The incident took place around a quarter to 12 when the woman from the hockey club cycled to her boyfriend in a cafe on the Hoogstraat in Vlaardingen.
At the intersection of Kortedijk and Werf van Pronk, she was stabbed off her bicycle by an as yet unknown man, the police writes. He was also on his bike and initially cycled past her, then turned around. At first, the victim thought she had been hit hard; later she found herself stabbed in the back. It appears that no vital organs were affected.
The victim was immediately taken to hospital for treatment. The knife has been confiscated. The police are investigating the incident and are looking at CCTV footage, among other things.
The man was wearing dark clothing and possibly a face covering with white accents and is about 1.70 tall.