Skip to content
TPF Hybrid

Methodology

How TPF actually works.

Most lifters reach a point where they’re doing everything right on paper and still aren’t sure if it’s working. TPF runs on real exercise science. How a set credits toward weekly volume, how fatigue accumulates, how much is enough and how much is too much — none of it is guessed. The science does the bookkeeping. The calls that matter stay with you.

The principles are few.

Hypertrophy and strength aren’t a mystery. Apply the right stimulus, recover, push the load up, keep showing up. Four principles. The methods built from them are infinite — the principles themselves barely change.

Most of what you read online is over-simplified, misapplied, or made artificially black-and-white. That’s where most athletes get stuck. TPF encodes the principles. You pick the methods.

How we know it works.

Every engine component is checked three ways.

  • 1

    Against the research. Every formula and weighting traces back to peer-reviewed work on stimulus, recovery, periodisation, and energy-system physiology. The papers are listed in full at the foot of this page — read them, argue with them, hold us to them.

  • 2

    Against real coaching practice. We run mainstream protocols — 5/3/1, RP-style hypertrophy, Norwegian 4×4, Daniels marathon plans — through the engine and verify the outputs match what those protocols are known to produce in practice.

  • 3

    Against the maths. Worked examples computed by hand. If the engine drifts from the closed-form answer, we investigate and recalibrate — or document why the model deliberately disagrees.

What the engine actually does.

Intensity & load

Every prescription carries a target intensity, not just sets and reps — a percentage of your 1RM, set against the prescribed reps-in-reserve. Where the app doesn’t have your 1RM on file yet, it suggests one from the rep range and the RIR. So the load is never left to guesswork: you train at the intensity the adaptation actually needs — heavy enough to drive the stimulus, not so light that the session quietly fails to earn it.

Strength & hypertrophy

The TPF Effective Sets™ system credits every working set on what actually drives growth — how close to failure you went, how heavy you lifted, how long you rested, and which muscles the lift really trains. Compounds count differently from isolation. Stretch position counts differently from short. Volume landmarks — the floor, the sweet spot, the ceiling — are tuned to your training age, not pulled from a textbook average.

Strength and hypertrophy don’t grow on the same curve. The engine knows it — separate dose-response models for each, anchored to Schoenfeld 2017 (hypertrophy) and Ralston 2017 (strength), scaled to your experience level. Beginners need less to grow and recover faster than trained lifters — the engine treats them differently rather than handing them an intermediate programme on day one.

Seven intensity techniques — cluster sets, myo-rep match, rest-pause, lengthened partials, 1¼ reps, drop sets, and straight sets — each earn an honest stimulus-to-fatigue weighting. Lengthened-bias work gets the stretch bonus the recent partial-ROM literature (Kassiano 2022, Wolf 2023) supports.

Exercise comparison — Bench Press Flat vs Incline, muscle activation per set with RC/set and primary/secondary muscles

Recovery cost

Every set adds to a running fatigue total, weighed against the capacity that comes with your training age. Daily and weekly views colour the picture green, amber, red — sustainable, high, over the line. Built on the Banister fitness-fatigue model (1991), the Vanrenterghem two-pathway fatigue framework (2017), and the Foster session-RPE literature (2001+).

What we don’t claim.

  • We don't predict injury. We flag sudden spikes in load. We don’t pretend to know when you’re going to get hurt — the evidence for that just isn’t strong enough.

  • We don't replace a coach. A coach who knows you, your life, your stress, and your technique is irreplaceable. Use both if you can.

  • We don't model what we can't see. Sleep, food, life stress, technique, genetics — those stay with you. You know your own context better than any app does.

The plan that works is the one you’ll stick to.

TPF hands you the engine and steps back. Pick the lifts you’ll actually do, on a schedule you’ll actually keep. The science counts the load. The calls stay with you.

Be your own expert.

Further reading

The science underneath.

Every curve, weighting, and dose-response in the engine traces back to a paper. Below: the principal sources, by domain. Each title links to the paper via Google Scholar — read it yourself.

Named protocols (Norwegian 4×4, Tabata, Yasso 800s, MAF, Cardiac Output Method, etc.) are cited for methodology comparison only — their inclusion doesn’t imply endorsement of TPF by the original authors or rights-holders.

Volume & dose-response

Proximity to failure & load

Stretched position & lengthened partials

Intensity techniques

Inter-set rest

Programming & periodisation

Conditioning & energy-systems physiology

Training load & recovery models

Concurrent training & EPOC

1RM estimation

Injury risk & load monitoring (caveated)

Every value and formula is version-controlled and documented internally. The specific weightings, multipliers, and per-exercise calibrations stay with TPF.

Coach, sport scientist, or just curious? Reach out via the contact link in the footer.