Set up once on your iPhone. Then do everything else from your Apple Watch.

Set up, in order

Step 1: Equipment. Add your bars and the plates your gym has, in the colors they are on the rack. Skip this if you never lift with plates.

Step 2: Body weight. Enter it in Settings so weighted chins and dips count for the right amount.

Step 3: Exercises. Add the lifts you do and name them whatever you call them. This is the step that matters.

Step 4: Programs. Build a routine from those exercises, if you work from one. Optional.

Step 5: Open LifterRep on your Watch. It installs alongside the phone app, and there is nothing to set up there.

Four kinds of exercise

Machine / Cable. Pin stacks, cables and plate-loaded arms.

Dumbbell. You log the number stamped on the dumbbell.

Barbell. You enter the total weight and the Watch works out the plates.

Bodyweight. Chins, dips, push-ups. Add weight if you use any. A negative number covers an assisted machine that takes weight off you.

During a workout

Choose Freeform (pick one lift and go) or a Program. Tap the weight or the reps to change them. The big button logs the set and starts your rest, and it tells you where you are: Log set 2 of 3. Your wrist taps when rest is over. When you're done, tap End and rate the workout Easy, Moderate, Hard or All Out.

Notes that follow you

Add a note to any exercise: Seat 4, back pad 2, incline 3. The Watch shows it the moment you reach that exercise.

After a workout

History on your iPhone lists every workout, newest first, with its length, total volume and effort rating. Open one to see each set exactly as you logged it. Logged the wrong number? Swipe the set to the left to delete it. Tap any exercise to see its estimated one-rep max and your volume over time.

Phone and Watch stay in step

The phone owns your library (bars, plates, exercises, programs) and sends it to the Watch. The Watch owns your workouts and sends them back. It happens on its own whenever the two are near each other.

Pounds or kilograms

Choose in Settings. Your exercises, bars and body weight convert, and your history is never rewritten. Each set remembers the unit it was lifted in.