[»Shermer's neck« is a rare injury in long-distance cycle races. Association with diplopia described for the first time].

: Shermer's neck was first described in 1983 in an ultra-distance cyclist and it is often associated with neck pain (in our patient diplopia as first symptom) and exhaustion and impaired neck motor function with inability to extend the neck against gravity. The diplopia, for the first time described in connection with Shermer's neck, was accentuated when elevating the eyes and looking at distance, most likely reflecting exhaustion in the elevator muscles of the eye. Shermer's neck usually appears after 800 km of non-stop bike racing. Risk factors include former neck injuries, staying low in aerobars for a long time, and wearing helmet light/cameras. Prevention includes neck strength training, muscle stretching, raising of handle bars and different kinds of chin support. The most important treatment is rest and not riding a bike. In our patient the diplopia was normalized after 4 hours of sleep. It can take 2-14 days to regain full neck motor function. The possibility of developing Shermer's neck and diplopia (»Berglund's diplopia«) must be taken into account when many untrained individuals participate in popular shorter races over about 300 km.