All you need to complete the challenge is a pair of dumbbells; Millis suggests starting with five-pounders, though you can increase the weight or use different weights for different exercises, so you feel appropriately challenged. It’s important not to race through these moves; instead take your time to feel your muscles work — both on the exertion (the pushing or pulling action) and on the release. On days when you’re doing more than one set (noted by “x2” or “x3”), take a one-minute break before starting the next one. And on days that have more than one exercise, do them back-to-back with minimal rest, only taking that one-minute break between sets if there are more than one. The schedule also includes all-important rest days, which is the downtime your muscles need to repair from the work you’ve done, so they can become stronger than ever. See our fundamentals guide, below, for each exercise’s how-to.

Bent-Over Rows ("Rows")

One of the best moves for your upper back, you’ll also get a little core work from stabilising your body position. Grasp the weights by your sides. Hinge your upper body down by sticking your butt way back and letting your knees bend slightly; you want your back to stay flat and your head to be neutral to your spine. As you hinge, let your arms hang down in front of you, fingers facing your body. Inhale, then exhale as you pull your elbows back and wide out to the sides; you should feel your shoulder blades pinch together as if you’re trying to trap a pen between them. Inhale as you lower your arms back down. Take your time with both movements, feeling your upper back work on the way up and on the way down.