Anky van Grunsven and Salinero at the 2009 European Championships. © Kit Houghton/FEI
They also said that van Grunsven's husband, Dutch dressage coach Sjef Jansen, had threatened Appels.
The image appeared in an article on Eurodressage on February 9, 2010 referring to the round-table discussion on Rollkur by FEI officials, who declared that "any head and neck position achieved through aggressive force is not acceptable, and aggressive riding must be sanctioned".
In the statement, Appels's lawyers LTA Weda said: "This is a system that Anky and her coach and partner Sjef Jansen have developed and where the horses neck to bend inwards [to the] extreme. The Royal Dutch Equestrian Federation has, following years of research and the decision of the FEI in February this year decided: 'Hyperflexion / Rollkür is from now defined as [flexion of the horse's neck achieved through aggressive force. The technique known as Low, Deep and Round (LDR), which achieves flexion without undue force, is acceptable]'."
The Dutch news website horses.nl said: "Anky van Grunsven makes use in training of low, deep and round (LDR). This allowed method is often confused with the now banned rollkür / hyperflexion method."
In the news report, van Grunsven's lawyer, Mr LM Schelstraete, said that despite the rider's face being cropped out, the horse was clearly recognisable as Salinero. "The omission of a face does suggest that the person has engaged in improper business. This presentation by Anky van Grunsven as offensive, criminalizing and therefore perceived as unlawful."
In the statement LTA Weda said that Jansen had "sworn at Appels like a sailor", and that Appels was "shocked by these intimidating and slanderous remarks" by the official team trainer of The Netherlands. She is considering legal action.
The case taken by van Grunsven is to be heard on September 8 in Den Bosch.