Washington’s trail network supports a healthful lifestyle, but it also presents occasional threats and dangers, dramatized last week by an attack in the District and other incidents that have been reported in the suburbs.

Although they are often described as isolated incidents and appear to affect a tiny proportion of trail users, attacks have occurred this month not only in the District but in Arlington and Fairfax counties, as well.

On Thursday, two days after a bicyclist was beaten on the Metropolitan Branch Trail in the District, a man was attacked on a path in the Reston area, which is threaded with a network of paved trails.

Fairfax police said that incident might be connected to three other robberies and assaults on paths in the Reston area since June 3. In three of the incidents, police said, victims on foot were approached by groups of young men who assaulted and robbed them.

In the fourth daylight attack in Reston, Fairfax police said, on June 9, a 42-year-old man was riding a bicycle on a path behind Hunters Woods Plaza, east of Reston Parkway, when four young men approached.

He was pushed off his bicycle, punched and kicked. Money and other items were taken, and the man was treated for fractures and other injuries.

In Arlington, a woman was stabbed three times in the neck about 11 a.m. June 1 after being accosted on a wooded park trail in the Glencarlyn area.

According to police, she was stabbed after screaming for help as the attacker tried to get her off the trail. The woman was hospitalized for least two days.

Also in Arlington, two bicyclists were attacked April 2 within about a half-hour on the Custis Trail. One man was knocked off his bike and injured. The other broke free of the assailants, police said.

Although the trails are heavily used, many have secluded spots where layout, vegetation or structures shield them from view.