What the evidence says—and does not say
Available syntheses find hypertrophy across varied loading prescriptions when sets involve sufficient effort. That does not make every option identical: heavier loads tend to improve maximal strength more, while very long sets may be limited by tolerance, breathing or RIR estimation before the target muscle.
| Finding | Useful decision | Limit |
|---|---|---|
| Multiple loads can produce hypertrophy | Do not declare a universal range | Many studies control effort or train to failure |
| Heavy loads favor maximal strength | Prioritize them when strength also matters | This does not mean more hypertrophy in every case |
| A 20% load underperformed in one small trial | Do not assume every light load is equivalent | Small sample and one protocol |
A matrix for choosing ranges by exercise
| Context | Starting range | Why it may fit | Change it when |
|---|---|---|---|
| Stable, loadable compound | 5–10 | Compact set and comparable loading | Technique breaks or joints object |
| Technically demanding compound | 6–12 | Balances load and control | General fatigue limits the target first |
| Machine or isolation | 8–15 | Allows control and small adjustments | You cannot stabilize or feel the target |
| Light isolation | 12–20 | Reduces absolute load | The set becomes cardio or counting degrades |
- Set the standard
Define range of motion, pause and technique that make repetitions comparable.
- Choose a window
Use enough room to absorb variation without changing the target every session.
- Test the effort
Adjust load so the set ends near planned RIR rather than an ego-driven number.
- Keep three exposures
Review a pattern, not one set, before moving the range.
Two reasonable choices
Machine press: 6–10 because it is stable and accepts load jumps. Lateral raise: 12–20 because one small jump changes difficulty substantially. Neither is universally better; both work when standard and effort remain comparable.
How to progress without abandoning the range
A range is a decision band, not a target for adding repetitions at any cost. Keep load and standard; accumulate repetitions while RIR stays on target. Once you repeatedly reach the top across all sets, add the smallest available load and accept returning toward the lower end.
| Log | Reading | Next session |
|---|---|---|
| 10, 9, 8 inside 6–10 at target RIR | Range partly mastered | Keep load and seek one more total rep |
| 10, 10, 10 with target standard and RIR | Top end consolidated | Add the smallest increment |
| 6, 5, 4 or worse technique | Load or fatigue does not fit | Hold, reduce or review context |
| More reps with shorter range of motion | Progress is not comparable | Restore the standard before adding |
The minimum log for a decision
Log exercise, load, repetitions, RIR and a limitation only when it changes the reading. Your last useful exposure should share enough of the current standard; comparing different variants creates false precision.
| Question | If yes | If no |
|---|---|---|
| Did the standard hold? | Compare reps and RIR | Fix technique or range |
| Did every set reach the ceiling? | Consider adding load | Keep the load |
| Did the intended muscle limit the work? | Keep the choice | Review exercise or range |
| Are several sessions comparable? | Decide from the pattern | Collect more data |
BUSTAFIT can preserve load, repetitions, RIR and workout history on iPhone so the next decision starts from a real reference. Judgment remains yours: the app does not prescribe a range or automatically interpret a performance drop.