Tummy time is physical activity for infants; it is an awake, prone position that is supervised and encouraged by an adult.
Tummy time is especially important since the onset of the “back to sleep” campaign.
Since infants are now placed in a supine position for sleep they need more awake time in a prone position.
Research shows significant benefits including, improved motor development, and indication of reduced risk of flat spots on back of head. Some studies specifically indicate a significant difference in achievement of rolling, crawling on abdomen, crawling on all fours and sitting earlier.
The age of your baby gives you guidelines for how long each “session” should be.
0 months 1–5 minutes at a time, 2–3 times per day
1 month up to 10 minutes at a time, 2–3 times per day
2 months up to 20 minutes per day, can be split up into multiple sessions
3 months up to 30 minutes per day, can be split into multiple sessions
4 months up to 40 minutes per day, can be split into multiple sessions
5–6 months up to 1 hour at a time, as long as baby isn’t fussy
[From https://www.healthline.com/health/parenting/tummy-time#tummy-time-by-age]
Citation: Hewitt L, Kerr E, Stanley RM, et al. Tummy Time and Infant Health Outcomes: A Systematic Review. Pediatrics. 2020;145(6):e20192168