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ObservationalLoad intensity
Untrained men trained for eight weeks in a low, intermediate or high repetition-maximum zone. Maximal strength improved most in the low-repetition group, repetitions at a submaximal load improved most in the high-repetition group, and only the low and intermediate zones produced fibre hypertrophy.
How Fibral applies it: Put a lifter's heaviest work in a low repetition-maximum zone when the goal is a bigger one-rep max, and keep very high repetition work out of the hypertrophy budget.
Limits and applicability
No limitation statement has been published for this note yet. Treat it as a general evidence-informed rule, not an individualized guarantee.
- Campos GE, Luecke TJ, Wendeln HK, Toma K, Hagerman FC, Murray TF, Ragg KE, Ratamess NA, Kraemer WJ, Staron RS. (2002). Muscular adaptations in response to three different resistance-training regimens: specificity of repetition maximum training zones. View source
Approved content v1 · updated Aug 17, 2026
Expert consensusLoad intensity
A review of the repetition continuum argues that the conventional mapping of heavy loads to strength, moderate loads to hypertrophy and light loads to endurance is not fully supported by current research. The authors propose instead that muscular adaptations can be obtained, and in some cases optimised, across a wide spectrum of loading zones.
How Fibral applies it: Choose load by what the lifter tolerates and enjoys within the evidenced spectrum rather than assuming a single rep range owns a single adaptation.
Limits and applicability
No limitation statement has been published for this note yet. Treat it as a general evidence-informed rule, not an individualized guarantee.
- Schoenfeld BJ, Grgic J, Van Every DW, Plotkin DL. (2021). Loading Recommendations for Muscle Strength, Hypertrophy, and Local Endurance: A Re-Examination of the Repetition Continuum. View source
Approved content v1 · updated Aug 17, 2026
Randomized trialLoad intensity
Men trained one limb at 20% of one-rep max and the contralateral limb at 40, 60 or 80% with volume load matched over twelve weeks. All loads increased strength and cross-sectional area, but the 20% condition was suboptimal for both while 80% was clearly superior for strength and size.
How Fibral applies it: Keep hypertrophy work at or above 40% of one-rep max, and use heavier loads when maximal strength is the goal.
Limits and applicability
No limitation statement has been published for this note yet. Treat it as a general evidence-informed rule, not an individualized guarantee.
- Lasevicius T, Ugrinowitsch C, Schoenfeld BJ, Roschel H, Tavares LD, De Souza EO, Laurentino G, Tricoli V. (2018). Effects of different intensities of resistance training with equated volume load on muscle strength and hypertrophy View source
Approved content v1 · updated Aug 17, 2026
Randomized trialLoad intensity
A systematic review found that the one-repetition maximum (1RM) test is a highly reliable measure of maximal strength when the protocol is standardized, showing very high test-retest reliability across both upper- and lower-body exercises and trained and untrained participants. Standardized 1RM assessment is therefore a dependable basis for prescribing and tracking load.
How Fibral applies it: Prescribe loads as a percentage of a standardized 1RM (or a validated estimate) and re-test periodically to track strength and progress loads.
Limits and applicability
No limitation statement has been published for this note yet. Treat it as a general evidence-informed rule, not an individualized guarantee.
- Grgic J, Lazinica B, Schoenfeld BJ, Pedisic Z (2020). Test-Retest Reliability of the One-Repetition Maximum (1RM) Strength Assessment: a Systematic Review View source
Approved content v4 · updated Aug 17, 2026
Meta-analysisLoad intensity
A large network meta-analysis of resistance-training prescriptions in healthy adults concluded that higher training loads are most effective for maximizing muscular strength, while hypertrophy is driven more by total volume, and that performing multiple weekly sets outperforms single-set training. Load and volume act on strength and size somewhat differently.
How Fibral applies it: Prescribe heavier loads when the goal is strength - the prescriptions that maximised strength used more than 80% of one repetition maximum - and prioritize accumulating volume across multiple sets when the goal is size.
Limits and applicability
No limitation statement has been published for this note yet. Treat it as a general evidence-informed rule, not an individualized guarantee.
- Currier BS, Mcleod JC, Banfield L, et al. (2023). Resistance training prescription for muscle strength and hypertrophy in healthy adults: a systematic review and network meta-analysis View source
Approved content v4 · updated Aug 17, 2026
Meta-analysisLoad intensity
A meta-analysis found that low-load and high-load resistance training produce similar muscle hypertrophy when every set is taken to momentary muscular failure, whereas maximal strength gains clearly favour heavier loads. Growth is load-tolerant across the spectrum of loading ranges the trials covered, which split low from high at 60% of one repetition maximum; maximal strength is not.
How Fibral applies it: For hypertrophy, pick load by preference and joint tolerance and take sets close to failure; for maximal strength, bias toward heavier loads instead.
Limits and applicability
No limitation statement has been published for this note yet. Treat it as a general evidence-informed rule, not an individualized guarantee.
- Schoenfeld BJ, Grgic J, Ogborn D, Krieger JW (2017). Strength and Hypertrophy Adaptations Between Low- vs. High-Load Resistance Training: A Systematic Review and Meta-analysis View source
Approved content v4 · updated Aug 17, 2026