Freezing of shoulder flexion impeding boule throwing: a form of task-specific focal dystonia in petanque players.

During a period of intensive practice, 2 petanque players developed freezing of shoulder flexion impeding boule throwing. This movement disorder was consistent with the diagnosis of task-specific focal dystonia. Polymyography showed that freezing was associated with bursts of low amplitude. In the absence of motor or sensory deficits, a motor apraxia could be considered.