Strength Training Formula

Junk Volume Threshold Formula

Junk volume is training volume above your Maximum Adaptive Volume (MAV) that produces no further hypertrophy or strength gain — only fatigue. Schoenfeld's 2017 meta-analysis pegs the dose-response: muscle growth tracks weekly set count up to a per-muscle ceiling. Above that ceiling, additional sets cost more recovery than they add. The formula sets a threshold per muscle group based on training age, intensity, and recovery quality.

5 VARIABLESPublished May 14, 2026Live Content

By Orbyd Editorial · AI Fit Hub Team

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Junk Volume Detector

Junk volume detector: paste a multi-week CSV training log and identify sets that don't drive strength or hypertrophy.

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Formula 5 variables Worked example Variations

Education · Not medical advice. Output is deterministic math from your inputs.Editorial standards Sponsor disclosure Corrections

Formula

Copy the exact expression or work through it step by step below.

 junk_volume_threshold = MAV × intensity_factor × recovery_factor
   MAV ≈ 12 + 0.5 × (training_age_years − 1)   sets/muscle/week
   intensity_factor: 1.0 (RPE 7-8), 0.8 (RPE 9-10)
   recovery_factor: 1.0 (sleep ≥7h, low life stress), 0.7 (poor recovery)

Variables

junk_volume_threshold

Sets above which additional volume is junk

Per-muscle weekly working-set count. Sets beyond this produce no measurable hypertrophy and increase joint/CNS fatigue.

MAV

Maximum Adaptive Volume

Per-muscle weekly set ceiling for hypertrophy. Beginners: 10-12 sets. Intermediates: 14-18 sets. Advanced: 20-25 sets. Above MAV is MRV (Maximum Recoverable Volume — survive but don't progress).

training_age_years

Years of consistent training

Years of bodybuilding-style training, not total gym attendance. Stop-and-start counters reset to 80% of prior level.

intensity_factor

Set intensity multiplier

Sets close to failure (RPE 9-10) deplete more glycogen and accumulate more fatigue per set. Lower MAV by 20% when most sets are high-RPE.

recovery_factor

Recovery quality multiplier

Poor sleep, high life stress, or undereating all lower the recoverable volume ceiling. A 6h-sleep, dieting lifter has 30% less MAV than the same lifter eating + sleeping well.

Step By Step

1

Determine training age (years of consistent lifting).

5 years of consistent training.
2

Compute base MAV.

MAV = 12 + 0.5 × (5 − 1) = 14 sets/muscle/week.
3

Apply intensity factor. Most sets at RPE 7-8 = 1.0. Most at RPE 9-10 = 0.8.

Training mostly RPE 8: factor 1.0. → MAV stays 14.
4

Apply recovery factor. Good sleep + adequate calories = 1.0. Cutting + 6h sleep = 0.7.

Maintenance phase, 7h sleep: factor 1.0. Junk threshold = 14 × 1.0 × 1.0 = 14 sets/week per muscle.
5

Compare actual weekly volume per muscle group. Anything above threshold is junk.

Logging shows 22 sets/week for chest. Threshold 14. → 8 sets are junk. Cut to ~16 to leave a stimulus margin.

Worked Example

5-year intermediate lifter, currently doing 22 sets chest/week at RPE 8 in maintenance

Training age

5 years

Most sets at RPE

7-8 (intensity_factor = 1.0)

Recovery state

Good (recovery_factor = 1.0)

Current chest volume

22 sets/week

MAV = 12 + 0.5 × (5 − 1) = 14 sets/muscle/week Junk threshold = 14 × 1.0 × 1.0 = 14 sets Current 22 sets − 14 threshold = 8 junk sets

8 chest sets/week are likely producing zero additional hypertrophy while costing ~30% more recovery time. Cut chest from 22 to 14-16 sets — reallocate the saved volume to lagging muscle groups (legs, back), or take an extra rest day.

Common Variations

Schoenfeld 2017: dose-response slope flattens above 10 sets/muscle/week; some growth continues to 20+ sets in trained subjects but diminishing returns are steep.

RP MEV/MAV/MRV framework: MEV (Minimum Effective Volume) ~6-8 sets, MAV (Maximum Adaptive Volume) ~12-16 sets, MRV (Maximum Recoverable Volume) ~20-25 sets. Each muscle group has its own range.

Frequency adjustment: same weekly volume split across 3 sessions outperforms 1 session by ~15% (Schoenfeld 2016). Junk volume threshold scales with frequency — 14 sets split into 2x7 sessions provides more stimulus than 1x14.

Periodized variation: volume can spike 30-50% above MAV for 1-2 weeks (overload) before deload, without long-term junk-volume penalty. Helms et al. 2018 — strategic overreach.

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Sources & References

Schoenfeld, Ogborn & Krieger (2017). Dose-response relationship between weekly resistance training volume and increases in muscle mass: A systematic review and meta-analysis. — Journal of Sports Sciences — foundational volume-hypertrophy meta-analysis
Schoenfeld, Ogborn & Krieger (2016). Effects of resistance training frequency on measures of muscle hypertrophy: A systematic review and meta-analysis. — Sports Medicine — frequency effects on volume distribution
Helms, Cronin, Storey & Zourdos (2018). RPE and velocity relationships for the back squat, bench press, and deadlift in powerlifters. — Journal of Strength & Conditioning Research — RPE calibration
Israetel et al. (Renaissance Periodization, 2017). Scientific Principles of Hypertrophy Training. — RP — MEV/MAV/MRV framework with practical application