How close to failure should you train?
Effort is the variable most people get wrong in both directions. Some grind every set to a standstill and spend the week recovering from it. Many more stop when the set gets uncomfortable, several reps before the muscle has anything to say about it, and then wonder why the programme is not working.
What the research shows
Training closer to failure tends to favour muscle growth, but the benefit is not unlimited.
A systematic review with meta-analysis of proximity-to-failure studies found hypertrophy favoured training nearer failure, with the effect clearest when the comparison set stopped well short of it. Differences between failure and a couple of reps short were small.
Refalo et al. · Sports Medicine · 2023 · Systematic reviewEffort-based prescription is a usable way to set daily load.
Research on RPE and reps-in-reserve scales in resistance training supports their use for autoregulating load, while noting that accuracy improves with experience and is poorest far from failure.
Zourdos et al. · J Strength Cond Res · 2016 · Peer-reviewed researchVolume of hard sets still matters alongside effort.
Dose-response analyses show muscle growth rising with weekly sets, meaning a handful of maximal sets does not substitute for an adequate number of near-maximal ones.
Schoenfeld, Ogborn & Krieger · J Sports Sci · 2017 · Systematic reviewReading your own effort
Bar speed is the most useful cue. When the concentric slows noticeably despite you trying to move it fast, you are within two reps of failure . Burning and discomfort arrive much earlier and mean far less.
Where to spend your hardest efforts
Main compound lifts at RIR 2–3
Suits — Keeps technique intact and fatigue manageable across the week
Costs — Requires honest load selection rather than heroics
Isolation work at RIR 0–1
Suits — Cheap stimulus; failure is safe on a machine or cable
Costs — Easy to overdo and blunt the next session
Why not just go to failure every set?
Because the cost is paid later. Sets to failure take longer to recover from, reduce the reps you can complete on subsequent sets and raise the chance of technical breakdown on loaded compound movements. The additional growth over stopping one or two reps short is small; the additional fatigue is not .
How CALIBR handles it
CALIBR asks for your effort on sets where it changes the next prescription, and treats an unrated set as a normal hard set rather than an easy one — so skipping the rating never causes the load to jump. Over time, your reported effort against the reps you actually completed is what moves your working weights.
Key takeaways
- One to three reps in reserve covers the productive range for most sets.
- Proximity to failure matters more than the rep number you chose.
- Save genuine failure for exercises where it is safe and cheap.
- Bar speed is a better cue than discomfort.
- Most people underestimate their reps in reserve; calibrate occasionally.
Common questions
References
- [1]Influence of resistance training proximity-to-failure on skeletal muscle hypertrophy: a systematic review with meta-analysisRefalo et al. · Sports Medicine · 2023 · Systematic review
- [2]Novel resistance training-specific rating of perceived exertion scale measuring repetitions in reserveZourdos et al. · J Strength Cond Res · 2016 · Peer-reviewed research
- [3]Dose-response relationship between weekly resistance training volume and increases in muscle mass: a systematic review and meta-analysisSchoenfeld, Ogborn & Krieger · J Sports Sci · 2017 · Systematic review
- [4]Progression models in resistance training for healthy adults (position stand)American College of Sports Medicine · Med Sci Sports Exerc · 2009 · Position stand
- [5]Effects of rest interval duration in resistance training on measures of muscular strength: a systematic reviewGrgic et al. · Sports Medicine · 2018 · Systematic review