quadriceps muscle of thigh

例句：

1. 1. The quadriceps arethe main muscles that help you stand upright.
   四头肌是帮助你站立的主要肌肉。
2. 2.The quadriceps are also responsiblefor stabilizing your knee joint.
   四头肌还负责稳定你的膝关节。
3. 3. In sports, athletes often strengthen their quadriceps to improve their performance.
   在体育比赛中，运动员经常加强他们的四头肌以提高表现。