Exercise Galaxy

How to read the galaxy

Every star is one exercise from the app's catalog. Two stars sit close when the two moves work the same muscles in similar amounts, so a cluster is a family of moves that load the body the same way. Distance says nothing about equipment, difficulty or how a move looks.

A star takes its colour from the muscle group of the move's top muscle, in the app's own group colours: pink for chest, purple for back, orange for shoulders, blue for arms, green for legs and gold for core. Zoom in, and the stars closest to you turn into the app's own icon for each exercise. Each cluster carries a name made from its own stars, which is the muscle most of them work hardest, led by a movement pattern when more than half of the cluster shares one. Open a star to see its muscles, the app's own muscle map with those muscles shaded, and the six moves closest to it.

How the stars are placed

The build reads each exercise's muscle figures from the catalog that ships inside the app, where every move lists up to 11 muscles with a percent for each. It turns a move into a list of 25 numbers, one per muscle in the app, and compares two moves by the angle between their lists. That way a light move and a heavy move with the same mix of muscles count as twins.

Next, the build merges moves that share the same mix of muscles and links each mix to its 14 closest mixes. In every round the links pull linked stars together, and each star is pushed away from a few random others, a layout method called UMAP (uniform manifold approximation and projection). We wrote that step for this page, and it uses a fixed random seed, so the same catalog gives the same galaxy on every build.

It all runs when the site is built, from the same files the app ships. When the catalog gains or corrects an exercise, the galaxy moves with it on the next build.

The body view

Press Body, and each exercise splits into one light for every muscle it works. The 1,321 exercises become 4,903 lights on the app's own muscle map. A light is bigger when the catalog gives that muscle a bigger percent, and each count on the figure says how many exercises work that muscle.

Only the muscle a light sits on is data, while its spot inside that muscle is an even spread with no meaning. A muscle's lights take turns between the right and left side of the body. The app draws some muscles larger than others, so the same number of lights looks thinner on a big muscle, and the counts on the figure are the numbers to trust.

Everything else on the figure is drawing, and its depth is our guess because the app's map is flat. The head, hands and feet are outlines, since the map gives them no muscles. Tibialis has no shape of its own in the map, so its one light sits on the front of the shin, where the app draws calves. We drew the poses and the squat by hand, so they are not motion capture. During the squat, each worked muscle glows by its percent in the catalog.

What the percentages are, and what they are not

The percentages are the app's estimates for crediting training volume, not lab measurements. Kinoku reads figures like these when it shares the work of a set out across the muscles a move names, and the muscle map and your volume charts read the result. We built these figures and refined them over many versions of the catalog, so treat a 60 next to a 40 as a ranking and not as a measured fact.

The app also adds a few helper muscles by exercise name, such as the rotator cuff on a lateral raise, and the galaxy includes those. The map shows the built-in catalog only, so your own custom exercises never appear here.

One more edge: inside the app, an older set of figures can replace the catalog's for some moves the first time you open the exercise library or the muscle map, and the barbell bench press is one of them. So for those moves your phone may show slightly different numbers than this page, which always shows the catalog's.

Every exercise, as a list

Here are the same 1,321 exercises, grouped by the clusters in the galaxy, with each move's top three muscles. The search box above the galaxy filters this list as well, and with scripts turned on a name opens its card.