What to do at the gym

The short version: warm up with a light set, do the big exercises that use many muscles first and the smaller ones after, take a few sets of each with proper rests in between, and over the week make sure every muscle gets enough work.

Chango puts all of this into one ready workout, so at the gym you just follow along.

The gym is full of choices

Walk in and there are racks, benches, cables and a dozen machines that all look like they do something important. Everyone seems to know exactly what they're doing. The question isn't really what you could do. It's what's worth doing today.

That's the question Chango answers before you get there. Your workout is ready when you open the app: which exercises, in which order, how many sets, how many reps and what weight. Here's why it's built the way it is.

Why the big exercises come first

Exercises that use several muscles at once, like the leg press, rows or the chest press, move the most weight and need the most energy. Research recommends doing them early in the workout, while you're fresh, and the smaller single-muscle exercises after [1].

So Chango orders your workout from big to small. You don't need to think about it: start from the top of the list and work your way down.

Why a light set before the heavy ones

The warm-up that helps most for strength is a lighter set of the exercise you're about to do. The benefit of general warm-ups like cycling is unclear [3].

That's why Chango puts a warm-up set before your heavier exercises. It's already in the plan, with the weight chosen for you.

Why a few sets, and why they should feel hard

One set rarely does the job. Several sets per exercise, with weights that make the last reps hard, is what research recommends for getting stronger [1], and the closer to your limit a set is taken, the more muscle it builds [5].

Chango gives you the sets, reps and weight for each exercise. Every set has a planned effort, so if it felt as planned, you just move on. If it felt harder or easier, change the effort, and Chango adjusts your next set right away.

Why you rest longer than you'd think

Between sets, longer rests let you lift more in the next one. In research, people who rested 3 minutes between sets gained more strength and muscle than those who rested 1 minute [4].

Chango sets the rest for each exercise: 3 minutes after heavy lifts, 2 minutes after other big ones and 90 seconds after smaller ones. The timer runs on your screen and on your lock screen, so you can put the phone down and breathe.

Why one workout isn't the whole story

What builds muscle is how much work each muscle gets over the week. Research shows that more weekly sets per muscle bring more growth, with around 10 sets a week or more working well [2]. No single workout can cover everything, and that's fine.

Chango keeps count for you. It plans each workout so that over the week every muscle gets its share, starting at a level that suits a new routine and growing as you get used to it. If a machine is taken, swap the exercise with one tap, and Chango picks another one for the same muscles.

What you'll notice

After every workout, the muscles you trained light up on your own 3D figure. Look at your week and you'll see whether everything got enough work, and enough of everything. Over a month or a year, the glow shows what really adds up: not the perfect workout, but showing up again and again.

If you're just getting started, read How to start gym training too.