of trauma associated with equestrian sports has been termed "horse riders' perineum". A case series of 4 female mountain bike riders and 2 female horse riders found both patient-reported perineal pain and evidence of sub-clinical changes in the clitoris; the relevance of these findings to horse riding is unknown. In men, sports-related injuries are among the major causes of testicular trauma. In a small controlled but unblinded study of 52 men, varicocele was significantly more common in equestrians than in non-equestrians. The difference between these two groups was small, however, compared to differences reported between extreme mountain bike riders and non-riders, and also between mountain bike riders and on-road bicycle riders. Horse-riding injuries to the scrotum (contusions) and testes (blunt trauma) were well known to surgeons in the 19th century and early 20th century. Injuries from collision with the pommel of a saddle are mentioned specifically. Criticism of horses in sport Organized welfare groups, such as the Humane Society of the United States, and animal rights groups such as People for the Ethical Treatment of Animals, have been known to criticise some horse sports with claims of animal cruelty. Horse racing is a popular equestrian sport which is practiced in many nations around the world. It is inextricably associated with gambling, where in certain events, stakes can become very high. Despite its illegality in most competitions, these conditions of extreme competitiveness can lead to the use of performing-enhancing drugs and extreme training techniques, which can result in negative side effects for the horses' well-being. The races themselves have also proved dangerous to the horses – especially steeplechasing, which requires the horse to jump hurdles whilst galloping at full speed. This can result in injury or death to the horse, as well as the jockey. A study by animal welfare group Animal Aid revealed that approximately 375 racehorses die yearly, with 30% of these either during or as a result of injuries from a race. The report also highlighted the increasing frequency of race-related illnesses, including bleeding lungs (exercise-induced pulmonary hemorrhage) and gastric ulcers. Animal rights groups are also primarily concerned that certain sports or training exercises may cause unnecessary pain or injuries to horse athletes. Some specific training or showing practices are so widely condemned that they have been made illegal at the national level and violations can incur criminal penalties. The most well-known is soring,'' a practice of applying