From here: http://www.livestrong.com/article/98061-benefits-pushups-women/
Chest muscles also receive a workout during push-ups and can help to alleviate sagging breasts.
From: http://www.livestrong.com/article/15977-home-remedies-sagging-breasts/
Step 4
Perform push-ups. Either do the standard push-up in which the entire body raises into the air or do the modified push-up in which the knees are bent and only the upper portion of the body comes up off the floor. Start with as many push-ups as you can comfortably do; gradually increase the amount in each session. Do push-ups at least three times a week.
Have any researches been done on these claims?