Find the weak side of your core.

You train your core. You have never measured it.

You can hold a plank. You do the class. You still do not know whether your left side keeps up with your right, or which of the deep muscles is doing the least.

Most core training is the same routine for everyone. The weak side stays weak, because nothing tells you it is there.

How it works

Train
Tell Proofload how long you have and where you are. It builds a workout for the equipment in front of you.
Prove
Two sets in every workout are proof sets. You go as long as you can with good form, and that result becomes your level.
See
Your core map fills in over your first few workouts. The next workout goes after whatever is weakest.

A workout, set by set

A 20-minute session at home with a chair, a wall and a foam roller, focused on the hips and lower back. Two exercises are proof sets: they come first and measure. Training sets follow and build. The map shows how much work each zone gets. Tap a zone to see which sets work it.

Length: ≈ 20 min
Proof set tests: 2
Training sets: 8
Focus: Hips, low back

Training load by zone

Hover or tap a zoneTap a zone

Front man · Back womanMan frontFront woman · Back manWoman front

Front · man

Back · woman

Training load · lighter → heavier
Not in this workout
Measured

Select a zoneHighlighted rows are the sets that work it.

Proof sets · each side measured fresh

1
Side Plank (from Knees)Left · Hold as long as form holds
Proof set
2
Prone Chest Raise (Hands at Temples)Both sides · Hold as long as form holds
Proof set
Protected rest · 2:00Five minutes since your left side plank. Cannot be skipped.
Rest
3
Side Plank (from Knees)Right · Hold as long as form holds
Proof set

Training · same side together, other side spaced out

4
Side-Lying Hip Abduction (Bent Knee)Left · 2 × 15 · 45 s rest
Training
5
Dead Bug (Contralateral)Both sides · 2 × 12 · 45 s rest
Training
6
Side-Lying Hip Abduction (Bent Knee)Right · 2 × 15 · 45 s rest
Training
7
Bird Dog (Dynamic)Both sides · 2 × 10 · 45 s rest
Training

Illustrative workout. Proof sets show no target and no previous result.

Arriving during the beta

Each side measured fresh

Tiring one side of the body can briefly weaken the other. So Proofload never measures your left and right back to back. The first sides of every proof set come first, the second sides come last, and at least five minutes separate the two sides of the same test.

If the work in between takes less than five minutes, a rest you cannot skip makes up the difference.
The starting side switches each time a test comes round, and the app records which side went first.
Training sets on one side stay together. The other side, and exercises that share muscles, are spaced apart.

In a randomised crossover study, the other leg was weaker 1 and 3 minutes after one leg was fatigued, and not at 5. Zahiri et al., 2024

A review of 35 studies found the effect in about half of them, more often in the legs. Halperin, Chapman & Behm, 2015

The first 10 minutes

Back to backProofload order

Side plank

LR

5:00

Supine march

LR

5:00

Chest raise

Both

Protected rest

Rest

0 min510 min

Every first side, then the two-sided test, then every second side. A short protected rest tops the gap up to five minutes.

One map, twenty zones

Each zone has a level from 1 to 15, shown as a number and a colour. A zone you have not tested yet says so. Drag the timeline back to your first week and watch the map change.

Today

Core map

Hover or tap a zoneTap a zone

Front woman · Back manWoman frontFront man · Back womanMan front

Front · woman

Back · man

Select a zoneEach zone shows its level, band and the other side.

ProofloadFunctional20 of 20 zones measured · +1.7 since week 1

Left vs right

Gluteus mediusLeft trails by 1.5
Left 3.2
Right 4.8
Hip flexorsLeft trails by 1.2
Left 5.8
Right 7.1
ObliquesLeft trails by 0.8
Left 6.6
Right 7.4
Quadratus lumborumLeft trails by 0.7
Left 6.2
Right 7.0

The four widest gaps this week. The aim is two long bars of equal length.

A forecast from your own results

Once a zone has four measurements, Proofload projects where it is heading. The projection uses your own rate of progress, never population averages, and it slows as you approach the ceiling, the way bodies do.

Always a range, never a promised date.
Hidden until there are at least four measurements of that zone.
Fitted to the remaining gap to Level 15, so it never draws a straight line upward.

Hip flexors (L)

Next 8 weeks: 6.1 – 6.6

Proof set result
Projected range
Illustrative data

Arriving during the beta

Resilience: how well your effort holds up

Resilience measures how much of your capacity carries from the first set of an exercise into the next. 100 means nothing was lost between sets.

Capacity of a set: reps done + reps left (10 − effort)
Resilience: 100 × average capacity ÷ best capacity

Counts only training sets of the same exercise, on the same side, at the same prescription, with the rest actually taken.
Shown as the median of your last five qualifying workouts, once you have four. Never a single workout.
Never part of a zone score or your Proofload level.

Percentage decrement was the most reliable of the fatigue measures compared in Glaister et al., 2008. Reps left come from an effort scale anchored to reps in reserve, Zourdos et al., 2016.

Resilience87median of last 5

18 workouts

Resilience can't go above 100, so it rises quickly at first and levels off as you get stronger. A dip after a step up is normal. Illustrative data.

Try it: two sets of a glute bridge

Set 112 reps · effort 7.0Capacity 15

Set 210 reps · effort 8.0Capacity 12

Set 2 reps

Set 2 effort

Resilience for this exercise today90

A library built as ladders

Every exercise sits on a rung with a level range. As a zone improves, the next workout moves you up the ladder instead of adding more of the same.

exercises: 61
progression ladders: 8
movement patterns: 7
scored zones: 20
equipment items: 11

Exercises by movement pattern

61 total

Anti-extension16
Hip stability12
Anti-rotation8
Spinal extension & mobility8
Anti-lateral flexion7
Balance5
Mobility5

Forearm PlankLevels 1–10
Forearm Plank with Leg LiftLevels 8–13
Long-Lever PlankLevels 12–15

Level 1Level 15

Rungs overlap by two or three levels, so a step up never lands you somewhere you cannot hold form.

Built for where you train today

Save a kit for each place. A workout only uses what is ticked.

HomeGymTravel

Home: 4 of 11 items ticked. A chair and a wall are ticked for everyone at the start.

Scored by fixed rules, not by AI

A proof set looks like any other exercise, and the card tells you it counts. There is no target on the screen and no reminder of last time, so the result is what you can do today.

The same result always gives the same level. AI only arranges the exercises in your workout.

Protocols from published research

Hold positions and test setups follow the studies they come from, such as the Biering-Sørensen back extension hold and the Ito prone chest raise.

Thresholds labelled as calibration

Where research gives no cut-off, the level thresholds are our calibration and are shown as such on the Method page, with no citation attached.

Level 15 is functional mastery

The scale tops out where more stops helping. A forearm plank is done at two minutes. Past that you are training patience.

Selected sources

Sore today? The workout adapts.

Before each workout you mark anything that hurts and rate it from 0 to 10. Proofload changes the sets that work that area and leaves the rest of the workout alone. A sore back gets more care: from 2 out of 10 the app keeps to a short list of gentle exercises.

Try it with a strained lower back at 3 out of 10. No proof set is measured, so a sore day never lowers your score. Bird dog is left out, the hip work is kept lighter, and the dead bug runs as planned. At 8 or higher there is no workout that day.

Kept lighterOne set, no more than last time
Left outNot in today's workout
Not measuredNo proof set today, so your last level stands

Proofload gives training guidance, not medical advice.

Anything bothering you today?

At this rating the app offers only a short list of exercises for a back injury. These are not on it. The app measures no set while the lower back hurts.

Length: ≈ 7 min
Proof set tests: 0
Training sets: 4

Today's workout

Side Plank (from Knees)Proof set · Not measured today, so your last level stands.
Not measured
Prone Chest Raise (Hands at Temples)Proof set · Not measured today, so your last level stands.
Not measured
Side Plank (from Knees)Proof set · Not measured today, so your last level stands.
Not measured
Side-Lying Hip Abduction (Bent Knee)Training · Left · one set, no more than last time
Kept lighter
Dead Bug (Contralateral)Training · Both sides · 2 × 12
Kept
Side-Lying Hip Abduction (Bent Knee)Training · Right · one set, no more than last time
Kept lighter
Bird Dog (Dynamic)Training · Left out today.
Left out

Partner program

Built to back up your coaching, not replace it.

Trainers, studios and clinicians already know what the people they work with need. Proofload adds a measurement of 20 core zones, left and right, for the days between your sessions. If it helps your clients, recommend it. If it does not, don't.

30%of net profit from every member you bring to Proofloadfor up to 24 months from the day they join.

Personal trainers
See where a client is weak and on which side before they arrive, and set the work for the days in between.
Gyms and fitness studios
Give members a measured core program that runs alongside your classes, with any equipment you have on the floor.
Healthcare practitioners
Give patients a structured way to keep training once a plan of care ends. Proofload gives training guidance, not treatment.

Request information

We will send the partner agreement and answer your questions. There is no cost to join and no minimum number of referrals.

Shares are paid on net profit per referred member, as defined in the partner agreement. Terms may differ by profession and region.

About the beta

Invite-only
We admit testers in small cohorts so every report gets read. Request an invite and we will email you an invite when a place opens.
Free while in beta
Testers use the full app at no cost. Your core map and history carry over when the beta ends.
Feedback goes to the team
Report a bug or rate a workout from inside the app. Things will change, and you will see what changed in the app's updates.

See your core map

Join the waitlist for the next beta cohort, or sign in if you already have an invite.

Request an invite Sign in