Does being sore mean I had a good workout?

Nikkiey's point across several episodes is that soreness is a terrible gauge. On Ep. 400 and Ep. 387 she explains that a big reason you're sore is that your muscle fibers weren't used to a new training block, and new doesn't automatically mean better. She estimates well over 80% of women leave the gym judging the session by whether they'll be sore tomorrow, which leads them to chase the feeling instead of the progress. Muscle isn't built in a 24- to 48-hour window. It's built over time.

She also reminds you that you don't build muscle during the workout. You break down muscle fibers there, and the growth happens during recovery, which depends on adequate sleep and enough food. On Ep. 147 she shares that when she started out and wasn't eating to support her training, she was so sore for one to two weeks that she couldn't train consistently, and she sees that derail a lot of women early on.

On Ep. 18 she adds the other side: if you're not sore but your strength is going up, you're doing great, because your body is adapting. You'll still feel some soreness at times, especially in the first two to three weeks of a new program or when you increase intensity. One nuance from Ep. 147: if you never get sore at all, she says about 90% of the time that means you're going through the motions and should challenge yourself more with the weight you lift. The measure is progression, not pain.