That's just from overdoing it, though. Do a few weeks of very low weight (if she's using weight) and low reps, and one set. Build up over time.
Edit: and it may seem counter intuitive, but exercising the same muscles when they're sore actually decreases the soreness. Is she sore? Do some stretches, some exercises (light if just beginning/getting back into it), some more stretching, and she'll feel better.
BeerMeMarie t1_iu5hpah wrote
Reply to comment by Junior_Arino in Exercise linked with increased longevity. Compared with just two minutes of vigorous activity per week, 15 minutes was associated with an 18% lower risk of death and a 15% lower likelihood of cardiovascular disease, while 12 minutes was associated with a 17% reduced risk of cancer by Wagamaga
That's just from overdoing it, though. Do a few weeks of very low weight (if she's using weight) and low reps, and one set. Build up over time.
Edit: and it may seem counter intuitive, but exercising the same muscles when they're sore actually decreases the soreness. Is she sore? Do some stretches, some exercises (light if just beginning/getting back into it), some more stretching, and she'll feel better.