The repeated forces are due to (1) inadequate muscle strength, power, endurance, and flexibility of the forearm muscles, (2) inadequate techniques of tennis playing, and (3) inadequate equipments.

• 而(1)肌肉的肌力、爆发力、持久力、柔软度不足(2)不适当的系球技巧(3)不适当的器材等都是使外髁张压力增加的原因。