What muscles does each exercise work, in numbers

What a percentage here means

A percentage is the share of one session’s target for that muscle which a single movement delivers, performed at its prescribed sets and reps. So:

100% means one exercise finishes that muscle for the session on its own. Do a set of lat pulldowns as prescribed and your lats are done.

45% means the movement does close to half the job for that muscle while it is really training something else. The barbell squat gives the glutes 50% - a real contribution, and not a glute exercise.

10% is a rounding error you should not count on. It is listed because it is true, not because it is useful.

Volume is counted in sets per muscle, with an assisting muscle counted as a fraction of a set - the quantification method with the best evidence behind it Pelland 2025. The figures are hand-calibrated per movement against the rules in our own audit, not lifted from EMG amplitude, which does not predict growth well enough to prescribe from Vigotsky 2022.

Why the list-without-numbers version misleads

Two habits follow from reading exercise descriptions that name muscles without weighting them.

You count an assist as coverage. “Rows work the biceps” is true, and if you then skip curls on that basis your biceps get about half of what they need. The row is a back exercise that involves the biceps, which is a different claim from a biceps exercise.

You count a compound twice. Bench press, incline press and dips all name “chest, front delts, triceps”. Doing all three does not cover three things; it covers one thing three times, and the front delts end up at triple their target while the side delts - which no pressing movement trains meaningfully - stay at zero. That is the single most common gap we measure, and it is invisible if all you have is a list of names.

Across our catalog a movement trains 3.9 muscle groups on average; the broadest single movement is the Turkish get-up at 10. Only 20 movements out of 228 train exactly one muscle. So almost every exercise you do is a partial contribution to several groups, and the only way to add them up is to know the fractions.

Every muscle group, and what trains it hardest

All 18 groups we track, how many of the 228 distinct catalog movements train each one at all, and the three that hit it hardest. Each name links to the full ranking for that muscle.

Two things in that table are worth pausing on. Abductors (outer hip) has the fewest movements of any group in the catalog by a wide margin - which is exactly why it is the group most routines miss entirely. And Abs has the most, which is why nobody misses abs and a great many people over-train them.

How to use this on your own routine

Take the movements you already do, add up each muscle’s percentages, and see what lands under 100. That is the whole method, and it is arithmetic rather than judgement.

You do not have to do it by hand. The coverage checker is free, needs no account, and runs entirely in your browser - tick what you train and it returns the body map, the groups falling short, and the two movements that close the biggest gaps. Nothing is sent anywhere.

Inside the app the same numbers are live: every movement carries its activation profile, the session total updates as you swap, and tapping any muscle lists every exercise that trains it in ranked order. All of that is free - what is paid is the solver that picks the shortest session hitting every target for you.