I could check the most recent NFHS participant statistics to see if that's a correct statement. In my area, I would guess that soccer, basketball, LAX, softball, and field hockey have more participants than does VB, but perhaps I'm mistaken.
The National Federation of High School Sports (NFHS) releases a high school athletics participation survey every year. However, it takes them some time to assemble and release the information, so they are usually a couple of years behind the current year in terms of sports. I suspect that the pandemic has also delayed reports a bit, as it will also greatly influence the participation numbers for high school athletics.
It turns out the AVCA was correct in their claim. The most recently released NFHS participation survey is for the 2018-19 school year. Their statistics for participation in girls sports are:
1. track & field - 488,267
2. volleyball - 452,808
3. basketball - 399,067
4. soccer - 394,105
5. softball - 362,038
6. cross country - 219,345
7. tennis - 189,436
8. swimming & diving - 173,088
9. competitive spirit - 161,358
10. lacrosse - 99,750
The AVCA statements was "Volleyball is the top team sport for girls in U.S. high schools." And while there are team awards in track & field, that sport is really a collection of individual competitions/athletes. VB does appear to be the top sport in terms of participation.
