Bought these for our 6 y/o, who rides a lot! Went with the smaller size at first because of the age / size scale, however, we ended up with the L/XL (he’s got tree trunks). Pads stay put, no fussing with pads on the trail. Bought elbows as well and the report is that they are super comfy too, and Mom and Dad have piece of mind as well with the generous protection. Would def recommend for any small serious rider! Thanks for looking after the groms!