| name | hypertrophy-training |
| description | Evidence-based muscle hypertrophy training, nutrition, exercise selection, periodization, recovery, supplements, and progress tracking. Use when Codex needs to build strength-training programs, set volume or RIR targets, choose exercises, troubleshoot plateaus, calculate macros/TDEE, or answer bodybuilding and muscle-growth questions. |
Evidence-Based Hypertrophy Training Guide
This skill provides a comprehensive overview of scientifically-backed principles for maximum muscle hypertrophy. All information is based on meta-analyses and systematic reviews from 2010 onwards, with emphasis on established findings from key researchers in the field.
Terminology: For definitions of terms like RIR, RPE, MEV/MAV/MRV, and other abbreviations, see references/glossary.md.
1. Basic Principles of Hypertrophy
1.1 Mechanical Tension - Primary Driver
Key Finding (Schoenfeld et al., 2017; Wackerhage et al., 2019):
- Mechanical tension is the primary stimulus for molecular mechanisms of hypertrophy
- Acute hormonal responses, metabolic stress, cell swelling ("pump") do not significantly contribute to hypertrophy
- Sarcoplasmic hypertrophy as a standalone phenomenon lacks strong scientific support
1.2 Volume Landmarks (Renaissance Periodization)
For detailed volume recommendations by muscle group, see volume-landmarks.md.
Quick Reference:
- MEV: 6-10 sets/muscle/week (minimum for growth)
- MAV: 12-20 sets/muscle/week (optimal for most)
- MRV: 20-26+ sets/muscle/week (maximum recoverable)
Note: Individual variation is ±50%. Start conservatively and adjust based on progress.
1.3 Optimal Per-Session Volume
Maximum per muscle per workout: 6-8 hard sets (Krieger, 2010 [PMID: 20300012]; Schoenfeld et al., 2017 dose-response [PMID: 27433992])
Why 6-8 sets specifically?
- Meta-analyses show diminishing returns above ~10 sets/session
- 6-8 sets = optimal stimulus vs. recovery ratio
- Higher volumes are better split across multiple sessions (increased frequency)
2. Training Variables
2.1 Training Frequency
Schoenfeld et al. (2016) meta-analysis:
- For hypertrophy: frequency has minimal impact when volume is matched
- For strength: higher frequency has clear benefit
- Practical recommendation: 2x per week per muscle (optimal for most)
2.2 Rep Range
Key Finding (Schoenfeld et al., 2017):
- 5-30+ reps produces comparable hypertrophy when training close to failure
- Higher loads (>75% 1RM) more effective for strength
- Lower loads require more sets to reach complete failure
Practical rep range distribution:
| Rep Range | Use Case | Why |
|---|
| 5-8 | Strength + hypertrophy, compound movements | High mechanical tension, efficient for nervous system |
| 8-12 | "Sweet spot" for hypertrophy | Balance between tension and metabolic stress, practical volume |
| 12-20 | Isolation, metabolic stress | Lower joint stress, good for pump and technique |
| 20-30 | BFR training, high fatigue | Effective only with BFR or for very experienced |
2.3 Proximity to Failure (RIR - Reps in Reserve)
Recommendations:
- 0-3 RIR for most sets
- Training to complete failure not necessary, but effective
- 1-2 RIR = optimal balance of stimulus vs. recovery
- Advanced lifters may need closer proximity to failure
2.4 Tempo / Time Under Tension
Research findings:
- Slow eccentric phase (4s) → greater 1RM improvement and hypertrophy
- Recommendation: 2-8 seconds total rep duration
- Controlled movement > fast or extremely slow
2.5 Rest Periods
- 2-3+ minutes for compound movements (maximize strength)
- 60-90 seconds for isolation (maintain volume)
- Rule: Rest enough to complete prescribed volume
3. Periodization
3.1 Periodization Models
| Model | Description | Best For |
|---|
| Linear | Progressive load increase, volume decrease | Beginners |
| DUP (Daily Undulating) | Different intensities each workout | Intermediate+ |
| Block | 3-6 week blocks with different focus | Advanced |
| Autoregulation | RPE/RIR-based management | All levels |
Meta-analysis DUP vs LP:
- DUP slightly better for strength (ES = 0.24)
- For hypertrophy: comparable
3.2 Mesocycle Structure
Week 1: Accumulation (lower intensity, higher volume)
Week 2: Accumulation (moderate intensity)
Week 3: Accumulation (higher intensity)
Week 4: Intensification (lower volume, higher loads)
Week 5: Deload (50% volume, 60-70% intensity)
3.3 Deload Protocols
For detailed deload protocols see periodization.md.
Quick Overview:
- Volume deload: 50% volume, full intensity
- Frequency: Every 4-6 weeks
When to deload:
- Systematically per plan
- With accumulating fatigue
- With stagnation 2+ weeks
4. Exercises and Exercise Selection
4.1 Lengthened Partials (Milo Wolf Research)
Key Finding (Wolf et al., 2023 [DOI: 10.47206/ijsc.v3i1.182]; Kassiano et al., 2023 [PMID: 37015016]):
- Training at stretched position may provide additional hypertrophic stimulus
- Lengthened partials = bottom 50-70% ROM
- Practical suggestion: Consider including lengthened partial training for some exercises. The optimal proportion is not yet established—current research compares full ROM vs partial ROM, not optimal ratios for mixed programming.
Application examples:
| Muscle | Exercises Emphasizing Stretch |
|---|
| Biceps | Preacher curl (bottom half), incline curl |
| Triceps | Overhead extension, skull crushers |
| Chest | DB fly (stop before peak), cable crossover low |
| Back | Pullovers, seated row with stretch emphasis |
| Quads | Leg extension (bottom half), sissy squat |
| Hamstrings | Seated leg curl (better than lying), RDL |
| Calves | Standing calf raise - deep stretch |
4.2 Stimulus-to-Fatigue Ratio (SFR)
High SFR exercises (prefer):
- Machine exercises with good resistance curve
- Cable exercises
- Exercises at stretched position
Low SFR exercises (limit):
- Heavy deadlifts (high systemic fatigue)
- Barbell rows (spinal erector fatigue)
- Leg press with extreme ROM
5. Nutrition for Hypertrophy
For complete nutritional protocols see nutrition.md.
Quick Overview
Protein: 1.6-2.2 g/kg body weight daily
Caloric surplus: +200-500 kcal (depending on training status)
Distribution: 4-6 protein doses daily, 0.4-0.55 g/kg per dose
Pre-sleep: Casein or blended protein (30-40g)
6. Supplementation
For complete tier-based overview see supplements.md.
Quick Overview
Tier 1 (Recommended): Creatine 3-5g/day, Caffeine 3-6mg/kg, Protein as needed
Tier 2 (Consider): Beta-alanine, Citrulline, Vitamin D (if deficient)
Not Recommended: Turkesterone, Ecdysterone, most "testosterone boosters"
7. Recovery
7.1 Sleep
Recommendation: 7-9 hours of quality sleep
| Factor | Impact on Hypertrophy |
|---|
| <6 hours sleep | -60% testosterone, ↓ MPS |
| Consistent timing | Better circadian rhythm |
| Room temperature | 18-20°C optimal |
7.2 Cold Water Immersion (CWI)
WARNING: CWI may IMPAIR hypertrophy!
- Roberts et al. (2015): Significantly lower hypertrophy with CWI
- Mechanism: Blunts inflammatory response needed for adaptation
- Recommendation: Avoid CWI after strength training (min 4-6 hours)
7.3 Active Recovery
- Light cardio (60-65% HRmax, 20-30 min)
- Mobility work
- Foam rolling (acute relief, doesn't affect hypertrophy)
8. Advanced Techniques
| Technique | Description | When to Use |
|---|
| Drop sets | Set to failure → -20-25% weight → continue | 1-2x per workout, isolation |
| Rest-pause | Set to failure → 15-20s → 4-6 reps | Effective accumulation |
| Myo-reps | 12-15 activation set → mini-sets 4-6 reps | Time-efficient |
| Giant sets | 3+ exercises without rest | Metabolic stress |
| Forced negatives | Assistance in concentric, solo eccentric | Sparingly, high load |
9. Training Splits
Overview
| Split | Frequency | Best For |
|---|
| Full Body | 3x/week | Beginners, time-constrained |
| Upper/Lower | 4x/week | Intermediate |
| PPL | 6x/week | Intermediate-Advanced |
| Arnold | 6x/week | Advanced bodybuilders |
| Bro Split | 5-6x/week | Enhanced athletes |
Recommended Structure by Level
Beginner (0-2 years):
- Split: Full Body 3x/week
- Volume: 10-12 sets/muscle/week
- RIR: 3-4 (learning technique)
- Progression: Linear (every workout)
Intermediate (2-5 years):
- Split: Upper/Lower or PPL
- Volume: 12-20 sets/muscle/week
- RIR: 3→1 during mesocycle
- Progression: Weekly or bi-weekly
Advanced (5+ years):
- Split: PPL, PHAT, or specialization
- Volume: 16-26+ sets/muscle/week
- RIR: 2-0, intensification techniques
- Progression: Block periodization
10. Weak Point Training
Strategies for Lagging Body Parts
- Prioritization: Train weak part first in workout
- Frequency: Increase to 3x/week
- Volume: Add 2-4 extra sets
- Exercise selection: Exercises emphasizing stretch for that muscle
- Mind-muscle connection: Slower tempo, visualization
11. High vs Low Responders
Important: Individual response to training varies significantly (up to ±50% in hypertrophy outcomes). The volume landmarks, rep ranges, and other recommendations in this guide represent averages. Track your own progress and adjust accordingly.
Distinguishing Factors
| Factor | High Responders |
|---|
| Ribosomal biogenesis | Higher |
| Satellite cells | Greater proliferation |
| Androgen receptors | Higher content |
| IGF-1 expression | Elevated |
Strategies for Low Responders
- Increase frequency (3-4x/week per muscle)
- Higher volume (20-30 sets/muscle/week)
- Vary stimuli (different rep ranges, exercises)
- Optimize recovery (protein 2.0+ g/kg, sleep 8+h)
- Patience - progress is slower but still possible
Reference Files
For detailed information see files in references/:
When to Use Which File
| Situation | Read File |
|---|
| Creating training plan | programs.md → periodization.md → exercises.md |
| Stagnation / plateau | periodization.md (deload) → techniques.md |
| Exercise selection for muscle group | exercises.md |
| Nutrition / macro questions | nutrition.md |
| Supplement evaluation | supplements.md |
| Recovery / fatigue / overtraining | recovery.md |
| Understanding why something works | mechanisms.md |
| Female-specific questions | female-training.md |
| Age-specific training (youth, masters, seniors) | age-specific-training.md |
| Injury / pain | injury-prevention.md → exercises.md (substitutions) |
| Progress tracking | progress-tracking.md |
| Motivation / adherence / mental strategies | psychology.md |
| Logging / tracking workouts | sample-logs.md → progress-tracking.md |
Troubleshooting Decision Tree
Problem?
├── Not stagnating, but want to optimize
│ └── Read: periodization.md → techniques.md
├── Strength stagnation
│ └── Read: periodization.md (deload) → programs.md
├── Hypertrophy stagnation
│ └── Read: mechanisms.md → exercises.md (lengthened partials)
├── Fatigue / poor recovery
│ └── Read: recovery.md → nutrition.md
├── Injury / pain
│ └── Read: injury-prevention.md → exercises.md (substitutions)
├── Nutrition questions
│ └── Read: nutrition.md → supplements.md
├── Female-specific questions
│ └── Read: female-training.md
├── Age-specific questions (youth, masters, seniors)
│ └── Read: age-specific-training.md
├── Progress tracking
│ └── Read: progress-tracking.md
├── Cardio / conditioning questions
│ └── Read: cardio-interference.md → recovery.md
└── Motivation / adherence / mental blocks
└── Read: psychology.md
Reference Files
mechanisms.md - Hypertrophy mechanisms (mTOR, MPS, satellite cells)muscle-imbalances.md - Bilateral asymmetries, postural issues, correction protocolsnutrition.md - Detailed nutritional protocols, DIAAS, timingperiodization.md - Periodization models (LP, DUP, Block)supplements.md - Complete tier-based supplement overviewrecovery.md - Recovery strategies, sleep, CWI warning, hormonal optimizationcardio-interference.md - Cardio integration, AMPK-mTOR, interference minimizationtechniques.md - Advanced techniques (drop sets, myo-reps, BFR)programs.md - Sample programs by levelexercises.md - Exercise database, SFR, substitutionsfemale-training.md - Female-specific training considerationsinjury-prevention.md - Injury prevention and managementprogress-tracking.md - Progress tracking, metrics, appsage-specific-training.md - Training adjustments by age group (youth, masters, seniors)psychology.md - Training psychology, motivation, adherence, habit formationglossary.md - Quick reference for training, physiology, and nutrition termssample-logs.md - Example training logs for different phases and levelsvolume-landmarks.md - Detailed volume landmarks (MEV/MAV/MRV) by muscle groupmeal-plans.md - Konkrétní příklady jídelníčků pro bulk/cut/recomp
Quick Navigation by Topic
| If you need... | Start with | Then see |
|---|
| Build a plan from scratch | programs.md | periodization.md → exercises.md |
| Optimize nutrition | nutrition.md | supplements.md |
| Break through plateau | periodization.md | techniques.md → recovery.md |
| Understand the science | mechanisms.md | glossary.md |
| Train with injury | injury-prevention.md | exercises.md (substitutions) |
| Prepare for competition | programs.md (competition prep) | nutrition.md (cutting) |
| Optimize hormones naturally | recovery.md (hormonal section) | nutrition.md |
| Body recomposition | nutrition.md (recomp section) | programs.md |
| Konkrétní jídelníčky | meal-plans.md | nutrition.md |
Plan Creation Workflow
When creating a complete training program:
1. Gather info → Age, goals, experience, schedule, equipment
2. Read `programs.md` → Select appropriate split
3. Read `exercises.md` → Choose exercises per muscle
4. Read `periodization.md` → Structure mesocycles
5. Read `nutrition.md` → Set macros and timing
6. Optional: `calculators.py` → TDEE, protein, volume
Calculators
The scripts/calculators.py script provides common training calculations:
| Command | Description | Example |
|---|
tdee | TDEE calculation (Mifflin-St Jeor) | python3 scripts/calculators.py tdee 80 180 30 m moderate |
macros | Macronutrient targets by goal | python3 scripts/calculators.py macros 80 2500 bulk |
1rm | Estimate 1RM from submaximal lift | python3 scripts/calculators.py 1rm 100 8 |
protein | Protein needs by status | python3 scripts/calculators.py protein 80 bulk intermediate |
weekly-volume | Volume assessment vs landmarks | python3 scripts/calculators.py weekly-volume 6 2 |
volume | Training volume metrics | python3 scripts/calculators.py volume 4 10 80 |
rir | RIR to %1RM conversion | python3 scripts/calculators.py rir 2 |
Usage:
python3 scripts/calculators.py <command> [args]
Key Researchers
- Brad Schoenfeld (Lehman College) - Hypertrophy, volume, mechanisms
- Stuart Phillips (McMaster) - Protein, mechanical tension
- Eric Helms (AUT) - RIR/RPE, natural bodybuilding
- Mike Israetel (RP Strength) - Volume landmarks
- Milo Wolf (Updated 2025) - Lengthened partials research, multi-site trials
- James Krieger (Weightology) - Meta-analyses
- Michael Zourdos (FAU) - DUP, autoregulation
Sources
- Schoenfeld BJ et al. (2017). Strength and hypertrophy adaptations. J Strength Cond Res. PMID: 28834797
- Schoenfeld BJ et al. (2016). Effects of resistance training frequency. Sports Med. PMID: 27102172
- Morton RW et al. (2018). Protein supplementation meta-analysis. Br J Sports Med. PMID: 28698222
- Wolf M et al. (2023). Partial vs full ROM resistance training: A systematic review and meta-analysis. Int J Strength Cond. DOI: 10.47206/ijsc.v3i1.182
- Roberts LA et al. (2015). Cold water immersion and muscle hypertrophy. J Physiol. PMID: 26174323
- Schoenfeld BJ et al. (2010-2022). Multiple meta-analyses on hypertrophy mechanisms.
- Roig M et al. (2009). The effects of eccentric versus concentric resistance training on muscle strength and mass in healthy adults: a systematic review with meta-analysis. Br J Sports Med. PMID: 18981046
- Wackerhage H et al. (2019). Molecular mechanisms of muscle hypertrophy. Eur J Sport Sci. PMID: 30741116
- Kassiano W et al. (2023). Greater gastrocnemius muscle hypertrophy after partial ROM training at long muscle lengths. J Strength Cond Res. PMID: 37015016
- Kassiano W et al. (2023). Which ROMs lead to Rome? Systematic review of ROM effects on hypertrophy. J Strength Cond Res. PMID: 36662126
- Krieger JW (2010). Single vs. multiple sets of resistance exercise for muscle hypertrophy: A meta-analysis. J Strength Cond Res. PMID: 20300012
- Da Silva JJ et al. (2023). Effects of eccentric vs concentric resistance training on strength and hypertrophy. J Strength Cond Res. PMID: 36989393
- Zourdos MC et al. (2016). DUP vs traditional periodization for strength gains. J Strength Cond Res. PMID: 26398700
- Grgic J et al. (2018). Effects of training frequency for muscular strength: A systematic review and meta-analysis. Sports Med. PMID: 29470825
- Wolf M et al. (2025). Lengthened partial ROM resistance training is equally effective as full ROM training. PeerJ. PMID: 39959841
- Wolf M et al. (2024). The effects of lengthened-partial range of motion resistance training of the limbs on arm and thigh muscle cross-sectional area: a multi-site cluster trial (preprint). SportRxiv. DOI: 10.51224/SRXIV.485
- Pelland JC et al. (2025). The Resistance Training Dose Response: Meta-Regressions Exploring the Effects of Weekly Volume and Frequency on Muscle Hypertrophy and Strength Gains. Sports Med. PMID: 41343037
- Piñero A et al. (2024). Throwing cold water on muscle growth: A systematic review with meta-analysis of the effects of postexercise cold water immersion on resistance training-induced hypertrophy. Eur J Sport Sci. 24(2):177-189. PMID: 38621735
- Does Muscle Length Influence Regional Hypertrophy? A Systematic Review and Meta-Analysis. Int J Sports Med. PMID: 40570881
Note: All citations are verifiable via PubMed or DOI.
