Volleyball courts packed with players stretched from one wall of the Boston Convention & Exhibition Center to the other — 85 in all — as thousands of girls, boys, women and men get ready to set, spike and dig their way through a three-day New England Regional Volleyball Association tournament.

“It’s like popcorn. You see balls popping up all over the place,” association commissioner Dave Peixoto said while surveying the packed convention hall that he expects 20,000 people to pass through by the time the tournament wraps up tomorrow night.

Volleyball has exploded in popularity in recent years. Membership in the New England association has increased 10 percent in each of the last four years, Peixoto said.

“The growth is phenomenal,” Peixoto said. “You have people learning to play on teams, team-building, and friendships that will last a lifetime.”

Seven thousand players on 550 junior club teams and 100 adult teams from across the country are battling over the weekend through pool play then tournament brackets — with the winner of the U18 girls teams getting a boost to the national championships in July.