training Dose Response: Meta-Regressions Exploring the Effects of Weekly Volume and Frequency on Muscle Hypertrophy and Strength Gains. Sports Medicine, 56, 481–505. Publication and DOI.
• Schoenfeld, B. J. et al. (2019). Calculating Set-Volume for the Limb Muscles with the Performance of Multi-Joint Exercises: Implications for Resistance Training Prescription. Sports, 7(7), 177. Full text and DOI.
• Kubo, K., Ikebukuro, T. and Yata, H. (2019). Effects of squat training with different depths on lower limb muscle volumes. European Journal of Applied Physiology, 119, 1933–1942. Publication and DOI.
• Kinoshita, M. et al. (2026). Hypertrophic Effects of Single- versus Multi-Joint Exercise: A Direct Comparison Between Knee Extension and Leg Press. Medicine & Science in Sports & Exercise, 58(7), 1566–1580. Publication and DOI.
• Robinson, Z. P. et al. (2024). Exploring the Dose–Response Relationship Between Estimated Resistance Training Proximity to Failure, Strength Gain, and Muscle Hypertrophy: A Series of Meta-Regressions. Sports Medicine, 54, 2209–2231. Publication and DOI.