Overview
The original SBS Strength Program (Stronger by Science / Greg Nuckols). 21 weeks = three 7-week blocks (deloads in Weeks 7/14/21); intensity rises and reps per set fall from block to block, taking main lifts from 70% to 95%. Unlike the "final set to failure" variation, autoregulation in this version works through set count: each exercise is done in sets of a fixed rep count, stopping when the reps in reserve (RIR) at the end of a set hit the threshold; completing 4-6 sets is normal, and anything above or below that means adjusting the training max (TM).
Who it's for
- Intermediate to advanced lifters; those who dislike going to failure every week and prefer to do more or fewer sets depending on how they feel.
- This entry is the 4-day full-body version (official default; 2x-6x and low-frequency versions also exist).
Weekly structure
Same as the RTF version: day 1 squat + incline bench press + sumo deadlift; day 2 bench press + front squat + push press; day 3 deadlift + close-grip bench press; day 4 press + paused squat. Main-lift weekly intensity waves (%TM): 70/75/80→72.5/77.5/82.5→60→75/80/85→77.5/82.5/87.5→60→80/85/90→85/90/95→60; accessories -10 points. Reps per set come from an intensity lookup (70% → 5, 80% → 3, 90% → 1); the RIR threshold drops as intensity rises (≤57.5% → 5, 60-67.5% → 4, 70-77.5% → 3, 80-87.5% → 2, 90-95% → 1, 97.5%+ → 0).
Progression rules (TM autoregulation)
Treat the in-app 1RM as the training max (TM). For each exercise, do sets until the RIR at the end of a set is ≤ the threshold:
- Completed fewer than 4 sets → that lift's TM -5%
- Completed 4-6 sets → no change
- Completed more than 6 sets → TM +2%
The data side uses 5 sets as a placeholder; in practice, just do 4-6 sets per the rules above (use "add a set" to fill in sets). The @RPE8 single check and deload-week semantics are the same as the RTF version: the measured single ÷ 0.9 can directly update TM; deload weeks (7/14/21) make no adjustments.
Notes
- A conservative starting 1RM is fine; the system will calibrate automatically.
- Upper back/accessory choices have no placeholders; paused squat is attached to squat (tempo 0-2-0, reduce for its own lower max).
- If you want a more objective adjustment signal, use the "final set to failure" variation; for a compromise between the two, use the "last set RIR" variation.
Intensity, Reps per Set & RIR Cutoff Table
The 21-week cycle rotates intensity upward every three weeks (with deloads on Weeks 7, 14, and 21). Instead of doing one all-out AMRAP set, you use the target %TM below to pick your reps per set and stop adding sets as soon as you reach the RIR cutoff:
| Intensity (% TM) |
Reps per Set (Main) |
Aux Lift Pairing |
Stop Set When RIR ≤ |
Deload / Role |
| 60% (50% Aux) |
5 reps |
5 reps |
Complete 4–6 sets (ignore RIR) |
Weeks 7, 14, 21 deload |
| 70% (60% Aux) |
5 reps |
7 reps |
3 RIR |
Block 1 accumulation |
| 75% (65% Aux) |
4 reps |
6 reps |
3 RIR |
Block 1–2 work |
| 80% (70% Aux) |
3 reps |
5 reps |
2 RIR |
Block 2 strength |
| 85% (75% Aux) |
2 reps |
4 reps |
2 RIR |
Block 2–3 transition |
| 90% (80% Aux) |
1 rep |
3 reps |
1 RIR |
Block 3 peaking (Weeks 17, 19) |
| 95% (85% Aux) |
1 rep |
2 reps |
1 RIR |
Block 3 peak (Week 20) |
Practical Setup Notes
- Start conservatively on paused squat and secondary lifts so Day 4 stays recoverable.
- If your estimated sets exceed 6 on Week 1, do 6–7 clean sets and let the +2% TM adjustment catch up automatically rather than grinding to 10+ sets.
FAQ
How is SBS Strength different from SBS Reps to Failure (RTF)?
SBS RTF asks you to push the final set to failure (or fixed AMRAP reps) every session. SBS Strength instead keeps every set submaximal at a fixed rep count and lets how many total sets you complete before reaching the RIR cutoff drive weekly Training Max updates.
Should I stop a set before form breaks down?
Yes. RIR (Reps in Reserve) assumes technical failure, not grinding with collapsed form. Once bar speed slows to the point that hitting the target reps again would only leave the listed RIR, wrap up that lift for the day.
What if I complete fewer than 4 sets because I felt tired that day?
Follow the rule consistently: log your sets accurately and step the TM down slightly (−5%), or hold TM if an outside factor (poor sleep or travel) caused a clear one-off dip.
Can I swap auxiliary variations like incline bench or front squat?
Yes. Pick close variations that target your weak points without heavy setup friction, and use a dedicated conservative max for slower-tempo movements such as paused squats.
Do I test a true 1RM on Week 21?
Week 21 is a lighter deload and readiness week leading into optional heavy singles (@RPE 8–9 or a new max test) before starting your next 21-week cycle.