Many horses in regular training/competing have an asymmetric motion pattern to a similar degree as horses examined for lameness. To what extent these asymmetries are caused by pain is unknown and might be a potential welfare problem for the horse. The aim is to investigate movement asymmetries in the Swedish ridinghorse population and to evaluate whether these may be caused by pain or not. Horses, judged as sound by the rider, in training/competition will be included in the study. Of a large number of horses (n=150) 50 riding horses, with asymmetric movements (quantified by an objective motion analysis on straight line and lungeing) will be included in an owner blinded treatment study (crossover design) with NSAID/placebo and be treated for 4 days with 14 days in between the two treatments. The motion pattern will be measured before and after each treatment and also blood NSAID concentrations will be measured. The horses will continue their ordinary training during the experiment.