Hypertrophy

Formula

Example

Chest training week for a hypertrophy block: 4 sets bench press (RPE 7-8, 8-10 reps) + 3 sets incline DB press (RPE 7-8, 10-12 reps) + 3 sets cable fly (RPE 8, 12-15 reps) = 10 chest sets, performed 2x/week = 20 weekly sets. Sits at the top of the effective hypertrophy range.

How Afitpilot Uses This

Hypertrophy is one of the focus types in our mesocycle distribution model. When a mesocycle is labelled 'hypertrophy 40% / strength 40% / conditioning 20%', the plan generator favours moderate-load, moderate-rep work (RPE 7-9, 6-15 reps) close to failure on the targeted percentage of sessions. Training frequency is the partner lever: hypertrophy-oriented plans default to 2x/week per major muscle group, which is what most weekly volume targets resolve to when split across sessions. Volume per muscle group is not yet tracked explicitly, that's an item on the improvements roadmap (muscle-group-volume). For now, hypertrophy intent shows up as set/rep prescriptions and target RPE rather than per-muscle weekly counts.

Hypertrophy across athlete profiles

Known Limitations

• •We don't yet track weekly volume per muscle group (Tier 1 improvements item). Two athletes with the same total session count may have wildly different per-muscle stimuli depending on exercise selection.
• •Hypertrophy is hard to measure directly without DEXA or ultrasound, we rely on e1RM trends as a proxy, but strength and hypertrophy gains can diverge, especially for advanced athletes.
• •The 10-20 weekly sets range is a population average. Individual response varies 2-3x; some athletes maximise at 8 sets/muscle/week, others need 25+.
• •Hypertrophy results require sustained caloric intake (typically a small surplus or maintenance) and ~1.6-2.2g protein/kg bodyweight. We don't capture nutrition data, a perfectly programmed hypertrophy block will produce nothing without the dietary input.

Science Context

The modern hypertrophy model rests on Schoenfeld's mechanistic framework (2010), mechanical tension, metabolic stress, and muscle damage as the three primary drivers. Subsequent meta-analyses (Schoenfeld 2017, 2019; Krieger 2010) consistently identify weekly set volume as the most robust predictor, with effective rep ranges spanning 5-30 reps provided proximity to failure is adequate. Recent work (Refalo 2024) suggests proximity to failure may be more nuanced than 'closer is better', sets to 0-3 RIR produce equivalent growth to sets taken to true failure, with substantially less fatigue. The current consensus: 10-20 hard sets per muscle per week, 5-30 reps per set, 0-3 RIR most of the time, with periodic deload.

Related Terms

• Volume (Total Reps)The total number of repetitions performed in a session, aggregated across all exercises. Volume is the most fundamental "how much work did you do?" metric.
• SetsA set is one continuous bout of exercise, the number of times you perform a group of consecutive reps before resting. Sets are the fundamental building block of every workout prescription.
• Compound vs Isolation ExercisesCompound exercises move multiple joints and recruit multiple major muscle groups in one rep (squat, deadlift, bench press, row, overhead press). Isolation exercises move primarily one joint and target a single muscle group (curl, leg extension, lateral raise, calf raise). Almost every strength program is built from a small number of compound lifts driving the bulk of the stimulus, with isolation work added to address weaknesses or directly target a specific muscle.
• Reps (Repetitions)One complete movement cycle of an exercise, one squat down and up, one press up and down. Reps are the atomic unit of training volume.
• Rep RangesThe traditional grouping of repetitions per set into broad training zones: low reps for strength, moderate reps for hypertrophy (muscle growth), and high reps for muscular endurance. Rep ranges are the most common way coaches communicate intent, "5x5", "3x8-12", "2x20" each implies different load, rest, and adaptation goals.