NEW YORK (CBSNewYork) – It’s a disturbing trend in New York each summer – packs of reckless teens on bikes taking up entire streets when the weather is warm.

Now, an Upper West Side man says he was outnumbered and attacked by one of these lawless groups.

Riverside Park is Stephen Edelstein’s favorite spot to enjoy views of the Hudson.

“I’m afraid to come down here now,” he told CBS2’s Ali Bauman.

The 74-year-old says he was looking out at the water by 79th Street last Friday around 5 p.m. when he felt several short, sharp punches in his back.

“I turned around… a swarm of kids on bikes and they were coming toward me… and they were riding fast,” Edelstein recalled.

The Manhattan resident was a victim of what police sources called “bike-outs” – roving bands of teenage cyclists – with many of them looking for trouble.

Large groups of unruly cyclists take over city streets as part of a “bike-out.” (Credit: CBS2)

Organized on social media, they ride in packs on major thoroughfares and lately seem to be spreading into parks as well.

“Fifteen, twenty of them that way and fifteen, twenty coming this way… one person started it. Another kid close by I felt like I was being targeted and I was gonna be hit by all those other kids.”

Edelstein says he swung his aluminum cane in self-defense. Then two bikers pushed him to the ground, which broke his hand.

“They want to be bullies,” the bike-out victim said.

Law abiding cyclists agree and want the hoards stopped.

Large groups of unruly cyclists take over city streets as part of a “bike-out.” (Credit: CBS2)

“Every once in a while you see one tearing up and down the river,” biker Aaron Krumheuer said.

“During the summertime especially, weekends, it’s dangerous,” Mourad Ourtai added.

Since police have to deal with these lawless packs of cyclists each summer, sources tell CBS2 this year the NYPD is trying to get ahead of the problem by putting bike patrol officers in the parks.

Metal barriers at park entrances, signs telling cyclists to dismount, and rumble strips are other ways police are trying to prevent reckless and menacing groups of riders from terrorizing New Yorkers.

Pedestrians say it’s not enough.

“These don’t slow bikers down,” Ourtai argued.

“I wanna have some sort of protection. This is not enough,” Edelstein said.

Police are investigating the attack on Edelstein as a second-degree assault, but so far have not made any arrests.