Read the guide · Training
How Letz decides when it is time to increase the weight
A plan that never changes stops working, and a plan that changes too quickly leads to injury. Letz uses double progression: you increase reps until you reach the top of the target range, and only then add weight. When strength stalls across several consecutive sessions, it suggests a deload week for that specific exercise rather than pushing through. And on days when your readiness is low, the session offers a shorter option—which you can accept or decline; the app never cuts your workout unilaterally. None of this is about training until you collapse: the ranges below show why leaving one or two reps in reserve delivers nearly all the gains at a fraction of the recovery cost.
Numbers derived from this rule
| Parameter | Range | Weight | Rule |
|---|---|---|---|
| Load increase when progressing | 2–10 % | 40% | When completing the rep range with proper technique, increase the load by 2 to 10% or add one rep per set.Progressive Overload and Periodization |
| Reps in reserve at the end of the set | 1–3 RIR1 variant by context | 70% | Ending sets with 1 to 3 reps in reserve already produces gains; absolute failure is not necessary and compromises recovery.Proximity to Muscular Failure · Load and Volume Autoregulation |
| Deload interval | 4–8 weeks | 20% | Every 4 to 8 weeks, or when performance and energy drop together, reduce volume for one week.Deload: reduced-load week |
Rules and studies
- 01Progressive Overload and PeriodizationProgressing load or repetitions yields similar gains; varying the stimulus over weeks supports maximal strength more than keeping everything fixed.The default progression is double progression: first repetitions within the target range, then load or difficulty; logged workout history powers the recommendation for the next step.
- 02Load and Volume AutoregulationRIR/RPE and objective measures can help adapt resistance training to daily fluctuations within a structured plan.Each exercise has a target RIR, and the coach suggests adjusting the load when logged sets are too easy or too hard.
- 03Proximity to Muscular FailureTraining to failure is not mandatory; sets finished with a few reps in reserve already produce gains, and hypertrophy improves as sets get closer to failure.The plan targets 1 to 3 reps in reserve (2 to 4 for beginners); the guided workout never requires failure and treats pain or breakdown in technique as a cue to stop.
- 04Deload: reduced-load weekCoaches agree that short periods of reduced stress help manage fatigue and prepare for the next block; experimental evidence remains scarce.The training screen suggests a week with fewer sets when the training block exceeds the upper target range, or when it is within range but adherence drops; individual exercise progression also prompts a deload week when a strength plateau is detected. It never prescribes stopping entirely.
- 05Breaks and detrainingStopping training for a few weeks progressively reduces strength and power; short breaks carry little cost, and what is lost returns once training resumes.After a logged break, the coach reduces load and volume for the first week instead of picking up right where you left off.
- 06Repetition Tempo, Range of Motion, and Exercise OrderFull range of motion outperforms partial range for lower-body strength and hypertrophy; repetition tempo matters little within broad boundaries; starting with compound exercises maximizes strength gains in them.Compound exercises come first in each session, exercise cues call for a controlled, pain-free range of motion, and the programmed repetition tempo uses a natural cadence.