When should I increase the weight?

The short version: add weight when you can do the top of your rep range in every set and it still doesn't feel too hard. Until then, add reps.

Chango does this for you: it raises your reps one at a time, then the weight, based on what you did last time and how it felt.

Why reps first, then weight

To keep getting stronger, your muscles need a little more challenge over time. You can give it two ways: more reps with the same weight, or more weight. Research shows that adding reps builds strength and muscle about as well as adding weight [1].

Chango uses both, in turns. Each exercise has a rep range, for example 6 to 10 reps for exercises that use many muscles and 8 to 12 for single-muscle ones. Your reps go up one at a time until you reach the top of the range in every set. Then the weight goes up by one step, the smallest the equipment allows, and the reps start lower again. This is called double progression.

You don't need to remember any of it. When you open the next workout, the weight and reps are already set.

Why how it felt matters

Reaching the top of the range isn't the whole story. If you got there but the last reps were a real struggle, adding weight now would likely be too much.

That's why every set in Chango has an effort on a 1 to 10 scale, close to the scale coaches use to estimate how many more reps you could have done [2]. Each set has a planned effort, so if it felt as planned, you just move on. If it felt harder or easier, you change it, and Chango adjusts your next set right away.

When all sets reached the top of the range and none felt harder than planned, the weight goes up next time. If a set felt very hard, the weight stays for one more round, and goes up the next time you reach the top again, so it never gets stuck.

Why the weight sometimes goes down

Some days are heavy. If you fall clearly short of the range with everything you have, the weight was too much for now, and Chango lowers it by one step. If you fall just short, it keeps the weight and aims for what you actually managed. Either way, you'll be back on track within a workout or two.

Why you start lighter after a break

After two weeks or more away, your first workout back is lighter, and the weights climb back up over the next workouts. That way you get back into it without a sore week.

What you'll notice

The numbers creep up without you planning it: a rep here, a step of weight there. Over months, it adds up. And on your 3D figure you'll see the work behind it, muscle by muscle.