Dressage rider and trainer Sjef Janssen has injured his hamstring during a riding accident.

The 65-year-old, who is the Belgian dressage team trainer, tore his hamstring muscle when making a “sudden, wrong movement”.

He is due to go to Amsterdam this week to be assessed and to discover whether the injury needs operating on.

Sjef is married to Dutch Olympic rider Anky van Grunsven.

A statement on Anky’s website read: “Due to an unfortunate move during riding, Sjef has torn his hamstrings completely last week.

“Sports doctor Peter Vergouwen of the Gelderse Vallei hospital confirmed the injury. The diagnosis was made by a MRI scan. Sjef will go to the AMC hospital in Amsterdam to examine if a surgical intervention could remedy the injury.

At the moment Sjef’s mobility is very limited, he moves around with crutches and a mobility scooter.”

Sjef who won team bronze for the Netherlands at the 1981 European Championships and was selected as team trainer for the Belgian riders in 2013. Earlier this year he had his contract extended until the end of 2016, meaning he will take the helm for Rio preparations.

To qualify a team Belgium must finish within the top three at this summer’s European Championships at Aachen. The only other route is for them to qualify three separate riders through the rankings system for a composite team.

Prior to joining Belgium, Sjef was previously dressage coach for the Dutch Olympic team. His wife Anky is the winning-most Olympian in dressage and is the only one to record three successive Olympic wins in the same event.